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2019 | Book | 1. edition

Structural Analysis of Historical Constructions

An Interdisciplinary Approach

Editors: Rafael Aguilar, Daniel Torrealva, Susana Moreira, Miguel A. Pando, Luis F. Ramos

Publisher: Springer International Publishing

Book Series : RILEM Bookseries

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About this book

This volume contains the proceedings of the 11th International Conference on Structural Analysis of Historical Constructions (SAHC) that was held in Cusco, Peru in 2018. It disseminates recent advances in the areas related to the structural analysis of historical and archaeological constructions. The challenges faced in this field show that accuracy and robustness of results rely heavily on an interdisciplinary approach, where different areas of expertise from managers, practitioners, and scientists work together.

Bearing this in mind, SAHC 2018 stimulated discussion on the new knowledge developed in the different disciplines involved in analysis, conservation, retrofit, and management of existing constructions. This book is organized according to the following topics: assessment and intervention of archaeological heritage, history of construction and building technology, advances in inspection and NDT, innovations in field and laboratory testing applied to historical construction and heritage, new technologies and techniques, risk and vulnerability assessments of heritage for multiple types of hazards, repair, strengthening, and retrofit of historical structures, numerical modeling and structural analysis, structural health monitoring, durability and sustainability, management and conservation strategies for heritage structures, and interdisciplinary projects and case studies.

This volume holds particular interest for all the community interested in the challenging task of preserving existing constructions, enable great opportunities, and also uncover new challenges in the field of structural analysis of historical and archeological constructions.

Table of Contents

Frontmatter

Keynotes

Frontmatter
An Interdisciplinary Approach to the Seismic Assessment of Built Cultural Heritage: Case Studies in Lisbon and Outskirts

The seismic assessment of built cultural heritage requires an interdisciplinary approach for efficiently dealing with all the steps involved: “knowledge path,” the subsequent structural analysis and the potential intervention design. In this study, this approach is presented with reference to the old masonry and mixed masonry-reinforced concrete residential buildings in Lisbon and also to the Sintra National Palace. The latter was selected as a significant case study in what concerns the wide range involved competences and mandatory role each of them plays. Particular attention was paid to the contribution of the historical information, the material and the geometric characterization of the structure (the “knowledge path”), all necessary steps to identify potential vulnerabilities and to enable the understanding of the effective structural models, also in view of proposing adequate retrofit solutions. For the seismic assessment of built heritage constructions in Lisbon, fragility functions were derived, using the Performance Based Analysis (PBA) and considering a Displacement Based Approach. The obtained results reveal the seismic vulnerability of the of built heritage constructions buildings in Lisbon and the corresponding need for structural retrofitting measures. For the seismic evaluation of the Sintra National Palace an interdisciplinary methodology was set in place and the details of the main initial adopted steps are presented and analysed, namely: historical studies and critical surveys, in situ experiments, numerical modelling and structural analysis.

Rita Bento
Vulnerability Evaluation of Historical Masonry Structures: Italian Churches and Towers

The evaluation of the seismic vulnerability for historical masonry structures like churches and towers (medieval defense towers, bell towers and city gates) is paramount for developed countries. This is particularly true for Italy, a high seismicity country where it is esteemed that more than 5% of the total architectural heritage is located (UNESCO source). Consistently with the need of a sound protection of such kind of structures against seismic events, specific Guidelines for the built heritage have been conceived, which provide useful hints to practitioners for an assessment, but still leave important open issues. The present paper reviews the existing numerical approaches used for churches and towers. For churches, a guidebook for a reliable evaluation of the seismic vulnerability is proposed, relying into a broad blend of different approaches ranging from the easiest ones –usually available to practitioners- to the most sophisticated, like for instance Non-Linear Dynamic Analyses with damaging materials. A simplified procedure of FE upper bound limit analysis with coarse mesh adaptation is finally reviewed, which is sufficiently simple for common use but at the same time allows a realistic prediction of the most vulnerable macro-elements and the collapse acceleration. For towers, a straightforward approach based on the vulnerability evaluation by means of five probable (observed) failure mechanisms is proposed to overcome the limitations of a too simplistic cantilever beam approximation and to avoid demanding non-linear computations with 3D FEs.

Gabriele Milani
Understanding Fire Safety of Historical Buildings

This paper addresses an issue rarely contemplated in the management of historical buildings, fire safety. Historical buildings are generally assessed within a framework of compliance when it comes to fire safety. There is an implication that “compliant” means “safe” and that the goals and objectives of compliance are perfectly aligned with those of fire safety. In the case of historical buildings this is a mistake that has resulted in the loss of major historical buildings through the centuries. This paper presents a new framework of analysis that uses adequate tools to evaluate and establish true performance assessment so that the goal of fire safety is well defined and implemented.

José L. Torero
It Always Takes a Village: Preserving Earthen Sites

The Getty Conservation Institute (GCI) has worked with different institutions and professionals around the world over the past thirty years, engaging in projects and initiatives to advance the field of earthen conservation. The GCI has sought to improve practice, by working across professions and cultures, using both advanced research and traditional know-how through its Getty Seismic Adobe Project (GSAP), the Terra Project (Terra), and nowadays the Earthen Architecture Initiative (EAI). Understanding how earthen buildings were constructed and adapted to their environments has been a fundamental principle of the different training courses, model projects, research and dissemination of information that the GCI has developed and continue working on. The current paper describes the work of the GCI and its multiple partners over the years to improve the field of earthen conservation while emphasizing the importance of multidisciplinary work.

Claudia Cancino

History of Construction and Building Technology

Frontmatter
House on a Bunker by Architect R. Romke de Vries: From Military Accommodation to Residential Refinement

The construction of houses on bunkers is not uncommon in post-war Holland, yet this project in The Hague, conceived by architect R. Romke de Vries between 1951 and 1955, sticks out as a pioneering design. A large concrete bunker was reused as an artificial rock foundation for the construction of a new house that was commissioned by contractor Jan van Kampen. In close collaboration with his client, Romke de Vries managed to create a remarkable synergy between both old and new constructions, interior design and garden layout, bringing together many of his previously published innovative design strategies for the post-war home interior. All fittings and furnishings were profoundly detailed and painted in a remarkable colour scheme. This essay is dealing with innovative residential issues by architect Romke de Vries with special attention to technical approaches, the colour scheme and the interaction between architect and client/contractor. This study also addresses objectives of basic comfort standards, improvement of the energetic performances, efficient approach of the damage phenomena and issues of building physics.

Ann Verdonck, Steven van der Goes
The Structural Function of Cross Beams During Vault Construction in the Maya Palace of the Governor at Uxmal, Yucatan

The Puuc style Maya Palace of the Governor at Uxmal, Yucatan (900-915 CE) is a single-story structure with a long, narrow profile, built on a rectangular plan composed by 20 vaulted rooms. The vaults are monolithic structures formed by two inclined planar surfaces, with the intrados defined by finely fit facing stones tenoned into a concrete core of limestone fragments immersed in lime mortar. At the intrados, a regular pattern of wooden cross beams connects the two planar faces of the vault. We test the role of the cross beams in maintaining static equilibrium during construction using linear FE models based on published material properties of Maya concrete and rigid-body mechanics. Results indicate that cross beams are necessary to prevent overturning conditions both at the vault springing and at base of the supporting wall during construction.

Todd Kelmar, Jiacheng Sun, Renato Perucchio
Deformation Process of Romanesque Masonry Constructions: The Case of Vall d’Aran Churches

The Vall d’Aran is located on the north face of the Spanish Pyrenees. There, we can find a unique ensemble of Romanesque churches built during the twelfth century, which have suffered large geometric deformations. Puig i Cadafalch (1908) pointed out that the basilica floor plan churches were initially covered with timber-frame roofs that transferred the weight vertically and were later substituted with barrel vaults supported on non-monolithic circular-section masonry columns. These columns have plumbed out through time, and the severity of the deformations is very conditioned by the sternotomy of the pieces, the general measures and the vaulted building system.The research analyses the geometric evolution of these churches, based on the quantification of their deformations in relation with the used construction system. The methodology is based on an exhaustive topographical campaign (2014–15) made with Terrestiral Laser Scanner. The study is conducted through sections from 3D models obtained from four different churches, from which the admissible mathematic-strain deformation will be studied. These churches have different construction phases and deformations that occurred over a period of six centuries, and they are prime study examples for this particular problem.

Sergio Coll-Pla, Mónica López-Piquer, Josep Lluis-Ginovart, Agustí Costa-Jover
A Double Dome Through the Ages
Building Technology and Performance of Esfahan Shah Mosque’s Dome

On 7th May 1611, the construction of Esfahan Shah mosque started to be a part of the re-modeling of Safavid capital, a building that adopts a glazed bulbous double dome as a hybrid structure of brick and wooden elements. This paper aims to present building techniques, construction process and conservation works of this complex dome through historical evidence and onsite surveying. For these purposes, following a brief history of the building, the paper explores the geometry, morphology and construction sequences. It subsequently addresses the conservation during the last century from Salnameh (1934–36) up to current intervention and their consequences. The paper necessarily illustrates cracks pattern, not only to recognize its causes via their type and geometry but also to address historical performance and structural capacity. According to the objectives, the study of the Shah dome plays an important role to better understand other similar cases. This paper concludes that structural analysis and future conservation could benefit from the achievements derived from historical research, which also allow further understanding of construction techniques.

Ali Tavakoli Dinani, Solmaz Sadeghi, Paulo B. Lourenço
Construction and Building Technology in Sanctuary of Roman Settlement Aquae Iasae with the Review of Conservation Works on the Site

During the Roman period, the area of Varaždinske Toplice (northwestern Croatia) was the site of the Aquae Iasae settlement, famous for the healing properties of its thermal sulphur water. Around the thermal spring, the Romans built the sanctuary and to its south, a bath complex. The excavations conducted from 2011 to 2015 have shown that in the 2nd century AD a rectangular structure of 8 × 13.5 meters in size was built around the natural hot spring i.e. a reservoir used for catchment, in the same manner as in the Roman settlement of Aquae Sulis (Bath). In order to make the ground suitable for construction oak piles were driven in below the walls before the foundations were laid down, while the terrain was stabilized in and around the reservoir. The walls of the reservoir – “sacred spring”, were built of large stone slabs, employing the opus quadratum technique. The walls were repaired in the 4th century AD using older inscriptions, reliefs, and even sculptures as regular construction material (more than 50 stone monuments were found). The spring itself contained more than 17,000 Roman coins left as votive offerings. Most of the finds were in a very bad condition because of the detrimental effects of sulphur water, which calls for rather complex conservation approach.

Dora Kušan Špalj, Nikoleta Perok, Tena Karavidović
Early Iron Roofs in Belgian Churches (1845–60)

This paper sets out to assess the early age of iron roof construction in Belgian churches and its evolution through an in-depth analysis of a selection of cases situated in Belgium, an early-industrialised country with a fast-developing iron industry. The study is based on fieldwork, archive and literature study of three early iron trusses in churches in Brussels, Antwerp and Ghent. By providing renewed insight into the early use of iron and the evolution of the construction principles in churches, this study intends to encourage researchers, architects or heritage assessors to consider the roof construction of churches with greater care.

Romain Wibaut, Ine Wouters, Thomas Coomans
Lightweight Structures and Conservation - Engineering and Architectural Perspective

The field of conservation of the built environment deals with different kinds of buildings, monuments and objects. This diversity of structures becomes wider and wider in our time and it contains many structures with advanced technology, that were built in the modern era. Those structures are more and more relevant to conservation of the built heritage. One group of these structures is the group of lightweight structures, in their contemporary meaning. Indeed, lightweight structures existed through all history. For example tents and lightweight shelters can be identified since early days. In addition, human beings usually aspired to lighten the weight of structures even in the case of heavy structures. But scientific, engineering and technological developments in the last eras enabled to lighten structures in an outstanding manner, creating great challenges to the conservation field. In spite of that, a large amount of research and practical activity in the conservation field is focused on heavy structures. Naturally, most of the historical structures that survived thousands of years are considered to be heavy structures. In this situation, dealing with lightweight structures from a conservation point of view is an essential activity in the field of conservation of the built heritage. There is a need to create theories and a body of knowledge dealing with lightweight structures and conservation. This research aims to contribute to create the foundations for this field of activity. It focuses on the roots and characteristics of light structures and their relevance for conservation.

Avraham Mosseri
Mid-20th Century Colombian Vaults. A Contemporary Tradition

Despite their extraordinary interest, Colombian vaults of the central third of the 20th century have been rarely studied. Some concrete vaulted shells of very specific buildings, such as the ones of the Cartagena baseball stadium, are well-known, but more inconspicuous vaults for the structures of smaller buildings remain undervalued –especially structures for single-family houses, which were then a laboratory for testing all types of variants of lightweight vaults, some of which would be used later in other major constructions. An important milestone in this type of construction is the Casa Pizano, a building that can be traced today due to a peculiar coincidence that made its vaults especially influential in the history of modern architecture: Le Corbusier rediscovered tile vaults in this Bogota house, and later used a similar technique in some buildings that would be very influential in turn. But local architects were at that time using not only tile vaults but also many other vaulted systems, from concrete shells to reinforced ceramics. This paper will highlight the most significant examples of small-scale vaulted structures built in the Colombia of the 1950s, and establish a possible narrative for these constructions. To achieve this, a basic taxonomy will be first drawn up; then three examples of representative buildings of the main constructive systems will be studied; and, finally, a brief analysis of the impact of these examples in the construction of vaulted buildings throughout Latin America will be attempted.

Julián García, Fernando Magdalena, Juan M. Medina
Building Techniques and Structural Damage of Historical Constructions Detected Through the Point Cloud Survey

The study of historical constructions belonging to the cultural and architectural heritage is often challenging as, in most cases, it is very complex to reach a full understanding and description of them, due to the long-lasting history and the numerous modifications throughout the centuries. Many instruments today available allow gathering information on the current state of these buildings and contemporarily can provide some evidence on their history and constructive techniques. As a matter of fact, data taken from the modern technique of laser scanning, applied to architectural heritage, can provide important information not only on the present deformed configuration of each building, but also on the construction techniques related to its components, their geometries and possible structural problems. By juxtaposing the slices taken from the point cloud survey, indeed, the correspondences or the differences of the profiles might prove either the regularities or the incongruences characterizing each building. The present study will prove the significance of such an investigation technique with reference to the case study provided by Santa Fosca church on Torcello Island. This is a Venetian-Byzantine church, dated back to the 11th century, very peculiar both from the structural and architectural point of view and subject to numerous interventions throughout the centuries.

Antonella Manzo, Claudio Chesi
Analysis and Proposal to Retrofit the Traditional Construction Systems (Earth) of the Former San José School, Cuenca, Ecuador

The objective of this research is to analyze the main traditional construction systems used in the heritage buildings of the city of Cuenca, which was included in 1999 in the UNESCO World Heritage list. These construction systems are adobe, bahareque, clay brick bearing walls and wooden structures for tiled roofs, portals and floors. The techniques are applied to the former San José School, a century old heritage building located in the historical center of Cuenca. The present article will emphasize the analysis and retrofit of the adobe, bahareque and clay brick walls. The former San José School currently requires a maintenance and structural retrofitting plan due to its state of deterioration. Its exceptional architectural value dates back to its designer and builder, the German Redemptorist Brother Johannes Stiehle, who was renowned for promoting the use of mixed construction systems of fired clay bricks and raw earth. Its technological value is based on the presence of several materials that mark the different construction stages of the heritage building. The applied methodology focuses on the evaluation, through the use of assessment and diagnosis cards as well as non-destructive prospecting, of the state of conservation of the bearing walls, its structure, its plastering, culminating with a study of the floors, ceilings as well as murals and panel paintings. The research concludes with an intervention plan that proposes the structural retrofitting of this heritage building, recognizing the richness of its traditional construction systems to guarantee its conservation for future generations.

César Piedra Landívar, María Cecilia Achig-Balarezo, Víctor Caldas Freire, Indira Salazar Silva, Fausto Cardoso Martínez
Iron Ties Originally Anchored into Masonry as a Historical Construction Technology – Case Study: A Church in Cyprus

Unreinforced masonry structures are vulnerable to seismic actions due to their limited capacity to sustain tensile stresses. The installation of iron tie-rods is a technique often applied as a remedy, especially in the Eastern Mediterranean. In Cyprus, this technology is encountered mostly in large-scale buildings, such as three-nave churches of the late 19th–early 20th century. A grid of iron tie-rods connecting walls and columns in both the longitudinal and transverse directions, was anchored into the masonry during the construction phase.In the reported study, the historical background and the traditional way of application of this technology was investigated through international and Cypriot literature review. The seismic response of an existing stone unreinforced masonry structure was examined, and a pull-out test was performed to investigate the effectiveness of the anchoring of the tie-rods within the masonry.The research concludes that the use of tie-rods originally anchored into masonry was a common technique adopted in various occasions through the centuries. During the 19th century was consciously used as a mean of protection against earthquake actions, in the Eastern Mediterranean. The numerical analysis has proven the activation of the tie-rods during the excitation and the pull-out test has shown the failure mechanism and the capacity of the anchorage.

Margarita Petrou, Dimos Charmpis
Learning from Regional Architecture: Sustainable Solutions in Traditional Portuguese Houses

Ever always, regional or vernacular architecture, whose empirical knowledge was transmitted from generation to generation, sought to obtain in its form and local construction technique the balance between nature and buildings.In the regional architecture, buildings reflect their adaptation to climate characteristics and geography. Using similar spatial forms organization and materials, families building their own homes people have created the harmony and integrity between buildings - the link was the popular culture that they used to follow and share.The paper will identify some principles from regional/vernacular architecture lessons that should guide practitioners and decision makers involved in the development of future sustainable buildings and environments.Using a case study of vernacular architecture of Portugal with unique geographical and cultural significant, the paper will seek to demonstrate the principles of vernacular design and technologies such as the traditional sustainable performance of housings and settlements in the study area.Based on a Portuguese case study of vernacular architecture, which represents the cultural identity of three important regions of the north of the country, the article intends to demonstrate the principles of vernacular construction techniques that explain the recognized sustainable performance of regional constructions and settlements in the study area.

Fernando Alves, Nuno Abrantes, Vítor Abrantes
Innovative Stone Vaults in Dalmatia in Antiquity and Renaissance

The most important historical structures in Dalmatia, region in the Mediterranean part of Croatia, listed on the UNESCO World Heritage List, are the Roman Emperor Diocletian’s Palace, which marks the beginning of the monumental large-scale architecture in stone in this region, and the Cathedral of St James in Šibenik, which is the highest achievement of stone vault construction in Dalmatia. The preserved vaults of Diocletian’s Palace show variety of vault types, in variety of materials. The most interesting stone vault in the Palace is the vault of the small Temple of Jupiter. The coffered barrel vault, assembled of relatively large elements, influenced the form and decoration of two vaults in the nearby town of Trogir, but also the unique vaults of the Šibenik Cathedral. The thin vaults of the Šibenik Cathedral are unique for their method of construction (assembling large thin stone elements into slender stone arches) and for their mechanical behavior, different from massive masonry vaults. Although different from the vault of the Temple of Jupiter in many aspects, it is still believed that the stone vault of the Jupiter’s Temple was an inspiration for the barrel vaults of the Šibenik Cathedral. The wooden vaults “a carena di nave” have been mentioned as another possible source of inspiration. The study of recent scientific literature on various techniques of Roman vaulting brought about the new hypothesis on the possible origin of constructional details and on the development of the original building method of the vaults of the Šibenik Cathedral.

Marina Šimunić Buršić
The Structure of Gothic Architecture in Evolving Contexts – The Case of “Bombay Gothic”, India

The beginning of industrial revolution saw the emergence of varied building types. The difficulty in erecting these structures necessitated breakthroughs in structural engineering and building techniques, leading to the structural principles of the Gothic Style being revived. Although, primarily, an ecclesiastical style, its structural principles and elements have been applied to varying types and contexts. This paper deals with one such context, namely Colonial Gothic architecture in India. The role played by structure in varying types mandates an examination of materials and construction techniques in the context The influence of the Gothic style across the world led to the origin of several revivals such as Victorian Gothic, Collegiate Gothic and Iron Gothic. While the architectural tectonics (the relationship between design, construction and space) of these types may vary across time, their structural principles have remained fairly constant. An examination of the style’s evolution is needed to conserve buildings that are an integral part of India’s declining architectural heritage, and to understand the role played by a structural system in the erection of buildings.

Padmanabhan Jayabharathi, Ranee Vedamuthu
Comparison of Erudite and Popular Timber Historical Buildings in the Former Erechim Colony, Rio Grande do Sul, Brazil

The former Erechim Colony located in the northern Rio Grande do Sul state of southern Brazil was officially established in 1908 with immigrants of different European nationalities. At the same time, official constructions were installed by the colonization organs and popular constructions were erected by the immigrants, all built in timber. It was made a comparison between erudite and popular timber historical buildings in this region, based on historical documents, surveys, photographs, iconographies and field research. There was a reflection on the distance and the approximation between these two modes of production. It was proved the existence of differences and similarities in terms of construction technology and details and architectural types between the two building models, erudite, produced by a professional specialist, and popular, a handmade built by immigrants with scarce resources. It is believed that this work may help for understanding a possible influence or interconnection between these architectures.

Natália Biscaglia Pereira, Ângela do Valle
The Structural Technology and Architecture of Timber Bridges in Song Dynasty Paintings

The construction of Timber Bridges in ancient China reached a peak during the Song Dynasty. The structural technology and the architecture were advanced and well developed. This paper studies and summarizes the structural technology and architecture of the Timber Bridges in the Song Dynasty paintings, while comparing it to historical relics with similar bridge structures. This paper aims to promote the culture of traditional Chinese Timber Bridges and to support the protection and timber maintenance of historic bridges.

Jie Liu, Xiaohe Liu, Yangyang Chai, Chen Cao, Shoushi Li
The Imperial Record Office in Delhi: An Architectural Paradox

Built within the new capital of British India, the Imperial Record Office: now the National Archives of India is considered an important representative example of culmination of imperial architecture. An integral part of a city of the Empire that continues to this day as democratic India’s capital, the building’s design and construction raises questions on the nature of architecture in one of the most significant British capital city building projects in the subcontinent. In pre-existent scholarship, the architecture and urban environment of Imperial Delhi has predominantly been accepted as a product of the past, as a ‘garden city’ with neoclassical expression. The proposed paper would share the process of generating new knowledge about this structure, carried out through documentation and investigations of the materials, fabric and construction along with the analyses of space planning and design. This brings forth unique aspects that testify the actual development of architectural modernity. Planned within a historic city in the early decades of the twentieth century, possessing both an airport (modern) and cantonment (typical of the pre-modern), these findings about the Imperial Record Office are exemplary to represent a paradox in Imperial Delhi’s built environment. The paper aims to demonstrate, through this case, how this building’s architecture was simultaneously a product of the past and an envisaged future. It shows how the structure’s attributes embody the complex process of an emerging modernity, dressed in a façade of architectural classicism.

Nalini M. Thakur, Saptarshi Sanyal
Concrete Thin Shells in the Sixties. Construction and Long-Term Behaviour

The new globalised and mass society at the end of World War II posed new challenges for architects and engineers. Double curvature structures (membranes and shells) in reinforced concrete were a frontier in the field of typological, spatial and expressive innovation. New materials, new technologies and new production systems supported research into shape-resistant structures that led in various directions. Two of the leading figures were the Swiss engineer Heinz Isler and the Italian Dante Bini: the first with his methods called “form finding” based on the use of physical modelling to determine the form and subsequently investigate its stability; the second with his research in the field of the industrialization of the construction process. These thin concrete shells, in which research into “limits” was a fundamental factor, have proved vulnerable to the passing of time. The analysis of the construction and monitoring of lifetime of these structures shows the distance between theoretical projects and construction of real shells. Despite the importance and authority of the leading figures who conducted research and built thin concrete shell structures, their destinies have been very different. Some have been demolished or considerably altered; others have been given careful maintenance and protection. Observing the behaviour of these structures with the passing of time offers an opportunity to reflect on the logic with which they were designed and built in a period of absolute formal and structural experimentation, besides placing the emphasis on fundamental aspects for the conservation and reuse of this fragile patrimony.

Francesca Albani, Carlo Dusi
Chechen Medieval Towers-Obelisks to the Issue of Architectural Form Interpretation

Stone constructions were built in Chechnya over the course of observable ancient history. Among them are the most common and well-known ones – towers. These are residential towers, watchtowers and towers-obelisks with pyramidal-stepped roofs classified as “military” in academic literature.This paper analyses the most accomplished towers in this line both esthetically and by the level of architectural mastery and construction technology – the so-called “military” towers. Those towers were constructed nearby inhabited dwellings as well as in most inaccessible places – on cliffs and steep slopes above rivers. They are built with no basement but in their foundation always have massive exceeding human height stones. The foundation square is 5 × 5 m narrowing greatly towards the top and reaching over twenty meters in height.The research conducted allows us to claim that the “military” towers were not capable of withstanding a siege, however brief, or protecting people seeking shelter within it. In our opinion, the “military” towers of Chechnya are in fact ceremonial constructions dedicated to the supreme god of Chechens’ pagan pantheon Dela.In the pre-Islamic period in the Chechen spiritual culture we observe an integral world picture with its own cosmogony, mythology and a pantheon of gods with the triad at the top – god of sun and light Dela, god of thunder Sela and goddess of fertility Tusholi. There are also material testimonies of spiritual practices of ancient Chechens that have reached our times - megaliths, sculptural images Tusholi, sanctuaries-selings devoted to Sela. Dela, undoubtedly, had his own temples that are the widespread in medieval Chechnya towers-obelisks with pyramidal-stepped roofs.

Tamara Adamovna Mazaeva
The First Industrial Period: A Forgotten Period in Brazilian Construction History

The study of the Brazilian construction history generally focuses on two main periods: the colonial or pre industrial and the modern or industrial. Between the two periods, the period, which is called here the “First Industrial Revolution Period”, is usually forgotten. This period is characterized by intensive use of brick and has characteristics that differ from the pre industrial period and also from the next period, which has cement and reinforced concrete as the main materials. In this paper, the importance and characteristics of this period are shown and a new time period list for the Brazilian construction history is proposed. Furthermore, the techniques and materials of the period are illustrated by the sample of construction of the first planned city in the country: Belo Horizonte. Belo Horizonte was constructed in order to make it the new capital of the Minas Gerais State, in the end of the 19th century, and all the “new” technology of the period was used in construction. The influence of the modern architectural movement with an approach that tries to deny the importance of the eclecticism and its technology in the history of architecture and construction is presented as one of the main causes for this unrealistic time period list of the Brazilian construction history, excluding this important period. The conclusion is that a more realistic timetable of the Brazilian construction history must include the First Industrial Period as part of it. Furthermore, it is confirmed by the successful use of this time period list in graduation and PhD programs.

Marco Antônio Penido de Rezende
Conservation and Restoration on Cement-Based Renders of Built Heritage in Shanghai, PR China

Lime-based mortars were mainly used in buildings until the second half of the 19th century, when they started being increasingly replaced by a new binder: Portland cement. And then at the first of 20th century, the cement had become the key role as the binder of renders at Shanghai Modern historic architecture. Those finishing coats show different style: plaster (stucco), fair faced brick, stone coat, etc. The prevalent finish coats were applied with cement-based render as a result of economic way to imitate the stone texture, which includes the water brush stone (It is called Shanghai plaster as well later), pebble dash, artificial stone with chopping (called Zhanjiashi in Chinese), wet dash, Terrozzo, Mane brush drag Sgraffito (called Lamao in Chinese including different statement) at the first half of last century. Some former restoration on renders was discovered to replace the original materials and change the original texture or even the color since the research and analysis on the binder and aggregate was neglected, which is too far from authenticity principle. This paper aims to discuss the restoration method on cement-based renders by analyzing data of lab experiment with petrography and wet-chemical method. Instead of just simply repeating the principle quoted from established standards, the paper tends to provide realistic goals and information to get a more rational and sustainable restoration method in order to avoid the damage coming from unqualified restoration as well as get the authentic texture and color as original facade showed.

Xiaomin Zhu, Yuee Zhou, Shibing Dai
Traditional Wall Construction Technology of the Ottoman Empire in Relation to the Seismic Resistance of Bath Structures in the Marmara Region

In the Ottoman Empire, traditional masonry structures were distributed all around the border lines of the country. Anatolian architecture reveals many different construction styles imported by nomad craftsman. The craftsman brought these construction styles from remote areas for the ever growing needs of the Ottoman Empire. Some of the traditional structures were constructed in cities that were in high seismic areas. The masonry walls were the main structural parts of the buildings which were naturally resistant to lateral forces. The whole structures of the buildings, as well as the walls, were affected by seismic forces. The collapse of the wall structures can be associated with many factors that include the type of stone as well as the forces that were applied to the structure and the materials used for joining the elements. From that point of view, the research question of this paper was to determine the evidence for traditional wall construction technology intended to withstand seismic activity. The answer to these questions would be clarified by the investigation of the construction techniques of the historical structures according to the seismic circumstances of the different locations of the case studies. The methodology of the research for the paper was the analysis of the morphology of the masonry wall structures in different regions with the support of typological tables. This research is a part of a study which was done during my PhD studies in Politecnico Di Milano.

Kerimcan Apak
Back to the Past – The History and Current Modernisations of Kleinische Decke Ceiling

Wooden or ceramic ceilings were commonly applied to the end of the 19th century (vaults were shaped in such a way to eliminate tensile stresses). In 1888, Joseph Monier developed a ceiling made of steel beams, filled with monolithic reinforced concrete slabs. At first, this type of ceiling gained no recognition since - according to a popular belief – it was rather unlikely to use steel and cement in one structure. In 1892, Johann Franz Kleine, a masonry master from Essen, patented a ceiling consisting of steel beams and a filling provided by ceramic boards reinforced with steel band, so-called Kleinesche Decke. Over 600 thousand m2 of different versions of this technology (light, light-heavy, heavy boards) were manufactured in the first year. Owing to its excellent load-bearing capacity and maximum rigidity, it was an alternative solution to flammable wooden structures and at the turn of the 20th century it quickly became one of the most commonly used types of ceiling. Furthermore, in the postwar period, old structures were often replaced with Kleinesche Decke, therefore the problem of renovations and modernisations of such ceilings still exists. Historic ceilings are renovated as a matter of routine and it is too often the case when final effects are completely different than the expected ones. What is more, assessment of the technical condition of components, which should be conducted before starting work, is ignored. And this assessment is crucial as it influences safety and technical condition of the building. Workers rely on their own experience only, the consequences of which will be illustrated with an example. It happens quite often that specific design specifications based on pre-design and final condition analyses are not available and this is one of the reasons for incorrect solutions.

Dariusz Bajno, Agnieszka Grzybowska, Rafał Tews, Łukasz Bednarz
Historic Evolution of the Temple of San Pedro and San Pablo de Zepita, and the Origins of the Structural Faults

The historic chronology of the San Pedro y San Pablo de Zepita identifies two construction stages over the period of approximately 130 years, time during which the religious architectural typology of the Peruvian Viceroyalty varied in form and style. It is posited that the Second construction stage reutilized the base of the temple of the first stage. In this process, walls were raised, spaces were enlarged, the structure was overloaded by a vault roof over the gospel, and the construction of an attached tower took place. This process generated the initial fault, the settling of the gospel wall, and displacement of the ground zone of lesser carrying capacity. The fault consequently generated fissuring in the clave of the vault, a crack in the mid-zone of the headwall, settling of the tower, and in the 20th century, partial collapses that correspond to the initial causes and to the sum of other factors of deterioration.

Violeta Paliza
Stone Masonry with Brick Stripe Courses: Study on a Historical Building Technique Diffused in Brianza District

The paper presents a research on a masonry building typology, formed by pebbles stones with brick courses, well known and spread in a wide area in Northern Italy, but never studied in depth. The sample of buildings selected for this work is located in Vimercate area, near Milan, where it has been possible to lay out a diachronic scheme of the geometrical features characterizing the listed masonry: dimensions of component materials, distance between the courses, etc. The studied sample included different buildings typologies, like churches, civil houses, palaces and villas, realized with brick stripes and pebble stones. Crossing historical information coming from different authors with the surveyed textures, a relationship between this technique and its mechanical characteristics was investigated. Therefore, it has been possible to observe the trends of the technique, referring to an optimal ratio between the thickness of the wall and the distance among brick stripes, as well some archaeometric data on the production and supply of bricks in the area through time.

Stefano Della Torre, Lorenzo Cantini, Rossella Moioli
Megalithic Shelters in Vale de Poldros, Portugal. The Cardenhas

Vale de Poldros is a mountain settlement in the north of Portugal where one finds a type of constructions – the cardenhas – whose origins go back to the megalithic culture. Similar architecture exists in other countries, predominantly located in mountainous areas, related to herding activities. Most cardenhas have two floors. In the upper floor slept the cowherds, while in the lower floor were kept the oxen in the summer months. The cardenhas have a square plan, and inside there is a single space in each floor, with no partitions. The walls are made out of dry stone, covered by a false cupola which was built by means of the superposition of stone slabs laid out in successive circles with a diminishing diameter, which progressively closed the space. Their construction incorporated sophisticated structural knowledge, which is also perceive in other constructive details. The pavement of the upper floor was made up of big stone slabs, supported by a structure of pillars and beams also of stone. The force transmitted by the grand masses of stone emphasize the formal beauty of the structure. The study has mapped the morphological evolution of the cardenhas of Vale de Poldros, as well as the evolution that led from them to subsequent morphologies of traditional rural houses. They are a clear evidence that primitive architecture is not a separate subject of the history of architecture, set in the past, but that, instead, there are lines of continuity and evolution between vernacular architecture and contemporary architectural typologies.

Manuel C. Teixeira

New Technologies and Techniques

Frontmatter
Connected Semantic Concepts as a Base for Optimal Recording and Computer-Based Modelling of Cultural Heritage Objects

3D and spectral digital recording of cultural heritage monuments is a common activity for their documentation, preservation, conservation management, and reconstruction. Recent developments in 3D and spectral technologies have provided enough flexibility in selecting one technology over another, depending on the data content and quality demands of the data application. Each technology has its own pros/cons, suited perfectly to some situations and not to others. They are mostly unknown to humanities experts, besides having a limited understanding of the data requirements demanded by the research question. These are often left to technical experts who again have a limited understanding of cultural heritage requirements. A common point of view has to be achieved through interdisciplinary discussions. Such agreements need to be documented for their future references and re-uses. We present a method based on semantic concepts that not only documents the semantic essence of such discussions, but also uses it to infer a guidance mechanism that recommends technologies/technical process to generate the required data based on individual needs. Experts’ knowledge is represented explicitly through a knowledge representation that allows machines to manage and infer recommendations. First, descriptive semantics guide end users to select the optimal technology/technologies for recording data. Second, structured knowledge controls the processing chain extracting and classifying objects contained in the acquired data. Circumstantial situations during object recording and the behaviour of the technologies in that situation are taken into account. We will explain the approach as such and give results from tests at a CH object.

J.-J. Ponciano, A. Karmacharya, S. Wefers, P. Atorf, F. Boochs
Semi-automated Creation of Accurate FE Meshes of Heritage Masonry Walls from Point Cloud Data

The structural analysis of buildings requires accurate spatial models. Additionally, spatial information on pathologies such as settlement-induced damage is paramount in the assessment of heritage assets. This spatial information is used as a basis for Finite Element Methods (FEM) to evaluate the stability of the structure. Traditional data acquisition approaches rely on manual measurements which are labor intensive and error prone. Therefore, major simplifications are made to document structures efficiently. The goal of this research is to provide faster and more accurate procedures to capture the spatial information required by a Finite Element (FE) mesh. This paper presents a semi-automated approach to create accurate models of complex heritage buildings for the purpose of structural analysis. By employing remote sensing techniques such as terrestrial laser scanning and photogrammetry, a complex mesh of the structure is created. Also, a methodology is proposed to capture crack information. A stepwise approach is elaborated to illustrate how the spatial information is adapted towards a FE mesh. The results show a significant difference between the geometry of our model and a traditional wire-frame model. Not only does accurate modelling result in deviating loads, it also affects the behavior of the object. Through the proposed approach, experts can develop highly accurate FE meshes to assess the stability of the structure up to as-built conditions and taking into account existing damage patterns.

Maarten Bassier, Gilles Hardy, Leidy Bejarano-Urrego, Anastasios Drougkas, Els Verstrynge, Koen Van Balen, Maarten Vergauwen
Numerical Modeling of Single Tube-Jack and Flat-Jack Tests in an Unreinforced Masonry Wall with a Regular Typology

Development of new non-destructive testing techniques and continued critical analysis of existing techniques is important to ensuring that the conditions of historical masonry structures are diagnosed accurately. This is the goal of a research project currently being carried out by the authors at the University of Minho, Guimarães, Portugal. In previous editions of the SAHC conferences tube-jack testing has been introduced as a non-destructive testing technique that has the potential to be used as an alternative to traditional flat-jack testing for determining the state of stress in and deformability characteristics of unreinforced masonry. In this paper, the results of numerical modeling single tube-jack tests and flat-jack tests in a masonry wall with a regular typology are presented. The DIANA finite element modeling program was used to model these tests in a masonry wall based on a laboratory test wall that was constructed and tested in another phase of the research program. The modeling results lead to several important conclusions and new questions to be answered through future research. The modeling of these tests revealed that the discrete line of tube-jacks functions as an equivalent flat-jack in pressurizing the masonry, as originally hypothesized, confirming the viability of the method.

Elizabeth Manning, Luis F. Ramos, Francisco M. Fernandes
The Strength of Wooden (Timber)-Glass Beams Combined with the Polyurethane Adhesive - DIC and Finite Element Analysis

Results of tests on timber-glass composite I-beams with flexible polyurethane adhesive joining glass web and timber flanges together are presented in the paper. The carried out tests on these elements, tested cyclically and statically, manifested that this kind of adhesive is able to withstand over 100,000 cycles in fatigue tests without degradation. The following ultimate static test up to failure, made on semi-scale cyclically tested specimen, manifested the same characteristic as the static test up to failure done on the similar specimen without applied cycles. The tested transparent timber-glass composite I-beams shows also a suitable protecting factor against sudden failure, making such systems safe in exploitation in heritage structures, where visitors are present.

Rodacki Konrad, Zając Bogusław, Kwiecień Arkadiusz, Marcin Tekieli, Kazimierz Furtak
On the Use of Sound Spectral Analysis for the In Situ Assessment of Structural Timber

This paper focuses on the possibility of using sound spectral analysis as a diagnostic technique for the assessment of existing timber structures. The basic idea is to perform a spectral analysis, through the Fast Fourier Transform (FFT) algorithm, of the sound (recorded by a smartphone microphone) that is produced by hitting the wood surface of the element with a hammer or an equivalent tool. The sound spectrum is compared to a reference spectrum obtained for sound wood in standard environmental conditions in order to detect the presence of damage or decay. Differently from “classic” stress wave propagation methods that are based on the determination of the time-of-flight of the stress wave, the proposed technique relies on the local acoustic properties of wood. A first insight on the method applicability was obtained by testing the technique on several timber specimens in different conditions, from sound to completely decayed. Registration of the signals was performed by using two different mid-market smartphone models. Moment analysis, by calculating the spectral and frequency energy centroid of the sound spectra, was used to evaluate and compare numerous experimental recordings. The parameters that have the most significant impact on the sound signal (e.g. impact tool, microphone distance, boundary conditions, etc.) and that can negatively influence the assessment were then identified and investigated. Finally, pros and cons of the presented method and future developments are examined and discussed.

Daniele Riccadonna, Gianni Schiro, Daniele Casagrande, Maurizio Piazza, Ivan Giongo
Application of Digital Close-Range Photogrammetry to the Modeling of Heritage Structural Elements for Its Analysis by FEM

The modeling of structural elements with complex geometries requires a lot of field and office work, even more so when these elements belong to heritage buildings, which usually have geometric damage caused by natural and anthropogenic weathering; damage to these elements are difficult to record and characterize, and even more difficult to model. However, since the accuracy of the results in modeling and numerical analysis of heritage structural elements by FEM largely depends on the quality of the model in terms of its geometry, the implementation of techniques is required, which results in fast, cheap and reliable modeling; allowing, in addition, the representation of the geometric complexity of the item, measuring and feeding the simulation with deterioration data. The modeling of structural elements, on heritage buildings by implementing digital close-range photogrammetry techniques allows a very good geometrical precision, which is almost impossible to obtain with conventional techniques of manual survey; on the other hand, while using techniques such as laser scanner allows to gather high quality information, on developing countries this equipment is unaffordable. One of the great advantages of the implementation of photogrammetry is the low cost of the equipment and software required; in addition, it only requires minimal staff training and a very basic knowledge in photography, allowing the integration of many people from different disciplines and academic backgrounds into the modeling work. This work shows the results of contrast structural evaluation of damaged stone elements modeled and analyzed using FEM with traditional techniques, and those modeled with photogrammetry techniques, comparing work times and accuracy results.

Miguel A. Soto-Zamora, Isaías E. Vízcaino-Hernández, Rodrigo A. Díaz-Zeledón, J. J. Velasco-González
Parameterization of Structural Faults in Large Historical Constructions for Further Structural Modelling Thanks to Laser Scanning Technology and Computer Vision Algorithms

Laser scanning technology has evolved significantly in the last decade, particularly, in those applications in terrestrial environments dealing with the documentation and inspection of civil engineering and architectural constructions. Even though there exist mature procedures to convert the so-called LiDAR point clouds in CAD models or even FEM models, the current trends in the technology are related to the automation of these operations. The development of robust automatic procedures for data segmentation and interpretation it is a key aspect so that the technology can definitely be accepted as a basic, accurate, and robust tool for reverse engineering of existing constructions. This paper presents the application of laser scanning technology to the structural evaluation of the Medieval Wall of Guimarães (Portugal). This laser scanning survey was conducted with the aim of having an accurate and detailed geometrical model of the large masonry construction that includes the existing deformations and structural faults. The parameterization of structural damages was possible thanks to the highly detailed point cloud collected, and its processing using computer vision algorithms. The geometric models obtained could be used for further structural analysis of the entire wall.

Ana Sánchez, Belén Riveiro, Iván Puente, Borja Conde, Nuno Mendes, Manuel Cabaleiro, Paulo B. Lourenço
Stop-Splayed Scarf-Joint Reinforcement with Timber Pegs Behaviour

Restoring ancient timber structures often involves cutting or reinforcing stop-splayed scarf-joints in beams or truss-rods. Steel nails, bolts and plates or adhesive resins and rods are commonly used, however these jointing technologies cause some disadvantages, such as moisture between steel and timber surfaces, hard reversibility of the intervention and a questionable aesthetic output in uncovered structures. The employment of timber pegs, inserted perpendicular to the grain, could be an efficient solution and is already preferred in some applications. Since no design rules for traditional timber joints or for timber pegged connections are given by European codes, investigations on scarf joint behaviour before and after reinforcement are needed aiming to reliable design procedures. In this study, the role of the fastener inside this tension resisting carpentry joint and its contribution in yield strength and stiffness have been investigated. Specific attention has been addressed to stiffness, which is positively influenced by the insertion of timber pegs. Three samples of fir scarf-joints have been tested, a total of eight specimens, with different configurations: without fasteners, with timber pegs and with steel pins. The different failure modes under tension load of the samples and their rheological behaviour have been studied and compared to trace force distribution between the resisting elements, that is the ash key and the added fasteners.

Carla Ceraldi, Alessia Costa, Maria Lippiello
Characterization of the Mechanical Properties of Ancient Masonry from a Non-destructive Method In Situ

This paper presents a methodology for determining the mechanical properties of the masonry elements by mean of seismic techniques and how these are included in a numerical model of a case study of a building. This work presents partial results of a research in process of doctoral thesis. It is part of the line of Non-Destructive Test (NDT) in situ that uses the measuring of seismic waves travel time to obtain shear and compressional waves; with these parameters it is possible to obtain the mechanical properties of the masonry of ancient buildings as Young’s Module, Poisson Ratio and density. The obtained data comes from a case study, the Temple of San Antonio de Padua, located in Aguascalientes, Mexico. In addition, a numerical model developed in SAP2000 is presented with the characterized properties obtained from the analysis. Results of this research will contribute future numerical analysis because it will be possible to obtain the values of each part of the building, and in this way, offer more reliable information about the behavior of the building.

Edith Estefanía Orenday-Tapia, Jesús Pacheco-Martínez, Raudel Padilla-Ceniceros, Héctor Ánimas-Rivera, José Ángel Ortiz-Lozano, Daniel Gaxiola-Apodaca
Developing Solutions Based on Shape Memory Alloys for Historical Constructions

The superelastic properties of Shape Memory Alloys (SMAs) can be used to improve the thermal and seismic behavior of steel tie-rods, which are often used in historical constructions. In this paper, a device prototype based on SMAs is presented, whose performances have been assessed through extensive experimental tests in thermal chamber and shaking table tests on reduced-scale testing models. The functioning principles of the device and the main steps for its implementation are first illustrated. The experimental behavior of the device is then examined. Finally, a recent example of application of the proposed technology to a historic single-aisle church, realized in the 13th century in Brindisi (southern Italy), and equipped with inadequate and deteriorated steel tied rods, is shown.

Donatello Cardone, Riccardo Angiuli, Giuseppe Gesualdi
Historic Digital Survey: Reality Capture and Automatic Data Processing for the Interpretation and Analysis of Historic Architectural Rubble Masonry

Detailed segmentation for the analysis of rubble masonry substrates is complex due to the lack of uniformity in size, geometry, coursing, bonding, and materials composition and texture of the individual stones. State-of-the-art technologies, such as Terrestrial Laser Scanning (TLS) or photogrammetry, deliver precise geometrical and coloured data that can be processed by means of innovative techniques to segment and label these masonry units. The automatic segmentation of individual stones supports further analysis of rubble masonry via several parameters related to their geometry and face colour. These can be utilized for deciphering architectural construction methods and changes in materials, as well as being employed for practical maintenance and repair operations. This paper presents a new strategy for investigating historic masonry substrates, especially from the perspective of data processing methods supporting the automated segmentation and labelling of rubble stone walls. In particular, an innovative method based on the Continuous Wavelet Transform (CWT) is proposed for the automatic segmentation of rubble stone walls, which subsequently enables the automated analysis of the individual stones and mortar regions. Different experiments have been conducted on two significant Cultural Heritage (CH) buildings in Scotland, with the results clearly demonstrating the potential of the proposed method for historic interpretation and analysis.

Enrique Valero, Frédéric Bosché, Alan Forster, Ewan Hyslop
Study of Early Age Stiffness Development in Lime–Cement Blended Mortars

Lime-cement blended mortars are frequently used in building conservation, as well as in new masonry constructions. Since mortar plays an important role in governing the non-linear behavior and global performance of masonry from the earliest moments of construction, this work intends to study the evolution of its elastic modulus from very early ages. The development of stiffness in blended mortars has been studied using a recently developed approach called EMM-ARM (Elasticity Modulus Monitoring through Ambient Response Method). The method is based on continuous modal identification of the first flexural resonant frequency of composite beams that contain the material to be tested. The evolution of resonant frequency identified during the experiment can be directly correlated with the Young’s modulus by using the dynamic equation of motion. The experimental program involves validation of the applicability of EMM-ARM in blended mortars by comparison with results from conventional static method of cyclic compression according to EN 12390-13. Three distinct blended mortars (with target workability of 175 mm) with 33%, 50% and 66.67% lime in binder and 1:3 binder aggregate ratio, by volume, have been studied. The evolution of Young’s modulus will permit discussion on interaction of binders involved in the mixes. Such a study will also make it possible to explore the consequences of the observed kinetics of stiffness evolution on the stress development within masonry structures since the early ages of application of the mortar interface.

Meera Ramesh, Miguel Azenha, Paulo B. Lourenço
Evaluation of a Rope Mesh Reinforcement System for Adobe Dwellings in Seismic Areas

Throughout the world millions of people are at unacceptable risk because they live in unreinforced earthen dwellings, which have consistently shown extremely poor structural behavior during earthquakes. This article presents a design procedure for the structural reinforcement system for one-story earthen constructions located in seismic areas. The proposed reinforcement consists of a mesh made of nylon ropes which envelopes completely all the earthen walls and maintains structural integrity even after the walls have been significantly damaged. It is thought that its use has the potential to protect the lives of millions of families which are currently are at risk, and the integrity of invaluable earthen historical monuments.

Marcial Blondet, Nicola Tarque, Julio Vargas, Hillary Vargas
Comparison of the Degree of Consolidation of Historic Plaster Layers by Means of Lime Hydrate Nanosuspensions

Historic masonry is usually coated with multiple plaster layers, exposed to long-term extreme loading (climatic effects, elevated moisture levels, salt crystallization and recrystallization, biological effects, etc.). As a consequence of the above negative cyclic effects, degradation processes are triggered off leading to a loss in plaster cohesion with the substrate masonry and successive falling-off of surface layers. The strengthening and rehabilitation of plasters with degraded binder components, impaired structure, insufficient adhesion of individual layers of plaster to the masonry surface, with elevated salt contents in the pore system and surface crusts represent a demanding task in terms of the stabilization of such degraded plasters and coatings. Consolidation (i.e. enhancement of mechanical characteristics) belongs to the basic objectives of the restoration of historic plasters, its principle is to return binder into the material structure, fill in existing hollow spaces, heal cracks, etc. Degraded lime plasters are strengthened with consolidating agents applied in the form of solutions, e.g. lime water, organosilicates or lime nanosuspensions, etc. The lime nanosuspension is composed of lime hydrate nanoparticles, dispersed in an alcoholic medium. Due to the deposition of calcium carbonate in the degraded material, the bonds are re-strengthened and the material consolidated. The article presents partial results of theoretical and experimental research addressing potential consolidation of historic plaster layers with lime nanosuspensions prepared by the synthesis of Ca(OH)2, which were successively modified and enriched with other components.

Klára Kroftová, Markéta Šmidtová, David Škoda, Ivo Kuřitka, Jiří Witzany
Study on Carbonation Initiated by Organics in Traditional Lime Mortar

The contribution of the research is to study carbonation process of shell lime mortar on addition of organics. Lime mortar of binder to aggregate ratio 1:3 with addition of Kadukkai (Terminalia Chebula), Jaggery (Unrefined sugar) and combined Kadukkai and Jaggery, in an amount of 1 kg, 3 kg and 0.5 kg + 1.5 kg respectively per 10 L of water have been used, where the influence of organics towards development of strength and durability is well identified to suggest the use in lime construction. Traditional phenolphthalein test was conducted to measure the carbonation depth and thermo gravimetric analysis with differential thermal analysis (TGA-DTA) was used to verify the degree of carbonation and carbonation profile of lime mortar specimen. On fermentation, the organics reduce to carbon-di-oxide within the mortar, altering the hydrated phases and also resulting in more formation of load bearing forms of calcite (calcium carbonate). XRD results interpret the hydrated phases such as Calcite, Calcium-Silicate-Hydrate (CSH) and Calcium-Aluminate-Hydrate (CAH) of the organic modified mortars under carbonation and it is in confirmation with TGA.

Simon Jayasingh, Thirumalini Selvaraj
Virtual Reality for the Enhancement of Structural Health Monitoring Experiences in Historical Constructions

This article presents a methodology to implement a virtual reality program for historical buildings, aiming to produce a new tool for an enhanced user experience in the fields of virtual visits and scientific tourism. The proposed methodology allows the user to walk, observe, and interact with cultural heritage buildings, as well as to observe details of the implementation and results of a real time structural health monitoring system. The methodology considers, first, developing 3D models of different parts of the building using terrestrial and aerial photogrammetry. Subsequently, the models are joined and processed to produce a simpler and lighter 3D version that is suitable for virtualization using Geomagic Design X. The resulting model is inserted into a video game engine Unity 3D to create a virtual environment. Interaction capabilities for movement and option selection are added by using the SteamVR SDK that allows to use the characteristics of HTC Vive. This methodology was applied to one of the most important churches of the Andean Baroque in Peru: San Pedro Apostol of Andahuaylillas. The virtual environment aimed to display the exterior and the choir of the church, general information about the building and its contents, the location of accelerometers in the building and real time information about its structural state derived from these sensors (natural frequencies, damping coefficients, maximum and RMS accelerations). Users who tested the virtual environment agreed on the potential of this methodology for improving touristic, educational and research activities.

Marcos Burgos, Benjamín Castaneda, Rafael Aguilar
Classification of Hardened Cement and Lime Mortar Using Short-Wave Infrared Spectrometry Data

This paper evaluated the feasibility of using spectrometry data in the short-wave infrared range (1,300–2,200 nm) to distinguish lime mortar and Type S cement mortar using 42 lab samples (21 lime-based, 21 cement-based) each 40×40×40 mm were created. A Partial Least Squares Discriminant Analysis model was developed using the mean spectra of 28 specimens as the calibration set. The results were tested on the mean spectra of the remaining 14 specimens as a validation set. The results showed that, spectrometry data were able to fully distinguish modern mortars (made with cement) from historic lime mortars with a 100% classification accuracy, which can be very useful in archaeological and architectural conservation applications. Specifically, being able to distinguish mortar composition in situ can provide critical information about the construction history of a structure, as well as to inform an appropriate intervention scheme when historic material needs to be repaired or replaced.

Zohreh Zahiri, Debra F. Laefer, Aoife Gowen
Improvements of the Ultrasonic Tomography for Applications to Historical Masonry Constructions

Non-destructive tests play a crucial role for rehabilitation, restoration and strengthening of historical masonry constructions: this justifies increasing research interests on this issue. In particular, sonic and ultrasonic tomography are among the most used NDT techniques for applications to historical constructions since they are relatively fast, reliable and inexpensive. Anyway, the resolution and the capability of those techniques in assessing hidden defects, voids, damage, the masonry layout and the mechanical properties of masonry can be further substantially improved. To this aim, several issues about the experimental setup, the modeling of propagation phenomena of acoustic waves, and the inversion algorithms should be addressed. In this paper some improvements of the ultrasonic tomography for masonry constructions are proposed, based on the implementation of advanced inversion algorithms, on the use of the information about wave attenuation (attenuation tomography) in addition to those related to the time of flight of acoustic waves, and on the enhancement of the experimental setup, in particular for what concerns the coupling between probes and masonry. With reference to tuff samples having known internal defects like holes, cuts and inclusions, the capability of the proposed approach is compared with the standard ultrasonic tomography. The experimental results show the effectiveness of the proposed approach, and suggest some directions for further improvements.

Domenico Camassa, Anna Castellano, Aguinaldo Fraddosio, Mario Daniele Piccioni
Correlation Between Sonic and Mechanical Test Results on Stone Masonry Walls

Heritage constructions are the inheritance of the society and must be preserved because of their historical and cultural value. To preserve and rehabilitate these structures, an extensive knowledge of its mechanical properties is required. To obtain this information priority should be given to the use of non-destructive techniques. In this work, it is proposed to use the correlation of sonic and mechanical tests, performed in seven double-leaf stone masonry walls constructed in the laboratory. Four types of two leaves masonry walls were constructed, with variations in its structural configuration. Based on uniaxial compression tests performed on these stone masonry walls, mechanical properties were obtained. These data were correlated with sonic test results. Two sonic test sequences were performed. In the first sequence, direct and indirect tests were performed before and after the damaging mechanical compression tests. For the second sequence of sonic tests, direct and indirect tests were implemented at each loading level during the compression test, for which fewer acquisition points were defined, to avoid loading redistribution and relaxation during the sonic data acquisition. Several difficulties were encountered in this process. Despite these difficulties, both used tests presented coherent and correlated results. For the sonic tests, as expected, the higher wave velocity locations are those from the direct test across the walls header blocks. With the sonic tests performed during the compression tests, it was possible to monitor the varying sonic behavior of the walls, and the accuracy of the sonic test results when compared with the compression test results.

Rachel Martini, Jorge Carvalho, António Arêde, Humberto Varum
Geometric and Radiometric Analysis of TLS Point Clouds to Diagnose the Conservation State of Historical Constructions. Case of Study in the Master Gate of San Francisco, Almeida, Portugal

This paper summarizes the experimental results obtained after the radiometric and geometric analysis of the 3D point cloud model of one of the most emblematic constructions inside the Fortress of Almeida (Portugal): the Master Gate of San Francisco. The data acquisition was performed with a Faro Focus 120 Terrestrial Laser Scanner previously calibrated. The evaluation of the construction involved the combination of both approaches through the use of K-Means unsupervised classification approach, the Efficient RANSAC Shape Detector and the CANUPO algorithms. As a result, an accurate identification of a wide diversity of indicators of damage (salt crusts, black crusts and deformations, among others) was achieved. The results of the proposed semi-automatic methodology have allowed, in a non-intrusive way, a robust identification of the different degradation mechanisms that are promoting the blistering of that construction’s masonry.

Luis Javier Sánchez-Aparicio, Susana Del Pozo, Luís F. Ramos, Francisco M. Fernandes
Diagonal Compression Behaviour of Masonry Walls Reinforced with FRM Coatings

In mortars used for strengthening of existing masonry walls the trend is toward the reduction of the thickness of the added external layers, but with a significant increase of the strength of the used FRM material (Fiber Reinforced Mortar). In the present analysis the focus is posed on some new lime mortar types which possess a very high strength in tension, although the elastic modulus remains in a normal range, in order to obtain a considerable toughness increase. The G-FRM system is composed with a glass fiber mesh that comply with this increased tensile resistance of the material, and this allow reducing the thickness of the reinforcing layers. A series of 12 diagonal compression tests of masonry walls reinforced with G-FRM has been completed in LISG Laboratory, comparing different FRM combinations. The walls were reinforced with three different lime mortar compounds with layer thicknesses of 12, 15 and 30 mm, on the basis of their nominal tensile strengths, and reinforced with three different glass fiber meshes. The performed tests showed that the interpretation of the observed behaviour needs a sound theoretical basis of the experimental setup, avoiding the simple analysis reported in standards and codes. A finite element model of the performed experiments was prepared, and an identification of the observed behaviour was carried out. As a conclusion, the G-FRM compounds were able to increase the load capacity of the walls more than 200% and demonstrated a very high bond with the masonry surface, reducing the need of transversal ties.

Andrea Benedetti
Preliminary Methodology for the Integration of Lean Construction, BIM and Virtual Reality in the Planning Phase of Structural Intervention in Heritage Structures

The main purpose of this article is to describe a proposed methodology to integrate modern construction management tools and procedures such as Lean Construction (LC), Building Information Modeling (BIM), and Virtual Reality (VR) in the planning phase of structural intervention of heritage structures. The proposed methodology that integrates these techniques is referred to as Lean Project Delivery System (LPDS). This paper explains the main principles, tools, techniques, practices and technologies, like VR, laser scanner, and photogrammetry that integrated result in synergy with the design, and planning components of the selection of the structural retrofitting alternatives. The proposed method associates the workflow design, workflow execution, LPDS elements and Management of Heritage Structures (MHS) requirements. The proposed LPDS methodology is applied to the St. Jerome Hall, a sector of the Church of the Nativity, located in Bethlehem, Palestine where the selection of the most feasible structural consolidation technique was required to retrofit this area due to some archaeological excavations. The conclusions drawn from the application of the proposed methodology to this case history may have some biases due to unique constraints in this project related to regional and project specific considerations. However, the paper hopes to contribute by providing an integrated framework for modeling and planning that can improve the state of practice in this area of knowledge.

Xavier Brioso, Claudia Calderón, Rafael Aguilar, Miguel A. Pando

Inspection, Non-destructive and Laboratory Testing

Frontmatter
Enhancement of the Identification of Historical Timber Element’s Local Stiffness Based on Resistance Drilling Measurements

Assessing aged historical timber structures’ residual capacity is challenging. Attempts to relate the results of local non-destructive tests to the timber element’s global behaviour have shown insufficient correlations. This research aims at enhancing the assessment of a historical timber element’s global mechanical behaviour based on local non-destructive testing. The first step, presented in this paper, is the identification of the local stiffness of a timber element based on resistance drilling measurements.An experimental test program was designed for beams in European Oak and is representative for the assessment of mechanical properties of timber elements in compression. This paper discusses the first part of the experimental test program, in which a total of 30 small samples with a cross section of 20 by 20 mm and a height of 60 mm were taken from three different timber elements. The aim is to link the results of resistance drilling measurements to the local timber stiffness. The second part of the experimental test program will investigate how to integrate the local stiffness into a Finite Element model in order to improve the numerical analysis of a timber element’s global mechanical behaviour in compression.The prediction of the timber element’s residual structural capacity using NDT tests contributes to a more accurate assessment of historical timber structures and their preservation.

Nathalie Van Roy, Els Verstrynge, Koenraad Van Balen
Inspection of Seismic Damage and Conservation Conditions in Modern School Buildings in Chile

The present study describes the procedures and results of inspections carried out in public school buildings constructed in Chile between the 40s and 80s. These buildings constitute part of the country’s modern heritage. The aim of the study was to empirically analyze – through documentation, in-situ observation and measurements with non-destructive testing – the state of damage and deterioration of school buildings, taking into account that these buildings continue functioning as before, even surpassing their useful life by more than 30 years, with minimal or no maintenance processes. Further to normal wear, tear and aging of materials, Chile’s frequent exposure to earthquakes has added lesions and structural damages. This study compares the behavior of buildings constructed with reinforced masonry from an early period (from the 40s to 60s) to the modular buildings constructed with industrialized systems and elements from a later period (from the 60s to 80s), considering the country’s seismicity and climatic diversities. In both cases the designs meet standards and regulations for quality and resistance. Pathological processes in structural and enveloping elements were recorded through direct observation. In addition, the instruments used (thermography, metal detector, humidity meter, Hammer test and laser level) enabled further analysis of the building’s constructive features. They account for possible causes of damage, monitor structural resistance conditions and measure constructive durability parameters.

Claudia Torres, Pablo Rojas
Laboratory and In Situ Calibrations of New Flat Jack Method for Assessing Masonry Shear Characteristics

The test methods currently used to assess the shear characteristics of masonry structures does not fit with the execution of in situ tests on existing buildings (especially heritage buildings) because they are usually strongly destructive. Furthermore the method of preparation of the sample causes damages that can reduce the mechanical characteristics of the masonry: for these reasons there are significant doubts about the effective representativeness of the results obtained from these methods. A new in situ testing technique (named FJ-SCT Method) has been developed by the authors based on the use of flat jacks to apply the horizontal load: this allows a great reduction in the impact of the test and therefore it makes the testing technique applicable on existing buildings. A calibration campaign was performed both in laboratory using a special testing frame and in situ (on Italian buildings seriously damaged by the 2012 Emilia earthquake) to evaluate the operability of the defined procedures. This campaign proved the technique to be reliable, the procedures to be efficient and effective and the results to be repeatable. The damages produced to the masonry by this test technique are limited, justified by the level of the results obtained and they can be easily repaired. The analysis of the calibration results, the proposal for the processing of shear strength data and the comparison with reference shear values taken from the Italian codes will be hereafter discussed.

Dario Foppoli, Alessandro Armanasco
Investigation of the Shear-Sliding Behavior of Masonry Through Shove Test: Experimental and Numerical Studies

To assess the shear properties of masonry for existing buildings, the shove test method proposed by ASTM C1531 can be carried out, in which the load required to slide a single brick with respect to the surrounding masonry is measured. To control the vertical stress-state on the tested brick, two flat-jacks can be inserted in mortar bed joints in close proximity of it, thus prescribing a predefined level of compression. Although this test seems straightforward, uncertainties have not been resolved yet regarding the actual vertical compressive stress present on the tested brick and the effect of dilatancy. To gain a better insight into the shear-sliding behavior of masonry during the shove test, both experimental tests and numerical simulations were considered in the current research. To analyze these aspects and to precisely define a testing protocol, the experimental tests were performed in a controlled laboratory environment on a single wythe calcium silicate brick masonry wall. In parallel, numerical analyses were carried out using a simplified micro-modeling strategy, in which every brick was modelled, and the mortar joints were considered as zero-thickness interfaces. A composite interface model was used, including a tension cut-off, a Coulomb friction domain and a compressive cap. For the analyzed case study, the numerical results allowed to gain a better understanding of the aspects influencing the shear-sliding behavior of masonry during the shove test.

Francesca Ferretti, Samira Jafari, Rita Esposito, Jan G. Rots, Claudio Mazzotti
A Proposed Test to Evaluate Efflorescence Potential of Ceramic Blocks

Masonry is susceptible to efflorescence, which in itself is an aesthetic problem, but the condition of efflorescence indicates that water is moving through the masonry in unintended ways and the presence of uncontrolled water can lead to serious issues, including structural problems. In this paper, the results obtained from a proposed test method to evaluate the potential of efflorescence of ceramic blocks are compared to that obtained using the method described in ASTM C67. The proposed method was developed because until 2017 there was no Brazilian Standard to evaluate the efflorescence potential for brick and structural clay tile. The method uses 2 × 2 × 20-cm specimens immersed in 5-cm of distilled water for 5 days in recipients covered with a rubber membrane. The method uses smaller samples than the standard method and has a 5-day instead of 7-day duration. Ceramic blocks from ten manufacturers from different Brazilian regions were used in this study. Results from the standard test method indicated that blocks from three manufacturers were susceptible to efflorescence while the results from the proposed method indicated that the blocks were not susceptible to efflorescence. The discrepancy in results may have been caused by the very small size of the specimens and the large amount of water in the containers used in the proposed method. The amount of soluble salts in the small specimens may not have been enough to detect their presence and the soluble salts in the submerged part of a specimen may have simply dissolved by the water.

Adriana Baptista, Aryane Carneiro, Guilherme Parsekian, Fernando Fonseca
Structural Behaviour of Dry Stack Stone Corbelled Vaults Under Lateral Support Movement

The preservation or restoration of any structural typology requires understanding of the load transfer mechanism under the influence of external actions. Scarce literature on the structural behaviour of existing dry stack stone corbelled arches and vaults has motivated the present study. The objective of the study is to have a better understanding on the failure mechanisms of corbelled vaults under different types of support movement, e.g. translations and rotations, both lateral (inward and outward) and vertical and the in-plane and out-of-plane directions. The current paper examines the in-plane behaviour under relative outward lateral spreading of the support. A test setup is specially fabricated for evaluating these lateral support movements in dry stone corbelled vaults. The prototype of the test model chosen for study is one of the existing entrance vaults of Ta Prohm Temple, Cambodia restricting to the bare arch form, a 2D representation. The angle of repose of a typical vault varies between 45 to 60°. The arch considered here is of 56° of angle of repose. Digital photogrammetric technique has been utilized in the study to capture the deformed geometry, which has proved to be very useful in monitoring the displacements of the rigid blocks. From the study it is concluded that these corbelled arch systems under relative in-plane outward support movement tend to fail by overturning inwards because of the rocking failure being dominant over sliding by virtue of the structural configuration, and available sliding friction.

Pratyusha Naik, Arun Menon
Influence of Geometry of Cylindrical Samples in the Mechanical Characterization of Existing Brickwork

The mechanical characterization of masonry is of paramount importance for the structural assessment of historical constructions against both vertical and horizontal actions. In particular, the compressive strength of masonry is normally regarded as a critical parameter for structural analysis. However, an accurate determination of the mechanical properties of masonry is a difficult task due to the complex and heterogeneous behavior of the material. The mechanical characterization of historical masonry is also hindered by the need to limit damage caused by inspection in culturally valuable buildings.Recent researches and standards point to the possibility of estimating the compressive strength of existing brickwork by testing cylindrical samples of at least 150 mm diameter extracted from the brickwork walls. This work investigates the possibility of carrying out similar tests on smaller diameter cylinders. Using smaller cylinders may allow the extraction of a larger amount of samples and also permit the reduction of the extent of damage caused to the building.This study presents a comparison between compression tests performed on 150 mm and 90 mm diameter cylindrical samples to evaluate the strength and stiffness of masonry consisting of lime mortar and clay bricks. The tests were carried out in the laboratory on samples extracted from masonry walls by using a dry core-drilling procedure and then regularized with high strength mortar caps. The experimental results show the relationship between the different geometries of core samples regarding strength values, failure modes and crack patterns. The study contributes to the application of experimental tests on cylindrical samples as a minor destructive technique to estimate the mechanical parameters of historical brickwork under compression.

Jorge Segura, Luca Pelà, Pere Roca
Estimation of Churches Frequencies Based on Simplified Geometry Parameters

Nowadays, the modal properties of structures can be obtained by experimental methods that are still expensive for professionals who have to deal with the seismic assessment. Additionally, for heritage buildings, due to their complexity, the identification of the modal properties can be challenging and requires of experience on the field. This paper aims to develop a methodology to predict the frequency response of churches based on simplified geometrical parameters. In this context, an extensive literature review was carried out to collect data, aiming to define the principal typologies of churches. Afterwards, a parametric analysis with numerical simulations of the eigenvalue problem was performed to identify which are the main geometrical parameters that influence the dynamic behavior of the churches. The correlations between the natural frequencies and relevant geometrical parameters are illustrated and discussed in order to develop a proposal for the estimation of the natural frequencies of the churches. Churches with single nave and three naves were defined as the two principal types of churches, and six equations were proposed, aiming to estimate the first three natural frequencies for each type of church. Finally, the methodology was validated on real case studies found in literature, in which experimental identification of frequencies was performed. This comparison allowed to evaluate the accuracy of the method to estimate the natural frequencies.

Saulo López, Luis Ramos, Michelangelo Laterza, Paulo B. Lourenço
Experimental Characterization of Mechanical Behaviour of Existing Tabique Walls Under Compressive and Shear Loading

The construction of old buildings made using tabique walls is one of the most relevant examples of vernacular architecture in Portugal. It exists throughout the country and is particularly relevant in the region of Viseu. However, the knowledge about this traditional building technique is still insufficient. On the other hand, survey campaigns carried out, showed an expressive variability of construction techniques associated with the tabique walls. Thus, it’s essential to know the materials applied, their main properties and the way they interconnect. Following an investigation carried out in old buildings (19th century) of Viseu city [1], this paper presents an experimental work for structural characterization of tabique walls, including references to the setup used to perform the lab tests on 4 samples deemed representative such wall types. The main objective was to characterize the mechanical properties of these walls under in-plane compression and shear forces. The obtained results and the main conclusions are presented. This work aims at providing contributions for a better understanding of the structural behavior of tabique walls.

José Padrão, António Arêde, João Miranda Guedes, Jorge Pinto
Estimation of Mortar Compressive Strength Based on Specimens Extracted from Masonry Bed Joints

The article presents the results of the Double Punch Test (DPT) conducted on cement-lime mortar. The tested specimens have dimensions of 5 cm ×  5 cm with a thickness of 12 mm and were obtained from bed joints of clay brick prisms prepared in the laboratory. For DPT purposes, 20 mm diameter steel punches were used. The reference mortar compressive strength was measured on standard specimens (4 cm × 4 cm × 16 cm), and the stress–strain relation was measured on cylinders (5 cm × 10 cm). Based on the reference compressive strength and DPT results, the correlation factor was established. The effect of the capping on the DPT strength was also measured and analyzed. Moreover, an individual FEM model was built and calibrated to simulate the DPT specimen failure mode and load-displacement behaviour. The results of the numerical simulations were compared to laboratory tests.

Dawid Łątka, Szymon Seręga, Piotr Matysek
A XVth Century Diamond Ashlar Façade: The Case Study of Palazzo Raimondi in Cremona

Between 1494 and 1496 Eliseo Raimondi, from a noble Cremonese family, designed and constructed the façade of his house, rebuilt on pre-existing buildings (some of which were demolished). Today, of the original configuration of the building, only the brick walls and the main façade are well preserved, in large part covered with a stone ashlar facing, magnificent simulacrum of a building once celebrated in the chronicles of the XIXth century. Examples of façades in rusticated diamond cut stones that pre-date the construction of Palazzo Raimondi are rare and well-known: Eliseo was influenced by the Venetian and Milanese constructive models used then as a reference for the façade of Palazzo Raimondi. The difficulties in the transport of Botticino marble and its consequent high cost led Eliseo to employ the stones only for the cladding of the façade, which is structured on solid brick masonry built with lime mortar, unlike the rest of the building where bed mortar mixed with earth is widely used. The masonry support was constructed in several steps: Eliseo was well aware of the problems, including those relating to the structural behaviour, that a stone facing would create on walls poorly resistant to shear. The paper will focus on the façade, built on an ashlar construction system, still well preserved nowadays.

Angelo Giuseppe Landi
From Brick to Element: Investigating the Mechanical Properties of Calcium Silicate Masonry

Since the 1980s in the Netherlands, the demand for accelerating the construction process and subsequently reducing the construction costs has led to the replacement of traditional brick masonry with larger masonry units assembled with a thin mortar layer. Accordingly, different masonry unit sizes ranging from traditional bricks (210 × 70 × 100-mm) to larger elements (900 × 650 × 100-mm) have been produced by the calcium silicate industry and widely used for the construction of unreinforced masonry (URM) buildings. To properly assess the performances of URM buildings, numerical and analytical methods require a complete description of the mechanical behavior of masonry at material level. Despite the widespread application of both calcium silicate brick and element masonry, a refined characterization of the mechanical properties of masonry has not received much attention. As a result, an experimental study was conducted at Delft University of Technology for the material characterization of calcium silicate brick and element masonry, with a view to assessments for induced seismicity in Groningen. By using well-designed testing set-ups, the compression, shear and bending properties of calcium silicate specimens were measured, with an aim to understand the strength, stiffness as well as softening post-peak behavior in compression and in shear of both masonry types. This paper provides insight into the nonlinear behavior of the calcium silicate brick and calcium silicate element masonry as a support to the development and validation of numerical and analytical models for the seismic assessment of URM structures.

Samira Jafari, Rita Esposito, Jan G. Rots
Seismic Behavior of Timber-Laced Masonry Structures in the Himalayan Belt

In many areas of high seismicity, one can witness traditional construction systems in brick masonry with timber elements. These traditional timber-reinforced constructions are based on empirical knowledge acquired through the generations in response to the natural hazards encountered. This timber-reinforced construction may be classified in to two categories, one is of timber-framed construction and another is of timber-laced construction. An important and interesting feature of these timber-reinforced masonry construction is their resilience to seismic action. In recent earthquakes (Turkey 1999, Kashmir 2005 and Sikkim 2011) these constructions showed excellent performance in contrast to the modern but unregulated multi-story RC buildings with URM infill. The seismicity of the Himalayan region in the Indian subcontinent is notorious. Several timber-reinforced construction systems have been developed in this region, depending upon the socio-economic-environment conditions; to name a few: Dhajji-Dewari, Taq, Kath-khuni and Ekra. This paper initially presents a comprehensive review of numerical and experimental studies on the traditional timber-framed constructions relevant to the Himalayan region, as there were few studies on the timber-laced masonry constructions a specific case study on Taq system had been carried out to identify critical parameters responsible for their desirable seismic performance.

D. Dhandapany, Arun Menon
Structural Characterization of Quarry Stone in Experimental Testing Using Digital Image Correlation as a Non-destructive Technique

In this research the use of digital image correlation technique (DIC) is applied as a non-destructive monitoring method with the aim to obtain the lineal and non-linear behavior of pink quarry stone similar to those found on masonry historical constructions of the 16th century on the central and northern part of Mexico. Uniaxial compression tests were carried out in order to demonstrate the suitability of the DIC technique to represent the behavior of pink quarry stone in terms of displacements and crack propagation regarding to another monitoring methods such as measurements using LVDT sensors. From the experimental tests it was possible to obtain the mechanical properties of pink quarry stone in terms of stresses, strains, Young’s modulus and Poisson’s ratio. Incongruences during the elastic stage of the compression tests were found in the analysis of quarry stone by DIC technique regarding the traditional sensors due to the brittle behavior of the material. It was possible to demonstrate the capability of the DIC technique to obtain the full-field displacements measurement on the material surface and it has the ability to identify the crack propagation on quarries, which is not possible to obtain using the conventional techniques.

Luis Pérez-Pinedo, Hiram Badillo-Almaráz, José Rodríguez-Rodríguez
Mechanical Characterization of Masonry Typologies in Israel via Flat Jack Tests

During the last decade, the Laboratory of the Department of Civil, Architectural, and Environmental Engineering department at the University of Padova, together with a Spin-Off of the same University, Expin srl, and the consultant engineering company Schaffer & Ronen ltd., carried out more than fifty on site single and double flat jacks on masonry panels of a relevant sample of existing masonry buildings in different historical sites in Israel. Typical Israeli masonry used in historical buildings consists of limestone, calcar (sand) stone, and Basalt stone masonry, with mostly lime based mortar as a binder. Double flat jack tests were employed on two main types of stone walls: single-faced and two-faced stone wall (the most common stone masonry arrangement). From these tests it was possible to obtain the characterization of the mechanical properties of the stone masonry panels tested, belonging to different construction eras and masonry types. Double flat jack tests were mainly carried out following the local state of stress determination via single flat jack. The paper presents the results with a classification of the masonry types mechanical characteristics. This ongoing work, to be complemented with laboratory tests in future stages, may represent a preparatory work for the development of reference characteristic values of the different masonry types of the country, to be included in Israeli technical standards.

Filippo Casarin, Meir Ronen, Yaacov Schaffer, Raffaele Italia, Massimo dalla Benetta, Matthew R. Kyler, Elvis Cescatti
Experimental Characterization of Solid Clay Bricks: Correlations Among Mechanical Properties

Strengthening interventions on existing structures, especially in the case of Architectural Heritage, require an in-depth knowledge of construction techniques, geometry and materials for an optimal design aiming at the minimum intervention approach ideal. Nonetheless, conservative values of material properties, often derived from codes or literature, might hinder the effectiveness of the design approach. Non-Destructive Tests (NDT) and Minor Destructive Tests (MDT) are fundamental tools for the characterization of existing materials with a minimum or no impact. The paper presents an experimental study that investigated the possibility of defining empirical correlations among the main mechanical properties of solid clay bricks, which are one of the most common unit for masonry load-bearing members. Extruded bricks, typical of modern constructions, and soft-mud bricks, resembling historical units, were tested to cover for the ample variability of solid clay bricks. The examined mechanical properties were compressive, bending, splitting and pull-off strengths. The dataset of mechanical properties allowed calibrating linear correlations expressing one property as a function of another, thus giving the possibility of estimating a set of strengths based on the results of the MDT pull-off test. An innovative aspect consisted in performing the four tests on the same unit, so that the calibrated linear correlations are based on punctual data instead of average values. A practical application can consist in the on-site execution of pull-off tests, which are minor destructive and can be easily performed on a wall surface, for estimating the compressive strength of clay units.

Enrico Garbin, Matteo Panizza, Maria Rosa Valluzzi
Internal Geometrical Characterization of Stone Masonry Walls Using Electrical Resistivity Tomography

Recent research using Electrical Resistivity Tomography (ERT) in the built heritage have generated high expectation regarding the determination of qualitative parameters of the structural elements in historic masonry. This paper presents a work focused in the application of ERT on masonry elements with an adapted resistivimeter, commonly used for geotechnical works. The main objective was to determine the viability of using the resistivity equipment in masonry elements through the calibration process and the analysis of the electrical response to obtain its internal geometrical characteristics for a future implementation of the technique in historical buildings. Dipole-dipole configuration was used in its manual form on three masonry elements situated in two different locations of the Aguascalientes city. The results revealed that the adapted resistivity equipment has a high potential to obtain internal geometric data in masonry elements.

Raudel Padilla Ceniceros, Jesús Pacheco Martínez, Martín Hernández Marín, José Ángel Ortiz Lozano, Edith Estefanía Orenday Tapia
Study on Stone Cultural Heritage’s Structural Stability Management – with a Focus on Cheomseongdae

The National Research Institute of Cultural Heritages (NRICH) has conducted comprehensive researches on stone cultural heritage’s structural stability management, including an earthquake simulation experiments and deterioration assessment on Cheomseongdae, an ancient astronomical observatory facility, from 2009 to 2013. This paper presents the results of this research, compares the analysis results with the damage caused by the earthquake with a magnitude of 5.8 (on Richter scale), which occurred in 2016, and offers a basic guideline for the comprehensive structural stability management, repair and reinforcement of the stone cultural heritage.

Jo Sang-Sun, Kim Derk-Moon, Kim Dong-Soo
The Application of Sonic Testing on Double-Leaf Historical Portuguese Masonry to Obtain Morphology and Mechanical Properties

In order to perform a conservation or repair intervention of a historic building, knowledge of the mechanical properties of the historical materials and building components is essential. Obtaining these properties should be performed inflicting as little damage to the historical fabric as possible. Methods to do so are defined as non-destructive test methods (NDT). The paper investigates the use of sonic testing (NDT) on historical masonry. Nine double-leaf wallets were constructed according to a traditional Portuguese building method, using light ochre schist and mortar made of local soil and water. Three wall variations were present concerning plaster finishing and grouting strengthening. A testing procedure was developed for sonic testing to determine the morphology and mechanical properties. The wallets were also classified according to the Masonry Quality Index method (MQI), which can be used to identify strength and stiffness parameters of masonry by visual inspection without testing procedures. The method was used in conjunction with the sonic testing. In addition, compression tests with loading and reloading cycles were performed. Young’s moduli could be compared to those obtained by the MQI method and the sonic testing. The results revealed that the Young’s moduli of the sonic testing had a good agreement with those of the compression testing, although the former presented an overestimation due to testing on the outer leaves. The Poisson’s ratio presented inconsistent results due to a high scatter on experimental values. The sonic testing also showed a good indication of weak zones in the masonry. The MQI method produced less accurate results in terms of stiffness estimation but has potential and should be investigated further.

Hendrik Van Eldere, Luís F. Ramos, Els Verstrynge, Naveen Shetty, Koen Van Balen, Carlos E. Barroso, Daniel V. Oliveira
Inspection and Analysis of Ancient Monastery of “São Romão de Neiva”, Portugal

The monastery of São Romão de Neiva is an ancient building located in the north of Portugal, in the district of Viana do Castelo and it is considered to be of national interest by the Portuguese Institute of Monuments (DGPC). Due to its importance, an inspection to identify damages and their causes was performed on this building. The inspection and diagnosis included a historical, geometrical and defects survey, and mechanical and physical characterization of the masonry stone. Non-destructive tests on the structural elements such as GPR and sonic tests were also carried out to assess the internal morphology of the stone masonry walls and estimate the quality and modulus of elasticity, respectively. Qualitative assessment of masonry walls using the MQI (Masonry Quality index) was also carried out. Finally, by means of a visual inspection of the structure, the assessment of the damages and pathologies on the structural elements was performed. This work focus on the most important experimental results and some recommendations to apply them on a structural analysis.

Jahdiel Villafuerte, Johann Arias, Cindy Calbimonte, Jorge Scaff, Graça Vasconcelos, Francisco Fernandes
Connections of Roof-Diaphragm to Perimeter Walls in Historic Masonry Buildings

Traditional seismic retrofit of historical masonry buildings is mainly aimed at inhibiting local mechanisms and at engaging the whole building into a box-like structural behavior through either perimeter ties, or floor and roof diaphragms. When the adoption of “minimally impairing” perimeter ties is unviable, floor and roof diaphragms are usually adopted. The effectiveness of such interventions requires careful design and detailing of their connections to the perimeter walls, which enable shear flow transfer from the out-of-plane loaded masonry walls to the diaphragms and from the diaphragms to the seismic resistant walls. Focus is made on the assessment of the structural performance of the connections of roof diaphragms to the perimeter walls. Stud connectors are investigated and a possible technical solution improving the connection capacity is presented. In the case of historic masonries, theoretical and numerical prediction of the connection capacity may be unviable because of the substantial heterogeneity of the masonry at local level. Accordingly, experimental in-situ tests may be the only viable solution to assess the connection capacity, thereby providing evidence of the feasibility of the intervention and providing useful reference design values to be used by design professionals. A specific experimental test is presented for the in-field measurement of the connection capacity, and experimental results are critically illustrated. A purpose designed testing frame is proposed, which allows mimicking the actual load and restrain conditions of the connections in a real application.

Alessandra Marini, Ezio Giuriani, Andrea Belleri, Stefania Cominelli, Chiara Passoni
Experimental Characterization of the Deterioration of Masonry Materials Due to Wet and Dry and Salt Crystallization Cycles

Considering that by 2050 the effects of climate change around the world will cause extreme conditions for the built environment, particularly for historic masonry constructions, it is important to understand in more detail the effect of different environmental conditions on the durability of masonry of stone. In this work, an experimental characterization of the deterioration process of the stone masonry submitted to wet and dry and salt crystallization cycles is presented and the results are discussed. For this, the effect of these conditions on the mechanical behavior under compression of stone masonry was evaluated. For the tests, samples composed of two and three units respectively were adopted. The experimental campaign was divided into two phases: (1) water absorption cycles by capillarity (clean water and water with a concentration of 3% and 10% sodium chloride) and drying cycles in samples at 60 °C. Sodium chloride was selected because it is often found in old buildings subject to cycles of humidity. For this, a special setup was designed to perform the immersion and drying of several samples at the same time, controlled by moisture and temperature sensors; (2) mechanical characterization of material and masonry assemblages under uniaxial compression tests after the cycles. From these experimental tests it was possible to evaluate the effect of the exposure conditions on the mechanical properties of the materials and masonry assemblages.

Sandra Graus, Graça Vasconcelos, Carlos Palha
Façades of an Iconic Building in Sao Paulo, Brazil: Assessment for Restoration Design

Regarded as an iconic symbol of modern architecture in Sao Paulo - Brazil, the Copan Building is a meaningful example. On recent years this building started to show some quality unconformities due to its age and deterioration of construction materials. The building’s massive façades are mainly covered by white and gray mosaic tiles, partially including the remarkable brises-soleil. Due to their large extension and lack of conservation plans, the façades had not received preventive maintenance and cleaning care for decades. Over the last few years, pathological signs showed up, like peeling of the ceramic tiling due to the lack of movement joints and deterioration of the plaster mortar, amongst other factors This study presents the applied methods for documentation of building construction data, such as materials and construction techniques, original and restoration projects, aiming to develop a continuous and systematic process of organization and knowledge production.

Fabiana Oliveira, Valéria Bonfim
Mechanical Characterization of Adobe Constructions Using Flat Jack Tests: Case Study of the Virgen de la Asunción de Sacsamarca Church

This article presents the results of an experimental campaign using the flat jack technique in an adobe church called “Virgen de la Asuncion” located in Sacsamarca, Peru. The main mechanical properties of this construction were determined using the single and the double flat jack tests. The flat jack test is considered as minor destructive test (MDT), which is appropriate for historical buildings due to the temporary and easily repairable damage generated. Single and double flat jack tests were carried out on the north and east facades of the church. The single flat jack test allowed the estimation of the local compressive stress levels through the continuous monitoring of the state of strain. The double flat jack test allowed determining the local stress-strain behavior in each facade of the church. The mechanical properties obtained in this research are similar to values obtained by other authors for historical adobe buildings using different methods.

Kiyoshi Tacas, Mauricio Gonzales, Rafael Aguilar
An Automatic Algorithm for the Execution and Elaboration of Sonic Pulse Velocity Tests in Direct and Tomographic Arrangements

The use of non-destructive tests (NDT) in the investigation phase of existing constructions plays a relevant role for the quick evaluation of the masonry quality during the survey phase and for the extension of results obtained from more punctual minor-destructive (MDT) or destructive tests (DT). As confirmed by last earthquakes occurred in the centre of Italy in 2016 and by previous phenomena already well described in literature, a weak masonry (e.g., with internal voids and poor core) is prone to early collapse even under medium-magnitude seismic events. In this framework, objective, quick and user-friendly tools aimed at the mechanical surveying of buildings may help in recognizing critical situations, e.g., vulnerable structural elements, poor masonry requiring consolidation, etc. Sonic pulse velocity method demonstrated to be effective in detection of different conditions inside masonry elements; nevertheless, the procedure is quite time-consuming, especially in case of tomographic test configuration. The paper describes an automatic algorithm, which significantly decrease the execution and elaboration time of sonic tests. It provides results directly on-site, so that the quality of the acquired signals can be checked in real-time. The comparison of those outcomes with the manual detection clearly shows the higher reliability and the lower dispersion of data. This tool also operates in the tomographic arrangement, thanks to an elaboration tool designed on purpose. The effectiveness of the new system is demonstrated by examples of application on masonry assemblages.

Elvis Cescatti, Luca Rosato, Maria Rosa Valluzzi, Filippo Casarin
Flexural Tests on Consolidation Effects on Stone

This paper describes laboratory verification tests for determining the efficiency of various consolidation treatments on Czech quartz sandstone. It compares material data acquired using circular discs and rectangular plates. While the application of rectangular plates enables the testing not only of strength but also of other material characteristics – e.g., moisture, water saturation or temperature dilation parameters – on identical specimens, the biaxial bending easily applicable only for mechanical testing gives data better describing material unisotropy. At the same time the influence of two different modes of consolidation agent application was taken into account – namely, capillary rise and brushing, which is typically used in conservation practice. Furthermore, cylinders and cubes were treated with the consolidation agents in order to determine their depth penetration ability. After maturing, the cylinders and cubes were cut into thin slices after being tested with ultrasonic measurements to determine differences in wave velocity across the specimen along the depth profile of the treated bulk. The experimental data were compared to ultrasonic tests as well as theoretically computed strength, for which a FEM model was used in the case of biaxial bending. Differences in consolidation effects are also discussed in relation to the chemical characteristics of the applied consolidation agents which were based in the case under study on ethylsilicate compounds and thus produced various amount of acting SiO2 gel inside the porous system. Both techniques were found to be useful in the testing of consolidation agents being developed before their introduction into conservation practice.

Luisa Natalia Peña Leal, Miloš Drdácký, Zuzana Slížková
Timber Roof Structure Rehabilitation of Municipal Council and Jail Building

This study aimed at the inspection and repair of the Municipal Council and Jail timber roof to guide the heritage of building restoration. This is a historical building of Colonial Brazil period, located at XV of November square, in Florianópolis city. The project was held on three different steps: (i) identification of wood species that composes the original roof structure, (ii) inspection of the roof structure in loco and (iii) structural roof re-design, with another commercial wood (Mezilaurus itauba Meisn.). The species identification was carried by the analysis of the organoleptic and anatomical properties of 5 samples. Microscope slides were manufactured for anatomical analysis with light microscope. Moreover, in loco inspection, percussion, scarification and non-destructive techniques were used. The moisture content of the inspected structural timber elements was evaluated with a resistive hygrometer. Eleven principal structural elements, organized in 36 sections, were inspected. The identification of the structural elements was made according to a previous survey of pathological manifestation. The sections were classified as: Not Damaged, Partially Damaged and Damaged. Within the 11 elements analyzed, 5 presented at least one damaged section, another 5 partially damaged and only 1 presented integrity in all sections. In detriment of the identified damages, the restrength of all wall plates and hip rafters was determined, as well as the timber recognized as being freijó specie (Cordia goeldiana), not suitable for the structural usage, and the elements that are able to present any type of damage or degradation, compromising the structure at the restoration moment.

Rodrigo Terezo, Ângela do Valle, João de D. Medeiros, Douglas Vanzella, Eduardo Schneid, Romeu Lucena
A Novel Approach to the in situ Compression Testing of Stone Masonry Walls

Masonry structures constitutes the urban core of several cities throughout the world, justifying the interest for the development of new testing techniques, capable of characterizing their main mechanical properties. The present paper approaches the in situ testing of stone masonry walls, describing the steps that led to the definition of a new compression test set-up. Said set-up was devised to be a modular and adaptable system, capable of being used in different types of walls, with different textures and unit types. Being self-balanced, the hereby-proposed scheme doesn´t introduce any new external loads into the whole building producing, at the same time, a uniform compression load. Throughout the paper, the peculiarities of masonry structures are mentioned, in order to justify some of the considerations taken into account in the development of the system. The results of an experimental campaign performed in an abandoned building in Oporto (Portugal) are presented, showing the outputs that can be extrapolated from the procedure, namely the characterization of the cyclic behavior of the walls and its deformability parameters.

Rui Silva, António Arêde, Patrício Rocha, Celeste Almeida
Quantitative Estimation Method for Rebar Corrosion Degree of RC Structures

It is well-known that not only cracks, which are caused by the expansion of the product due to the corrosion of rebar, occur in concrete, but also a performance of the ultimate strength decreases according to the decrease of cross section in rebar. Moreover, the cavitation and spalling of the covered concrete also occur and then the remarkable decline of durability and ultimate strength will be caused by the accelerated progress of degradation due to the exposure of re-bar to atmosphere. Above all, it seems to be very important that the situation of corrosion of rebar in concrete structure is investigated. The method to investigate the situation most correctly in the present is the way by which chipping and observation by watch at covered concrete. However, it’s difficult realistically to judge the re-bar situation in a wide range in existing structure by a chipping investigation, and the reinforced corrosion situation is often judged partially. In this paper, nondestructive evaluation of corrosion of rebar in reinforce concrete is investigated. Employing the thermal on concrete surface by the thermography, heat stored in reinforcing rebar due to electro-magnetic heating is applied to estimate qualitatively the corrosion degree.

Hideki Oshita, Ichimei Sou
Static and Dynamic Testing on a Brick Masonry Pavilion Vault of the San Francesco di Paola Convent, in Roccabernarda (KR), Italy

The work describes the static and dynamic experimentation carried out on a pavilion vault, reconstructed in brick masonry with traditional techniques in an old partially collapsed convent. The vault was instrumented by using special bricks in some points, equipped with strain gauges inside them, in order to measure the stress state under static and dynamic conditions. The static tests were carried out through vertical loads at the extrados, uniformly distributed over the entire plan or, asymmetrically, only on a quarter of the vault plan. The dynamic tests were carried out by inducing the vibration to the entire convent through explosive charges, placed at a short distance and calibrated in such a way as to induce an excitation that is as similar as possible to an impulsive earthquake motion of low intensity. The results have shown the good behavior of this structural element under dynamic conditions, even if the level of excitation was rather low. Moreover, a first calibration of this type of experimental investigation was made, useful also for other type of tests (e.g. out-of-plane).

Michele Candela, Pasquale Lopetrone, Antonio Borri, Sergio Lagomarsino
Analysis and Monitoring Methodology of the Wooden Structure - Historic Military Architecture

The paper presents a building of the former officers’ mess in Southern Poland. Paper is focus on the current condition of the building, mainly on the external walls made by timber framing, undergoing more than 130 years of climate impacts and their consequences. The paper presents the results of a comprehensive analysis of the state of construction of the object. Static and strength calculations of the structure were made, including original dimensions and actual (effective) dimensions (result of resistographic tests). These activities allowed for reliable and comprehensive assessment of the technical condition of the officers’ mess building.

Dariusz Bajno, Łukasz Bednarz, Agnieszka Grzybowska, Rafał Tews
Restoration of Reinforced Lime Concrete Sunshades of a Century Old Heritage Building in New Delhi, India

The Rashtrapati Bhavan, the official residence of the President of India, is a Grade-I heritage structure. The reinforced concrete cantilever sunshades in this building are at a height of about 20 m above ground and span about two-kilometer along the perimeter of the building. In the late 1990s, some sunshades experienced corrosion and were repaired using polymer modified cementitious mortar. However, these repaired sunshades and others are now exhibiting severe corrosion and concrete spalling- posing a serious falling hazard for visitors and inhabitants. This paper presents a systematic evaluation of the concrete used in the sunshades and the assessment of corrosion and structural conditions of the sunshades. Concrete was found to be made of non-hydraulic lime and carbonated - indicating high probability of corrosion. Hence, about 200 sunshade locations from various parts of the building were visually and non-destructively assessed and distress-maps were developed. For this, an instrumented hammer was used on 15 test points per sunshade panel area (of about 1 × 2 m size). Based on the impulse waveform patterns, estimated strengths and visible damage, the panels were classified into distress levels of negligible, moderate and severe. About 58 to 86% of the sunshades were found to be severely damaged. Also, service level load test was conducted (upto a load of 75 kN) at a representative location, to assess the effect of corrosion on the load-deflection behaviour of the cantilever. The possible repair strategy and challenges associated with adopting conventional methods, are discussed in the paper.

Dyana Joseline, Hareesh Haridasan, Sundar Rathnarajan, Divya Rani, Thangadurai Raja, Radhakrishna G. Pillai, Amlan K. Sengupta, Arun Menon
Mechanical Behaviour of Metal Anchors in Historic Brick Masonry: An Experimental Approach

Many historic buildings degrade and partially collapse due to the action of time and to lack of maintenance; only their façades remain. Their consolidation and reuse have fundamental importance to preserve the architectural heritage. In several cases, these buildings are made of brick masonry and interventions demand using metallic structures. The connection between the masonry, which has already lost its initial strength capacity, and the proposed structure must be carefully analysed to avoid structural damages to the building. The aim of the current study is to investigate the mechanical behaviour of metal anchors used to connect the walls to the metallic structure, whether provisionally or permanently, for shoring purposes or for building repairs, strengthening or rehabilitation ones. An experimental campaign was carried out; it included pull-out tests applied to two types of adhesive (chemical and grout) and mechanical anchors in brick masonry built in laboratory using hydraulic lime mortar and low mechanical strength bricks. Tensile force results were compared to predictive analytical formulas available in the literature. The current research contributes to the selection of the most efficient structural bond in terms of adhesion in historic brick masonry, thus contributing to the preservation of the historical, artistic and cultural heritage.

Rosana Muñoz, Paulo B. Lourenço
Analyzing the Historical Earth Construction for Achieving Earthquake Safety

Earthen wall has low thermal conductivity and very good energy storage capacity, it can contribute to minimizing the global energy consumption. Although one third of the global population lives in earthen houses, construction technology is still not advanced in this field. Earthen buildings when damaged or collapsed, pose a higher threat to human health than other buildings, through inhalation of soil-dust which can be fatal.Construction techniques of earthen buildings should be steered to use the industrialized technology. The industrial technology to produce earthen buildings should be incorporated into the scope of higher education in architecture and civil engineering. The main factors for improving the technology are durability and earthquake-resistance of the buildings.This article will discuss some researches on earthquake safety conducted at Istanbul Technical University; outline the findings of laboratory and seismic table tests on load bearing wall structure and compare the results in the light of the methods on historical earthen buildings.

Bilge Işik

Numerical Modeling and Structural Analysis

Frontmatter
Structural Assessment of Old Masonry Dams

Mexico has an important number of masonry dams that were constructed from 17th century to 19th century and continue to operate until now. They have never been analyzed and their failure or collapse cause economic and human losses - including the historical value. Additionally, some towns have been established downstream of many dams, increasing the risk of a disaster in case of failure of the dam; therein lies the importance of the structural stability. The selected dam was analyzed by traditional methods, where the resultant of all forces acting on the dam must lie in the third middle of the base and the hypothesis of no tension material is assumed. Sometimes, this approach is too conservative and mostly does not reflect the real structural behavior of the dam. Based on the obtained results by traditional methods, the structural assessment of ancient masonry dams was studied under the rigid body spring model (RBSM), considering non-lineal behavior and was made a parametric study to identify the mechanical properties that have more influence on the structural behavior. Parametric analyses show that the tensile strength of the masonry is the property of greater influence on the structural behavior

Laura Robles, Fernando Peña
Finite Element Modeling of Cross-Wall Ties in Multi-wythe Walls

Ties have been inserted directly across multi-wythe walls to join one exterior wythe of the wall to the other with the intent of improving the compressive strength of the wall and to maintain in-plane connection between the wythes. Experimental work has shown that such ties have little, if any, effect on compressive strength, but that the ties can restrain lateral expansion (Poisson effects) locally. We created a variety of 3-D finite element models to simulate the behaviour of these traditional transverse ties. A simplified micro-model provided insight regarding stress transfer between the different elements of the system, and suggested that the traditional distribution of ties is inefficient. Macro-models were used to investigate the role of a single tie in resisting different loading conditions and results showed that minimal benefits are gained in terms of vertical stresses and deformations under vertical and lateral loading conditions. The most significant benefit of the transverse tie was the reduction in local out-of-plane deformation. A subsequent benefit was the reduction of vertical stresses that are produced by local rotation of the wythes. The use of different materials in the external wythes produced similar results to eccentric loading and both situations cause the tie to bend in a double curvature shape: the benefits of the transverse tie in both cases were again minimal. As most ties are inserted in walls already carrying their service loads, the effects observed only develop from additional loads applied to the wall.

Mahmoud El-Rayes, Nigel Shrive
Numerical Modeling of Crack Propagation in Masonry Structures

Before implementing permanent monitoring systems or reinforcements on a historic structure with identified cracks, it is imperative to understand how cracking patterns may have originated and how they affect the current state of the structure. This work outlines a mixed numerical approach for understanding the causes of masonry cracking and the resulting effects on structural performance. By combining Finite Element Modeling and Distinct Element Modeling, the structural response of an undamaged version of a building can be calculated for a combination of loading scenarios (including dead load, lateral loads, and differential settlement). The results of the loading scenarios can be compared to the current state of the building for a probabilistic understanding of potential causes. This combined approach was used to examine the large cracks running longitudinally on the subterranean walls of the Florence Baptistery. Various combinations of loading scenarios were run for an undamaged model of the wall. Additionally, various geometries of the joints were simulated to understand how the accuracy of input geometries can affect simulation results.

Rebecca Napolitano, Michael Hess, Rachel Coe-Scharff, Branko Glisic
Numerical Modelling of Hypothetical Quincha Walls on Samaipata Rock

The Samaipata or, more specifically, the Fuerte de Samaipata is a pre-Spanish archaeological site in Bolivia (since 1998 on the UNESCO World Heritage List). The main feature of the site is a natural rock which served as wak’a (a sacred place). Despite the strong dominance of the Incaic character, the site is multicultural and its origins date back to around 300 AD. Its current appearance is the result of at least 1200 years of cultural developments. At the end of the 20th century, the site was extensively studied and documented by German scholars. Recently, due to the threat of progressing erosion, a new project has been launched by a Polish team, whose main objective is to document the entire site with 3D laser scanning.The most distinguishing feature of the site is a complex arrangement of figural and geometrical petroglyphs, canals, and water reservoirs, as well as niches or entire rooms. The elements that attract less scholarly attention are long rows of small circular holes drilled into the rock. They are commonly associated with the vertical posts of quincha walls. However, there are doubts about the ability of the quincha wall to resist the extremely strong winds that can act on the top of the rock. Computer simulation is the proposed measure to clarify these reservations. The 3D model is based on the 3D laser scanning results, while FEM is used for solving structural analysis problems. Meteorological data and strength parameters of local wood species will provide supplementary data.

Jacek Kościuk, Janusz Kogut
Simulation of Distinct Element Joint Stiffness of the Historical Masonry Structure Model by Micro-Tremor Measurement

Historical masonry structures are generally vulnerable to unsettlement and earthquake ground motion. It is desirable to evaluate their static and dynamic mechanisms by a numerical method to preserve and reinforce them. We studied a reduced-scale corbel arch model of the part of the Bayon temple in Angkor, Cambodia. Two dimensional DEM (Discrete Element Method) was used to simulate the experimental displacement at the top due to the enforced unsettlement. Friction angle and contact parameters estimated in preliminary experiments were adapted in DEM simulation. For the static unsettlement simulation DEM worked well; however, the simulation for the fundamental frequency and the mode shape in micro-tremor simulation with the same parameters depicted the much higher fundamental frequency. We reassessed a friction angle, joint normal and joint shear stiffness and found that the constraint on joint stiffness imposed by the static experiment was not sensitive enough for the dynamic case and search of the parameters in broad extents were necessary. The reevaluated contact parameters for the static experiment were effective for the dynamic experiment as well.

Yu Yamashita, Toshiro Maeda
Numerical Analysis of Settlement-Induced Damage to a Masonry Church Nave Wall

Differential soil settlements can induce structural damage to heritage buildings, causing not only economic but also cultural value losses. In 1963, the Saint Jacob’s church in Leuven was permanently closed to the public because of severe settlement-induced damage caused by insufficient bearing capacity of the foundation. Currently, the church is stabilized using a temporary shoring system. This work aims at implementing a practical modelling approach to predict damage on church nave walls subjected to differential settlements. For that purpose, a finite element model of the Saint Jacob’s church nave was generated and validated through on-site monitoring data including levelling, damage survey and laser scanning. The model takes into account the non-linear behavior of the masonry by means of continuum smeared cracking. The paper introduces two approaches to model the settlement on the structure. One of them consists in the direct application of vertical displacements underneath the structure according to the deformation profile measured on-site. In the second approach, interfaces with different stiffness are placed at the base allowing the structure to deform under its self-weight. In addition, the effect of the settlement profile type in the damage level is analyzed.

Leidy Bejarano-Urrego, Els Verstrynge, Anastasios Drougkas, Giorgia Giardina, Maarten Bassier, Maarten Vergauwen, Koen Van Balen
Influence of the Thickness of Vaults and Buttresses in the Structural Response of Mexican Colonial Temples

To evaluate the participation of the particular structural elements in the structural response of typical Mexican colonial temples, numerical parametric analyses were performed. From previous studies, the influence of the vaults, towers and buttresses in the out-of-plane behavior has been demonstrate. With the main objective to evaluated the influenced of the thickness of the vault and buttresses, some nonlinear analysis in a typical Mexican colonial temple model were realized. Numerical models were made with different thicknesses of vaults and buttresses. The first results show for gravity actions, that the vault is a fundamental element to reduce the perpendicular displacements to the plane of the façade, but also induces a lateral pushing on the longitudinal walls that can become critical. When thinner is the thickness of the vault, most significantly are this kind of displacements, mainly in the façade. The presence of the buttresses are fundamental to increase the strength of the longitudinal walls under the effect of the pushing forces due by the vaults.

Marcos M. Chávez, Fernando Peña
Simulation of Masonry Arch Bridges Using 3D Discrete Element Modeling

The analysis of masonry arch bridges is still a challenge for engineers due to its complex and nonlinear behavior. In practice, structural behavior of masonry arch bridges is studied by following relatively simple methods, e.g. limit analysis, which does not require a significant number of parameters. Two-dimensional nonlinear finite element models are also common in the literature; however, these do not reflect the full structural response, since they neglect the out-of-plane actions. These models neglect spandrel walls, 3D point load effect and skew arches, among other effects. The objective of this study is to present a methodology that can simulate three-dimensional masonry arch bridge behavior comprehensively and can include various possible failure mechanisms. Discrete element method (DEM), which is a discontinuum approach, is used to understand the influence of essential structural components, such as the arch barrel, spandrel wall and back-fill material on several masonry arch structures. The masonry units are modeled using discrete blocks and back-fill material is generated as a continuum mesh, based on the plasticity theory. Load carrying capacity and related collapse mechanisms are investigated through a set of parametric studies on the mechanical properties of back-fill material. Out-of-plane spandrel wall failures were further explored by taking advantage of a discontinuous approach. The results indicated that soil characteristics (elastic modulus, internal friction angle and cohesion) have remarkable influence on the behavior and load carrying capacity of the masonry arch bridges. Further, the analyses are also validated with previously published experimental work as well as an existing historical bridge.

Bora Pulatsu, Ece Erdogmus, Paulo B. Lourenço
Finite Element Modelling and Limit Analysis of Fastnet Lighthouse Under Impulsive Ocean Waves

Being exposed to strong ocean waves for more than a century, the Fastnet lighthouse is assessed for its structural response to the intense lateral loading. The Finite Element Method (FEM) was implemented for the structural analysis using the commercial software Abaqus. The lighthouse is built with large and meticulously dovetailed granite blocks which make it a very unique structural system. Three different finite element model configurations were tested, modelling the lighthouse as continuous homogeneous (elastic and nonlinear), and as discontinuous with contact interfaces between each course of blocks allowing uplift and sliding. The applicability and efficacy of these approaches is discussed. The impact load of the wave was applied as a time-history sequence, assuming that the wave breaks just in front of the structure surface corresponding to the least favourable scenario. Different intensities and heights were considered for the impact load. Finally, the FEM results are also compared with the results of the limit analysis method which calculates the minimum intensity of lateral static load that is necessary for causing uplift and overturning of rigid bodies. This comparison demonstrates the usefulness of the limit analysis method as a tool for quick preliminary assessment of the lateral load bearing capacity of this particular structural typology. This work is part of the STORMLAMP project (STructural behaviour Of Rock Mounted Lighthouses At the Mercy of imPulsive waves) funded by the UK Engineering and Physical Sciences Research Council, which is gratefully acknowledged.

Athanasios Pappas, Dina D’Ayala, Alessandro Antonini, Alison Raby
19th Century Iron Dome Structures in the Vienna Hofburg. An Insight into the Simplified Structural Assessment of that Period and Its Evaluation Using Modern Engineering Software

The use of iron load-bearing systems in all types of building structures (e.g. infrastructure, commercial buildings, sacred buildings, prestigious buildings) gained enormous importance during the urban development and expansion of Vienna’s city center in the second half of the 19th century. A recent case study on the iron dome structures in what is known as the Michaelertrakt of the Vienna Hofburg provided the results of a detailed geometrical survey using high-tech instruments as well as archive documents containing a simplified structural analysis and dimensioning of the cross sections of the cupola as annex to the proposal for construction in terms of weight and costs. The geometrical survey data served as a basis for subsequent structural modeling within a commercial structural engineering software. Taken together, the data allow both an examination of the simplified structural assessment methods used at the end of the 19th century and an assessment of the present status of the historic dome structures with further information for their maintenance. The design for only vertical loading was in line with the theory of J. W. Schwedler. The extensions from A. Föppl were referenced for the design of the bracing system subjected to wind loads. The restrictions of the hand calculation formerly used made it necessary to make several simplifications, such as setting of additional hinges with consequences for the bending moments and superposition of different load cases. Finally, the consequences for neglecting the compatibility of displacements within this type of shell structure could now be evaluated and validated.

Georg Hochreiner, Gudrun Styhler-Aydın
Finite Element Thrust Line Analysis (FETLA) Based Sensitivity Analysis of the Thrust Line of a Masonry Dome with Tension Rings

Ancient masonry dome structures were designed by master builders using simple geometrical rules, which are similar to the graphical thrust line approach. Most of these masonry domes were designed as a series of arches. Such simplification fails to incorporate the effects of hoop forces. As a result, almost every ancient masonry dome happens to exist with vertical cracks due to hoop tension. Tension rings are used to enhance the capacity of these masonry domes by imparting hoop tension resistance. Design of tension rings requires the assessment of the forces in dome masonry and tension rings. The graphical thrust line based analysis fails to incorporate the effect of hoop forces on the dome stability and hence it cannot be used for analysing domes with tension rings. On the other hand, discretisation-based methods of analysis, like the finite element method, requires precise information on material properties of the masonry dome for its stability study. In this paper, the sensitivity of the analysis results – to the mechanical properties of the dome and ring materials adopted – is studied using the Finite Element Thrust Line Analysis (FETLA). It is found that ring-strengthened masonry domes can be analysed using this analysis method, without the need for an accurate assessment of mechanical properties of the masonry.

Siddhartha Ghosh, Mahesh N. Varma, Gabriele Milani
Experimental and Numerical Analysis of Historical Aseismic Construction System

Timber frames have been used in masonry buildings since a very early age to enhance their seismic performance. Several construction techniques have been conceived over the centuries for this purpose; among them, the so-called casa baraccata is relatively unknown and yet relevant as it has been employed since the 17th century in Calabria, a region in Southern Italy historically characterized by frequent and powerful seismic sequences. After a particularly devastating earthquake nearly destroyed the two cities of Reggio Calabria and Messina in late December 1908, Calabrian engineer Pasquale Frezza patented an anti-seismic construction technique that further improved the casa baraccata by embedding fictile tubules in its masonry walls. Those are hollow clay bricks, employed since the Roman Empire in buildings all around the Mediterranean Sea, that allow for a reduction of participating mass of the structure, hence helping its resistance to dynamic loads. This paper investigates the seismic effectiveness of the construction technique patented by Frezza. First, a diagonal compressive test is carried out on a specimen wall built according to Frezza’s recommendations, with the aim of evaluating its shear strength. Then, a numerical analysis is performed in the commercial FE software Abaqus to simulate the experimental test and validate its results. The shear strength measured from the experimental test is higher than the usual values for ordinary and historical masonry walls, and the numerical results are able to grasp the overall behavior of the wall as resulting from the diagonal compressive test.

Simone Tiberti, Carmelo Scuro, Rosamaria Codispoti, Renato S. Olivito, Gabriele Milani
Tracking of Localized Cracks in the Finite Element Analysis of Masonry Walls

Macro-models are a common choice for the numerical analysis of large-scale masonry structures. Despite their efficiency in terms of pre-processing and computational cost, these strategies often result in a poor representation of cracking, not properly localized and biased by the finite element mesh orientation. This work presents a remedy to the previous shortcomings through the enhancement of the standard smeared crack approach with a crack-tracking algorithm. The smeared crack approach reduces the computational cost and ensures a computationally efficient analysis of small- and large-scale structures. The crack-tracking algorithm aids the localized representation of cracking and improves the mesh-objectivity of the numerical results. A novel crack-tracking algorithm is introduced allowing the modelling of intersecting and multi-directional cracks, which commonly occur in masonry structures under cyclic loading. At constitutive level, a simple and explicit algorithmic formulation is presented, which includes the description of irreversible deformations into an orthotropic continuum damage model. The proposed numerical model is used to simulate the response of an experimentally tested masonry wall under shear cyclic loading.

Savvas Saloustros, Luca Pelà, Miguel Cervera, Pere Roca
Structural Behaviour of Gopurams in South Indian Temples

The multi-storied masonry “Gopuram” or the ceremonial entrance gateway, an ubiquitous structure in a South Indian temple, was a feature introduced circa 14th c. AD in order to confer architectural status to structurally insignificant ancient shrines. The gopurams of the Meenakshi Temple in Madurai (1600 AD), the Ranganathaswamy Temple in Srirangam (17th c. AD) and the Ekambareswar Temple in Kancheepuram (16th c. AD), 52 m, 72 m and 59 m tall, respectively, are representative of the highly evolved Dravidian temple architecture. The current research is an attempt to understand the structural behaviour of the gopuram with a focus on a centuries-old incomplete structure in the town of Thiruvellarai in Tamil Nadu. The paper presents outcomes of detailed field and laboratory investigations on the sub-structure, the superstructure and structural materials of the gopuram, that provide insight into the structural configuration of the gopuram. It then examines the structural response to gravity and lateral forces, through non-linear finite element models of the structure. One of the significant aspects studied is the role of the core masonry in the structural response of the multi-leaf masonry structure of the gopuram. In addition the role of floor diaphragms in the structural stability of the gopuram is investigated. The outcome of the study is expected to provide important insights to the reasons for structural distress and collapse of such structures, particularly the Vijayagopuram at Srikalahasti in Andhra Pradesh in South India that collapsed in May 2010.

Satyadhrik Sharma, Arun Menon, Hareesh Haridasan, Shibu Samson
Assessment of the Structural Damage on the Former San Agustin Temple Using Numerical Modelling

This paper presents the assessment of the structural damage of the former temple of San Agustin, located on the Historic Centre of Zacatecas, one of the UNESCO World Heritage sites in Mexico. The original masonry construction which dates from 1575 was restored and re-consecrated in 1782 has suffered several damages after the second half of the XIX century. In 1948 work to recover and restore the existing damage was performed and it was concluded by 1969. However, in recent years, new signs of damage have appeared on different sections of the historical construction; for example, the north wall presents about 2 percent of inclination with respect to the vertical and one of the central arcs is completely deformed showing an ellipse-like shape. The numerical modelling performed on this study is achieved by means of a 3D finite element analysis of the present spatial configuration of the front part of the building since this is the most damaged part of the construction. Natural periods of the principal mass participating modes obtained on the numerical model are in well agreement with the periods measured by environment noise tests. The FEM model represents adequately the damage present on the vault of the main nave. Finally, recommendations about the improvements that can be applied on the actual FEM model are given based on the results obtained in order to give a better assessment of the vulnerability of the building and to formulate recommendations for its conservation.

Hiram Badillo-Almaraz, Agustín Orduña-Bustamante, Octavio Quintero-Sifuentes, Justo Orozco-Rojas
Three-Dimensional Numerical Modelling of Historical Masonry Structures Affected by Tunnelling-Induced Settlements

This paper focuses on the interaction between tunnelling and historical masonry structures. These latter often characterise the centre of many cities and should be preserved from possible tunnelling-induced damage. In recent years the Authors of this contribution have adopted an advanced numerical approach to investigate this issue in the two-dimensional domain, schematising the block masonry structure as a homogenised anisotropic medium [1, 2]. This study extends the approach to three-dimensional conditions. The behaviour of masonry is described by a modified version of the Jointed Rock model, named hereafter as Jointed Masonry model, an anisotropic elastic perfectly plastic constitutive model implemented in the code Plaxis 3D. This model takes into account the directional properties of the medium, identifying the orientation of three planes along which the Mohr-Coulomb yield criterion applies. The paper first briefly describes how the original Jointed Rock model was modified to more realistically account for some specific features of the nonlinear mechanics of masonry. This is followed by the 3D analysis of a tunnelling-structure interaction problem, aimed at highlighting the key features of the proposed masonry model.

Angelo Amorosi, Daniela Boldini, Gianmarco de Felice, Wanda Guglielmina Lasciarrea, Marialaura Malena
Analysis of the Dome of India’s Presidential Residence

The Rashtrapati Bhavan or the Presidential Residence on Raisina Hill in New Delhi is an iconic structure designed by Sir Edwin Lutyens in the Indo-Saracenic style and completed in 1929. The structure is made of brick masonry, sandstone cladding, lime and reinforced cement concrete. This paper gives an insight into the investigative process that was followed to determine the causative mechanism of the observed structural distress in the inner dome of the central double-dome of the Rashtrapati Bhavan. During the visual scrutiny of the building, a crack of significant dimension in the north-eastern niche of the domed hall and a small crack in the diametrically opposite niche were detected. In order to evaluate the severity of the observed cracks, a systematic and holistic approach that comprised of historical and geometric surveys, assessment of the sub-structure morphology and the use of relevant non-destructive and minor destructive tests on the superstructure was adopted. The findings from the above-mentioned sources, served as valuable input for the finite element model of the structure, that was developed using DIANA. The non-linear gravity and pushover analyses conducted on the model confirmed the speculation made on the basis of the visual and geometrical assessment, that the opening of the stairwell in the vicinity of the affected niche presents an inherent weakness at the drum of the dome. The paper describes the in-situ tests, relevant structural features for the numerical analysis, modelling aspects and the results from the analysis.

Chrysl A. Aranha, Arun Menon, Amlan K. Sengupta
Dynamic Behaviour Analysis of an English-Bond Masonry Prototype Using a Homogenized-Based Discrete FE Model

Full Finite Element strategies (the so called micro- and macro- models) are still nowadays the most used ones for the study of large masonry structures. However, macro-modelling still lacks accuracy at a meso-scale in terms of damage localization. On the other hand, micro-models are rather computational demanding and require a cumbersome modelling stage. Thus, homogenization-based frameworks give considerable advantages. Moreover, the study of English bond masonry appears to be disregarded in comparison to the running bond one. On this behalf, a two-step procedure based on homogenization theory is herein presented for the dynamic study of English-bond masonry structures. The presented homogenization approach uses two models at a micro-scale: (i) a plane-stress FE discretization within the concepts of Kirchhoff-Love plate theory; and (ii) a three-dimensional micro-model accounting with the mortar joint discontinuity existent at the thickness direction. Bricks are meshed with elastic elements with linear interpolation and joints are reduced to interfaces which obey to the nonlinear behaviour described by the so-called combined cracking-shearing-crushing model. The procedure allows obtaining homogenized bending moment/torque curvature relationships to be used at a structural level within a FE discrete model implemented in a commercial code. The model relies in rigid quadrilateral elements interconnected by homogenized bending/torque nonlinear springs. The framework is used to study the dynamic behaviour of an English-bond masonry wall benchmark. A macroscopic strategy is also considered to enrich the study. The numerical results are compared with the experimental data and a good agreement has been found.

Luís Carlos Silva, Gabriele Milani, Paulo B. Lourenço
On the Stability Analysis of a Geometrically Complex Leaning Historic Structure

In this paper, a simple approach for the stability analysis of the southwest leaning ruined tower of the Caerphilly castle (Wales, UK) is discussed. To account for the actual complex geometry of the tower, a mesh generation procedure recently proposed by the authors is used to automatically transform the 3D point cloud surveyed from the tower into a 3D solid finite element model. A simple approach based on nonlinear static analyses is pursued to evaluate the stability condition of the tower. Geometric nonlinearity and nonlinear plastic-damaging behavior of masonry are supposed. Results show that the proposed approach could serve as a simplified method to evaluate the stability of leaning historic structures considering their actual geometry.

Antonio Maria D’Altri, Gabriele Milani, Stefano de Miranda, Giovanni Castellazzi, Vasilis Sarhosis
Seismic Vulnerability Assessment of Sri Kedarnath Temple in India

Sri Kedarnath temple, located in the Central Seismic Gap in Himalayan region in India is an ancient Hindu temple, which represents India’s rich history of culture, religion, science and technology. The temple structure is composed of concentric enclosures with the innermost sanctum sanctorum roofed with corbelled dome and tapering tower. Multi-leaf, dry stack stone masonry constructions with strong irregularities in plan and elevation along with the uncertainties related to the material and geometric characteristics of the temple pose various challenges to systematic seismic verification. Role of diaphragms to resist the lateral load is another area of concern. In addition, the selection of a unique seismic analysis strategy was a challenge. On the other hand, the effectiveness of non-linear dynamic analysis depends largely on selection of ground motion records, apart from the challenge of high computational demand. The current study addresses these issues by analyzing the outcomes of a comprehensive parametric study. Non-linear static and dynamic analyses have been performed on the 3D numerical model by considering the uncertainties in material parameters such as Elastic modulus of stone, Friction angle and compressive strength of stone joints. Synthetic ground motion records with PGA varying from 0.2 g to 1.0 g were used for TH analysis. The study reveals that the tapering tower above the sanctum is susceptible to collapse due to sliding shear failure.

Tamali Bhowmik, G. Mahesh Reddy, Arun Menon, S. T. G. Raghukanth
Simple Homogenized Numerical Model for the Analysis of Multi-leaf Masonry Walls

A simple numerical model for the analysis of multi-leaf walls is discussed. These are featured rather frequently in masonry buildings across Europe, and are characterized by a low resistance to out-of-plane actions, which often causes the partial or total collapse of the structure. A 2D FE mesh is created directly from the sketch of each wythe, which is later exploited for deriving the 2D homogenized failure surface of the single layers. A weighted average is operated among the homogenized stresses to obtain the failure surface of the multi-leaf wall. Then, the out-of-plane bending moment for each layer is evaluated by assuming a constant distribution of the homogenized stress over the thickness. The overall out-of-plane failure surface in terms of bending moments is then obtained for the whole wall, assuming each layer to behave separately in bending. The model is applied on two walls displaying distinct layouts of units: one presents a running bond masonry consisting of tuff blocks, the other is constituted by randomly-assembled stones. The results show an overall higher resistance of the randomly-assembled wall with respect to the running bond one, both for the in- and out-of-plane behaviors.

Simone Tiberti, Gabriele Milani
Diagonal Compressive Tests on Double Wythe Brick Ancient Masonry Panels Unreinforced and Reinforced with Innovative Cement Based Materials: Advanced FE Simulations

The paper presents the numerical results obtained testing a series of masonry panels. The experimental campaign is characterized by some in-situ diagonal compressive tests performed on both unreinforced and reinforced walls with overall dimensions equal to 1000 × 1000 × 300 mm3. The present study is intended to analyze from a numerical point of view, the behavior of ancient double wythe brick masonry panels subjected to in-plane diagonal compressive loads. To this scope, two different types of strengthening have been applied on the tested walls: (i) TRM (Textile Reinforced Mortar) materials symmetrically applied on the panel and (ii) an asymmetric reinforcement made with a layer of TRM materials and with a NSM (Near Surface Mounted) technique on the other. A series of numerical analyses have been carried out by means of a sophisticated heterogeneous micro-modeling technique, by means of which bricks, mortar joints and the strengthening systems have been modeled separately. In detail, a Concrete Damage Plasticity model, already implemented into the FE software Abaqus, has been used to describe the possible crushing and cracking failures of the constituent materials. Finally, the numerical outcomes have been comparatively assessed with respect to the experimental results and the damage patterns obtained at the end of the tests, showing a promising agreement.

Elisa Bertolesi, Gabriele Milani
Nonlinear Analysis of Masonry Walls Based on a Damage-Plastic Formulation

Masonry structures subjected to seismic actions exhibit a complex nonlinear behaviour. To obtain a comprehensive representation of all the occurring nonlinear mechanisms, constitutive models including damage and plasticity are required and nonlinear dynamic analyses are considered the most reliable. Hence, models considering both degrading effects and hereditary nature of restoring forces are needed. Different approaches can be adopted, relying on microscopic, macroscopic, multi-scale and macroelement formulations. The latter are often adopted for real cases, mainly to reduce the computational burden of the analyses. The proposed macroelement accounts for typical flexural and shear in-plane failure mechanisms via two flexural hinges and a shear link, arranged in series with an elastic beam. The hysteretic behaviour is reproduced by a smooth model, in which the introduction of a damage function describes both strength and stiffness degradation effects. The model is used to perform comparisons with experimental results on masonry walls, with the aim of validating the numerical procedure and its capabilities to describe nonlinear masonry response.

Domenico Liberatore, Daniela Addessi, Marialuigia Sangirardi
Nonlinear Parametric Static Analysis of Rubble Stone Masonry Walls in Lisbon

Unreinforced masonry construction is predominant in many urban areas world-wide. Many of these constructions are vulnerable to earthquakes, which are the main cause of damage and loss of cultural heritage. Thus, seismic assessment should be provided in a reliable way by using proper mechanical parameters and an appropriate modeling approach. This paper focus on the numerical study of the in-plane behavior of rubble stone masonry walls with air lime mortar, which is a typical material for old masonry buildings in Lisbon. The first part of the paper is focused on the performance on nonlinear numerical static analysis in order to calibrate the static cyclic experimental tests carried out within the scope of a research project. In the second part, the calibrated models were used to carry out parametric analysis varying the geometrical parameter in terms of ratio h/l and axial load. The modelling approach was executed using software based on the finite element method, DIANA. This parametric assessment is a starting point for further analysis for the entire building with the aim to evaluate efficiently the influence of some input parameters. Regarding the obtained results, the good match between experimental and numerical results was obtained in terms of strength and ductility capacity, as well as in terms of stiffness and failure mode. Results obtained for parametric analysis are presented and discussed.

Maria Madalena Ponte, Jelena Milosevic, Rita Bento
Case Study: Assessment of the Load-Carrying Capacity of Multi-span Masonry Ancient Roman Arch Bridge Situated in “Campana”, Near L’Aquila City (IT)

The “Campana” Roman bridge is a masonry type structure located near L’Aquila in a small village seriously damaged by the catastrophic earthquake that struck the city of L’Aquila on the 6th of April 2009. This bridge is a strategic access point for the village of Campana both for the common use and for the heavy trucks involved in the construction activities due to seismic event. This ancient bridge was built in order to carry smaller load than current ones. The Campana village Major asked for performing the assessment of the bridge real carrying capacity. The structure is a multi-span arch bridge with 6 arches with a total length of 33 m. The evaluation process is based on CNR guidelines “DT 213/2015” in agreement with the current Italian Technical Code DM 14.01.2008, starting with the experimental testing program in order to get information about the geometric dimensions and the masonries’ mechanical parameters. Two different analysis methods were used in the carrying capacity analysis: (1) Computational limit analysis methods (also known as ‘plastic’ or ‘mechanism’ methods) based on the Heyman hypothesis; (2) Finite element methods “FEM” with 3d FE model discretized with “bricks” elements. The results of the two methods were compared and the “AF” Adequacy Factor was defined. Seismic analysis has also been included in the study with the aim of evaluating the bridge structural behavior under dynamic actions.

Lorenzo Fanale, Dante Galeota, Antonio Pietrucci
Bearing Capacity of Masonry Walls in Churches by Means of a Probabilistic Assessment

The nonlinear computational modeling of the enclosure masonry walls in historical churches was combined with stochastic simulation techniques. The approach is interdisciplinary and shows the possibility of utilization of efficient advanced numerical tools and techniques for analysis of historical structures. The numerical results confirmed sufficient load bearing capacity of the analyzed masonry walls, and validated the structure sense of medieval architects and manual skills of local bricklayers.

Pavel Kuklik, Evi Susanti, Martin Valek, Drahomír Novak, Radomrr Pukl
Square Cross Vaults on Spreading Supports

This paper investigates the static of masonry square cross vaults on spreading supports through the limit analysis approach adopting a rigid no-tension constitutive model with no sliding. Compatible three-dimensional mechanisms are considered and a rigorous application of thrust line analysis is adopted, in order to evaluate vaulted structure capacity in terms of collapse displacement and associated thrust. For a better understanding of the behaviour of the square cross vault under large displacements, the related case of the elliptical arch on spreading supports is first analysed. The effect of the main geometric parameters and the different possible failure mechanisms are examined and discussed.

Claudio Intrigila, Nicola Antonio Nodargi, Paolo Bisegna
Effects of Degrading Mechanisms on Masonry Dynamic Response

A nonlocal damage-plastic model, accounting for the main nonlinear mechanisms characterizing masonry mechanical behavior, is introduced in a finite element framework and used to analyze the out-of-plane response of a tuff masonry wall. A simple structural scheme is considered where the wall is completely restrained at the base and free at the top. First, the wall response is numerically studied under monotonic and cyclic quasi-static conditions, then the exploration is extended to dynamic field. Base sinusoidal accelerations with increasing amplitudes and fixed frequency are assigned and the numerical responses are compared with experimental outcomes of shaking table tests. Finally, with the aim of fully exploring the effects of the degrading mechanisms on the wall resistance capacity, the response to earthquake records is investigated.

Daniela Addessi, Cristina Gatta, Enrico Cappelli, Fabrizio Vestroni
Structural Evaluation and Preliminary Analysis of the St. Jerome Hall of the Church of the Nativity in Bethlehem

The St. Jerome Hall (SJH) located within the Church of the Nativity complex in Bethlehem, Palestine, is a stone masonry building originally built circa the 4th Century. Excavations associated to an archaeological project inside the SJH has exposed structural and foundation elements creating concerns of potentially inadequate structural and foundation performance. This paper summarizes the results of an in-situ study aimed at assessing the structural and foundation condition considering the archaeological-related excavations. The structural assessment involved a detailed laser scanning survey, visual inspections, IR thermography and a wide variety of nondestructive testing (surface wave analysis and operational modal analysis). Nondestructive testing (NDT) allowed for the evaluation of mechanical responses of different structural elements as well as identification of damage. A 3D finite element (FE) model was then used to evaluate the current level of loading at the base of the columns and walls, as well as at the ceiling influenced by the current excavated condition of the hall. Numerical results showed that the current stresses in walls and columns are lower that the estimated strength; however, retrofitting should be considered in one of the columns to avoid compromising the stability of the structural system.

E. Mauricio Gonzales, Miguel A. Pando, Matthew Whelan, Dante Fratta, Luis F. Ramos, Rafael Aguilar
Structural Assessment of Masonry Arches Using Admissible Geometrical Domains

Following Méry’s thrust line approach, this paper presents an alternative method to define the structural safety of masonry arches, based on admissible geometrical domains. These are implemented in a parametric model built on the reciprocal diagrams of graphic statics. The application to a case study – a semi-circular masonry arch loaded by a central point load – helps drawing a comparison with the classical geometric safety factor as defined by Jacques Heyman. The model is also used to evaluate the impact of geometrical as well as resistance hypotheses on the structural safety level. Analyses first confirm that stereotomy only slightly influences the load bearing capacity of the arch. They also validate the common use of an infinite compressive strength for arches’ constitutive material, since considering a typical value of 10 MPa reduces structural performances by less than 2%. Finally, a methodology using admissible geometrical domains is suggested to get insights on the robustness of masonry arches.

Aurélie Deschuyteneer, Jean-François Rondeaux, Denis Zastavni
Rotational Stiffness of Connections in a Historical Steel Railway Bridge

Traditionally, bridges were solved with steel trusses designed under certain assumptions such as the members being loaded only with axial forces. This assumption is only true if the connections allow the rotation between elements, which in reality is not the case. There are always certain forces transmitted depending on the stiffness of the connection. The following work is intended to determine the rotational stiffness in the connections of a historical steel railway bridge. Different configurations of connections are modeled using component based finite element method (CBFEM) to obtain the real value of the stiffness in the joints. As a result of this analysis, a linear correlation between the value of the rotational stiffness and the number of rivets in the connections is observed. Similarly, there is a linear correlation with the stiffness of the element that is connected in the joint. These results can help to provide an estimate of the rotational stiffness to be considered in a more realistic approach for the assessment of historical railway bridges.

Oscar Minor, Pavel Ryjáček
Lower Bound Limit Analysis of Masonry Vaults Under General Load Conditions

Here the lower-bound Theorem of Limit Analysis is applied to historic masonry vaults modeled as continuous no-tension bodies where singular stress fields can take place. To this aim, by following the line traced by Heyman [1], a unilateral membrane entirely contained into the thickness of the vault is searched. According to the approach in [2], the problem is reduced to a second order partial differential equation relating the shape function of the membrane and the Airy function associated to the equilibrium stress field. The employ of a suitable numerical procedure together with the formulation of a suitable constrained optimization problem allow us for finding solutions for vaults of general shapes and in presence of arbitrary loads. Moreover, the optimization procedure allows for exploring the entire spectrum of the load bearing capacity of the vault. The effectiveness of the proposed approach is discussed for the representative case of a barrel vault, for which the Geometric Factor of Safety (GFS) under the self-weight and the seismic capacity are studied.

Aguinaldo Fraddosio, Nicola Lepore, Mario Daniele Piccioni
Seismic Modelling of a Masonry Monument Including the Interaction of the Vaults, Longitudinal Walls and Soil

The efficient preservation of masonry monuments presents several challenges given that they are characterized by much larger uncertainties than ordinary buildings and conventional analysis tools may fail in providing a reliable characterization of their structural behavior. A complete understanding of the structural behavior of masonry monuments requires integration of historical, topographical, structural, and geotechnical information. From 2010, an interdisciplinary committee has been established to study the Cathedral of Modena, a masterpiece of Romanesque architecture in Italy. Great effort has been devoted to the assessment of the structural health of the Cathedral, revealing that the vaults are the most vulnerable components, and that the dynamic response may be significantly affected by differential soil properties at the supports. The Discrete Element Method provides a useful numerical tool to assess the dynamic behavior of masonry buildings, though previous work has been primarily focused on the structural response with less attention devoted to soil-structure interaction. In this study, a simplified modeling technique is employed to account for soil structure interaction within the DEM framework. More specifically, a specific cross section of the Cathedral, characterized by different soil properties at the supports and the absence of tie-rods, is studied. The results indicate the importance of the soil effects on the structural response.

Simonetta Baraccani, Michele Palermo, Tomaso Trombetti, Matthew DeJong
Non-linear Modelling of a Geomesh-Reinforced Earthen Wall Subjected to Dynamic Loading

Earthen structures externally reinforced with geogrid mesh are becoming a viable alternative for improving the seismic vulnerability of adobe dwellings. The ductile properties of the geogrid provide the necessary deformability to the overall structure so that it may resist a moderate earthquake with certain damage and prevent loss of life. This practice has been studied thoroughly, on an experimental basis, in countries like Peru, but an adequate numerical model that simulates the combined cyclic and non-linear behavior of the adobe and the geogrid reinforcement is still a work in progress. This research aims to improve a previous model of a geomesh-reinforced adobe wall where the geogrid was idealized as a linear-elastic material with an equivalent initial elastic modulus. Now, the new constitutive law for the geogrid reproduces a non-linear elasto-plastic stress-strain relationship which aims to simulate the hysteretic cycles of a real cyclic pushover test of an geomesh-reinforced adobe wall. Lastly, the calibrated numerical model is subjected to dynamic base loadings with the aim of simulating earthquakes of varying magnitudes. These results will be useful for future studies to evaluate the seismic performance of reinforced earthen structures.

Hugo Portugal, Nicola Tarque
Structural Analysis and Damage Assessment of a Historical Masonry Palace – A Case Study

The paper presents a case study of a historical masonry palace built in 1856 in Timisoara, Romania. The building has been recently evaluated, due to a series of damages that appeared during renovation work, also due to the age of the building. In order to evaluate the current state of the building, non-destructive evaluation techniques have been used. In the first part of the paper, a full 3D linear analysis was performed, in order to determine the structural performance under horizontal loads. Then, in the second part, was performed a finite element analysis, on the areas of the building with visible damages, in order to determine the best retrofitting solutions. The numerical simulations have provided the most vulnerable areas of the building and have given a general picture for the damage evaluation, also have provided useful hints for future structural monitoring.

Eva Partene, Marius Mosoarca, Valeriu Stoian

Vulnerability and Risk Analysis Regarding Natural and Man-made

Frontmatter
Seismic Vulnerability and Risk Assessment of Historic Constructions: The Case of Masonry and Adobe Churches in Italy and Chile

Nowadays, disasters in seismic-prone areas such as Italy and Chile, continue to cause dramatic human and economic consequences and affecting, among others, very ancient and historical churches, due to their high seismic vulnerability and probably due to the lack of risk management plans for the conservation of cultural property. This paper focuses on rapid seismic risk assessment by applying two simplified methods, based on expert judgement and observed damage, in old masonry churches, which aim to identify the most vulnerable elements and correlated threats that would act as site effects under the seismic action, for establishing intervention priority lists and for planning preventive conservation projects. The case studies are: the church of Sant’Agostino, built in stone masonry and located in Matera, an area with moderate seismicity in southern Italy; the church of San Francisco de Chiu Chiu, built in adobe and located in Calama, an area with average seismicity in the Andean northern Chile; and the church of San Francisco Barón, built in adobe and brick masonry, and located in Valparaíso, an area with high seismicity on the central coast of Chile.

Daniela Díaz Fuentes, Michelangelo Laterza, Michele D’Amato
Investigating Exposure in Historical Scenarios: How People Behave in Fires, Earthquakes and Floods

In case of a disaster, the individuals’ safety depends on interactions between buildings vulnerability, related post-event damages and environmental conditions, human reaction to hazardous situations. Such interferences are critical in historical scenarios, because of particular environment features (e.g.: high buildings vulnerabilities; urban layout which is not designed to face actual emergency; individuals’ familiarity with architectural spaces, especially for tourists). Current risk assessment methods are limited to define exposure in terms of population’s presence in the scenario, but analysis should consider human behaviors in emergency, and especially during the evacuation process. Simulation models for evaluating evacuation motion have been recently developed to this aim, and so to evaluate the effectiveness of risk-reduction strategies. Nevertheless, models development and validation should be supported by experimental data to effectively represent the “human factor” in critical conditions. Hence, this paper combines previous literature results and real-life emergency analyses (performed on videotapes database from all over the World), by focusing on three main natural disasters recurrent for historical scenarios: fires, earthquakes and flood. Behavioral analyses try to define significant man-environment interactions from a qualitative and quantitative point of view. Results show how noticed behaviors can be distinguished in common ones and peculiar ones (referring to a specific disaster). Quantitative analyses referring to motion quantities evidence differences between the considered emergencies and underline the importance to adopt specific model inputs for each simulated disaster.

Gabriele Bernardini, Enrico Quagliarini, Marco D’Orazio
Flooding Pedestrians’ Evacuation in Historical Urban Scenario: A Tool for Risk Assessment Including Human Behaviors

In the future, safety in historical city centers will be significantly affected by climate change-related disasters, such as floods. Risk assessment in these scenarios requires the combination of a series of factors: possible events characterization; urban layout configuration, its influence on flooding spreading and induced environmental modification; human factor, especially during first emergency phases. Historic urban scenario features (e.g.: compact urban fabrics; position near floodplains; possible inefficient early warning systems) additionally increase individuals’ risks. According to a “behavioral design” approach, developing flood evacuation simulation tools would help safety designers in assessing population’s exposure and then in suggesting emergency strategies to help citizens during such hazardous phases. This paper proposes a flooding evacuation simulation tool, which jointly represents the individuals’ evacuation motion towards safe areas, and the floodwaters spreading in the urban scenario. In particular, the simulator is founded on previous literature results concerning emergency behaviors and motion quantities (e.g.: evacuation speed as function of floodwaters flow) and adopts an agent-based model architecture. A part of the historic city center of Senigallia, an Italian city that suffered a significant flood in 2014, is chosen as application case-study to show tool capabilities. Results outline risk levels for individuals, and evidence critical points (in the urban space and during the time) for man-floodwaters-environment interactions (e.g.: being swept away by floodwaters). By evaluating probable evacuees’ choices in different scenarios, the tool is proposed to check the effectiveness of solutions for reducing evacuation process risks (e.g.: emergency planning; architectural elements development; interventions for floodwaters collection also in urban scenarios).

Gabriele Bernardini, Matteo Postacchini, Enrico Quagliarini, Marco D’Orazio, Maurizio Brocchini
Sacral Buildings in Slovenia – Seismic Risk Assessment Through Simplified Methodologies

In this paper seismic vulnerability of sacral buildings in seismic prone areas is discussed. In Slovenia there are more than 2900 sacral buildings, for which there is no database of their current condition or vulnerability. On the sample of 64 Slovenian religious buildings (different architectural styles) the use of different simple methods for seismic risk assessment of sacral architecture is demonstrated. The emphasize is on quick and simple methods, which on the basis of the basic data of the asset can provide seismic risk assessment that will serve mainly to identify the most critical buildings. For this purpose, methods of Lourenço (2005) and Lagomarsino (2004) were used. The results of different methods are compared and advantages and disadvantages of each method are discussed. Following the analysis on sample of 64 buildings it may be concluded that the percentage of buildings at risk in Slovenia may vary between 44% and 89% depending on the method used. Method relying on γ3 index provide the most conservative results, while the method with γ1 index provide very optimistic results in comparison to the results of macroseismic methodology provided by RISK-UE. It is also shown that some of conceptually completely different methodologies may provide comparable results. Comparison with the results from non-linear analysis on sample of 15 buildings according to EC8-3 provisions shows that simplified methodology with γ3 index on average provide the most consistent results.

Anton Štampfl, Vlatko Bosiljkov
Seismic Vulnerability Assessment of Unreinforced Masonry Churches in Central Chile

In the central region of Chile, the unreinforced masonry (URM) churches underwent extensive structural damage during the 2010 Maule earthquake (Mw 8.8), highlighting the importance of implementing seismic risk reduction plans. These religious buildings are characterized by profound typological and constructive peculiarities, originated by the combination of the local build culture with European architectural revivalisms(i.e., Neo-Baroque, Neo-Classic, Neo-Renaissance and Neo-Gothic)during the Spanish domination (1536–1818). The uniqueness of this heritage and the seismic risk of the Chilean territory lead to the need to define a systematic method to assess the seismic vulnerability of the Chilean URM churches. In this paper, some results of an in-depth investigation on a representative stock of churches are reported. The investigation was based on a database implementation with geometrical, constructive, and structural characteristics of 40 URM churches in the Metropolitan Region of Chile. A preliminary qualitative assessment of the seismic capacity of these churches is provided using a survey of geometric indices. Than specific damages observed after the 2010 earthquake have been related to the recurrent failure mechanisms of masonry structures, taking into account 21 local mechanisms involving the macro-elements of the churches. The average level of damage suffered by each church was calculated through the global damage index and a histogram of damage levels frequencies has been arranged. These results are preliminar suitable probabilistic tools to support seismic risk reduction plans.

Nuria Chiara Palazzi, Luisa Rovero, Ugo Tonietti, Juan Carlos de la Llera, Cristian Sandoval
Seismic Assessment of the Palace of Priors in Perugia

The seismic assessment of historical structures necessitates considering conservation and safety objectives as well as the possible presence of cultural heritage assets. To this end, this paper emphasises the results of a seismic evaluation procedure carried out by the authors on an illustrative case of study, the Palace of Priors in Perugia, that in addition to being one of the most important local governor buildings built, during the High Middle Ages, by Italian communes of Central Italy, it is characterized by the presence of a lot of artistic assets as well. Within this context, strong emphasis was placed on the seismic risk assessment of the structure carried out with reference to the Italian guidelines for heritage protection and conservation. More specifically, the paper investigates and critically discusses the seismic response of the building by using 3 different types of evaluation: territorial level analysis (LV1), local level analysis (LV2) and global level analysis (LV3).

Giulio Castori, Romina Sisti, Antonio Borri, Marco Corradi, Alessandro De Maria
Seismic Vulnerability Scenarios for Timisoara, Romania

Romania is an European country with two major seismic zones, Vrancea and Banat. Timisoara is one of the biggest cities in Romania, located in Banat seismic area, characterized by shallow earthquakes, with depths between 2 and 20 km and important vertical forces. In the historical area of Timisoara there were classified different types of structures, using the HAZUS method (HAZUS 1999). Seismic vulnerability analysis was done using different methodologies, Vulnerability Index, Tremuri, Vulnus and the Romanian methodology according to code P100-3/2013 in order to assess the behavior of historical buildings. Based on the results obtained after applying the three methodologies, there will be further made fragility curves for buildings located in the 3 historic zones of Timisoara city. In particular the probability to have in-plane or out-of-plane damages obtained by Vulnus is correlated with the results of the nonlinear analysis made with Tremuri software considering different limit state. Subsequently, considering the typical earthquakes in Banat area, it was possible to define the seismic response for three buildings, as a preview of seismic response of the city and the impact of the earthquake. This type of analysis was made for the most frequent earthquake type. This article makes plain the first step in estimating the hazard seismic scenarios for the evaluation of the losses in terms of human life and financial problems, offering the support for further prevention and intervention strategies.

Iasmina Apostol, Marius Mosoarca, Nicola Chieffo, Eugen Onescu
Bartolomeo Ammannati’s Fountain: Comparisons Between Different Numerical Models

This paper focuses on the evaluation of the seismic performance of Venus, the central sculpture of Bartolomeo Ammannati’s Juno Fountain. A 3D geometrical model based on a laser scanner survey has been obtained and employed to build the finite element model (FEM) used in the analyses. The seismic response of the sculpture has been checked by performing different dynamic analyses, applying a spectrum-compatible ground motion and using different computer codes and assumptions. The considered numerical models differ from each other regarding the material behavior (linear and non-linear) and the connection between the statue and its base. Information useful for the seismic assessment of the artefact has been provided, thanks to the different models used.

Barbara Pintucchi, Tommaso Rotunno, Marco Tanganelli, Stefania Viti
Assessment of the Seismic Vulnerability of an Unreinforced Masonry Structure Based on Discrete-Macro Dynamic Analyses

UnReinforced Masonry (URM) structures experience severe damage due to in-plane and out-of-plane mechanisms when subjected to seismic actions. The assessment of the seismic vulnerability of URM generally requires complex analytical procedures consisting of the application of sophisticated numerical models. However, these models may request a high computational effort or may present an over-simplified scheme, mainly when the out-of-plane mechanisms are neglected. In this sense, a 3-dimensional macro-element model is here used for a preliminary assessment of the seismic vulnerability of a URM prototype characterized by an out-of-plane collapse mechanism. In this paper, the seismic vulnerability of this type of constructions is investigated by means of fragility functions in accordance with specific damage states and a given seismic input. The structural safety assessment was conducted by means of time history analyses with a limited computational effort. In addition, the evaluation of the limit states is here performed by means of an alternative approach named as Capacity Dominium based on the application of nonlinear static analyses.

César Chácara, Paulo B. Lourenço, Francesco Cannizzaro, Bartolomeo Pantò, Ivo Caliò
Vulnerability Assessment of Monumental Masonry Structures Including Uncertainty

Existing heritage structures are frequently composed of diverse masonry typologies, corresponding either to various structural members (e.g. arches, walls, piers) or to additions constructed in different eras. The identification of the material properties of the different masonry typologies is usually demanding due to the high cost of the necessary specialized in-situ experimental testing procedures and to the restrictions posed by the cultural value of historical buildings. This lack of information underlines the importance of probabilistic studies considering the uncertainties connected with the evaluation of the material properties. Such activities become essential in studies dealing with the conservation of built cultural heritage against hazardous events, such as earthquakes. This work investigates the seismic vulnerability assessment of large monumental structures with complex geometry. The church of Santa Maria del Mar in Barcelona is considered as a case study, and a representative macro-element of the bay structure is studied against in-plane horizontal loading through pushover analysis. A Monte Carlo simulation is used to estimate the effect of the uncertainties on the material properties, which are considered as random variables. The developed fragility curves express the safety level and the damage expected on the structure for different seismic hazard scenarios.

Savvas Saloustros, Luca Pelà, Francesca Romana Contrafatto, Pere Roca, Ioannis Petromichelakis
Seismic Vulnerability of Old Italian Railway Stations

Most of Italian railway stations date back to the second half of the 19th century, when the railway network was created. Although originally belonging to different companies and in spite of some modifications occurred over the years, most of these stations are masonry buildings conceived according to similar standards, with typical dimensions and morphology mostly depending on the expected traffic of passengers and goods. The common structural features of these buildings allow grouping them into building typologies, characterized by a similar structural response. This is relevant for the assessment of the seismic vulnerability of these structures, whose damage or collapse could lead to critical consequences, due to the potentially high number of victims and to the risk of interruption of critical lines. Nonlinear global analyses by equivalent-frame macroelement modelling and linear kinematic analyses of possible local failure modes have been used to assess the seismic response of building prototypes representative of the most common architectural typologies. A logic tree approach was used to consider uncertainties in mechanical properties, geometry and construction details for the derivation of fragility curves for different limit states.

Andrea Penna, Alessandro Galasco, Marco Tondelli, Maria Rota, Guido Magenes
Defining Behavioral Pattern for Historical Buildings in Izmir, Turkey

Izmir is one of the major western Anatolian cities in Turkey. Due to its prime location and its port, Izmir has become one of the busiest trade centers since the Ottoman Era. Additionally, its unique urban features have led the way for the city to host some of the most important civilizations throughout history. There are many important historical buildings sustained damages due to experienced earthquakes over the years. Currently, the historical buildings are under threat due to the high seismicity of the region. The frequency of earthquakes and the poor seismic performance of historic buildings in the past necessitate the seismic risk assessment of this historical buildings. Such assessment is also a necessity for the proper restoration and renovation of historic buildings in the city. This research provides an investigation of the historical building profile located in the historical Kemeralti district of Izmir, Turkey. Historical mosques have been investigated in site investigations via Rapid Visual Inspection Method. Base Scores and Critical-Benchmark Scores were determined based on-site investigations. Final score has been found out by using these two achieved scores. The scores were given in tables within a correlation of each other in the study. Based on site investigation, a behavioral pattern is defined for historical buildings in Izmir, Turkey.

Kasim A. Korkmaz, Saadet Toker-Beeson
An Interdisciplinary Approach for the Seismic Vulnerability Assessment of Historic Masonry Buildings: The Case Study of the Ex Jesuits College in Amantea (Italy)

The paper gives attention to the interdisciplinary approach used to solve the structural problems detected in the ex Jesuit College of Amantea (Italy), built in XVII century. The first objective of this study has been to identify the causes of the structural instabilities and to define the physical, chemical and mechanical properties of building materials. After, the attention has been focused on the vertical flexural mechanism linked to several factors, such as the absence of tie-rods and the important pushing forces of the vaults. These factors cause a no box-like behaviour of the structure. The characterization phase has achieved a high level of knowledge, which have allowed less onerous assessments. Through the kinematic analysis, the value of the seismic acceleration multiplier has been defined, performed on the mechanism considered more plausible in relation to the in act instabilities. After, a nonlinear analysis has been carried out to evaluate the system capacity curves, considering the unconsolidated and consolidated structure. The analyses have considered the reinforcement of the masonry building using traditional and innovative techniques. The curves obtained in relationship to the considered states (unconsolidated and consolidated) have been compared. At the end, the results of the analytical study has been correlated with the numerical one, performed in the linear field using the software 3MuriML. This paper highlights the controls of the careful structural surveys on the building in order to understand the behaviour of the masonry elements of the architecture.

Renato S. Olivito, Saverio Porzio, Alessandro Tedesco
An Extensive Survey of the Historic Center of Cusco for Its Seismic Vulnerability Assessment

This paper presents the main important typological data collected during an extensive survey carried out on the buildings of the historic center of Cusco, Peru. These data will represent the basis for a future analysis devoted to large scale seismic vulnerability assessment, to develop, in a structured and efficient manner, policies and measures for the seismic risk mitigation. Starting from the collection of available data and from the historical analysis of the urban development of the center, also accounting for earthquakes of the past, the most representative architectural typologies are identified. Moreover, statistical analyses are carried out, in order to detect the most recurrent structural details. On these bases, the main potential fragilities are identified, giving a preliminary idea of the structural behavior of the considered buildings under seismic forces.

Enrico Spacone, Giuseppe Brando, Matteo Peruch, Claudio Mazzanti, Karim Sovero, Nicola Tarque
Preliminary Analysis on the Effects of 2016 Central Italy Earthquake on One-Nave Churches

The seismic events occurred in Central Italy in 2016 caused severe damage to the monumental heritage and in particular to churches. The current study examines the effects on 68 one-nave churches located in Marche, Umbria and Lazio, based on a large number of post-earthquake inspections, which have been carried out within the activity of the Italian Consortium ReLUIS. To define the damage level in post-earthquake status, a macro-element approach has been adopted. The collected data have been processed in order to obtain Damage Probability Matrices (DPMs) for two separate groups of churches, which have been defined according to different occurred levels of macro seismic intensity. Then, according to the methodology proposed by the Italian Guidelines on cultural heritage, a vulnerability index has been determined for each church, taking into account the presence of fragility indicators and antiseismic devices. Finally, the expected damage level has been evaluated using a first level predictive model, allowing a comparison with the observed damage, as it was detected after the earthquake. The obtained outcomes prove that the adopted predictive model is quite reliable for reproducing actual damage scenarios.

Gianfranco De Matteis, Mattia Zizi
Simplified Assessment of the Seismic Vulnerability of Churches After the 2009 L’Aquila Earthquake

The Italian cultural heritage is made of a large number of valuable historical masonry constructions characterized by several chronological, typological, constructive and structural peculiarities. Old masonry churches surely are the most important asset of this heritage. Lessons learnt from past earthquakes emphasize the necessity to establish effective methodologies for the seismic vulnerability assessment at large scale and for defining possible risk mitigation strategies. Based on this premise, this paper aims at calibrating a procedure for assessing a vulnerability index of churches. This procedure is based on the damage provoked by the 2009 L’Aquila Earthquake, with particular reference to three nave churches located in Sulmona-Valva and L’Aquila Dioceses in Abruzzi. In a first step, the damage scenario provoked by the considered event is presented in terms of Damage Probability Matrices. Then, a procedure for assessing the expected damage is properly calibrated in order to reproduce the real damage scenarios observed on the churches under investigation. After its calibration, the model is applied to define suitable fragility curves.

Gianfranco De Matteis, Giuseppe Brando, Valentina Corlito

Seismic Analysis and RetroFIt

Frontmatter
Numerical Seismic Response and Failure Modes of Old URM Walls Under Lateral Loading

Most of existing constructions were built of unreinforced masonry. The performance of this material is different from the masonry units and mortar joints. This behavior is governed by the physical and mechanical characteristics of the composite, self-weight, transmitted vertical loading and earthquake shaking. The heterogeneity of masonry is also reflected in the anisotropic behavior of this material, which presents different performance and failure modes when subjected to lateral seismic forces. The main objective of the present paper is the simulation of typical failure mechanisms of compact URM walls without transmitted vertical loading, only taking into account their self-weight. The numerical behavior and failure mechanisms at the masonry walls (with solid section and perforated) was captured by the used material model and the pushover method. The obtained failure modes by bed-joint sliding at the solid section wall and stepped shear cracks at the wall with window are similar to the observed in post-earthquake investigations on URM walls with light cover reported in literature. The low tensile strength of masonry and the lack of vertical loading on the studied unreinforced masonry walls induced different failure mechanisms and behavior. In brief, the identification of in-plane performance and collapse is difficult to predict and strongly depends on the physical and mechanical properties of masonry, vertical loading and seismic forces.

Adolfo Preciado, Alejandro Ramirez-Gaytan
Nonlinear FE Analysis of the Response to Lateral Accelerations of the Triumphal Arch of the Church of Andahuaylillas, Peru

The Saint Peter Apostle church of Andahuaylillas is a colonial church in the Cusco-Puno area of the Andes, dating to the late 16th or early 17th century and built primarily with adobe brick masonry. The church is characterized by a triumphal arch made with fired clay bricks and surmounted by a high tympanum of adobe masonry. The arch is stabilized by lateral walls of mixed stone-adobe construction. As part of the seismic assessment of the building, this work focuses on the evaluation of the triumphal arch subjected to in-plane lateral accelerations by pushover analysis based on nonlinear FE explicit formulation. Detailed 2- and 3D FE models are constructed from measurements taken on location and observed material distributions of adobe, fired bricks, and stone. The FE models are analyzed in Abaqus/CAE Explicit under gravitational loading and monotonically increasing lateral accelerations, simulating quasi-static conditions until collapse. The concrete damaged plasticity formulation is adopted to represent masonry materials with nonlinear tensile and compressive behavior based on the Lourenço’s model. Local and global collapse conditions are identified from the energy and reactions curves. The effects of lateral walls and their material composition, nave walls, and the brick arch on the lateral capacity the triumphal arch are systematically evaluated.

Selman Tezcan, Niharika Tambe, Christopher Muir, Rafael Aguilar, Renato Perucchio
Seismic Retrofit of a Historical Building Using Cored and Internal Grouted Reinforcing

The building, constructed in 1929, was an airport terminal, and included a 2,322 m2 two-story structure and a four-story tower. The building sustained damage from the 1994 Northridge earthquake and was mothballed in accordance with Department of Interior standards. An extensive inspection and testing program was developed for evaluating the strength of the in-place materials and for the development of retrofit solutions. To preserve the historical fabric of the building, grouted reinforcing was selected to strengthen the existing masonry walls to act as shear walls. The reinforcing system consisted of removal of a wall core from near the center of an existing unreinforced wall and installation of stainless steel reinforcing. Coring/reinforcing was from the top continuously into the existing footing. To meet the requirements for an intermediate reinforced masonry shear wall, horizontal cores were also provided. The horizontal cores were off-center from the vertical cores to avoid intersection. Drilling was dry, to minimize effect on the heritage walls, with debris handled by a vacuum and filtration system to keep minimum dust. Reinforced walls were designed to resist both out-of-plane forces from wind and seismic as well as in-plane seismic shears. The advantages of internal reinforcing included minimal site/interior disturbance and preservation of historic building fabric, in addition to supplying resistance to future earthquakes. Voids in the existing walls identified early during construction, apparently due to poor workmanship, were subsequently injected with a flowable, compatible material. Success was confirmed by performing pre-injection and post-injection scanning using microwave radar and borescope examination.

Donald W. Harvey, Wayne Ruth, Matthew K. Ruth, Michael P. Schuller
A Methodology to Account for Crushing Effects During Out-of-Plane Collapse of Masonry

Out-of-plane collapse of walls is perhaps one of the most common modes of failure of masonry structures during earthquakes. Depending on the restraint conditions, walls can fail by developing a hinge along their height, thereby resulting in the formation of a two-block out-of-plane collapse mechanism. Equations of motion derived for this mechanism thus far have modelled the cracked wall as a single-degree-of-freedom (SDOF) system made up of two rigid bodies. However, most of these formulations assume that the interfaces between the blocks themselves, as well as between the blocks and the supports, are rigid. Alternatively, equations of motion have also been derived for two-block systems with flexible interfaces, which model the system as having four degrees of freedom, which is considerably more complicated than the SDOF model. Neither of these formulations account for the finite compressive strength of the interfaces, upon the exceedance of which crushing occurs, thus further reducing the dynamic resistance of the structure. This paper presents the derivation of an equation of motion for a cracked wall section taking into account the presence of flexible interfaces as well as crushing effects. Using as a case-study a typical multi-story spanning masonry wall, the importance of considering crushing during out-of-plane collapse is then quantified for a range of interface properties and loading conditions.

Anjali Mehrotra, Matthew J. DeJong
Macro-modeling of Adobe Piers for Seismic Analysis of Adobe Dwellings in Cuenca, Ecuador

Ecuador lies on the eastern rim of the seismically active area known as the Pacific Ring of Fire. In 1999, Cuenca’s unique architecture and historical buildings were listed in the UNESCO World Heritage Trust sites; many of these dwellings are composed of adobe walls. The aim of this papers is to present the mechanical characteristics of adobe walls representative of Cuenca’s historical buildings and a equivalent frame model to approximate the strength and vulnerability of a historical building, the behavior of masonry is represented from a macro-model approach. The properties of units and piers are obtained from experimental tests performed in the laboratories of the University of Cuenca. The numerical procedure is based on a macro-element model that is capable of reproducing flexural-rocking and shear failure modes. The macro-element is capable of representing with only one element the behavior of a whole masonry panel. The numerical results of adobe piers are compared with those of experimental tests, showing similar values for the elastic and inelastic ranges with close approximation of maximum shear strength and type of failure. This comparison allowed to estimate the mechanical properties of the macro-element model, which were used to model a historical building, Seminario San Luis. Research in this area will contribute to the conservation of historical dwellings and for future retrofitting and strengthening.

Rosa Quezada, Eddy Aguilar, Hernán García
Seismic Behaviour of a Historic Five-Tiered Pagoda in Nepal

The present paper discusses a five-tier pagoda in Nepal from the viewpoint of the damage observed after an earthquake. Nepal is a highly seismic-prone country and many structures experience significant damage during earthquakes. Structures are typically composed of timber and masonry which consists of burnt or sundried bricks and mud mortar. The Kathmandu Valley including three major Nepalese cities Bhaktapur, Kathmandu, Patan has been inscribed on the World Heritage List since 1979 as a representative example of unique Newari culture. In the paper, Kumbeshwar temple in Patan is studied. The top-tier was collapsed after the earthquake occurred in Nepal in 2015. The collapse mechanism is described and studied through kinematic limit analysis and preliminary FE analysis. The paper introduces an architecturally characteristic monument in Nepal and would contribute to understanding of seismic behaviour of multi-tier pagodas.

Yohei Endo, Toshikazu Hanazato
Seismic Assessment of the Matera Cathedral

This paper presents the seismic assessment of the Cathedral of Matera, in southern Italy, to determine the capacity of the structure when subjected to earthquakes. This church dates back to the 13th century and is one of the most representative monuments of the Apulian Romanesque architecture. Within the context of the evaluation of the seismic response of the cathedral, modal identification tests were performed in order identify and characterize the main dynamic properties of the structure. The results of these tests were used to develop a representative finite element model, which is able to provide the response to seismic actions. A pushover analysis was performed to characterize the seismic behavior of the structure. The results of the seismic analyses on the cathedral show that its vulnerability is high, being the transversal direction the less stiff and resistant. Elements as the nave and the façade, along with the bell tower, might be the most vulnerable to seismic actions. Additionally, it was observed that components as the trusses of the central nave strongly modify the seismic response and capacity of the structure. Apparently, the structure might not be able to withstand a strong earthquake from the region or might present several damage after one. Hence, it is recommendable to perform further studies about the seismic behavior, especially of the most vulnerable elements.

E. Ramírez, Paulo B. Lourenço, Michele D’Amato
Seismic Demand on Historical Constructions During the 2016–2017 Central Italy Earthquake Sequence

Between August 2016 and January 2017 nine shallow events with moment magnitude between 5.0 and 6.5 occurred in Central Italy, with largest magnitude being the most severe in Italy since 1980. Several thousands of heritage buildings have been affected to a different degree by the ground motion shaking, highlighting some specific behaviours in the most stricken areas. In and around Amatrice extensive masonry fragmentation, cracking of large walls without openings, as well as survival of tall towers and slender bell gables have been observed. On the contrary, in and around Norcia bell gables and churches collapsed. In this paper, surveyed response is interpreted both in terms of construction characteristics and by means of conventional (pseudo-acceleration) and unconventional (energy and rocking) spectra. It is shown that in Amatrice high frequency content of the first earthquake affected short masonry structures with very poor quality mortar, whereas in Norcia low-frequency content affected structures undergoing out-of-plane rocking or local mechanisms.

Luigi Sorrentino, Omar AlShawa, Laura Liberatore, Domenico Liberatore, Fabrizio Mollaioli
Distinct Element Modelling of the Out-of-Plane Seismic Behaviour of Masonry Walls

The out-of-plane vulnerability of perimeter walls is one of the main issues in the seismic response of historic masonry structures. Their dynamic behaviour is highly non-linear and is influenced by the discontinuous nature of the material. A range of failure modes may occur, such as onset of a mechanism, leaf separation, disaggregation, or sliding. Simplified approaches based on rigid-block dynamics may be unconservative, especially for poor-quality masonry, which is typical of a large proportion of our built heritage. Distinct element method (DEM), in which masonry is modelled as an assembly of discrete blocks and zero-thickness joints, appears suitable to simulate the dynamic response of masonry structures. In this work, DEM is used to analyse the out-of-plane bending response of two masonry walls, a two-leaf rubble stone masonry wall and a single-leaf wall in regular tuff blocks. Their seismic behaviour is simulated through non-linear dynamic analyses and compared to shake table test results for validation. DEM provides a good description of the seismic response of the walls, despite the high sensitivity to input parameters (stiffness, friction angle, tensile strength, cohesion and damping), which need to be calibrated in a suitable way.

Pietro Meriggi, Bartolomeo Pantò, Stefano De Santis, Anna Mordanova, Gianmarco de Felice
Experimental Seismic Response of a Half-Scale Stone Masonry Building Aggregate: Effects of Retrofit Strategies

A unidirectional shaking-table test on the half-scale prototype of a natural stone masonry building aggregate was performed as part of an extensive experimental and numerical research project, investigating the seismic vulnerability of historical buildings in the city of Basel, Switzerland. The prototype structure was characterized by architectural and construction details typical of Basel’s heritage residential building stock. The specimen represented a building aggregate consisting of two adjacent structural units, poorly connected on one side as if they were built at different times. The building specimen was three-story high and was built using double-leaf random stone masonry walls with undressed blocks and river pebbles. Timber floors, simply supported by the transverse walls, constituted flexible diaphragms in their plane. The two units were covered by roofs with different truss configurations, pitches, and side-gable wall heights. Steel wall-to-diaphragm connections were pre-installed but not initially fastened to the prototype; similarly, longitudinal and transverse steel tie-rods were also pre-installed at each floor without anchor plates. Both retrofit strategies were activated after a significant damage level was reached during the dynamic tests. This paper describes the seismic behavior of the prototype, analyzing the response of the bare masonry structure at various stages of the incremental dynamic test and investigating the effects of the retrofit interventions. The analysis focuses in particular on the dynamic behavior evolution, on the hysteretic response, and on the lateral displacement demand, in relation to the damage limit states associated with the observed mechanisms.

Ilaria Senaldi, Gabriele Guerrini, Martina Caruso, Francesco Graziotti, Guido Magenes, Katrin Beyer, Andrea Penna
Evaluation of the Seismic Performance of a Dwelling of Confined Masonry Walls

The usage of confined masonry walls in the construction of one or two floor houses in Chile is a common practice. For the analysis and design of these structures is used NCh2123 and the decree DS61, however, with these standards it’s not possible to estimate the seismic performance in front of an earthquake. The purpose of this study is to evaluate the seismic performance in a two-floor house with confined masonry walls, the house is structured with ceramic bricks walls type MQM of 14 cm thickness, bordered with columns and concrete beams. To evaluate the seismic performance of the house, the methodology FEMA P-695 is used, which involves static non-linear analysis and incremental dynamic analysis. A simplified nonlinear model of the structure is developed in the OpenSees program, and to simulate the nonlinear behavior of the walls, force-displacement relationships proposed in the literature are considered and obtained in experimental tests. For the incremental dynamic analysis a total of 44 seismic records occurred in Chile and the maximum acceleration of the soil is used as a measure of seismic intensity. From the analysis, the over-resistance factor and the ductility are determined, the acceptability of the response factor of the structure (R = 4) is verified. Additionally, collapse fragility curves are obtained that estimate the probability of collapse of this type of housing as a function of the intensity.

Edgar Ccanchi, Adhemir Taboada
Structural Characterization for the Seismic Protection of Heritage Churches

The high vulnerability of ancient masonry churches and their condition of cultural heritage assets make their seismic protection a complex operation. Structural analysis offers valuable support, but requires a realistic modelling of the building structure. Acquiring a thorough knowledge of the building constructional characteristics is, therefore, fundamental and may be achieved combining information from different sources. Besides regular surveying operations and limited diagnostic tests, other tools are available to obtain a detailed picture of the situation. For the case of churches, that often are many centuries old and have evolved with several structural changes during their lifetime, a historical research aimed at the reconstruction of the different phases of the building transformation is extremely useful to point out its characteristics, and possibly its hidden criticalities. A different but equally useful contribution comes from the recently developed high-power software tools for 3D modelling, allowing to visualize the shape of the asset but also to understand in detail its geometry and its building process. The combination of these two very different means offers a deep insight of the building features. Three Italian heritage churches testify here the positive results achieved by a synergic use of different knowledge sources, and in particular with crossing documental information and direct inspection supported by effective representation tools.

Maria Adelaide Parisi, Claudio Chesi
Survey, Assessment and Conservation of Post-industrial Cultural Heritage: The Case of the Thin Concrete Vault in Casale, Italy

The “Paraboloide” of Casale (Italy) was built around 1926 to be a clinker warehouse, and nowadays is a relevant example of the Italian concrete industrial heritage. The thin parabolic vault and the construction methodology are as innovative as other much better-known realizations of the dawn of the reinforced concrete era. Thanks to the adoption of LiDAR (Laser Imaging Detection and Ranging) technology, a detailed three-dimensional survey of the structure geometry has been carried out, including not only the emerging parabolic vault, but also the complex and very interesting underground structure. Homogeneous level of precision and continuous metric information of each, straight and curved, structural elements turned out to be crucial to the correct identification of design principles and construction solutions adopted at the time of the construction, which is mandatory for the correct refurbishment of the “Paraboloide”. The decay analysis of the most difficult regions to reach was carried out combining the laser survey information with a series of terrestrial photogrammetric pictures. A finite element analysis of the structure, accounting for the presence of reinforcements, was carried out in order to assess the initial and the present structural safety. In addition, the principal intervention criteria, both related to structural safety requirements and conservation prescriptions, are briefly summarized.

Stefano Invernizzi, Antonia Spanò, Filiberto Chiabrando
Structural Analysis and Evaluation of the Historic Haydarpasa Railway Station

Haydarpasa Railway Station, a well-known symbolic gateway to the metropolitan city Istanbul, was built at the beginning of the 20th century. It was designed by the architects Otto Ritter and Helmuth Conu and built by the German construction company Philipp Holzmann. The neo-classical structure is the first station of the Anatolian Railroad and an important piece of Turkish cultural heritage. Following the fire in 2010 that caused serious damages on the central and northern parts of the roof, restoration of the building was initiated. Detailed structural and architectural site investigations were performed in order to identify structural weaknesses such as material flaws, cracking, and inappropriate interventions. This study deals generally with the structural analysis and evaluation of the station based on numerical analyses. In order to examine the seismic performance of the structure, a finite element model of the existing structural system was created and analyzed using a finite element analysis software. Afterwards, repair and strengthening strategies were proposed to address the existing structural problems in the light of site observations and the finite element analysis results of the existing state of the structure.

Guzide Aslankaya, Cenk Ustundag
Seismic Stability Analysis of Historical Construction: A Case Study - Wazirpur Tomb

The non-engineered construction of masonry structures has been proved to be the most vulnerable during earthquake and have cited maximum damage during past earthquakes in India [4]. India is a country which is known for its culture and historical importance, therefore the need for an extensive monitoring and stability assessment of historical monuments is required. The historical monuments have been built without taking into consideration the effect of seismic parameters mentioned in latest Indian Standard of Earthquake Resistant Design of Structures. The present study is an attempt to assess the vulnerability & the stability of the historical masonry structures against the horizontal forces produced by major earthquakes using finite element (FE) simulation technique [1, 2]. The Wazirpur Tomb - an example of historical construction has been considered for the present study. The construction of box-like structure of the tomb has been done using locally available sandstone & lime mortar. The Response Spectrum Analysis [3] has been carried out & the response in terms of engineering parameters, such as natural frequency of structure, displacements, stresses etc. have been noted & discussed. The maximum stresses obtained from FE simulation technique have been compared with the permissible compressive & flexural stresses.

Khalid Moin, M. Arastu, Inbisat ul Haq Rafiqi, Monir Khalil, Ahmad Shoaib Amiri, Saqib Qamar
The Washington Monument - Post-earthquake Damage Inventory, Repair, and Seismic Vulnerability Assessment

Due to a 2011 earthquake, The Washington Monument—one of the tallest unreinforced masonry structures in the world—sustained cracking, spalling, and permanent displacement of its marble components. This occurred most significantly in its pyramidion, the pyramidal construction comprising its upper 17 m. After its closure, a post-earthquake damage assessment employing rope access inventoried damage providing a benchmark for calibrating computer models. A seismic vulnerability assessment relating to future earthquake response focused on the monument’s three distinct structural regions; its pyramidion, shaft, and foundation. Seismic hazard studies were conducted to develop a science-based understanding of the shaking intensity that actually occurred during the 2011 event, and of the shaking that might someday occur during future MCE earthquakes. Models designed to capture the most important structural characteristics of the unreinforced masonry tower were subjected to Nonlinear Modal Time History Analysis. These include soil-structure interaction and explicit modelling of the P-V interaction at critical stone block interfaces to simulate the behavior of mortared joints. After the models were validated using the 2011 ground motions and the damage inventory, the effects of postulated MCE events were determined and the significance of the predicted damage was evaluated and compared to what occurred in 2011. Relying on the inherent strengths of the historic masonry, recommendations for repair and supplemental supports were developed that targeted only critical vulnerabilities identified by the assessment and were carried out during a repair project prior to re-opening of the monument in 2014.

Terrence F. Paret, Owen Rosenboom
On Site Surveying of a Historical Structure for Numerical Models Development and Seismic Retrofitting Design

The restoration of the building heritage in the Abruzzo Region (Italy) is related to a detailed analysis of the technical and constructive aspects in the minor architecture of its historic centers. This paper describes the studies carried out for the recovery and seismic improvement of an aggregate in the historical center of Celano (AQ). The theme offered the opportunity to experience the potential of new digital imaging techniques with the use of “FARO-Focus3D” laser scanners based on acquisition of “phase-shift” points and integrated with HDR photography. The laser scanner provided a virtual model of the structure while the HDR cameras provided information to characterize the individual constructive elements. The cognitive framework obtained with the new technology has been a valuable tool in designing retrofitting interventions. The 3D laser scanner relief detected the constructive vertical misalignments of the bearing walls and allowed to evaluate the degradation of the materials and the crack patterns. Complementarily, the surveys and the experimental tests have given the possibility to determine the mechanical and constructive characteristics of its masonry. Thanks to these studies, useful numerical “pre and post-intervention” models for the design phases were developed. The level of safety, starting from a minimum pre-intervention safety coefficient of 0.18%, reached a post-intervention coefficient of 0.61% (respect to a full safety one required for a new building) that has guaranteed the seismic practicability of that historical structure.

Alberto Viskovic, Pasqualino Carusi, Martina Di Cerchio
Seismic Retrofit and Historic Preservation of a San Francisco Banking Temple

Constructed in 1892 with a seamless addition completed in 1904, the Hibernia Bank Building is an unreinforced brick and granite masonry San Francisco banking temple. After being abandoned for over a decade, in 2010 a new owner sought to renovate the building to once again allow occupancy, but this time for assembly use. Seismic improvements supplemented the inherent strengths of the historic masonry, especially the structural mechanism of rocking that allowed the unreinforced masonry building to survive the 1906 earthquake relatively unscathed. Limited concrete shear walls were added as part of the retrofit, but placed discretely and surgically in the structure, located away from historic finishes which have survived remarkably intact despite decades of neglect. This paper will discuss the three-dimensional computer model that was used to validate the seismic retrofit scheme, including the use of nonlinear rocking piers, as well as the design of the concrete diaphragm strengthening using externally bonded and near-surface mounted Fiber Reinforced Polymers (FRPs).

Owen Rosenboom, Terrence Paret
La Sagrada Familia: Approaches to Seismic Analysis

La Sagrada Familia in Barcelona is currently 135 years into its construction, with an expected completion date of 2026. Since its inception by Antoni Gaudí in 1882, radical analysis and design methods have been required to imagine its architectural form and understand the engineering performance of what will be, once complete, the tallest church in the world. Gaudí famously used hanging chain models to realise the catenary form of his structures, a method which pre-empted modern form-finding software and enabled him to devise an organic optimised form long before this could be achieved with computers.When Gaudi designed the Sagrada Familia in the late 19th century, the influence of seismicity on structures was not well understood, and therefore not considered in the original design. To justify the seismic design of six towers due for construction on top of La Sagrada Familia today, a detailed non-linear model has been created, and subjected to time history analysis. The model is excited in the time domain by the Spanish code design level earthquake, filtered by the presence of the church below. The analysis represents the non-linear behaviour of masonry to assess the ductility capacity and collapse limits of the towers. The model has been calibrated using on-site measurements taken of the dynamic properties of the current structure, modified by assumptions about cracking under seismic excitation.This paper describes the modelling and analysis methodology undertaken, before highlighting further potential uses of the techniques.

Marc Easton, Damian N. Grant, Laura Hulme
Seismic Assessment of the Church of San Sebastian in Cusco, Peru by Means of Pushover Nonlinear Analysis

The present paper seeks to evaluate the seismic performance of the San Sebastian church and its vulnerability to seismic events. This colonial temple dates back to the 16th century and is located in Cusco, Perú. The church stands out for being one of the first five Andean temples erected in the city of Cusco and also for being one of the most outstanding expressions of baroque art. Due to its artistic and cultural value, this church was declared National Cultural Heritage in 1972. Unfortunately, the periodic occurrence of seismic events and a fateful fire occurred in 2016 have endangered the survival of the structure and the safety of visitors. Aiming to evaluate the current situation of the church, this research developed a pathological identification through visual inspection and IR thermography as a non-destructive technique. A numerical analysis was also performed by means of a nonlinear pushover analysis that allowed estimating the evolution of the damage and the capacity of the structure in a seismic event. The results of the analysis showed that the main failure mechanisms of the structure would be the decoupling of the church front portion (towers and choir), generating concentrated damage in the arches that support the choir, as well as longitudinal cracks in the nave walls. The seismic capacity related to these failures is around 0.20 g, which is much lower than the recommended demand from the Peruvian code for the region of Cusco – 0.25 g – meaning that the church is highly vulnerable to seismic loads.

María F. Noel, Susana Moreira, Carolina Briceño, Enrique López-Hurtado, Rafael Aguilar
The Response of Masonry Barrel Vaults to Repetitive Static and Dynamic Loads and Example of Rehabilitation of Historic Barrel Vaults

The article will present the main results of experimental and theoretical research into non-reinforced barrel vault constructions and barrel vault construction reinforced with composites based on high-strength fibres and epoxy resin, or special polymer cement mortar. Vaulted constructions of historic and heritage buildings are extremely sensitive to deformations of the supporting construction, and their response to seismic effects may often be accompanied by cracking and mechanical vault failures. The results of research and study into the dynamic behaviour of barrel vaults brings new knowledge applicable in the prevention of vault failures in regions with an increased intensity of natural or technical seismicity, for the identification and localisation of failures using e.g. MAC or COMAC criteria. It can also be valuable in their serviceability assessment and service life extension. The second part of the article presents the results of theoretical and experimental analysis and a practical example of the stabilisation and reinforcement of 16 extensively damaged barrel vaults (with a 3.05 m span) with large lunettes situated over the cloister in the Premonstrate Monastery in Teplá (built in the 16th century), located in a seismically active region of West Bohemia.

Jiří Witzany, Miroš Pirner, Radek Zigler, Tomáš Čejka, Shota Urushadze, Jan Kubát
Seismic Pounding Analysis of Palazzotto Borbonico “Vecchio” and “Nuovo” in Naples

Recent investigations of past earthquake damages in Italy highlighted the importance of assessing the seismic pounding between adjacent buildings. The problem of the safety verification of adjacent buildings is becoming extremely relevant as pounding effects may be highly destructive. The seismic vulnerability connected to this phenomenon is usually increased when the adjacent buildings present different construction materials and were realized before building codes prescribed a minimum size for separation joints in seismic areas. The case study which is here discussed refers to the city of Naples, Italy, a seismically active site, and to a couple of buildings which were built in different centuries and present different structural materials, i.e., masonry and timber for the historical one, called “Palazzotto Borbonico Vecchio”, and reinforced concrete for the modern one, “Palazzotto Nuovo”. Such buildings constitute two independent dynamic units, as it is clearly shown by the separation joint which was spontaneously generated along the bearing masonry wall that they share. The structures have been analyzed by means of three Finite Element models, both individually and joined; the global F.E.M. allows to consider the non-linear effect due to the buildings collision. Several linear and non-linear dynamic analyses have been performed in order to investigate the correct separation distance required for avoiding the pounding phenomenon, and the effects of pounding, varying parametrically the gap distance and the stiffness of the link elements.

Claudio Chesi, Antonio Ingrassia, Valentina Sumini
Seismic Behavior of Historical Conical Masonry Vaults

This paper presents the results of a study of the earthquake resistance and behavior of historical Persian conical vaults. Masonry towers dating back to the 13th century AD, were used as funeraries in the Varamin region of Iran e.g. the Gunbad-I ‘Ala al-Din tomb located in Varamin south of Teheran. Such tomb towers suffered damage during previous earthquakes e.g. Bou’in – Zahra earthquake of 2002. This mausoleum basically consists of a tall cylindrical brick structure with a conical vault roof over an interior spherical dome. A 3-D finite element analysis model of an idealized conical masonry vault (including the interior spherical dome), over an idealized cylindrical shell was developed using the SAP2000 software, and analyzed under the action of gravity plus seismic loading. The conical roof vault height is 11.3 m with a span of 10.6 m. The height of the cylindrical shell wall is 15 m. The ultimate objective of the study is to develop a practical approach to the understanding of the seismic resistance of conical brick vaults on cylindrical shell walls. The major focus of the analysis results is the distribution of reactions at the base of the conical vaults, relative to the cylindrical shell wall, and the cylindrical shell wall relative to the base. The lateral displacement at the peak of the roof conical vault were very small indicting that this structure is very stiff.

Satwant Rihal, William Koh, John Edmisten
Bell Towers of Lima’s Cathedral: An Architectural-Engineering Combined Seismic Study

This paper focuses on the seismic evaluation of the Bell Towers of Lima’s Cathedral. The church, which dates back to 1535, has been modified and reconstructed several times over the centuries, changing its structural assembly in terms of lightening and strengthening. Focusing on the massive 45 m tall towers, linear kinematic analyses have been performed in order to evaluate their vulnerability. The results show how its actual performance is far below the safety requirements of the Peruvian code. Such code, however, lacks of regulations aimed at increasing structural safety of existing buildings and, thus, it does not provide any reference on the minimum safety level to reach on a monumental construction such as the Cathedral. A simple intervention using steel ties has been proposed in order to increase such performance on nearly all the considered collapse mechanisms, however the reference value of structural safety, due to absence of other prescription, has been set as the ultimate limit state for new constructions.

Edoardo Rossi, Adriana Scaletti, Nicola Tarque, Filippo Grande, Rosario Gigliotti, Marco Faggella
Experimental Earthquake Response of Two-Storey Scaled URM Buildings

As an immediate response following the 14 November 2016 the Mw 7.8 Kaikoura, New Zealand earthquake, the Ministry for Business, Innovation and Employment together with representatives from local government, researchers and practitioners discussed possible strategies for how to address the elevated risk of fatalities posed by unreinforced masonry (URM) façades and parapets. The outcome from the discussion was a policy that requires securing of street-facing parapets and façade with a particular focus on heritage precincts with high pedestrian traffic. Implementation of the policy is currently ongoing and an experimental campaign has been initiated to provide building owners and practicing engineers with a better understanding of the performance of different levels of building strengthening and also propose simple, speedy and cost-effective retrofit solutions. The experimental campaign involved replication of the earthquake behaviour of scaled two-storey unreinforced clay brick masonry buildings using a shake-table. The building performance was first tested in the as-built condition in order to establish a benchmark for the proposed retrofit techniques. Two different levels of strengthening were investigated: (i) simple wall-to-diaphragm connections, (ii) additional vertical strong-backs installed on the top floor wall interior surface and moment-resisting frames placed at the ground floor. Scaled building and material characteristics as well as the obtained results during the shaking table tests in terms of response of the structure, damage mechanisms and performance achieved are reported herein.

Marta Giaretton, Jason Ingham, Dmytro Dizhur
Numerical Interpretation of Structural Behavior of Stone Arches of Historical Storehouses Building

The paper presents the numerical analysis performed for interpreting structural behavior of an historical masonry storehouse in Trieste, Italy. The large complex subject of the study is dated back to XIX Century and it is nowadays disused and in an advanced state of deterioration. The monumental building, after a detailed survey defining geometry and characteristics, were extensively tested by means of a comprehensive experimental campaign conducted on its walls, foundations and arches. The main outcomes of the in-situ and laboratory tests allowed to defining the properties and the behavior of some structural elements. The collected experimental data allowed defining and calibrating of detailed finite element models (global and partial) of the building composed of walls, columns, arches and vaults. The main goals of the modelling were the calibration of global material parameters to obtain a correct interpretation of the experimental tests conducted and the study of behaviour and capacity of the building when subject to horizontal loadings, such those due to a seismic excitation. Furthermore, nonlinear analyses were performed to estimate the ductility of the stonework arches-vaults system, taking also into account, or excluding, the flexibility of the foundation system.

Marco Bovo, Claudio Mazzotti, Marco Savoia
Stone Bags Seismic Isolation for Vernacular Earth and Stone Construction

The Andean Region is permanently affected by earthquakes and its rich cultural heritage is a prey to relentless destruction. Built on earth and stone, they are an important vulnerability factor. This article considers the case of old Caral (5000 years old), built with their own ancestral seismic knowledge. Experimental research to achieve earthquake resistant earthen buildings began in Peru almost half a century ago and was concentrated on social housing. 13 years later it cover the vernacular patrimonial one. The need to have Conservation Principles adopted by the National Committees of ICOMOS, such as since 2012 the case of Peru, is in order to apply criteria of deep knowledge of the cultural heritage, minimal and respectful intervention, use of reinforcements of compatible materials and reversible solutions, which provides greater durability in spite of natural disasters (Earthquakes producing collapses of constructions and Enso associated to rains and floods). This Project was developed through an Agreement of the Ministry of Housing of Peru and the Pontifical Catholic University of Peru.

Julio Vargas Neumann, Carlos Sosa Cárdenas, José Montoya Robles

Repair and Strengthening Techniques

Frontmatter
Strengthening of Masonry Vaults with Textile Reinforced Mortars

Masonry vaults are dramatically vulnerable against non-symmetric loads, relative support displacements and earthquakes. In numerous existing structures, retrofitting is needed to improve the safety level and, for this purpose, externally bonded composites are particularly useful and have already been installed in the field. This paper describes an experimental investigation performed to gain an improved knowledge on the response of masonry vaults reinforced with Textile Reinforced Mortar (TRM) composites. Three full-scale vault specimens, provided with backfill and buttresses, were subjected to cyclic loading at 1/3 span. Displacements were measured with the help of Digital Image Correlation, which also provided information on damage pattern and arch-fill interaction. TRM was installed either to the extrados or to the intrados and proved effective to prevent or delay the onset of the four-hinge mechanism, which was replaced by crushing of the masonry. Stress and damage concentrations were avoided; the strength was increased by 2–3 times and the deflection capacity by up to ten times.

Stefano De Santis, Francesca Roscini, Gianmarco de Felice
Experimental Investigation of the Structural Response of Adobe Buildings to Lateral Loading Before and After the Implementation of Compatible Grout Repairs

In the framework of this study, a 1:2 scaled replica of a traditional single-storey adobe building was constructed and tested at the laboratories of the University of Cyprus. The main objectives of the experimental program were to evaluate the structural performance of adobe buildings under horizontal loads (simulating seismic action) and to investigate the effectiveness of cracking repair by means of injection with a compatible grout. The model was initially subjected to a series of monotonic static lateral loading cycles that led to the development of extensive cracking damage and to significant reduction of the load-bearing capacity and overall stiffness. A compatible clay-based grout was then developed using the same soil as the one composing the model’s adobes. This material was injected into the cracked sections of the masonry and the repaired model was re-tested. The clay-based grout successfully restored structural continuity, precluding the re-opening of injected cracks during subsequent loading cycles. The recorded load-deformation response revealed that the grout repair reinstated the original stiffness of the structure and recovered more than 90% of the initial lateral strength. The results indicate that clay-based grouts can be used for re-establishing the stability of adobe constructions under static loads.

Rogiros Illampas, Rui A. Silva, Dimos C. Charmpis, Paulo B. Lourenço, Ioannis Ioannou
Full–Scale Pull–Down Tests on a Two–Storied Rammed Earth Building with Possible Strengthening Interventions

This paper reports pull–down tests performed on full–scale two–storied rammed earth (RE) buildings to assess the out–of–plane performance of RE construction in Bhutan. An innovative strengthening technique is also proposed for strength enhancement of the RE walls. The tests involved two types of specimens, an unreinforced RE structure and an identical reinforced counterpart. The pull–down load was applied on top of the facade. The strengthening strategy involved reinforced concrete sections of dowels and wedges inserted between the RE blocks at regular intervals. The wooden floor beams at the first–floor level were also anchored to the RE blocks in the reinforced specimen. Micro–tremor measurements of the structures were done prior to the pull–down tests. A maximum of 59% increment in peak pull–down load was observed for the reinforced RE specimen compared to its unreinforced counterpart. The unreinforced RE wall showed damage to a larger area of façade, whereas, the reinforced RE specimen showed damage to a relatively smaller zone with controlled failure mechanism.

Kshitij C. Shrestha, Takayoshi Aoki, Takaaki Konishi, Mitsuhiro Miyamoto, Jingyao Zhang, Noriyuki Takahashi, Phuntsho Wangmo, Takumi Aramaki, Noboru Yuasa
External Post-tensioning System for the Strengthening of Historical Stone Masonry Bridges

Most historical stone masonry bridges were designed and built several centuries ago based in loads comparatively lower than the ones to which those structures are subjected to nowadays. Because of this fact and the normal decay and damage presented by historical structures, the need of strengthening arises and gives place to proposals such as the one presented in this paper. The objective of this paper is to present the evaluation of the feasibility of the use of an external post-tensioning arrangement to strengthen historical stone masonry bridges. The arrangement proposed is an alternative to those already existent and developed by other authors. To verify the assumed hypothesis, the proposal was analyzed with a general-purpose finite element method software, ANSYS. A qualitative assessment of this and other strengthening techniques available and used nowadays is also presented to evaluate its application suitability to historical structures. The results obtained via simple non-linear FEM models show that the proposal effectively increases the ultimate load capacity of the arch ring. It is also shown that the external post-tensioning arrangement can contain at certain level the horizontal thrust at the abutments. The proposed technique is deemed to be sympathetic and has great potential to be used to repair, strengthen and retrofit historical stone masonry bridges.

Alejandro Jiménez Rios, Dermot O’Dwyer
Proposal of a CLT Reinforcement of Old Timber Floors

Despite the fact that, from the mechanical point of view, there is no ageing issues of timber elements when they are properly used, many old timber structures require important interventions because of changes in uses (which modifies the regulating rules for example), of material decay (misuse of timber) or possibly of a faulty design or construction. In particular, timber floors in old structures often present large deflections and most the time had been designed for a maximum load much lower than the one prescribed by contemporary rules. After an introduction about timber floors and a short review about the reinforcement technics that exist, the present paper presents a new proposal for their reinforcement. The solution developed in the present paper uses a Cross Laminated Timber (CLT) panel screwed over the existing floor, keeping a small gap between the panel and the existing joists. In this way, the new “composite” floor presents higher stiffness and the gap is used for horizontal line runs. For the design of such a “composite floor”, modified Johanssen’s equations (including the gap between the CLT panel and the joists) are proposed and their application on a case study is presented.

Bertrand Roensmaens, Laurent Van Parys, Jorge Branco, Thierry Descamps
Mix Proportion and Engineering Behavior of San-Ho-Tu Building Material for Temples and Ancestral Clan Houses

The San-Ho-Tu building material is manufactured by adequately mixing a ternary mixture of sintered oyster shell ash, laterite and sand with water. It has been broadly used for construction and restoration of the ancestral temples and clan houses in China and Taiwan for hundreds of years due to its adequate engineering properties and easy availability of raw constituents. The main purpose of this study is aimed at understanding its engineering properties and proper mix proportioning. Cylindrical specimens of ϕ50 × 100 mm for nine sets of mixtures were cast, including three sets of traditional San-Ho-Tu building material (L-group), three sets of L-group mixtures with Portland cement (C-group) and three sets of single oyster ash paste an laterite paste (S-group). They were tested for compressive and tensile strengths at six ages of 7, 14, 21, 28, 56 and 90 days, respectively. Experimental results showed that at 90 days, the average compressive strengths of three specimens for S-group, L-group and M-group were 296.2, 2144.1 and 4915.4 kPa respectively. The ratios of the splitting tensile strengths to the corresponding compressive strength of San-Ho-Tu cylindrical specimens were between 16.1% and 19.9% which were higher than those of 10.0% and 14.0% for concrete cylinder made from the pure Portland cement paste.

Ching-Jong Chang, Ta-Peng Chang, Chun-Tao Chen, Yu-Wen Liu
A TRM-Based Compatible Strengthening Solution for Rammed Earth Heritage: Investigation of the Bond Behavior

Raw earth is among the most ancient building materials and the related building techniques are found widespread around the world. Currently, it is estimated that about 25% of the global population lives in earthen buildings and about 10% of the UNESCO World Heritage is built with earth. Nevertheless, an important overlap can be observed when the geographical distribution of raw earth constructions is compared with that of the seismic hazard. This circumstance, combined with the seismic vulnerability of earthen buildings, results in a high seismic risk, as demonstrated by recent moderate earthquakes. Despite the current awareness for this problem, little has been done so far to develop proper strengthening solutions for the rammed earth heritage. Based on the effectiveness of externally bonded fibers for masonry buildings, the strengthening of rammed earth walls with an earth mortar coating reinforced with a geomesh is here adopted as a compatible solution. The objective of this work is to investigate and characterize the bond behavior of the above mentioned strengthening solution to further describe the response of the interaction mortar-mesh. To this purpose, an experimental program was undertaken based on a series of pull-out tests. Specimens were prepared using earth mortar, two different types of meshes (glass fiber and nylon) and considering different bonded lengths. The results highlighted distinct bond behaviors. In the case of the glass fiber mesh, the bond was granted by friction and mechanical interlocking, while the mechanical anchorage promoted by the transversal yarns granted the bond of the nylon mesh.

Antonio Romanazzi, Daniel V. Oliveira, Rui A. Silva
Mechanical Behavior of Polyurethane Adhesives Applied to Timber Joints in Repair of Historical Timber Structures

This paper presents results of tests on polyurethane to timber joints, made of flexible adhesives, causing reduction of stress concentrations and redistribution of them over larger bonding area. The carried out tests on timber elements, polymers and constructed polymer flexible joints with timber elements resulted in promising ability of the joint to transfer compressive, tensile and shear stresses. Two kinds of polyurethanes of different stiffness were tested statically and cyclically. The obtained results indicate that the tested flexible adhesives can give advantages when are applied in repair of historical timber structures.

Kwiecień Arkadiusz, Rodacki Konrad, Zając Bogusław, Tomasz Kozik
In-Plane Behavior of Timber Diaphragms Retrofitted with CLT Panels

Traditional un-reinforced masonry (URM) buildings often comprise flexible wooden floor diaphragms where a layer of floorboards is laid perpendicularly over the timber joists and fixed by means of nails. It is not rare that such floor structures need to be improved in order to satisfy serviceability and ultimate limit states criteria, as concerns their behavior both under out-of-plane and in-plane loading. A common retrofit technique, mainly aimed at improving out-of-plane floor performance, consists in the application of a layer of cross-laminated timber (CLT) panels laid over the existing floorboards and oriented parallel to the joists. Appropriate panel-to-joist shear connection determines a joist-slab composite behavior that results in a significant improvement of both the of out-of-plane strength and stiffness. In addition, if adequate connections between adjacent panels are provided, CLT elements can also increase the in-plane strength/stiffness, a key-aspect in defining the seismic response of URM buildings. Both force distribution among vertical resisting piers and out-of-plane deformation of masonry walls are in fact affected by the diaphragm in-plane behavior. Inadequate in-plane response from the diaphragms can lead to the out-of-plane collapse of large masonry portions (1st mode failures). Non-linear static and non-linear dynamic simulations proved that the above mentioned retrofit strategy can effectively increase diaphragm in-plane stiffness and limit the in-plane displacement demand of diaphragms subjected to seismic shaking.

Ermes Rizzi, Mirko Capovilla, Maurizio Piazza, Ivan Giongo
Influence of Masonry Texture on the Shear Strength of FRCM Reinforced Panels

One of the innovative retrofitting systems for the improvement of the shear behavior of masonry elements is the use of Fiber Reinforced Cementitious Matrix (FRCM). Indeed, their application on masonry panels can determine a less brittle shear failure with respect to unreinforced panels and an increase in the load bearing capacity. The masonry typologies on which this strengthening technique can be applied are extremely variable, depending on the nature of the components, the characteristics of the mortar, the masonry texture and the transversal connection between the wall wythes. The goal of this work, part of an extended experimental campaign, was to analyze the effectiveness of the same strengthening system applied on two different masonry typologies. Therefore, diagonal compression tests were performed on four masonry samples realized using clay bricks and hydraulic lime-based mortar. In particular, the brick masonry panels were characterized by two different textures: Flemish bond and header bond. The tests were executed according to ASTM E519 under displacement control in order to capture the post-peak behavior. Benefits observed in the capacity, shear stiffness and ductility of the samples were analyzed, with reference to the differences between construction typologies. Finally, the results were compared with the theoretical ones computed using the formulations proposed in the Italian Guidelines CNR DT 200.

Andrea Incerti, Anna Rosa Tilocca, Francesca Ferretti, Claudio Mazzotti
Repair of an Arched Masonry Construction for a Historic Bridge Intervention

The Levensauer Bridge near Kiel in northern Germany is replaced by a new construction according to an enlargement of Kiel Canal. The old bridge has a span of 163 m, a height of 43 m and was built from 1892 to 1894 with two steel arches between huge masonry supports. Each of the supports consist of two massive masonry piers of solid brickwork with dimensions of 19 to 28 m and a height up to 30 m. Both piers are connected with a brick vault of 17 m span and a thickness of 1.3 to 1.7 m. Due to demands of nature conservation, the southern masonry support has to be preserved as a substantial habitat for bats. During enlargement works, horizontal and vertical displacements of the canal-side masonry pier have to be considered to ensure the safety of the construction. Small scale tests to verify the admissible spreading of the vault support have been performed by the authors [2]. The paper describes the ongoing repairing works of the vault, the piers and two massive wing-walls. Scientific approaches have been used to assess the properties of the brickwork, the damaging of the structure, the adaption of strengthening techniques and to define parameters for Engineering works. As a result, recommendations for the strengthening of vaulted structures under expected displacements are suggested.

Birger Gigla, Thomas Janßen
Patterns of Earthquake Damage to Korean Stone Pagoda and Seismic Hazard Mitigation Techniques

This study is for the seismic hazard mitigation performance of the repair techniques applied to the three story stone pagoda in the Bulguksa Temple. This pagoda had been repaired before the earthquake in September 2016. Unlike other stone pagodas, there was no damage from the earthquake in the stone pagodas. We tested the repair techniques applied to the stone pagodas. As a result of the test, we confirmed that some structural and material techniques applied to the repair reduced the damage of the earthquake.

Chan Min Park, Derk Moon Kim, Ho Su Kim
Possibilities of Using Fiber Reinforced Mortar and Textile Reinforced Mortar for Strengthening Masonry Columns in Rehabilitation Projects

While working on rehabilitating buildings we run across structural masonry columns that carry very little bending strength and have a limited compression capacity. These columns are frequently placed between window openings. The possibility of traditionally strengthening them with reinforced concrete or steel elements risks to alter their geometry, their capacity on sustaining moisture transfer and alter their thermal insulating characteristics possibly leading to other problems caused by condensation. On new buildings that use contemporary masonry elements and have monolithic walls we come across the situation of having column like masonry elements between two windows. These elements are typically not load bearing but must resist wind pressure and dynamic horizontal loads from earthquakes while limiting thermal bridging between external and internal surfaces. This paper explores solutions for strengthening the masonry columns mentioned above using fiber reinforced mortar (FRM) and textile reinforced mortar (TRM). It also explores if there are advantages in combining the two solutions in order to limit crack development while gaining load bearing and flexural strength. The relative small thickness of the mortar on the surface provides the opportunity to limit the heat transfer and keep the external appearance of the masonry columns in comparison to using much thicker concrete strengthening solutions. For the historic buildings, the use of compatible lime based mortars as a matrix for fibers and textile mesh is explored. This would limit the potential damage that could be done by using cement mortars that seal the traditional mortar masonry and would achieve more structural strength.

Dragos Bocan, Catalina Bocan, Alexandra Keller
Safeguarding and Retrofitting of the Western Eivan of the Takht-e Soleyman, Iran

The Western Eivan is a part of the World Heritage Site of Takht-e Soleyman in Iran. The ruins of the large hall show grave structural damages. The structure is built of brick work, natural stone masonry and gypsum based mortar. In the last two years several works were executed like archeological soundings, documentation of the existing historic building substance, performance of a 3 D laser scan, materials and damage mapping as well as taking of material samples and performance and supporting of a gypsum burning process. Beyond that it was developed a concept for the stabilization of the north wall of the Eivan. At the building site two test walls were designed and drilling and grouting technology as well as the developed grout was tested. In 2017 the buttress on the north side of the ruin was safeguarded and retrofitted with the selected techniques. The presented paper highlights the preliminary research and the safeguarding approach for the iconic ruin.

Wolfram Jaeger, Lorenz Korn, Toralf Burkert, Christian Fuchs
Numerical Study of NSM FRP Strengthened Masonry Walls

The application of external reinforcement with fiber reinforced polymer (FRP) to increase structural behavior of masonry structures has been a research focus area during the past decade. The near-surface mounting (NSM) technique is a relatively new retrofitting technique involves bonding FRP bars/strips insert into grooves cut into the surface of masonry. A numerical study was carried out to investigate the in-plane shear behavior of brick masonry wall strengthened with NSM FRP strips. A 2-D finite element (FE) model was used to simulate the structure behavior of strengthened masonry walls. The masonry was modeled by micro-modeling approach and FRP strips was modeled as attaching to the masonry mesh using the shear bond-slip relationships determined from experimental pull tests. The key shear behaviors of strengthened masonry wall panels in diagonal tension/shear tests was produced, including load-displacement response, crack development, and reinforcement contribution. Then, a parametric study was carried out to examine the contribution of different material and geometry property of FRP strips in the load carry capacity and shear ductility of strengthened masonry wall panels. Finally, the FE modeling for a real façade predicts the improvement of shear resistance which contributed by NSM FRP strengthening.

Xuan Wang, Chi Chiu Lam, Vai Pan Iu, Kun Pang Kou
Characteristics and Preservation of Civilian Conservation Corps Construction in the United States

The need to employ millions of unemployed U.S. workers during the 1930’s Great Depression led to two major “New Deal” programs in the United States: the Civilian Conservation Corps (CCC) and the Works Progress Administration (WPA). These programs were responsible for construction, in a relatively short period of time, of an impressive amount of public-purposed buildings, from City Halls to water treatment plants, to roads and bridges, and a diverse and comprehensive series of park structures. These historical constructions were built with mostly untrained workers under the guidance of trained supervisors, using predominately standardized designs modified for local conditions, and constructed with locally available field-gathered materials such as stone, log, and earth. These constructions were built quickly, yet the vast majority are still in place and performing their functions admirably. The primary current condition problem is the original use of Portland cement and the apparent expectation that it was waterproof and its use was sufficient, without reinforcement, for structural cohesion without following traditional masonry bonding and coursing requirements. Assessment of the condition of many of these constructions yields important conclusions of the longer-term conditions of the materials, particularly as was constructed in ways not generally implemented today. Of importance, the original program is replicable with some modifications to reflect the best use of materials and designs while maintaining a high degree of historic authenticity.

John Feinberg, P. E. Michael Schuller
Structural Upgrade of Steel Stub Girders

In the early 1970’s J.P. Colaco Ph.D. developed the steel stub girder system. This innovative structural system aimed at providing construction savings through the integration of mechanical, electrical and plumbing service ducts into the part of the building volume that is only occupied by the floor framing system. It was noted that overall depth of floor systems could be large, leading to significant increases in the overall height of buildings, the steel tonnage for the project and the associated cost of façade systems with greater areas. The stub girder system made extensive use of fairly simple shop fabrication techniques and the composite action of the concrete slab and steel load carrying capacity members. This composite floor system had significantly more strength, stiffness and ductility, while the amount of structural steel was reduced. The stub girder system was widely used for a variety of steel-framed buildings in North America (Canada, U.S.A. and Mexico) ranging from 2–70 stories for about two decades. However, due to the relative complexity of the analysis required, labor intensive construction nature and transformations suffered in the international steel market, the use of the system has become nonexistent. Today, structural engineers often get involved in projects where there is a need to upgrade the structural capacity of floors of existing buildings that contain this system, and there is very limited information and knowledge about it. The purpose of this paper is to describe the system, the approach for its analysis, and the techniques to strengthen the system. The paper will also provide some practical recommendations through the analysis of a case study.

Kevin Vazquez Vilchis
Experimental Study of the Seismic Behavior of Two-Leaf Masonry Wall with and Without Confinement

The historic monuments from the viceregal period in the south of Peru are the great part of the historic centers in the most important cities. They were mostly built with “sándwich” walls. They are built with volcanic stones which are parallelepiped in shape, and an intermediate sand and cal filling. During seismic waves these walls have shown the highest vulnerability. The main objective of this study is to know the behavior of unreinforced and reinforced masonry walls with concrete confinement, under the monotonic lateral test comparing them by increasing the capacity of resistance and the deformation of the reinforced walls. The experimental tests consisted in to try out three walls on the scale of 1/10, each with a different precompression load; these were tested at 0.5% drift, corresponding to a moderate earthquake. After this test, the reinforced concrete confinement frame was inserted, and the 3 samples were retested until they collapse. The 3 walls were tested under lateral load without reinforcement, there was a failure due to the flexion at the base by a drift of 0.04% and it lost stability. The reinforced wall increased its capacity of resistance and deformation, it shows an adequate ductility for severe earthquakes, being the drift got for the failure by flexion at 0.06% and a drift for a failure by cut at 0.8%.

Maison Puma, Edison Guerrero, Juan Copa, Fidel Copa
Revaluation of Historical Buildings with Timber-Concrete Composite in Compliance with Fire Resistance Demands

The requirements concerning the guarantee of sufficient fire resistance of structures have significantly changed with time. Hence, when revaluating or reconstructing existing older or even historical buildings a decision about necessary measures for ensuring the demanded fire resistance is needed. Timber-concrete composite is a proven technology for reconstruction and strengthening of existing timber beam ceilings. Timber-concrete composite floors have a high load-bearing capacity and very advantageous building-physical properties like fire resistance and sound insulation. A further essential benefit is the circumstance that the bottom side of timber beam floors may be unchanged in the reconstruction process. This fact very often is a basic demand for reconstruction of historical buildings. The paper analyses Germany’s recent fire protection regulations for reconstruction of historical buildings. It is verified that timber-concrete composite is a profitable solution for improvement of fire protection of existing buildings.

Klaus Holschemacher, Ulrike Quapp
SRG Composite Systems for Strengthening Masonry Structures: From Laboratory to Field Applications

The use of Fiber Reinforced Polymer/Grout (FRP/G) composites for the external strengthening and repair of masonry structures has met over the years an increasing consensus at both the academic and industrial levels.One of the most promising systems consist of Ultra-High Tensile Strength Steel galvanized micro wires twisted in cords or ropes, assembled parallel to each other to form unidirectional fabrics. Steel textiles can be externally bonded to the substrate via wet lay-up, by using either epoxy resin/mineral mortar, obtaining a composite known as Steel Reinforced Polymer/Grout (SRP/G). The inorganic matrix offers several advantages such as a great reduction in material costs, an higher vapour permeability and resistance to high temperatures as well as a much higher compatibility without compromising bond with the substrate and overall performance. A number of research studies have been carried out on SRP and SRG systems in the last fifteen years. Fundamental mechanical properties, durability and shear bond performance on masonry substrates have been investigated through tests on small- and medium-scale specimens (panels, brickwork pillars and masonry arches). These studies have shown that SRP and SRG are an effective, durable and cost efficient solution for the externally bonded reinforcement of structures. This paper briefly introduces to the main properties and mechanical characteristics of steel fibers, presents few research results of tests performed on real scale structural members (walls, arches) and introduces some case studies on masonry structures demonstrating the different field applications of this new and effective strengthening solution.

Paolo Casadei, Paolo Girardello
Structural Rehabilitation of Santa Maria de Los Reyes Convent. Seville (Spain)

The Santa Maria de los Reyes convent, built in the 18th century, is located inside the historical center of Seville and presents an architectural ensemble of Mudejar and Mannerist styles. Its rehabilitation project involved the foundation consolidation and the structural strengthening of the building components. Given its historical and architectural importance, an adequate and responsible intervention was required and the degree of structural protection of the whole complex had to be high. This requirement led to the concurrence of numerous structural rehabilitation techniques for the achievement of the rehabilitation. The correct application of these techniques including composite materials, grouting and prestressing proved to be suitable for the rehabilitation of architectural heritage when it is consistently studied during the engineering phase. The intervention respected the architectural value of the rehabilitated elements and minimized the visual impact in the patrimonial complex.

Luis Diaz de la Cruz, Ángel Rozas, Pablo Vilchez, Jorge Herrera
Correction of Pattern of Subsidence and Structural Rehabilitation of the Old San Agustín Temple in Mexico City

This paper deals with the major rehabilitation of an important historic building, which had suffered heavy damage due to the great subsidence it had experienced since its origin to the present day. The first phase of the rehabilitation consisted in several campaigns of selective stiffening of the most deformable layers of the subsoil in order to decrease and, above all, to make more uniform, the subsidence of both the main temple and its adjacent chapel. Subsequently, the structure and its foundations were retrofitted to correct the damages and restore the integrity of the original building, as well as to make it less sensitive to future subsidence. To do this, the two bodies of the building were separated by creating a construction joint between them, because the sinking patterns of the two parts were incompatible. In the paper, emphasis is placed on the interpretation of the results of monitoring the behavior of the two buildings throughout the different phases of the intervention, as well as after its completion, especially concerning the correction of their sinking patterns.

Abraham R. Sánchez Ramírez, Roberto Meli
A Comparison Between the Bond Behavior of SRP and SRG Strengthening Systems Applied to a Masonry Substrate

Strengthening and rehabilitation of existing masonry buildings is a topic that attracts the interest of the scientific community worldwide. Fiber reinforced polymer (FRP) composites have been largely employed for structural rehabilitation of masonry structures due to their ease of installation and their high strength-to-weight ratio, since the end of the previous century. Recently, fiber reinforced cementitious matrix (FRCM) composites have become an appealing alternative to traditional FRPs, because they employ an inorganic matrix to embed the fibers, which provides a better vapor compatibility with masonry substrate and better resistance to high temperatures than FRPs. To reduce the cost of carbon and glass fibers, the use of new types of fibers, such as high strength steel cords, has been explored. Steel reinforced polymer (SRP) and steel reinforced grout (SRG) are still moving their first steps in the world of structural rehabilitation, but they have shown potentials to become a suitable alternative to other FRP and FRCM composites, respectively. In this work, SRP and SRG composites are bonded to masonry blocks and tested using a direct single-lap shear test set-up to investigate the debonding phenomenon. Two different types of mortar grout are employed for the SRG. A comparison between SRP and SRG composites is presented in terms of debonding capacity and failure modes.

Mattia Santandrea, Giulia Baietti, Seyedmohammad Kahangi Shahreza, Christian Carloni
Mortar Plaster and Reinforcement Use to Repair and Stiff Brazil Historical Constructions

Many Brazilian historical constructions built using the techniques of daub, paving clay or adobe have presented many pathologies and sometimes even ruptures risk of walls. In order to recover such pathologies, or to reinforce such walls, it is suggested to use cement-rich mortar plaster or reinforced mortar plaster with welded steel mesh, applied to the wall with non-structural blocks. With this, it is gained net area, resulting in a greater strength and inertia. For this purpose, nine walls were tested for compression, being three walls of non-structural blocks without mortar plaster, three walls with mortar plaster and three walls with mortar plaster reinforced with welded steel mesh. Three specimens had the dimensions of 1.20 m by 2.60 m and the other six, called small walls, had dimensions of 0.90 m by 1.04 m. In these tests, simple compression loads capacity were obtained and it can be concluded that the application of the mortar plaster substantially increased the walls load capacity, as compared to the walls without mortar plaster. An increase of up to eight times in the rupture load was observed. The tests performed with the walls containing welded steel mesh inserted in the mortar plaster were not conclusive, although comparing them with the walls without mortar plaster, there was also gain of significant mechanical resistance.

Lucílio Flávio Cyrino, Roberto Márcio da Silva, Alba Bruna Cintra De Grandi

Assessment and Intervention of Archaeological Heritage

Frontmatter
Conservation Efforts on the Middle Phrygian Gate Complex at Gordion, Turkey

The Early Phrygians constructed the fortress city of Gordion (modern day Turkey), ca. 950–800 BCE. Gordion is renowned as the seat of the most famous Phrygian king, Midas of the Golden Touch, and also where Alexander the Great cut the Gordian knot (333 BCE). Although the ancient site was discovered in the late 1800s, it was not until the 1950s that large-scale excavations were begun by the University of Pennsylvania. Excavations showed that in the 8th century the Phrygians buried the Early Phrygian city with clay fill and rubble packing that formed the base for the new citadel fortifications and the Middle Phrygian Gate Complex guarding the city. Since the Gate Complex was first exposed in the 1950s, faces of the excavated rubble masonry have been subjected to environmental and weathering effects. More recently, sections had spalled off and left several large stone blocks of the Middle Phrygian wall resting above in imminent danger of collapse. In 2016, a site conservation project was undertaken to preserve portions of the Middle Phrygian architecture and stabilize the remains of the rubble masonry in the vicinity of the Gate Complex for safety reasons to protect visitors and the staff. This paper provides information on the conservation and stabilization efforts which have (i) illuminated the Middle Phrygian building strategies, (ii) enhanced the understanding gained during the original excavation in the 1950s, (iii) made the exposed rubble safe again, and (iv) improved the visitor’s experience of the overall site and spectacular Early Phrygian Gate Complex.

Semih Gonen, David T. Biggs
The Adaptation of Medieval Castle Ruins in Zabkowice Slaskie (Poland) for Touristic Services

The ruins of the medieval castle from the 14th century are the subject of the analysis presented in this paper. The castle is located in Zabkowice Slaskie (known as Frankenstein), in the Sudeten Foreland (Poland) on the former Wroclaw-Prague trade route. Destroyed and rebuilt several times, it was a remarkable work of Renaissance architecture and in its most representative form from the beginning of the 16th century. The castle was abandoned at the end of the 18th century and since then has fallen into destruction, finally being qualified as a permanent ruin. In 2011, conceptual and design conservation works were undertaken to secure the facility in order to make the ruins available for tourists. At the same time new buildings were introduced to the castle area to fulfill a variety of new utility functions. The authors of this paper have focused on the architectural and structural solutions of the adaptation of the ruins in the northwestern part of the castle, proposing the concept of a self-supporting laminated timber construction for a tourist information and exhibition center building as an element which can attracts visitors. Inspiration for the proposed concept of adaptation was the execution on the site of the ancient ruins of a new construction of laminated timber structures, which has recently become very popular in Europe.

Jacek Baranski, Jerzy Szolomicki, Piotr Berkowski, Grzegorz Dmochowski, Aleksandra Michalska
Seismic Analysis of the Stylite Tower at Umm ar-Rasas

A seismic vulnerability analysis carried out on the Stylite Tower at Umm ar-Rasas, Jordan, which is a UNESCO World Heritage Site, is presented in this paper. The monument, a unique survived example of stylite towers in the Middle East, presents evidence of structural damage due to earthquakes. The study was based on preliminary investigations, which consisted in Schmidt-hammer tests executed on stone blocks and passive tromography tests on the ground. Two models were implemented for the tower. In the first one, the tower was considered as a rigid structure supported by means of an elasto-perfect plastic cushion at the base. In the second one, a finite element model was setup, with solid elements characterized by a Drucker-Prager yield criterion. In both cases a push over analysis was performed, which resulted in a very low resistance of the tower to seismic actions. The work is part of a preservation effort which will include the design of a retrofit intervention.

Paolo Clemente, Giuseppe Delmonaco, Lucamaria Puzzilli, Fernando Saitta
Damage Assessment of Livas and Kastels in Gaziantep, Turkey

Gaziantep, a city on southeast Turkey, has no natural water source as lake. The water requirement of the city was met by transferring water from water source by carving water tunnels called “Livas” in history. Limestone and chalk formation of the city made it possible to carve this historic underground water way system. The water through Livas system was carried to the wells and pools in the houses and fountains and Kastels. Kastels were underground, rock cut and stone masonry public places where water came to the pools and dispersed to the bath and toilets of the system. For the people of Gaziantep, Kastels were social and cultural living space used for hundreds of years especially during hot summer days. Such system was unique to Gaziantep. Today, due to the city water and technological air conditioning system, these historic places are neglected and most of the Livas system is broken receiving sewage of the nearby houses. Out of known thirteen kastels in Gaziantep, seven of them have disappeared and only six of them have reached today. Also two of the six is about to disappear for various damages caused by nature and human. The aim of this study is to document Livas and Kastels and make damage assessment of existing Kastels to contribute to their problem of disappearance and preservation. And, deteriorations caused by nature and human in Kastels will be searched.

H. Merve Altan, Görün Arun
Understanding the Function of Roman Bonding Courses: A Numerical Approach

Bonding courses, also called leveling courses, are a universal feature of Roman architecture. This recognizable technique of the Roman builders spans the ancient empire from Great Britain to Turkey. Even though this technique is essentially ubiquitous, the full extent of its structural functionality remains in question. The literature is far from being unanimous. Some sources claim that bonding courses were originally used to give a level finish at the end of each stage of construction, resulting in potential lines of cleavage, and thus being detrimental in the design. Contradicting these ideas, others have suggested that bonding courses are advantageous because they help resist crack propagation and foundation settlement. The aim of this paper is to study the bonding courses from an engineering perspective and contribute to a better understanding of their structural functionality. This interdisciplinary work uses a combination of Finite Element Modeling (FEM) and Distinct Element Modeling (DEM) to simulate structural response of bonding courses to a variety of scenarios, including dead load, lateral loads, and differential settlement. Important properties of FDEM are a possibility to model discontinuous (jointed) structures and to implement an explicit time-step in the analysis. Enabling jointed structures to be properly simulated, this approach is proper for masonry where the stones are mechanically much stronger than the mortar joints. To ensure historical accuracy and rigorous engineering analysis, this project is realized in collaboration between the Civil and Environmental Engineering Department at Princeton University and the Institute for Mediterranean Archaeology.

Rebecca Napolitano, Laura Lansing, Branko Glisic
Integration of Finite Element and Graphic Methods in the Study of the Government Complex in Caesarea Maritima (IL)

Caesarea Maritima is one of the most important archaeological sites in Israel. Excavations and studies have been carried out on it since the mid-20th century and have unearthed ruins of the ancient Herodian, Roman, Byzantine and Crusader monuments and buildings.This paper focuses on the Roman government complex, placed to the south of the harbour and dating back to the late 1st century. It was originally organised on two storeys, with the lower constituted by several barrel vaults functioning as substructures for the main rooms at the upper level. Nowadays, structures of the first floor are just poorly conserved, while those at the ground floor are better preserved, especially as regards the four masonry vaults of the Western group, originally developing for almost 30 m and still partially standing after two millennia of history.The aim of the present work is to analyze the current state of conservation of the complex. In particular, the deformation of the Western vaults are evaluated through the integration of two procedures: the finite element method, to perform structural linear analyses on a three-dimensional numerical model, and the graphic method, to identify the thrust lines in each vault section by the funicular polygons.Results point out that the loads borne by vaults nowadays are not the main cause of their deformed shape: on the contrary, it must be searched in the past actions. However, the current conditions turn out to be precarious, thus highlighting the need of adopting proper measures for safeguarding the archaeological ruins.

Angela Pengo, Claudia Marson, Maria Rosa Valluzzi, Michael Cohen, Yaacov Schaffer, Claudio Modena
Protecting the Value of Archaeological Heritage: Frame of Reference in Value Assessments

Today archaeological research goals in the field of heritage management are shaped by the possibilities and limitations of value assessments that can provide clear and justified statements that support decisions on employed protection systems and management methods. But the reliability of value assessments is related to the existing knowledge about spatial and temporal features of a particular element of archaeological heritage as an insight into the distribution and relative preservation of a certain type of archaeological remains. Because of that, the lack of regional archaeological research is still the most common obstacle in the development of specific evaluation methods and meaningful evaluation criteria. As comparability of value judgments is the basic prerequisite of any effective evaluation and the most significant element of the value formulation process, the most important factor of the assessment becomes the frame of reference in relation to which the value judgements are made. Based on two case studies which cover different Bronze Age settlements with regionally specific types of preserved architectural elements, the authors will show the significance and meaning of the frame of reference in the process of value assessment. Development of such a system aims, not only to enable a deeper understanding of specific types of archaeological remains but also to provide the basis for the development of predictive modelling and implementation of the systems of expected values in heritage evaluation as an essential prerequisite for the effective process of archaeological heritage management.

Filomena Sirovica, Andreja Kudelić
The Bahrain Pearling Path: Urban Planning, Structural Investigation and Design of the Strengthening Interventions

The Bahrain Pearling Path (or Pearling Testimony) is a cultural heritage site inscribed on the UNESCO World Heritage List in 2012. The site consists of seventeen buildings in Muharraq City, three offshore oyster beds, part of the seashore and the Qal’at Bu Mahir fortress on the southern tip of Muharraq Island, from where boats used to set off for the oyster beds. The listed buildings include residences of wealthy merchants, shops, storehouses and a mosque. The site is the last remaining complete example of the cultural tradition of pearling and the wealth it generated at a time when the trade dominated the Gulf economy (2nd century to the 1930s, when Japan developed cultured pearls). In the framework of the restoration activities undertaken by the Bahrain Authority for Culture and Antiquities (BACA), an effort is currently ongoing for the re-use of the existing buildings preserving their structural behavior, also according to the ICOMOS ISCARSAH restoration principles. An extensive investigation campaign, preparatory for the successive strengthening interventions, was then carried out in 2017, aiming at defining the main mechanical features and characteristics of the stone masonry walls (composed by the locally named “coral stone”) and of the timber floors, originally (and still today) composed by round mangrove logs. The paper refers on the investigation campaign outcomes and the subsequent design criteria for an effective, however respectful, strengthening intervention.

Marco Motisi, Filippo Casarin, Gionata Rizzi, Franco Pianon, Alessandro Zamara, Lucia Gomez-Robles
Ruins and Archaeological Artifacts: Vulnerabilities Analysis for Their Conservation Through the Original Computer Program BrickWORK

Architectural ruins in archeological sites constitutes cultural heritage of a country. Every day there is the risk of archaeological artifacts being lost or of undergoing a slow and progressive deterioration, for at least three reasons: the presence of visitors who are often the cause of damage, the material vulnerabilities and the intrinsic vulnerabilities of ruined constructions. Leaving aside the first type, material vulnerability is primarily due to chemical and physical transformations undergone by the artifact which has been buried for a long time. After excavation, their prolonged exposure to weathering, frost-thaw alternate cycles, humidity variation, etc., reduce mechanical properties of materials such as stones and mortars. Furthermore, ruined constructions are lacking in most of the original structural portions which acted as constraints and therefore they are in the condition of unstable equilibrium and are very vulnerable under seismic actions. Indeed, (timber) floors are the first members which undergo decay or collapse. Therefore, archaeological artifacts generally appear as a discontinuous set of walls or columns and consequently easily vulnerable. Lastly, ruins retain “memory” of past events, visible in the cracking patterns and collapses provoked by seismic events which make them even more vulnerable. In this paper the analysis of main vulnerabilities of ruined constructions is performed. The analysis is carried out on meaningful case studies in the archeological site of Pompeii and Arpino (Italy), using a structural software suitably developed by the authors, and provides data to allow one to propose targeted methodologies for protection and conservation.

Stefano Galassi, Nicola Ruggieri, Giacomo Tempesta
Structural Investigations and Modelling of Seismic Behaviour on Ruins in the Monumental Area of Hierapolis of Phrygia

The archaeological site of Hierapolis of Phrygia presents a number of ruins, which date back to the II century B.C. They are located in a medium-high seismic area crossed by a system of faults still active. The valorisation plan of the site aims at establishing an archaeo-seismological area, i.e., a site where tourists can visit structures keeping the signs of past earthquakes in proper safety conditions. To this purpose, the knowledge phase is a fundamental step in the preservation process. The paper presents the results of a series of investigation procedures applied to several incomplete structures still standing in the area, namely: the Martyrion of St. Philip, the tombs A18 and A20, and the monumental latrines. The geometrical survey and the elaboration of images were used in combination, as base for the evaluation of the conservation conditions, the interventions applied in the past, and the deterioration and damage states of the structures. To integrate the analysis, soil and structures were also inspected on site with NDT procedures. In particular, tests provided the seismic soil classification (by MASW, HVSR) and the qualification of masonry elements (by SPVT, GPR). Limit analysis and FEM approach were adopted to characterize the actual seismic behaviour of the structural assemblages and to predict their possible future damage. Results pointed out the high vulnerability of large portions of the structures still standing in the site.

Maria Rosa Valluzzi, Claudia Marson, Sabrina Taffarel, Matteo Salvalaggio, Rita Deiana, Jacopo Boaga

Durability and Sustainability

Frontmatter
Extensive Renovation, Modernization and Redevelopment of the Helsinki Olympic Stadium in Finland

The Helsinki Olympic Stadium, completed in 1938, represents functionalism and is described as the most beautiful sports stadium in the world. Since 2006 the Stadium has been added on the list of protected sites by the National Board of Antiquities in Finland. The conditional survey conducted in 2009 showed that the structure had been affected by water damage in several areas. Furthermore, the Stadium no longer met the modern criteria for hosting major international events since it was built decades ago. In consequence it was deemed necessary the structural complex undergo a major upgrade and redevelopment. In 2016 a modernization project started focusing on particular fields: (1) to perform extensive renovation of the existing structure by replacing the technical building systems by building new infrastructure, updating the logistical solutions as well as expanding refreshment and service points for the public, and (2) to redevelop and upgrade this historical site into a modern, multipurpose area. The Olympic Stadium is scheduled to be re-opened in 2019. In all phases of renovation, the concept of sustainable building solution and state-of-the-art design tools are applied to comply with special regulations and requirements due to the high historical and architectural value of the Olympic Stadium. After completion of the extensive renovation project, the new, eye-catching modern venue will promote infrastructure capable of hosting major international sports and cultural events.

Kari Avellan, Erika Belopotocanova
Thermal Compatibility of Rigid and Flexible Adhesives to Substrates of Historical Structures

This paper presents influence of thermal stress factors of various adhesives and substrates on generation of stress in heritage structures. Comparison of them indicates that flexible polyurethane adhesives decrease peaks of stress concentrations significantly in accordance to stiff epoxy ones. Moreover, flexible polyurethanes work stable in elevated temperatures, because the exploitation range of temperatures covers area of stable mechanical properties behind the glass transition of the polyurethanes. The carried out SLST in normal and elevated temperatures, made on stiff and flexible adhesives and on substrates of various stiffness, confirmed that the tested flexible polyurethane PS adhesive is stable and compatible to heritage substrates.

Zając Bogusław, Kwiecień Arkadiusz
Sustainable Buildings: The Rehabilitation Project

The city of Lisbon currently faces some problems regarding built heritage management. This because the conservation state of buildings has been neglected for years. Today, the historic area of the city is characterized with buildings in high state of degradation, whose maintenance was in many cases non-existent. The care that a building requires is constantly underwritten and most of the interventions that have actually been verified are plastic rather than structural. Which brings us to another problem, since it is a city with eminent seismic risk. Part of the proposed solutions don’t even show respect for the built heritage history or the necessary attention to the existing mechanical capabilities, which is an obstacle to a balanced and sustainable development. In view of the above, this article purpose is to verify how rehabilitation can make a building sustainable in an city lacking with immediate results. Sustainability should be understood as the communion of indicators that foster proposals with solutions that last in time, economically accessible and of zero or reduced environmental impacts. To this end, case study of a apartment rehabilitation project located in Lisbon’s historic area will be presented, with characteristics that marked a constructive time and on which any proposal can not be invasive. It is intended to discuss some rehabilitation solutions in buildings whose construction system requires a series of structural, aesthetic and technical care, in particular as regards the relationship between the various materials (existing and proposed) and also energy efficiency.

Célia Maia, Bruno Dias
Comfort Assessment of Heritage Buildings in Cuenca-Ecuador

Intervention in heritage buildings with the purpose of extending their life span has been widely discussed on international forums for decades. Building comfort principles are intended to be incorporated within these heritage buildings; nevertheless, the intent implies extensive renovation with loss of important heritage values. This paper focuses on comfort strategies in selected heritage buildings of the city of Cuenca in Ecuador. The research reported here was initiated by an historic study and a heritage value assessment supported by the Nara Grid along with inhabitant’s interviews. Indoor and outdoor conditions were analyzed with datta logger equipment and climatic software tools. Then the collected data was interpreted and compared with the Ecuadorian Construction Norm. The outcomes showed possible intervention strategies to improve indoor comfort conditions of the heritage buildings without altering their values. Moreover, the research shows the potential of heritage buildings as resilient tools for sustainable development and that the improvement of quality of life of its residents is possible with less invasive interventions. In addition, the results showed that indoor conditions of heritage buildings could be improved; however, according to the current Ecuadorian Construction Norm, they will not always reach the ideal comfort range. Thus, the researchers encourage a revision of the existing Ecuadorian Construction Norm which under its current form is not fully applicable to the existing heritage assets. The norm gap shows restrictions and contradictions for the conservation of heritage buildings. Consequently, some interventions can destroy important heritage values.

Jaime Guerra Galán, José David Heras Barros, Vanessa Orellana Gutiérrez, Verónica Heras Barros
Evaluation of Compressed Lime Plaster tadelakt as a Protective Covering for Earth Structures

If we observe popular constructive traditions, we could obtain solutions for our current construction necessities that require less use of the limited resources available. An example of these traditions is tadelakt, a historical Moroccan coating created 2,000 years ago and whose name, translated from the Arabic means, “rubbing”; it is based on highly hydraulic lime from the hills surrounding Marrakech, mineral pigments and vegetable soap. It was discovered by accident, when people realized that by circular motions of a stone on a lime plaster it could be obtained as a water resistance finish, this is why it has been used in spaces and surfaces subjected to constant contact with water and humidity, for example the interior of the hammams (public baths), ancient earth constructions currently located in Morocco. Other benefits of tadelakt are its high durability and its possibility of returning to nature without negative consequences for the environment. The objective of this work is to evaluate quantitatively the protective properties of the tadelakt made with easy available materials (similar to the originals) for earth structures. This was defined through permeability tests made of adobe samples covered with the tadelakt plaster adapted to México, determining that this technique is a proper option to protect and conserve historical buildings made of earth due to the low permeability of the finish that protects the earth of the direct contact with water and at the same time allows the subtract to performs its function of temperature and humidity exchange between inside and outside.

Brenda Estefanía Díaz Macías
Durability Modeling to Determine Long Term Performance of Historic Concrete Structures

Understanding the impact of material degradation, rates of deterioration, and condition state changes are critical in making sound repair choices for historic concrete structures. Forecasting remaining service life and planning for durability is critical, particularly when the subject structure is an irreplaceable landmark. By monitoring the long-term performance of a structure, a corrosion and degradation rates can be established. Multiple parameters on the subject reinforced concrete structure are tested and monitored. The data is then utilized in durability and service life models to understand where the structure is in regard to critical performance thresholds and when failures may occur. This approach, when applied to historic structures, can help provide an understanding of ‘anticipated remaining service life’ and to assist in developing a proactive repair. This will minimize future degradation to the historic building fabric. For this paper, an approach to carbonation-based durability models will be presented in relation to historic concrete buildings.

Gina Crevello, Irene Matteini, Paul Noyce
Salt-Induced Deterioration on FRP-Brick Masonry Bond

In the past decades, several studies have shown how fiber reinforced polymer (FRP) composites are an effective technique to strengthen unreinforced brick masonry structures. However, very little is known about their durability against environmental aggression such as salt attack and freeze-thaw cycles, or elevated moisture content. This paper presents an investigation on influence of salt attack on the stress transfer between the FRP composite and the masonry substrate. In fact, it is well known that, in certain conditions, soluble salts crystallize within the pores of materials, leading to crystallization pressures that may overcome their tensile strength. To investigate this effect, FRP-masonry joints were subjected to salt crystallization cycles according to a conditioning procedure designed by the authors. After conditioning, direct shear tests were conducted on the masonry joints to investigate the interfacial bond between the substrate and the composite. Materials characterization was carried out in order correlate the results of the direct shear tests with the salt distribution within the specimens. For comparison, direct shear tests were conducted on FRP-masonry joints that were not subjected to any cycle and therefore used as control.

Cristina Gentilini, Elisa Franzoni, Mattia Santandrea, Christian Carloni
Historic Surfaces Consolidation - Multiple Treatments. Captured History of Changes and Advancement in the Field of Conservation via Microstructural Consolidation

This paper discusses the question of historic surfaces’ microstructural consolidation with the benefit of hindsight, considering multiple treatments obtained within the long period of time. Numerous previous experiences have revealed and pointed out that the findings and outcomes considered as right and suitable in scientific literature as well as in conservation practice during the moment of the first surface intervention have been recognized to be, within long period of time, the main cause of new major damage. A case study – Duomo di Milano façade – has been analyzed with the indication of the stratigraphical changes of its surface aimed for forming a cause-effect relation of different applications, their replacements and effectiveness. A question of proper conservation methodology was raised concerning the meaning and preservation of each strata traced on the historic architectural surfaces.

Agnieszka Defus, Marco Realini
Utilize Shape Memory Alloys for the Structural Intervention of Historical Structures

An emerging material with unique properties, ideal for various structural intervention techniques, is shape memory alloy (SMA). SMAs are special metallic alloys which, unlike classic metal alloys, have the ability to recover large deformations and return to a pre-determined shape through heating or unloading. SMAs possess several advantages over steel or fiber reinforced polymers (FRP). Their unique properties make them suitable in a variety of applications in structural intervention of historical constructions such as load-isolating, load-limiting and re-centering applications. Additionally, they have the ability to re-apply prestress forces that are lost due to straining of the material or slippage. Finally, SMA has a relatively high resistance to fire and corrosion. The first known application of using SMA bars for a structural intervention was in 2000 for a seismic retrofit for the bell tower of the Church of San Giorgio at Trignano, Italy after being damaged in a 4.8 Richter earthquake. The success of the intervention technique involving SMA bars was proven when the tower sustained another earthquake with the same epicenter and magnitude as the previous one, yet showed no signs of damage afterwards. This paper presents the state of the art review of utilizing SMA for the structural intervention of historical structures. It highlights the material’s unique characteristics and demonstrates its applicability in the field.

Benjamin T. Forrest, Raafat El-Hacha
The Effects of Bird Excrements on Copper and Bronze

This study was aimed at understanding the effects of pigeon excrements on copper and bronze. Specimens of pure copper sheets, copper sheets with a naturally developed patina, and bronze sheets were exposed to six different contaminants representing bird dropping components. The contaminated metals were aged in two climatic chambers. Both chambers were set at room temperature and a relative humidity of 100%, but one chamber was dosed with SO2 gas in order to simulate atmospheric pollution. Samples were monitored at various intervals over a span of four weeks. Ion exchange chromatography results showed that the bird excrements consisted of phosphorous, chloride, sulfate, ammonium, potassium, and sodium. The x-ray diffraction tests gave a composition of quartz, weddellite, aphthitalite, and magnesium ammonium phosphate hydrate. The surface contaminant pH levels were around a pH of 5. Digital microscopy showed changes in the metal surface colour and texture. After four weeks in climatic chambers, minimal differences could be seen between specimens exposed and not exposed to SO2. Scanning electron microscopy with energy-dispersive X-ray spectrometry exhibited the change in surface texture and identified the presence of fungi and dust particles. Bird excrements do promote the corrosion process of metals. The presence of patina can act as a protective layer towards corrosion for a short time.

Kristen Balogh, Zuzana Slížková, Kateřina Kreislová
Towards a More Realistic and Effective Use of Sodium Sulfate in Accelerated Ageing of Natural Stone

Soluble salts are considered a major cause of damage to historic constructions. The selection of materials for the repair of buildings affected by salts is usually carried out by estimating their resistance to salt crystallization based on laboratory tests. This study aimed to improve the ageing procedure of the European standard EN 12370 (Natural stone test methods: Determination of resistance to salt crystallization) towards a more realistic way of reproducing ageing on-site. This was done through the investigation of various environmental and procedural factors that influence the action of sodium sulfate. Four variations of the EN 12370 procedure considered the effect of different testing conditions (salt solution concentration, contamination procedure, drying temperature). Experiments were carried out on three types of natural stone to investigate the effect of different ageing variables on the deterioration of materials with different properties, namely regarding the porous structure and mechanical strength. The ageing process was monitored using non-destructive techniques: visual observation, mass variation, mass loss, and ultrasonic pulse velocity. After the completion of the ageing tests, the specimens were also examined using destructive methods: salt distribution and microstructural analysis using scanning electron microscopy. The results showed that the salt solution concentration was the most important variable determining damage. The contamination method also had a significant effect, whereas changes in the drying temperature had the least quantifiable impact. The effects the different testing conditions had on the deterioration of the stones are discussed and recommendations for future developments are given.

Krista MacWilliam, Cristiana Nunes
The Impact of Humidity on the Resistance of Historic Adobe Monuments

The research work that we propose for the consideration of the university community is denominated. The impact of humidity on the resistance of historic adobe monuments. The hypothesis of our job is formulated in the following terms: The model of resistance diminution because of humidity problems on the historic adobe monuments reports less resistance than the traditional model of adobe resistance for the historic monuments. In the investigation, it has been found a new mathematical model which represents the decrease in the adobe resistance when it is affected by humidity problems in the historic monuments, this equation has been evaluated with five real cases of historic monuments that have been affected by humidity problems. Having been checked the hypothesis and the mathematical model proposed with real cases, it is proposed the incorporation of this math model in the national building regulations in force in its norm E080 [1].

Romer Lovón, Eric Lovón
Graphics of Rigidity Compatibility of Composing Members of Isostatic and Hyperstatic Structures

The present work proposes the basis for the elaboration of interrelation graphics of rigidity that allows the restorer to make compatible the properties of recent manufacture structural elements on its inclusion over the original components of historical constructions, as a guide for the intervention and rehabilitation of the building heritage. The construction of graphics should carry out the function as a standard homologation pattern of section properties between base elements of the receiving system and those of the inclusion reinforcement, depending on its geometrical characteristics, used materials, age and time effects into the search of homogeneous behavior of continuous and discontinuous systems and its response before estimated functioning demands throughout the time. The homologation of the sections rigidity could be postponed or even accelerated on a transition period of adaptation depending on the stability of the original structural arrangements, the importance of the intervention, magnitude and the aim of rehabilitation projected.

César Fonseca

Management of Heritage Structures and Conservation Strategies

Frontmatter
Archival Documents as Sources of Historic Structures’ Construction Materials and Technique: Three Case Studies from Ottoman Architecture

A series of archival documents recently discovered in Topkapı Palace Museum Archives and Prime Ministry Ottoman Archives in Istanbul shed light on many aspects of several Ottoman structures, which were long forgotten or little known. These documents date from a ten-year period from late seventeenth to early eighteenth century, and they are mostly building registers and letters that give invaluable information about the architectural features of structures, some of which have long disappeared. Moreover, these documents supply the details about construction techniques, materials and unit prices of the period, which are crucial for the structural analysis and preservation of those buildings. In addition, invaluable information is obtained from these documents about the construction site organization, use of spolia, kinds and prices of decorative elements used inside buildings, budgets and decision making processes in Ottoman architectural practice. These documents were composed for constructions or repairs related with a mosque, bridges, fountains and their waterways, all of which were commissioned by Gülnuş Sultan (d. 1715), who occupied the seat of Queen Mother between 1695 and 1715 in the Ottoman Empire. Therefore, this paper takes three specific structures and uses the power of archival documents to reveal an important dimension of Ottoman architectural history. By exploiting these documents to comprehend the construction materials and kinds of labor of a certain period, this paper aims at forming a basis to choose appropriate conservation techniques and materials to preserve those specific examples of heritage architecture as well as their contemporaries.

Muzaffer Özgüleş
Preparation for Stabilizing the Early Phrygian Gate Complex at Gordion, Turkey

The Early Phrygians (ca. 950-800 BC) constructed the fortress city of Gordion in central Turkey (modern day Yassıhöyük). Gordion is renowned as the seat of the most famous Phrygian king, Midas of the Golden Touch, and also for being the spot where history records Alexander the Great cut the Gordian Knot (333 BC). In the late 1800s, German archeologists rediscovered Gordion, but it was not until the 1950s that large-scale excavations were begun by the University of Pennsylvania. Those excavations uncovered the Early Phrygian Citadel Gate Complex which comprises the best-preserved Iron Age gate building in the eastern Mediterranean and ancient Near Eastern worlds and is of inestimable cultural-historical significance. In 1999, Turkey experienced two destructive earthquakes along the North Anatolian fault in the northwest. Although centered nearly 230 km from Gordion, the earthquakes increased a bulge in one wall of the Gate Complex that was first identified in 1989. Since then, the bulge has enlarged to the point where a partial collapse was likely. In 2014, a site conservation project began to conserve and stabilize the bulging wall. This has required the use of a mat foundation made of timber railroad ties, specialized scaffolding, and a custom-made gantry system. This paper describes the initial conservation efforts of the project including (a) description and investigation of the site, (b) foundation preparation to protect the heritage site, and (c) design and installation of the gantry and scaffolding system. The ongoing conservation of the wall will be the subject of future papers.

David T. Biggs, Semih Gonen, C. Brian Rose, Elisa Del Bono, Aysem Kilinc-Unlu
An Exploratory Study on Project Delivery Frameworks for Heritage Conservation in India

The degree of sophistication required for governing a project depends on its complexity and scale. Although most heritage conservation projects have smaller budgets than new construction, the high uncertainty and complexities, necessitate robust project management framework. A well-defined project delivery framework is a key success factor for heritage conservation projects. India, with its rich cultural and geographical diversities, and more than 5000 years old civilization, has innumerable heritage sites spread across the country. Heritage conservation is a highly fragmented sector in India, with different agencies responsible for the protection and conservation of various heritage structures, and the modes, methods, and extent of conservation witnessed at these sites are of divergent nature. The objective of this paper is to study the different types of project delivery models used for heritage conservation in India. The authors have done an exploratory study on 50 heritage sites, where restoration projects are currently being executed or have been recently completed. The available project documents have been reviewed, and conservation professionals and other main stakeholders have been interviewed to map the project governance frameworks used for the projects. The 50 projects studied were categorized based on factors such as heritage category, ownership, implementing agency, scale of project, project frequency, funding pattern, apart from project delivery model and the relation between the factors studied analytically. The results indicate that Project Frequency and Funding Pattern are the significant factors influencing the selection of project delivery models for heritage conservation.

Debopam Roy, Satyanarayana N. Kalidindi, Arun Menon
Natural and Synthetic Consolidants for Earth Heritage: A Review

Since ancient times, natural products have been used to preserve earthen structures. Old recipes with cactus resin, bee wax, or linseed oil, have passed through generations and, in some countries, are still used nowadays. On the other hand, 20th and 21st centuries brought synthetic products as a solution to restore and conserve historical buildings. Although these synthetic products were extensively studied for stone-based monuments, they are also being used in earth heritage. The act of consolidating a degraded surface is, in conservation field, one of the most sensitive points, since the options available do not offer reliable solutions. Most of the times, the product applied, specifically in earth heritage, do not embrace two of the most important aspects in any conservation procedure: compatibility and reversibility. This paper aims to review the main consolidants (natural and synthetic) commonly used in earth heritage conservation, and also to draw the attention for the importance of a solid diagnosis of the initial state of conservation. With this review, it was possible to understand a lack of homogeneity in the identification of decay phenomena, as well as in recognizing its mechanisms of occurrence, and consequently in choosing the proper consolidant or treatment.

Telma Ribeiro, Daniel V. Oliveira, Paulo B. Lourenço
The Collapse and Restoration of the Church of Saint Mary of Itria in Piazza Armerina (Sicily, Italy)

The paper illustrates the damages occurred to masonry buildings due to incorrect consolidation interventions dated back to the 1980s that, according to the culture of the time, were oriented to the replacement of structural elements with new heavy ones, thus changing the static scheme. The case study concerns the seventeenth century church of Saint Mary of Itria in Piazza Armerina, affected in 2007 by the collapse of the one side wall of the apse. After illustrating the historical evolution and the actual state of the building, the investigations carried out to identify the causes of collapse and provide for appropriate reconstruction interventions are reported. The results of hydro-geological and geotechnical surveys lead to exclude foundations subsidence from the causes of the collapse. The study is focused on the analysis of the interventions carried out between 1980 and 1985 for the replacement of the existing wooden covering with girder and hollow block floors, connected with RC curb. The structural analysis was carried out under two load conditions before the collapse with the existing RC roof and with the previous wooden one, showed irrelevant load increase. Thus, the cause of collapse was identified in a variation on the load distribution. The planned intervention concerned the reconstruction of the wall with collapse recovery stones and blocks of similar physical-mechanical properties, the improvement of the walls resistance with mortar injections, the construction of curbs on the top of the walls, the stretching of transversal tie-rods and the introduction of new ones.

Tiziana Basiricò, Samantha Campione, Antonio Cottone
From Preventive Conservation of Heritage to Preventive Conservation of Society: Three Case Studies in the South of Ecuador

The preventive conservation of heritage has developed management and behavioral strategies that, starting from common concepts, have resulted in specific and diverse actions, depending on the local characteristics of the environment in which they are applied. In Ecuador, the experiences developed in the vlirCPM (World Heritage City Preservation Management) research project of the University of Cuenca have been put to the test through methodologies and strategies applied in Cuenca, a World Heritage Site declared by UNESCO in 1999, and in the rural settlement of Susudel, which at the time of the investigation was not yet protected as a national heritage. In these sites three maintenance campaigns were carried out, two in Susudel and one in Cuenca, making it possible to perform a comparative analysis between the methodological processes applied and the results obtained, which is the main objective of this research. This proposal critically explains these methodologies, identifying the concepts applied, characterizing the specific characteristics of each reality and explaining the entrepreneurial potential inspired by these experiences. The preventive conservation of heritage, the applied actions (maintenance and reinforcement of structural elements) and their impact on the involved communities can form a powerful social stimulus that includes: the preservation of heritage, social cohesion, the empowerment of inherited assets and the strengthening of identity. The present research concludes with reflections related to the identification of the factors of the preventive conservation of heritage that have an impact on the preventive conservation of society, its memory and its values.

Fausto Cardoso Martínez, María Cecilia Achig-Balarezo, Gabriela Barsallo Chávez
Sustainability, Disaster Risk and Conservation Problems of Industrial Heritages Between Yedikule and Küçükçekmece, Istanbul

Only 36 of 256 factories that operated from the Ottoman period to the mid-20th century in Istanbul could reach today. Some of them were abandoned, some buildings were reused and some were reused together with their environment. In terms of conservation it is crucial to give the building a new function in order to help it survive, at the same time however, one has to be careful not to significantly change original characteristics of the building and not to break its connection with history. Due to the scale of the factories, the industrial heritage has to be protected together with its area. The ongoing urban transformation in Istanbul affects the visibility of these preserved examples of industrial heritage. In addition, researches draw attention to the probable risk of an earthquake in the near future in Istanbul, where several disasters have happened in previous history. This paper, discusses the conservation and sustainability of industrial heritages which are located in the area between Yedikule, on the border of the historical peninsula and Küçükçekmece Lake by the Marmara Sea, Turkey. The industrial heritage in the region concerned was evaluated in terms of its location, scale, existing structures, its current use and its structural and constructional features, taking the disaster risk into account. Four samples were evaluated, using data derived from on-site observations of the materials’ characteristics, the technology and structural systems the current condition of the building elements and their decoration features. The study emphasizes the necessity of protecting industrial heritage in Istanbul.

Gamze Kaymak Heinz, Gül Yücel
Traditional Residential Architecture in Albania and Kosovo – Mason-Carpenter Structures and Their Future Restoration

The distinct traditional building substance in Albania and Kosovo is made up of impressive residential houses (banesa) for rich landlords, warlords, tax collectors and merchants performing a rural-urban lifestyle. Therefore, a sophisticated blend of the all-time defendable Albanian tower house (kulla), still existing quite intact in the western Kosovo plains, and the comfortable Turkish residence was developed during the long centuries of the Ottoman rule over Western Balkans. With the distinct knowledge of the widely renowned Albanian interdisciplinary craftsmanship of stone cutters, masons and carpenters, earthquake resistant and comfortable structures were successfully erected on most difficult morphological sites, which nowadays for manifold reasons are heavily endangered. This article tries to describe the reasons for those man-caused dangers and, in three case-studies from Dranoc, Gjakova and Gjirokastra, already taken counter-measures. Interestingly all those efforts are not only interdisciplinary approached, but try also to create sustainable regional employment by means of maintenance and restoration work. Especially the Gjirokastra model with its revival of the former state-protected “conservation ateliers” looks promising. Nowadays the knowledge of those “conservation-atelier” craftsmen is not formally recognized and left out of the market. Therefore, and to revive the apprentice school idea, Cultural Heritage without Borders has started a vocational training program to guarantee employability for tomorrow.

Caroline Jaeger-Klein, Arnisa Kryeziu, Elena Mamani, Kaltrina Thaçi
Cultural Significance: Linking Actors and Methods

Central to the entire discipline of architectural heritage conservation is the concept of cultural significance. It refers to the collection of values associated with a cultural property which act as a guide for decision making process. However, recent evidence suggests that cultural values belong to a dynamic and complex system which changes permanently. As result of that, new values might be added to previous ones, while in other cases, irreparable losses might be triggered. Thus, preservation of architectural properties is clearly conditioned by the capacity to reveal the major range of values through the implication of a variety of actors. The case study of two traditional neighborhoods of Cuenca, Ecuador seeks to examine similarities and complementarities on cultural values identification by two different actors: academic and civil members. A holistic approach is utilised, integrating the most recent recommendations from the cultural field referred to the cultural mapping and recommendations from the Socio-praxis discipline. This study makes a major contribution to research on values-based management by proposing a methodology to link an interdisciplinary approach with an active community participation. The paper has been divided into four parts. The first part describes the conceptual framework, the second presents a brief description of the territorial context of analysis, while the third part presents the methodological process and tools utilized to identify cultural values. Finally, the conclusion gives a brief summary and critique of the findings concerning to the values identified as well as to the utilized methods.

Gabriela García, Jorge Amaya, Alicia Tenze
Academy, Cultural Heritage and Innovation in the Province of Azuay, Ecuador

In recent decades, studying the link between the institutional sector and civil community has taken on a major importance. In this context, the university has been playing an important role on identifying needs and possible solutions through its creative and innovative capacities. Based on the study of the adobe productive sector in two rural areas of the province of “Azuay” (“Sinincay and Susudel”) Ecuador, the present research analyses the territorial contributions that the Faculty of Architecture and Urbanism of the University of Cuenca has been generating in this artisanal sector. The current situation of the sector is described and contrasted by a model of articulation between the actors involved in order to coordinate efforts in the creation of sectorial and territorial value. Besides, this model might contribute to create competitive strategies on the production of “adobe” and to strength one of the sectors which support the cultural heritage preservation in the Andean Region.

Jorge Amaya, Gabriela García, David Jara
Building Information Modeling and Structural Analysis in the Knowledge Path of a Historical Construction

In the field of historical buildings, the development of the knowledge of the structural characteristics is essential to assess the structural risks of a construction. The preservation of memory, the respect for heritage principles and the interdisciplinarity of the subject make analysis more complex. An exhaustive knowledge path of historical constructions goes through a deep analysis of all interventions carried out, the constructive evolution, the geometric and mechanical characteristics of the building, the structural forces that have already act in the past and in the current configuration, the built environment and the atmospheric environmental factors, the maintenance interventions, etc. Using exhaustive methodologies capable of satisfying the needs of designers is important due to the large number of factors influencing such a study and the difficulty of obtaining and collecting information. The objective of this work is to investigate existing and proven options of methodologies in order to apply them to the field of built heritage constructions. The main aim is to achieve an overall study of the historical building characteristics. Defining an interpretive model allows both a qualitative interpretation of the structural performance and a structural analysis for a quantitative evaluation. In the paper, a multidisciplinary analysis is proposed adopting two proven methodologies: the knowledge path and Building Information Modeling (BIM). The chosen case study is the Troop Barracks in the old fortress located in Anhatomirim Island (SC), Brazil. This aims to show how the proposed methodologies can be adapted to historical building in structural masonry and wooden horizontal elements.

Alfredo Calì, Ângela do Valle, Poliana Dias de Moraes
Re-modeling of the Monumental Building According to Existing Standards on Cultural Heritage Protection

The authors of the paper present a few valid problems, based on selected examples placed in Poland in the European Union. The issues of interest are seen by the authors and the others who apply with these matters in their job and which concern to all possible means by teaching those people who have practical, and therefore the biggest, effect on the method our inheritance is being modeled. By execute obligations of authors as constructors, resident engineers, as well as university masterships, they can say with whole awareness, that technology universities, which is purpose at teaching next civil engineers, does not lead up them to execute work in such a gentle area as historic constructions.The authors hope that the question picked up in this paper will gleam off a productive debate on leading up better and more fine learned program, for students, civil engineers or local officers which will protect both the state and the world legacy.

Krzysztof Ałykow, Magdalena Napiórkowska-Ałykow
Management and Restauration of Two National Historical Monuments of Earthen in Salta, Argentina

Two houses, one constructed in the middle of the XVIII century, the other one in the principle of the XIX century, both in earthen and declared National Historical Monuments, had implicated a great endeavor of management and professional technics for their restauration and valorization. The Leguizamon House of earthen and two floors represented a new challenge for the Earthen Heritage Management. Indeed, the pathology a deterioration detected in 2009 were very significant, and the fact that in Argentina this kind of work with this particular complexity and scale was never done represented a great difficulty. Beside, in this country, it does not exist special rules on architectural earthen restauration and construction. The Güemes House also represented an important challenge for the management because this dwelling of one floor was a private property with a deep meaning for the Argentinian Independence History. The professional advices of the Engineer Daniel Torrealva Davila from Peru led the restauration process of both historical monuments. In both case, they have been followed the guide lines of intervention for historical buildings in Peru, and the consolidation was addressed respecting the International Convention criteria and rules specialized in this specific issue. They were used structural reinforcement technics and materials absolutely news in Argentina which became national referents for their methodology and results obtained. It is important to note that during all the restauration process the original constructive frameworks, technologies and materials were respect, using structural reinforcement under the reversibility and low intervention criteria.

Mario Lazarovich, Emanuel Casso
Re-tolling the Bells – Preservation of an Historic Bell Tower

The Eveleigh Railway Workshops were the major locus of construction of steam locomotives in New South Wales, Australia, and the largest railway workshops in the Southern Hemisphere in their heyday. The site, located in the inner-city suburb of Redfern in Sydney, operated from 1888–1988 and was then adapted into the Australian Technology Park (ATP), a commercial business park focused on innovative technology and research. A considerable amount of the preservation work on the site was, however, only half-done at the time of adaptation, and Extent Heritage spent much of the last ten years assisting the ATP management with backlog maintenance and preservation projects. One major incomplete project was the preservation of the bell tower on the former Works Managers’ Office. A late 19th century rendered masonry building with later extensions, it is surmounted by a cast iron belfry with a bell that originally sounded the beginning and end of the work day at the site. Failure within the tower was causing major impacts within the building itself. Extent directed the project to conserve the bell tower and belfry, which required sympathetic modifications to the structure to address the practical conservation issues and manage the requirements for future maintenance and access. This paper will explore the issues uncovered and the techniques used to conserve the belfry and bell tower, and the decisions made to facilitate ease of future maintenance.

MacLaren North
Structural and Conservation Analysis of an Industrial Masonry Chimney in Monza, Italy

During the industrial revolution, the diffusion of furnaces for different productive activities implied a spread use of masonry chimneys that characterized the city landscape. The Italian Ministry of Cultural Heritage have included a large number of them in the list of “protected buildings”. Thus, they have to be maintained in a good state of conservation and repaired when necessary. Unfortunately, in the Northern Italy most factories have fallen into disuse and chimneys turn out to be the only protruding element, surrounded by abandoned buildings, often partially collapsed. This work presents the assessment of a masonry chimney in Monza, near Milan, approximately 90 years’ old that was part of the thermal plant for the production of felts. The plant was dismissed and abandoned in the ’70s. The circular chimney, built in a truncated cone shape through a brickwork double wall, is approximately 40 m high. For the recovery plan of the area, an investigation on the state of damage was required, since the chimney showed a visible crack pattern and local decay. The assessment was carried out through a multidisciplinary approach. An experimental campaign included geometrical survey, out-of-plumb measurement and crack pattern survey as well as the investigation of the damage along the whole height of the chimney. The endoscopic inspections allowed to investigate the construction phases and technique. With the measured data, a numerical model was developed and structural analyses under wind and earthquake loads were developed. The damage pattern was compatible with the significant effects due to wind action.

Giuliana Cardani, Paola Condoleo, Nicola Cefis, Maria GabriellaMulas
Preservation of Heritage Buildings Against Natural Processes: The Case of the Saint George Church (Old Cairo, Egypt)

The Saint George church (Old Cairo, Egypt) is a unique masonry building complex comprising structures of different time periods (Pharaonic, Medieval, Roman periods, 1909 construction, 1909–1930 modifications, 1941 reconstruction). The area has been affected by floods before the construction of Aswan High Dam and high groundwater level of Nile River resulting in loading and unloading of soils and ground settlements. Moreover, the high groundwater level flooded the lower floor levels of the structure. The building complex is founded on native dense alluvial sands, silts and clayey soils, during the low water periods of river flow. Parts of the temple are founded on shallow depth, while its inner part is built on remnants of a Roman tower, which is founded on deeper soils. The church was at moderate risk to damage from extensive construction vibrations, differential settlements from groundwater lowering or earthquakes. Taking into account the aforementioned, the geological, geotechnical and hydrogeological conditions of its site were studied and church failures comprising mainly cracks were mapped and attributed to the construction complexity of the building and to differential settlements induced by groundwater level fluctuations. Based on the results of this study, lowering of the water table as part of a greater dewatering project was proposed and expected settlements were calculated. After terminating groundwater lowering, differential settlements were measured confirming the abovementioned calculations. For further protection and preservation of the monument, the maintenance of the groundwater level below the oldest foundations along with the installation of crack monitoring systems were proposed.

Efthymios Lekkas, Spyridon Mavroulis, Alexia Grampas, Vassiliki Alexoudi
Restoration of the Municipal Theatre of Ouro Preto, MG, Brazil

Ouro Preto is among the most significant symbolic cities in Brazilian history and culture. The town was declared a National Monument in 1933, protected by the National Historic and Artistic Heritage Institute (Instituto do Patrimônio Histórico e Artístico Nacional – IPHAN) in 1938, and in 1980 it was the first Brazilian city included in UNESCO World Heritage List (Fig. 1). The Municipal Theatre of Ouro Preto, which belongs to the architectural and urban complex, is listed by IPHAN and is one of the oldest in operation in the Americas. The aim of this paper is to analyze the restoration works of the Municipal Theatre of Ouro Preto. Firstly, an architectural reading of the theatre was made, examining the materials and building system used in its construction, its surroundings in various periods, the physical, functional and visual relationship with the city, its symbolic meaning and the heritage designation process. Regarding the restoration works, the analysis has considered the causes of deterioration, diagnosis and state of conservation, previous interventions, the restoration project and intervention methods. The conclusions considered the interventions in the light of modern principles of cultural heritage preservation, the importance of the restoration works of the Municipal Theatre of Ouro Preto and its use as a public cultural space for the city.Fig. 1.Map of Ouro Preto – 1888. Collection, National Library of Rio de Janeiro.

Benedito Tadeu de Oliveira
Protection of Historical Structures and Interventions for Repair and Strengthening with Emphasis on Antiseismic Conservation

It is not certain that a historical and monumental building that sustained successfully the effects of previous earthquakes will endure the forthcoming ones. In most cases, previous earthquakes have already caused minor or major non-structural or structural damage. The accumulation of this damage may severely affect the antiseismic performance to a future earthquake with larger acceleration, velocity and displacement values and its effects especially when other damaging factors including physicochemical decay of structural settlements, differential settlements, possible fires among others, have caused further reduction of the bearing capacity of the building. Thus, the need for the preservation of historical and monumental buildings and their strengthening against seismic risk and related damage is evident and crucial. All methods and techniques of preservation and strengthening should be applied to these structures with the least possible alteration of their form. Besides the preservation of these cultural objects, the need for their antiseismic performance is dictated by the legal obligation to ensure safety and health of residents, neighbors, visitors and conservators of the structure. This aspect of interest in the bearing capacity of historical and monumental buildings is of great importance in modern society.

Spyridon Mavroulis, Vassiliki Alexoudi, Alexia Grambas, Ioannis Taflampas, Efthymios Lekkas, Panayotis Carydis
Synergies Between Lean Construction and Management of Heritage Structures and Conservation Strategies - A General Overview

The present article’s main purpose is to describe the synergies generated from the simultaneous application of the Lean Construction philosophy (LC) and Management of Heritage Structures and Conservation Strategies (MHS&CS). We explain the main principles, tools, techniques, modern technologies and practices of the Lean Construction philosophy and Lean Project Delivery System (LPDS) that could integrate and make synergy with the elaboration of MHS&CS study, and with the implementation of the MHS&CS plan. We relate the workflow design, workflow execution, the LPDS elements and the MHS&CS requirements. The methodology employed is based on a review of the literature published in the last 10 years, in which information was collected from the International Conference of Lean Construction (IGLC) papers and a set of mainstreams in civil and building engineering journals. This paper hopes to contribute by providing a proposal for a MHS&CS plan adapted to the LPSD model.

Xavier Brioso, Rafael Aguilar, Claudia Calderón-Hernandez
Reconsidering the Vaulted Forms of Cuba’s National School of Ballet

The vaulted forms and undulating walkways of Cuba’s National School of Ballet (Ballet School) are considered light and graceful, and yet, despite efforts by many Cubans and non-Cubans, these structures sit unoccupied and exposed to a persistently warm and wet tropical environment. The design and construction of the Ballet School structural system was thought to be one of the few modern examples of an ancient construction technique known as tile vaulting (also Catalan vaulting or, in US, Guastavino vaulting) that has defied standardized computational analysis. Given this exciting possibility, there has been a growing interest in conducting formal engineering analyses on the structures, however their remote location has prevented any such advances. In addition to the ongoing physical deterioration of the structure from environmental exposure, the construction-record documents are in jeopardy of being lost forever, therefore, it is deemed a critical time to digitally document the structure and corresponding documents from an engineering perspective, which would grant universal access to the structure thus allowing future engineering analyses. Given the Ballet School’s complex and interwoven cultural, social, political, architectural, and engineering backstory, this work implements an interdisciplinary approach of study, which is imperative if preservation of this structural icon is to be successful. While conducting this archival work, original architectural drawings, historic photographs, and interviews with key members of the design and construction team were reconciled with fieldwork conducted in November 2016 which resulted in the major discovery of a reinforced-concrete, grid-shell system underneath the adobe tile cladding.

Isabella Douglas, Rebecca Napolitano, Maria Garlock, Branko Glisic

Structural Health Monitoring

Frontmatter
Protection and Monitoring of Three Temples Close to the Excavation of a Tunnel in Guadalajara, Mexico

Because of the threat that the excavation of the tunnel would damage adjacent buildings, soil stabilization works were carried out in the areas adjacent to the tunnel. Moreover, three important historic temples were retrofitted to reduce their vulnerability, and a network of automatic sensors was installed and operated to monitor their structural behavior. The paper describes the structural engineering studies carried out for the diagnosis as well as those related to the design of the retrofitting of the three buildings. The behavior of the three temples during the stabilization works of the subsoil and during the passage of the tunneling machine is discussed. In general terms, the performance of the three temples was satisfactory; the only damage consisted in the reopening of some preexisting cracks, which were repaired soon after the passage of the boring machine. The case of the temple of San Francisco required some additional studies: environmental vibration measurements were performed to determine the dynamic properties of the structure before and after the passage of tunneling machine in order to detect possible damage, as well as to determine the effect of the changes in the soil properties in the seismic response of the temple.

Roberto Meli, Abraham R. Sánchez Ramírez, Miguel Rodríguez
The Influence of Bell’s Swaying on Neo-Gothic Cathedral

One of the negative aspects of technological progress is the threat to historical heritage by the impacts of technical seismicity. Dynamic load represents a significant threat to the safety and durability of historic buildings. The long-term effects of these types of loads lead to degradation of materials and connections, cause the occurrence of cracks and can increase the size of these cracks, and potentially lead to large-scale damage. Loads which would be safe for undamaged structures could become critical. This risk is present for various types of historic buildings; differences may occur due to the condition of walls, the amount of dynamic load and maintenance quality – which also includes the timely identification of damage (building diagnostics) and subsequent timely (and hence not too expensive) repairs. The aim of this paper is minimizing the effect of the bell’s ringing on the Church.

Shota Urushadze, Miroš Pirner
Health Monitoring with Acceleration Measurement for Maintenance and Management in World Heritage Angkor Wat

The Angkor Wat World Heritage Site is a monument of ancient Angkor. The site is located in the northwestern part of Cambodia, and contains elements of Hindu temple architecture. It is a typical sightseeing spot that bustles with visitors throughout the year. The site’s building structures have been affected by age and deterioration due to natural phenomena such as wind, as well as by foot traffic from a large number of tourists. For maintaining and managing the site’s structures, it is desirable to check their status through the use of sensor monitoring. The presence of microtremors was measured with a portable high-sensitivity acceleration sensor in the first, second, and third story corridors of Angkor Wat. Acceleration measurements were also carried out for 10-min durations at several points in each corridor. The vibration characteristics of the structure were obtained from a frequency analysis of the acceleration data measured at the central tower of the third story corridor. By taking measurements at the first story corridor, the walking patterns of tourists were determined, and it was found that pedestrian traffic at the structure’s entrance was the most common. It has been inferred that there is a heavy burden on the structure’s entrance, and that early maintenance is desirable. The results of the measurement analysis indicate that periodic or continuous monitoring is useful for World Heritage Sites such as Angkor Wat. Furthermore, the future direction on World Heritage monitoring and the need for the smart sensing technology were discussed.

Narito Kurata, Kiyohiko Hattori, Katsuhiro Temma
Monitoring, Assessment and Diagnosis of Fraeylemaborg in Groningen, Netherlands

Fraeylemaborg is a noble house in an earthquake-stricken area of the Netherlands due to the induced seismicity events in the region. The structure is located in the middle of the town of Slochteren which gave its name to the largest gas field in the world upon its discovery in 1959. The gas extraction has caused small-magnitude shallow earthquakes during the last decade, damaging not only the residential inventory but also the historical structures in the area. The main building of Fraeylemaborg sits on an artificial island surrounded by water channels, rendering the problem of earthquake response even more complicated. A small part of the main structure on the island was built in the 14th century, while the construction of additional parts and morphological alterations had taken place until the 18th century. The structure has been subjected to several small magnitude earthquakes causing damages on the load bearing system. An extensive renovation and repair of damages took place in recent years, however the latest seismic events imposed again damage to the structure. This paper presents a project of monitoring, assessment and diagnosis of problems for the Fraeylemaborg, the most important “borg” of the region, underlining the particularities of the induced seismicity problem. The FE model has been calibrated by using ambient vibration tests. Combination of earthquake and soil settlement loads have been applied on the calibrated model. The paper develops scenarios that help in explaining the reasons behind the damages on this structure during the recent shallow and low-magnitude induced seismicity earthquakes.

Dimitris Dais, Eleni Smyrou, Ihsan Engin Bal, Jelle Pama
Detachment Monitoring of Repair Mortar Applied to Historical Masonry Stone by Acoustic Emission Technique

In the repair of historical masonry walls, the plaster de-bonding frequently happens because of the long-term mechanical incompatibility of new mortar. A new laboratory methodology is described for evaluate the mechanical adhesion of the repair mortar applied in the restoration work at the Sacro Monte di Varallo (UNESCO heritage site). The acoustic emission (AE) technique has allowed to predict the fracture mode and to evaluate the repair mortar applied to historical masonry stone. This non-destructive methodology was able to identify defects and damages in masonry structures. Through shear tests, the specific geometry of assembled specimen can verify the detachment process of repair mortar. The AE technique permits to estimate the amount of energy released in de-bonding surface between repair mortar and stone during damage process. The authors have elaborated a numerical simulation to follow the experimental data. The evolution of de-bonding process of a plaster in a stone brick – mortar system was assess by means of the Acoustic Emission technique, which can follow the numerical model. Therefore, the experimental procedure was able to characterize the mechanical behavior of detachment mortar, useful for selection of repair plaster applied to historical masonry stone.

Alessandro Grazzini, Giuseppe Lacidogna, Silvio Valente, Federico Accornero
Strategy of Structural Monitoring of Heritage Structures for Phase 1B for Jaipur Metro – An Overview

Construction of metro below heritage sites and dense areas of city poses a complex challenge. Metro construction is proposed in Jaipur Walled City below Chandpole Gate, a world heritage site and within the influence zones of 2500 heritage buildings, 2 world heritage sites and a minaret at varying depths from 4.75 m to 22 m. Alluvium soil is mainly found along the stretch of project. In India, little technical data is available about the consequences of soil settlements, caused by tunnels bored in the vicinity of existing heritage buildings. In case of tunnelling in sensitive locality, monitoring plays crucial role in raising alarms. Considering the horizontal and vertical alignment of TBMs, zone of influence is marked from special 3D analysis. Analytical model indicated no appreciable effect beyond 60 m of tunnel line. Detailed building surveys are carried out to classify into three types depending upon the vulnerability. Structures are attended wherever required and monitored before and during tunneling work. Alarm levels, trigger levels are established for different types of structures. Key findings of pre-condition building surveys along with monitoring methods and preventive measures taken before and during construction work of tunnel are discussed. Regular monitoring is done for cracks, settlements, distortion and tilt. Work also involved archaeological exploration of the chaupads and the careful analstylosis and reconstruction of the chaupads. Two tunnels are constructed successfully. Strategy presented will help engineers and professionals to establish the need for repair or the need to reduce the settlement by modify tunnelling process.

Shashank Mehendale, Abha Lambah, Ashwani Kumar Saxena, Akhilesh Kumar Saxena, Sanjay Takekar
Environmental and Dynamic Remote Monitoring of Historical Adobe Buildings: The Case Study of the Andahuaylillas Church in Cusco, Peru

Constant survey of historical constructions is very important to ensure their conservation. In the case of ancient buildings, their use, the materials aging, vibrations, environmental effects (temperature, rain, snow) and seismic events are all possible causes of deterioration and damage. A continuous Structural Health Monitoring can provide useful information for automated condition evaluations of the health-state of historic buildings; however, it is known that the effects of environmental conditions such as the variation of temperature and humidity can make this assessment difficult. Therefore, continuous monitoring of environmental conditions and dynamic parameters is needed to develop suitable models to assess the current health-state. Additionally, historical structures could be located in a place where the harsh local conditions (viability, electricity, internet connection, etc.) or the distance from the inhabited centers can make monitoring activities challenging. This paper reports an innovative dynamic and environmental remote monitoring system implemented on the historical adobe church of San Pedro of Andahuaylillas, built in the sixteenth century, suitable example of Andean historical earthen constructions, strategically located on an Inca road system, 60 km south of Cusco. Firstly, the monitoring methodology is discussed, and subsequently, the case study is presented. The data is recorded locally and is automatically sent to Lima (1200 km away from Cusco) where the dynamic data is automatically processed to identify the modal parameters of the church. Preliminary results of a 6-month monitoring campaign is finally shown.

Giacomo Zonno, Rafael Aguilar, Benjamin Castañeda, Rubén Boroschek, Paulo B. Lourenço
Example Applications of Satellite Monitoring for Post-tunnelling Settlement Damage Assessment for the Crossrail Project in London

Structural monitoring of surface building displacements is a significant component of the total financial investment for underground construction projects in urban areas. While traditional monitoring requires in-situ (terrestrial) measurements and trigger levels based on preliminary evaluation of vulnerable structures, very recent advances in Interferometric Synthetic Aperture Radar (InSAR) techniques enable remote monitoring over extensive areas, providing rapid, semi-automatic, and dense measurements with millimetre accuracy. Despite the well-established use of InSAR in geophysical applications, only a few studies are currently available on the use of satellite-based monitoring for the assessment of building deformations and structural damage. The aim of this project is to investigate the potential of InSAR monitoring data as an input to post-tunnelling damage assessment procedures. First, InSAR-based measurements of building displacements, induced by the excavation of Crossrail tunnels in London, were acquired and processed. Then, following the definition of a step-by-step procedure, the satellite-based building displacements were used to evaluate structural deformation parameters typically used in extensive damage assessment procedures. Results show that the number of available measures per single building can enable the estimation of deformation parameters, a capability that is not economically feasible for large scale projects using traditional monitoring systems. The comparison with greenfield predictions offers new insight into the effect of soil-structure interaction and demonstrates the suitability of InSAR monitoring for post-tunnelling damage assessment of structures. The outcome of this work can have a significant economic impact on the construction industry and can advance the knowledge of building and infrastructure response to ground subsidence.

Giorgia Giardina, Pietro Milillo, Matthew J. DeJong, Daniele Perissin, Giovanni Milillo
Long-Term Vibration Measurements to Enhance the Knowledge of a Historic Bell-Tower

The results of the long-term vibration monitoring program, carried out on the bell-tower of Santa Maria del Carrobiolo in Monza (Italy), are reported in the paper. The dynamic monitoring was motivated by the weak structural layout of the historic building, with two fronts of the tower being supported by the load-bearing structures of the apse and South aisle of the adjacent church. The main results of the dynamic monitoring for a period of one year highlight distinctive behavior of the bell-tower, such as the frequency veering exhibited by the lower modes with increased temperature. Subsequently, in order to mitigate the contributions of the environmental effects on resonant frequencies, the application of the multiple linear regression (MLR) and the principal component analysis (PCA) tools have been investigated.

Carmelo Gentile, Antonello Ruccolo, Antonella Saisi
Implementation of a Web Platform to Present Real Time Dynamic Monitoring Data from Heritage Structures

In Peru, there are many monuments of high cultural and historical value, and with this, a rising need to ensure their conservation and optimal preservation over the years. Future structural damage situations can be avoided, and better restoration plans can be proposed by using non-invasive diagnostic techniques. This requires a constant process of monitoring to evaluate their structural state over time. For this purpose, a remote monitoring visualizing tool was proposed by using simple and reliable off the shelf applications. By establishing this system, it is now possible to visualize real time data from different projects, enabling the access to this data from any electronic device with internet connection through the web platform. The paper shows a detail description of the developed tool based on the following stages: (i) Acquisition and centralization of acceleration data, (ii) Wireless transfer/reception and processing of acquired data in a base station; and (iii) Dynamic visualization of processed data through a web platform. Accelerometers, data acquisition system, data processing software (LabVIEW), file transferring software (Bitvise and OneDrive), as well as web server services (Amazon Web Server) were used to acquire, transmit, process and visualize the changes in acceleration. The developed tool is use to monitor the “Church of San Juan Bautista de Huaro”. In this case study, the tool presents real time information about modal frequencies, damping, maximum accelerations, and maximum RMS, which are relevant to understand the current “health” of the structure.

David Fosca, Patricia Pórcel, Giacomo Zonno, Benjamín Castañeda, Rafael Aguilar
Structural Health Monitoring and Assessment of Seismic Vulnerability of Historic Monuments on the Great Silk Road Based on Laser Scanning

The high-definition laser scanning technology is used in an extensive ongoing structural assessment of historic monuments in Uzbekistan. The laser scanning studies were conducted in Tashkent, Bukhara, Samarkand and Shakhrisyabz. As a representative sample, the research results based on data obtained in Samarkand and Shakhrisyabz are discussed herein. Samarkand is one of the oldest inhabited cities in Central Asia. Because of its strategic location on the Great Silk Road, an ancient trade route between China and the Mediterranean, Samarkand was one of the greatest cities of Central Asia. Shakhrisyabz is located in southern Uzbekistan approximately 80 km south of Samarkand, Uzbekistan. Once a major city of Central Asia, it is primarily known today as the birthplace of the 14th century Turco-Mongol conqueror Timur. The scanned monuments are on the UNESCO World Heritage List. To monitor the buildings’ possible settlement due to poor soil conditions, special high-resolution laser targets were permanently installed. A detailed finite element model of monuments was generated from the as-found geometry captured by laser scans. The physical properties of the monuments were investigated by material tests of the major components recovered from the historic sites. The calibrated numerical models were used for comprehensive seismic analysis of the monuments. To monitor the structural health of the monuments, they were repeatedly scanned in order to estimate whether the structural degradation is progressing. Based on the results of numerical simulations and health monitoring results, recommendations on further preservation of the historic monuments were developed.

Shakhzod Takhirov, Amir Gilani, Brian Quigley, Liliya Myagkova
Static and Dynamic Investigation of the Taro Masonry Bridge in Parma, Italy

The Taro bridge has a very long history since was built by Antonio Cocconcelli in 1820. The bridge is composed of 20 arch spans and is arranged in the shape of three center Perronet arches with flood holes in the piers. The road over the bridge has two lanes and is set for the highest truck loading category. After the second World War has been used intensively for road transportation and due to some intrinsic features of the structure, in recent times many brick and stone detachments occurred. Recently, in order to assess the health of the bridge, static and dynamic testing was carried out, by using a set of 8 trucks filled with sand. A Finite Element Model was worked out for the data interpretation, and the parameters of the model were identified on the basis of the vibration frequencies. In order to test the effectiveness of the model, a comparison is made with the static load testing, finding a very good agreement. The main identified parameter are the compliance of the foundation blocks, and the elastic modulus of the fill. The analysis shows that models with different number of spans are all capable to identify the main frequencies of the bridge, if the correct value of the main parameters is introduced.

Andrea Benedetti, Camilla Colla, Giacomo Pignagnoli, Mirco Tarozzi
Structural Analysis and Monitoring Suggestions for an 11th Century Shipwreck

The Serce Limani shipwreck from the 11th century Hellenistic Period in Asia Minor is currently under exhibition in Bodrum Castle. The castle itself also dates back to 15th century and serves as a museum today. This shipwreck is the oldest known ship with a structural skeleton and represents the transition of ship construction from shell to skeleton. Currently, the restoration of the Bodrum Castle is underway and the shipwreck structure is located in an ordinary masonry building, which is to be demolished within the restoration project. During the restoration works, it is of prime importance to conserve the 11th century shipwreck, which is the main exhibition feature of the museum, unaffected from the restoration process. For this purpose, a temporary steel protection structure will be constructed around the shipwreck. For estimating the structural safety of the shipwreck and the critical level of vibrations, the shipwreck is structurally modelled as realistic as possible considering frame/shell element properties and the current restraint conditions of the shipwreck. The modal analysis is then performed and the results from the analysis are utilized to determine the main requirements for developing SHM (structural health monitoring) system of the shipwreck structure. Accordingly, the outline of structural modelling and proposed structural monitoring approach are presented in this study.

Selcuk Bas, Omer Karakus, Oguz Ceylan, Alper Ilki

Interdisciplinary Projects and Case Studies

Frontmatter
The Sobrado Vallim Rehabilitation Project

This paper presents the assessment of the historical two story Sobrado Vallim building located in Bananal, in the state of São Paulo, Brazil. The Sobrado Vallim was built as the house of the local coffee Baron. Since being unoccupied by the family, the building has served as a school and as the City Hall; more recently the building has housed a local community association. The first story is formed by rammed earth walls supporting a wood floor. The walls on the second floor are built with adobe blocks, and several wood columns embedded into the walls support the wood roof trusses. The building has been unoccupied for several years and a temporary shoring system has been designed and installed to prevent possible collapse. The analyses included measuring and defining the building structural elements to determine their capacity. The rammed earth walls compression strength was determined using flatjacks. Samples of the adobe blocks were obtained so that their physical and mechanical properties could be determined through laboratory testing. Thermography was used to assess the wood elements condition. The proposed structural solution was to maintain the shell of the building and construct a steel frame structure within the existing elements. The steel frame would reduce the span and partially support the roof trusses at their mid-length. The ends of the wood trusses would still bear on the existing second floor walls. The proposed solution reduced significantly the loads on the existing elements, allowing the form the building to be maintained.

Guilherme Parsekian, Douglas Barreto, Marcos Carilho, Vera Domschke, Fernando Fonseca
Framework for a Maintenance-Focused Conservation System

This paper layout the challenges and opportunities in establishing a framework for a conservation system that focuses on maintenance. The study highlighted the requirements for, and constraints of managing and maintaining heritage buildings. Three case studies were considered and in addition, seventeen experts’ interviews, comparative field observations and deliberate archival records were employed to bring out the initial framework. Using focus group discussions of seven experts, the framework was reviewed and validated in order to ensure the development of a model for an effective maintenance management plan and monitoring of heritage buildings. The research investigated how maintenance and monitoring can successfully be implemented as part of the conservation plan.

Arturo Cruz, Vaughan Coffey, Tommy H. T. Chan
Historical and Structural Analysis of a Deteriorated Reinforced Concrete Structure: Student Residence Camilo Torres in Leuven (Belgium)

An increased number of reinforced concrete (RC) structures play an important role in today’s restoration and renovation activity. Unfortunately, we are nowadays experiencing degradation issues, leading to several important technical challenges. Camilo Torres, a student residence of KU Leuven built in 1968 in Leuven (Belgium), is an example of architectural heritage dealing with corrosion problems. The focus of this paper is the historical and on-site investigation of the corroded RC components of the Camilo Torres residence to provide input for structural assessment and the renovation process. Firstly, the history of the building and used materials are investigated. Secondly, on-site analysis is performed to inventorise the damage. Results are compared with findings from previous on-site investigations executed in 2000 and 2014 to examine the damage progress. It was found that the main damage is caused by carbonation-induced corrosion leading to cracking and spalling of the concrete cover. An important part of the rebars have a concrete cover less than 25 mm due to construction errors. Also the presence of honeycombs accelerates the corrosion process.

Charlotte Van Steen, Lydia Koptsopoulou, Els Verstrynge
Reshaping the Villa – Complex Intervention in a 1930’s Structure

The elegant 1930’s villa is situated in a central residential district in Timisoara, Romania. It is positioned back to the small complex of the archbishop’s residence and offices. The damaged modernist structure is to be rehabilitated and expanded to accommodate a Youth Center, connected by landscaping to the archbishop’s complex. Despite not being designed according to seismic codes, the structure showed no sign of degradation caused by seismic action. Therefore, the interventions objectives are: retrofitting the concrete structure, restoring the exteriors and interiors, expanding the house with an auditorium endowed with a stained-glass wall designed by a major artist and creating a connecting landform with the existing park. The retrofitting of the post and beam concrete structure had to leave intact the roofing system, the stairs and the window sills. The scarcity of documentation was compensated by the existence of an intact twin villa, offering information about finishing details. The new auditorium materializes as a “floating” prism, connected to the park by a landform; the stained-glass wall acts as a background for a small chapel in the park. Coordinating these fields is calling for a high degree of interdisciplinary work. An intervention scenario was formulated to offer a common platform in terms of intervention ethics. The continued monitoring of the site conduced to a “creative” adjustment of the project against the values discovered and (continuously) reinstalled. The project aims to restore the villa’s typology in a contemporary perspective, allowing a great flexibility of use for the complex.

Ioan Andreescu, Marius Moșoarcă, Dan-Răzvan Dinu
The Lossetti Tower in Beura-Cardezza (Italy): Structural Assessment and Rehabilitation of a Historical Dry Stone Masonry Building

Dry stone masonry (DSM) is an ancient construction method widely used for vernacular and military buildings in rural and mountain regions. The use of this particular method is due to the large availability of natural stone that characterized these areas. The consolidation of DSM buildings is a challenging issue: in fact, this kind of masonry proved to be scarcely reliable under eccentric and horizontal loads and in absence of elements that are long enough to cross the masonry in its thickness. However, there are very few techniques that can preserve the peculiarities of a masonry texture. This paper presents the design approach that was used for the structural rehabilitation of the Lossetti Tower, a medieval DSM watchtower located in Beura-Cardezza (Italy, Piemonte Region). First, a preliminary research on the building was conducted. Secondly, to better understand the masonry quality, both a 3D laser scanning geometric survey and a technological study of the masonry typology and texture of the tower were executed. Thirdly, to evaluate the mechanical behaviour, a diagonal compression test on the DSM specimens was performed. Finally, after a structural assessment, was developed a tailored design of the strengthening intervention by using the technique of continuous basalt fibers stitching. The proposed system consists in creating a mesh of basalt fiber ropes, that passes through the masonry thickness and ties the blocks together. This system also allows to connect the wall in the transverse direction and to improve the monolithic behaviour of masonry panels in perfect compatibility with the original materials and it was preferred to the more invasive ones also for its reversibility.

Francesco Monni, Enrico Quagliarini, Stefano Lenci
Evaluation of Primitive Extraction Methods from Point Clouds of Cultural Heritage Buildings

This article focuses on the development of tools for automatic recognition and segmentation of the main geometrical characteristics of heritage buildings (walls, towers, roofs, slopes, etc.) to simplify a 3D point cloud into simpler model based on geometric primitives. After evaluation of well known techniques for point cloud segmentation, an hybrid method based on region growing algorithm and primitive fitting by Sample Consensus appears as the most successful. Then, a refinement process is applied by grouping close-by points into voxels and assigning them to the closest primitive. The final algorithm is tested in the front wall of the castle of Chambord, France showing a 94.40% coincidence between the geometric primitives found and manual ground truth. This algorithm might prove useful for obtaining simpler models of cultural heritage structures, which can be used for storage, manipulation and even other types of analysis such as finite element models.

Carlos Pérez-Sinticala, Romain Janvier, Xavier Brunetaud, Sylvie Treuillet, Rafael Aguilar, Benjamín Castañeda
The Unique Baroque Carousel in Hanau, Germany – Renovation, Restauration and Rebuilding of Movement

The carousel, built in 1780, is located on an artificially created hill in a historical spa garden. It is the only still existing carousel worldwide with this unique construction. The building consists of two floors: the above ground pavilion and the underground cylindrical masonry structure. The pavilion is a copy of a Greek round temple with two rows of columns. The interior row are 12 suspended columns, which support a stationary platform. It has got a cupola roof with 12 half-trusses joined at a central column. This roof construction is bearing the platform and the roof, spanning over 15.00 m and is resting on the exterior row of oak columns. These are standing on the underground natural stone masonry. The drive system for the carousel is located in the basement. It looks like a spoke wheel with 16 spokes and a central timber column, which drives a timber ring with the horses and carriages. The spoke wheel was first moved by man power and later by horses. Over the centuries, there were substantial damages by rot, house longhorn beetles and war damages. The result of the damages were vertical deformations of 32 cm, so that the movement did not work for a long time. The aim of the restoration was to conserve as much as possible of the original timber structure and to rebuild the movement with a modern drive system. The carousel is now operating again.

Bernd Mittnacht
The Medieval Grange of Cuna – Siena (Italy)- Interdisciplinary Studies on Masonry Structures

A team of specialist in different subject worked together with a multidisciplinary approach for the conservation of the complex of the Grange of Cuna, the administrative and storage center of the bigger farm of Santa Maria della Scala Hospital in Siena (Italy) in Middle Ages. Laser scanner surveys, archival and bibliographic researches, stratigraphic surveys, structural surveys were carried on and studied by the members of the team on the complex of 167 rooms. The results obtained by specialist approach was frequently discussed and compared in order to obtain a deeper knowledge of the complex of buildings. Structural engineer studies concerned the identification of different typologies of masonry and the structural diagnostics to mechanical characterization. Double flat jack and sonic inspection were performed on tapial adobe, brick masonry with lime and mud mortar.

Elena Manzoni, Filippo Casarin, Silvia Dandria, Alberto Dusi, Marco Giamello, Elisabetta Giorgi, Fabio Gabbrielli, Andrea Magrini, Fausto Randazzo
Compressive Strength of Fired-Clay Brick with Variations in Composition of Rice Husk Ash Compared with Ancient Bricks in Dvāravatī Peroid, Northeast Thailand

Clay raw materials are approved by using stream sediments from a river in the Northeast of Thailand. These sediments at grain sieved for particle size below 75 µm are mixed with black-rice husk ash (RHA) at various ratios of 1:1, 1:2, and 1:3. The clay/RHA mixtures are cast and fired at 900, 1,000, 1,100, and 1,200 °C. A uniaxial compressive test is carried out for all types of specimens acquired from different firing temperatures. The increase of firing temperature increases the overall strength with the exception of the firing temperature of 1,100 °C when RHA is present in the mixture. Results show that inclusive specimens with increased amount of RHA decrease their ultimate compressive strength and elastic modulus. The reduction of the strength with increased RHA is remarkable for specimens fired at 1,100 °C. The compressive strength, elastic modulus of fired-clay blocks shows a linear relationship when compared between two firing temperatures of 900 and 1,200 °C but dramatically fluctuations at firing temperatures between 1,000 and 1,100 °C. The primary conclusion is that the strength of the fired-clay blocks is governed by the quartz-tridymite-cristobalite phase transformation. It is found that cristobalite transforms from tridymite at temperatures as low as 1,100 °C. The strengths and mineral components of the mixed-fired-clay blocks (1:2) at 1,000–1,200 °C can be related to ancient bricks in Fa Daed Song Yang (FDSY), during Dvāravatī period. However, the FDSY bricks show obviously plastic deformation with yield strength of 1.0–1.4 MPa and elastic modulus of 100–230 MPa.

Kritika Trakoolngam, Sarunya Promkotra, Tawiwan Kangsadan
Using Earthquake-Induced Damage on Historical Constructions for the Detection of the Basic Seismological Parameters of Historical Earthquakes

Earthquake-induced damage on historical constructions can reflect the basic characteristics of earthquakes including epicenter location, the seismogenic fault type, the focal depth and the seismic intensity based on the application of macroseismic scales. Taking into account historical buildings response to recent earthquakes, it is concluded that shallow near-field events caused similar building damage. Symmetrical buckling and compression damage of structural elements, bursting of over-stressed elements, symmetrical distribution of damage around a vertical axis and other spatial homothetic motions reflect shallow near-field earthquakes with prevailing vertical component of the earthquake ground motion. Following this approach based solely on field macroseismic observations on historical structures, important conclusions related to historical earthquakes may be drawn. In the case of the 1755 Great Lisbon earthquake, data derived from on-site inspection of well-preserved still-standing damaged historical buildings in Lisbon and artworks illustrating buildings that suffered damage from this sequence were used. In brief, the studied buildings present damage with symmetrical distribution around a vertical axis and partial collapse of upper parts within their footprint. Based on the aforementioned, this damage is attributed to a shallow earthquake with epicenter located very close to Lisbon, a strong vertical component and perhaps of not so great magnitude preceding or following the 1755 Great Lisbon earthquake with epicenter determined in the ocean to the west of Lisbon and generated the devastating tsunami. It is suggested that the aforementioned approach can be applied either in historic earthquakes or complementarily in recent events when the available seismological information are inadequate.

Spyridon Mavroulis, Alexia Grampas, Vassiliki Alexoudi, Ioannis Taflampas, Panayotis Carydis, Efthymios Lekkas
In Favour of Collaborative Research Methodologies. The Case of the Architectural Design for the Renewal of São Francisco de Real Convent, in Braga, Portugal

This paper reports on the architectural design process for the reuse of São Francisco Convent and its adaptation into the Archaeology Unit of Minho University, which was conducted in a strong interdisciplinary collaboration between several disciplines, such as Archaeology, History and Engineering. The convent was built in the sixteenth century, reusing the 7th century pre-existing mausoleum of São Frutuoso and the medieval monastic installations, undergoing a deep reform during the 18th century. Responding to contemporary functional and symbolic demands over the centuries, the ensemble’s spatial metamorphoses were not registered and this lack of information originated relevant academic debates throughout the 20th century.The architectural design required a thorough research on the history of the building, developed in strict collaboration with archaeologists working on site and the Engineering team that lead inspection and diagnosis reports. This collaboration allowed to understand the building’s transformation in its longue durée, decoding some of the functional, constructive and symbolic logics that determined its evolution, articulating essential knowledge when defining the proposed solution for the convent and the ex-novo buildings. Regarding tectonic decisions, some options were intentionally distinctive while others agreed upon traditional techniques and materials, ensuring a coherent design logic and the ensemble’s integrity in its contemporary circumstance. Both the process that sustained the architectural design and the solution established, proved that only an intervention based on collaborative methodologies can enable the holistic understanding of the heritage building as a document to be read and interpreted in its effective ampleness.

Maria Manuel Oliveira, João Pedro Fonte, João Pereira Silva
Diagnosis and Structural Assessment of the Fortress and Convent of Ínsua de São Isidro

Documentation, inspection and structural analysis are fundamental techniques to understand the behavior of historical constructions, determine their vulnerability and to propose interventions. The interventions on heritage buildings and their efficiency are highly related with the knowledge of the structure. Within this framework, an assessment focused on the Chapel of the Fortress and Convent of Ínsua de São Isidro, placed on an inhabited island in the northwest of Portugal, is presented. The study of this monument represents a challenging task, due to its severe deterioration, mainly caused by weathering and inadequate interventions, and its location (limited access). Nonetheless, the analysis was carried out using three approaches. In the first approach, a detailed historical review and general visual inspection of the entire complex were done. Next, the visual inspection and non-destructive tests in the chapel were carried out, aiming at obtaining the properties of the structure. The non-destructive tests included sonic tests, impact-echo tests, GPR tests, photogrammetry and dynamic identification tests. In the third approach, a numerical model of the chapel was prepared and calibrated. Finally, the structural assessment for the vertical and seismic loading was performed. The results showed that the chapel presents an appropriated load capacity. However, interventions to safeguard the integrity of the chapel must be considered. Furthermore, further studies are recommended, aiming at validating the conclusions obtained from the numerical modelling.

Santiago Granda, Saulo Lopez, Fabiana Navia, Eduardo Ramirez, Rafael Ramirez, Luis F. Ramos, Nuno Mendes
Importance of Environmental Monitoring After Rehabilitation of Heritage Masonry Buildings in Seismic Zone: Case Study

In high seismic risk area, updating or renewing existing structures will increasingly impact the sustainability of local communities. This problem is heightened in the restoration of buildings with historical patrimonial value, where the importance is given by the architectural and historical values, and the structural challenge is more important when they have to be enabled for public use (such as schools, churches or museums). In the case of large masonry heritage buildings in high seismic risk area, the lack of monitoring of environmental conditions can directly impact on structural integrity. In this case we analyze the pathologies founded in a heritage school because of the conditions of habitability, after its value and new functioning as a museum. For this purpose, the condition of the thick walls and reinforcement structure has been evaluated and measurements of temperature and humidity were carried out in different stations, both in open spaces and in enclosed spaces, obtaining results that demonstrate the importance of environmental monitoring after the putting in value, to avoid pathologies that can affect the safety and durability of the rehabilitated structure.

María Domizio, Noemi Maldonado, Luis Fernández Luco, Pablo Arena
Restoration of the Ottoman Bath on Kastellorizo

The restoration project concerns of the 19th century Ottoman hammam of Kastellorizo. The hammam is a bath installation of the Muslim quarter in the unique settlement of the most remote Greek island in the southeastern Aegean Sea. Before restoration, it was abandoned and downgraded, despite its location adjacent to the most powerful landmark of the island, the “Red Castle”, at the highest point of the Kavos promontory. With the initiative of “Friends of Kastellorizo”, the vision of preserving and enhancing the hammam in order for it to be fully and functionally restored, was realised. The hammam is a small building of general external dimensions 4.15 × 3.95 m covered with a dome. It comprises only a hot room, with a separate narrow space attached for the water tank with the furnace underneath. Due to a long period of neglect, the hammam had lost many of its basic elements. These were both structural and functional, such as the hypocaust, the furnace, the staircase, the doors, the basins, tabs etc. Restoring the monument was a very challenging and multifaceted task. Apart from restoring the functional network in traditional terms, we had to respect all historical layering such as the Italian graffiti and inscriptions from WWII. Conservation methods and non-destructive methods for construction analysis and network inspection had to be employed. Thus, the approach was interdisciplinary, with many specialists working together with the aim of re-integrating the monument into the local community, by completely recovering its original state and reinstating its function as a bath.

Fotini Chalvantzi, Konstantinos I. Toumpakaris, Archontoula Diakomanoli, Klisthenis Dimitriadis, Alexandra Gavrili
Sensitivity and Preliminary Analyses for the Seismic Assessment of Ardinghelli Palace

When dealing with the seismic assessment of historical buildings, a higher diversity in uncertainties related to construction details, geometry, and material properties is expected. Moreover, for the conservation of the monument a very low invasiveness degree is required during the investigation process. The procedures available in standards, based on the definition of a Knowledge Level for the whole structure, by following investigation plans that do not take into consideration the specific features of the building, may not serve efficiently in this context. These facts rise the need for a new procedure, rationally implemented to best fit the characteristics of the structure under investigation time by time. Within this context, the procedure based on a Sensitivity and a Preliminary Analyses proposed in Cattari et al. 2014 and Haddad et al. 2016/2017 is executed on Ardinghelli Palace in L’Aquila Italy. The sensitivity analysis is addressed to detect the uncertain parameters mostly affecting the structural response and defines what to investigate. While the preliminary analysis carries out a complementary role in identifying where in the structure shall we investigate, in order to set an effective investigation plan and increase the knowledge about it.

Jamil Haddad, Serena Cattari, Sergio Lagomarsino
Safety of the Architectural Heritage: Structural Assessment of the Zuccaro’s Tower in Mantua

The paper focuses on the experimental procedures adopted for assessing the structural condition of the Zuccaro’s Tower situated in Mantua. A research program was planned and included historic and documentary research, direct survey and dynamic tests in operational conditions. The paper reports the outcomes of a wide multi-disciplinary research and underlines the strategic importance of direct visual survey (indicating the regions affected by major discontinuities) and dynamic tests (revealing anomalous warping distortion of the tower’s cross-sections) in the preliminary assessment of the ancient structure.

Antonella Saisi, Stefania Terenzoni, Antonello Ruccolo, Carmelo Gentile
Preliminary Structural Diagnosis of the Sacsamarca Church in Peru Using Photogrammetry and IR Thermography

The application of different diagnostic techniques in a historical construction allows the obtained information to complement each other, which contributes to a detailed and complete data of the conservation state of a building. This paper provides a structural diagnosis of the church “Virgen de la Asunción” of Sacsamarca village in Ayacucho, Peru. Due to exposure to weathering, torrential rains, and past seismic activity, the Sacsamarca church has a poor conservation state. Hence, it is necessary to identify properly the structural pathologies and their extension in the church. A first part of the research was the development of a three-dimensional geometrical model using aerial and terrestrial photogrammetry, aiming to characterize the general damage state of the building, including inaccessible zones. The data generated from the aerial and terrestrial acquisition allowed a detailed identification of the pathologies on the façades. A photographic record was used to detect the anomalies in the interior of the church. Finally, a passive thermography campaign was carried out in order to find additional damage and corroborate the pathologies identified during the visual inspection. The structural diagnosis evidenced that the southern and western wall of the church of Sacsamarca present a high collapse risk, for which emergency actions for their stabilization are recommended.

Carolina Briceño, Mauricio Gonzales, Carlos Yaya, Susana Moreira, Rafael Aguilar
Production of Organic Lime Mortar to Adapt CO2 for Construction of Scared Groves @ Auroville, Puducherry, India

Lime is one of the oldest construction material and it shows greater durability properties. The main aim of the study is to analyse the organic modified lime mortars used as bedding and plastering mortar at Sacred Groves, Auroville Pondicherry, India. Locally available organics namely kadukai (Terminalia chebula) and jaggery (Unrefined sugar) were used to alter the properties of lime based mortars as added by ancestors in traditional buildings. Organics on fermentation reduce to carbon - di - oxide and enhances the formation of calcite and alters the hydrated phases and mechanical properties of lime mortar. Lime and quarry dust in the ratio of 1:3 with fermented herbal extract were casted and tested for compressive, flexural strength. Organic modified mortars shown better performance than reference mortars. Analytical techniques XRD, FESEM with EDX and FT-IR were undergone to study hydrated phases, morphology and presence of organics.

Sriram Pradeep, Thirumalini Selvaraj
Structural Balance of Historical Aggregates

Historical urban centers present valuable buildings with different structural types and different ages or stiles, in total structural disorder. Those buildings present different structural problems as cracks and local damages. But they usually work together, as aggregates, transmitting the forces from one building to another. The way they interact is very difficult to be evaluated or calculated, but form a static balance of the aggregate, both for buildings with severe damages and buildings with high structural behavior. That is the reason why any consolidation or demolition work should be made taking into consideration this static balance. This article presents in which manner the historical buildings located on St. George square, Timisoara, Romania interacted as aggregate during centuries and how this interaction influenced the structural and architectural final design solution. Also, the damage that was discovered on the neighborhood buildings during the intervention, generated changes to the initial project, in order to respect the natural behavior of the historical aggregate.

Marius Mosoarca, Valeriu Stoian, Margareta Florea, Marius Niculescu
Promoting Vernacular Architecture, A Basis for Building Back Safer? A Case Study from Nepal

Reconstruction projects must rely on local resources and capacities to effectively reduce inhabitants’ vulnerability on the long run. Vernacular architecture often reveals disaster-resilient strategies that are affordable and accessible to most people. Documenting and validating these practices through scientific research help in promoting them at different institutional and political levels. The work presented in this paper is a first step on the identification of the main factors affecting the incorporation of new practices in local building cultures and on the understanding of the extent to which these practices actually improve inhabitants’ resilience. It results from a comparative study of two reconstruction projects in Nepal on the one hand and on the other hand from the research conducted by 3SR on a technique that is being reincorporated into inhabitants’ building cultures: the regular insertion of seismic bands. The experimental campaign included tests on seismic bands built with different materials and cyclically loaded to assess the energy dissipated by the different configurations. The strong connection between academic and operational settings allowed for a direct contribution to the activities carried out by local stakeholders. Yet, the main factor affecting the people’s acceptance of Building Back Safer (BBS) messages was the official guidelines they had to comply with to get subsidies; but it often resulted in important safety issues as their unaffordability induced improper implementations. Working on social aspects and side by side with local authorities is thus essential to widely implement proper BBS messages.

Eugénie Crété, Santosh Yadav, Yannick Sieffert, Majid Hajmirbaba, Julien Hosta, Miguel Ferreira Mendes, Olivier Moles, Pawan Shrestha, Philippe Garnier
Enhancing Livability Through Universal Usability: A Case of City Palace Museum of Udaipur

Udaipur, the historic capital of Mewar region in the Northwest part of India, founded in 1559AD is one of the most popular tourist destinations worldwide. The magnificent city palace complex of Udaipur stands on a low ridge of Aravalli range overlooking Lake Pichola on the west side. The city palace complex exhibits its 16th century strategic defensive planning and consists of series of palaces which are built over generations and represents as one unit though dividing the area spatially into private royal areas and public zones at different levels due to topography. Since 1969 a major portion of the city palace complex was set up as a museum and attracts on an average 8, 00,000 domestic and overseas visitors. One of the key requirements for an inclusive and sustainable society is that everyone should be able to participate in and enjoy the social, economic and cultural assets of that society (NDA 2011). For some people like persons with disabilities and elderly, it is difficult or sometimes impossible to access or visit heritage buildings and places. Making the built heritage more accessible in an appropriate and sensitive manner can increase awareness and appreciation of its historic, cultural, social and economic value (NDA 2011). This paper represents the process involved in proposing solutions for Universal Access in the heritage site of Udaipur City Palace Complex. To achieve this a systematical strategy was followed involving rigorous literature review, visit to the site and access audit, documentation, assessment and finally the various solutions to the problems identified.

Shweta Vardia, Rachna Khare, Poonam Khan
Durability, Sustainability and Restorability of the Saudi Desert Village of Historic Al-Ghat

Al-Ghat is a small desert settlement in central Saudi Arabia. Its traditional urban and architectural characteristics reveal the ability of earlier societies to combat harsh desert conditions and create pleasant indoor and outdoor environments. This paper analytically discusses these characteristics. The analysis covers the urban form, open spaces and land uses. Architecturally, components of a typical traditional dwelling of al-Ghat are explained in terms of spatial usage, construction materials and techniques, and decoration. The explanation is also interrelated with local environmental and socio-cultural traits of al-Ghat. Though old al-Ghat has been abandoned by its inhabitants, the paper ends exploring the current public efforts of restoration.

Hisham Mortada
Restoration of the Masonry Arch Bridge Over Jamor River in the National Palace of Queluz

The National Palace of Queluz is a reference of Portuguese Heritage and is listed as National Monument since 1910. Its Gardens extend to around 16 acres and have become a reference in European historical gardens due to their complex and harmonious landscaping. However, over the years, the Palace and the Gardens have been severely damaged by a great fire and various floods. In 2012 the management of the Palace and the Gardens was awarded to Parques de Sintra – Monte da Lua and a global restoration project was started. This paper focus on part of that project: the restoration of a masonry arch bridge over the Jamor River that accesses to the Botanical Garden. This bridge was probably constructed between 1752 and 1790 when a lot of construction work took place in the south part of the Gardens. However due to the cyclic floods and other causes, some repair works were made throughout the years, which included the use of concrete in 1967. In this project it was identified a range of pathologies and some severe structural problems, such as the loss of material in the left abutment as well as a crack that crosses the bridge vertically and horizontally. The intervention strategy, based on the minimal intervention philosophy, was defined by a multidisciplinary team and combines structural operations, that include the strengthening of the left abutment through micro piles and the repair and retrofitting of the arch using carbon fibers, with conservation works on originals mortars, bricklaying and pictorial finishing.

Marta Alves, Catarina Vaz, Augusto Gomes, Francisco Virtuoso
The Restoration of the Skokloster Castle Roof Structure

The roof structure of the 17th century Skokloster castle has recently been restored. The task of finding a solution to the restoration of the timber structure was delicate, as: (a) the roof structure has a highly complex structural behaviour; (b) Skokloster Castle is of remarkably high cultural value; (c) Skokloster Castle has a specific role in Swedish restoration history, as it contributed in the 1960s and 70s to the establishment of a new ideological approach, characterised by the ambition to make as gentle interventions as possible; and (d) successful restoration required methods that would allow for close collaboration and dialogue between the engineers, the architect and the craftsmen. The roof structures were documented by traditional measuring techniques and with laser scanning techniques. Comparative studies of European baroque roof structures were carried out. Modelling and FEM analysis were undertaken to assess the structural behaviour and to design restoration measures. The simulations made using FEM were also combined with visualisation to support the dialogue between the engineers, the architect and the craftsmen.The design of the roof structure has similarities with comparable 17th century roof structures in central European countries, but without some of their qualities. The structure had poorly designed corners, causing weaknesses in the structure. Restoration measures carried out in the 1970s were found to be ineffective. The solution involved an amelioration of the original design, based on designs found in 17th century literature as well as in archetypes found in Romanian Baroque roofs.

Carl Thelin, Folke Höst
Experimental Dynamic Behavior of Historical Buildings at Scale Model: San Raymundo Church, Guatemala

Guatemala has an enormous set of churches of colonial architecture dating from the fifteenth century. Many of these considered part of the National Cultural Patrimony. It is necessary to identify the dynamic characteristics of historic buildings, to determine the response of their structures and materials under strong seismic movements, for retrofit engineering purposes. At present this information of historical structures is very scarce. This study to the Church of San Raymundo, a colonial church that presented severe damage by the earthquake in Guatemala on February 4, 1976, is a first contribution to the implementation of the Sendai Framework Cultural Heritage and Architectural Patrimony Preservation initiatives in Guatemala. This study was carried out in the Seismology Laboratory of the Research Institute of Engineering, Mathematics and Physical Sciences (in3) of the Mariano Gálvez University of Guatemala. The model was built to scale 1:8.75, with dimensions 2.80 × 3.00 × 1.75 m. The model was instrumented with accelerometers and deformation sensors to record the behavior of the structure and was subjected to local earthquakes registered in the Seismological Service (in3), on a 3 m × 3 m bi-axial seismic simulator. Resulting in damage to the structure, the collapse of the dome and vault with the earthquake scaled from November 7, 2012 in the department of San Marcos, Guatemala. The obtained results allow evaluating and acquiring experience of the dynamic behavior of historical buildings and that said results are compared with those of the mathematical model for future studies of structures of similar characteristics.

Rolando Torres, Alberto Blanco, Janeth De Paz, Jorge Campo
Backmatter
Metadata
Title
Structural Analysis of Historical Constructions
Editors
Rafael Aguilar
Daniel Torrealva
Susana Moreira
Miguel A. Pando
Luis F. Ramos
Copyright Year
2019
Publisher
Springer International Publishing
Electronic ISBN
978-3-319-99441-3
Print ISBN
978-3-319-99440-6
DOI
https://doi.org/10.1007/978-3-319-99441-3