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2022 | Buch

Progresses in European Earthquake Engineering and Seismology

Third European Conference on Earthquake Engineering and Seismology – Bucharest, 2022


Über dieses Buch

This book encompasses the most challenging topics in earthquake engineering and seismology aiming at seismic risk reduction and reveals the outstanding progresses made in Europe in the past four years. Earthquakes pose a significant threat to countries around the world. But, equipped with the right knowledge and tools, engineers and seismologists can support policy and decision makers and building officials in creating a safer future for all of us. In this paradigm, the Third European Conference on Earthquake Engineering and Seismology (3ECEES) is organized in Bucharest (Romania) in September 2022 by the Romanian Association for Earthquake Engineering, Technical University of Civil Engineering of Bucharest and National Institute for Earth Physics. This outstanding scientific event is the third in a series started in 2006 in Geneva, Switzerland and continued in 2014 in Istanbul, Turkey.

The papers included in this book are written by the most prominent contemporary European scholars in the two-folded fields of 3ECEES. The Distinguished Nicholas Ambraseys, along with 28 invited lectures providing the best knowledge in the fields of earthquake engineering and seismology, are shared with the general readership of this book. The book is organized in three parts, as follows: (1) Seismicity, engineering seismology and seismic hazard, (2) Seismic risk assessment and mitigation, and (3) Structural earthquake engineering. The 29 contributed papers for this book are shared among these three parts almost equally.

Chapter “The Challenge of the Integrated Seismic Strengthening and Environmental Upgrading of Existing Buildings” is available open access under a Creative Commons Attribution 4.0 International License via



Seismicity, Engineering Seismology and Seismic Hazard

The 2020 European Seismic Hazard Model: Milestones and Lessons Learned
The 2020 update of the European Seismic Hazard Model (ESHM20) is the most recent seismic hazard model of the Euro-Mediterranean region. It was built upon unified and homogenized datasets including earthquake catalogues, active faults, ground motion recordings and state-of-the-art modelling components, i.e. earthquake rates forecast and regionally variable ground motion characteristic models. ESHM20 replaces the 2013 European Seismic Hazard Model (ESHM13), and it is the first regional model to provide two informative hazard maps for the next update of the European Seismic Design Code (CEN EC8). ESHM20 is also one of the key components of the first publicly available seismic risk model for Europe. This chapter provides a short summary of ESHM20 by highlighting its main features and describing some lessons learned during the model’s development.
Laurentiu Danciu, Graeme Weatherill, Andrea Rovida, Roberto Basili, Pierre-Yves Bard, Céline Beauval, Shyam Nandan, Marco Pagani, Helen Crowley, Karin Sesetyan, Susana Villanova, Celso Reyes, M. Marti, Fabrice Cotton, Stefan Wiemer, Domenico Giardini
Developments Relating to Seismic Action in the Eurocode 8 of Next Generation
The purpose of this paper is to present the main changes introduced by CEN-TC250-SC8 concerning seismic action in the next revision of Eurocode 8, consisting principally of:
  • Introducing the concept of seismic action class in place of seismicity level.
  • Anchoring the standard spectrum by its plateau value, Sα, and its value at 1 s spectral period, Sβ, instead of the PGA.
  • Introducing, in an informative annex, two European hazard maps, one for Sα, and one for Sβ, both defined for 475 years return period, based on the ESHM20 hazard model.
  • Revising the site categorization by introducing the bed rock depth in addition to the shear wave velocity.
  • Introducing new site amplification factors based on this site categorisation and dependent on input motion level.
  • Introducing a new spatial model of input motion for bridges and pipelines.
  • Providing miscellaneous specifications on conventional values of magnitude and strong motion duration, dependence of spectra to damping, …
Pierre Labbé, Roberto Paolucci
Hard as a Rock? Reconsidering Rock-Site Seismic Response and Reference Ground Motions
It is well known that ground motion on soil can be amplified at low frequencies due to the stiffness (shear-wave velocity) contrasts and geometry of near-surface layers, giving rise to various categories in terms of site classification. The seismic response of rock can be more difficult to characterise. In general applications, it is often considered as rather homogeneous. In more specialised applications, the differences between soft and hard rock are taken into account. It has been shown analytically that at higher frequencies, ground motion on hard rock can he stronger than on soft rock, if the reduction in attenuation (damping) is stronger than the amplification due to velocity contrasts. Empirical datasets however indicate that quantifying this amplification effect is not straightforward. Stiffness itself is not a good proxy for damping in rock, and its apparent damping may also include other parameters such as amplification, leading to significant uncertainty and variability in rock-site response. This can have strong implications for seismology (reference stations, seismic source), cascading to engineering seismology (ground-motion prediction/adjustment, hazard), and earthquake engineering (input motions, critical infrastructure safety). This paper uses example cases to illustrate the effect that differences in attenuation can have on the response spectral features of a range of rock sites, from soft to very hard, all belonging to the same class as per EC8 (class A). The short-period amplification illustrated indicates that it would be interesting to revisit rock-site classification in more detail.
Olga-Joan Ktenidou
Tomb Raiders of the Lost Accelerogram: A Fresh Look on a Stale Problem
Throughout recorded history, accelerograms have displayed an unfortunate tendency to become unrecorded and lost. Statistically speaking, even after the advent of low-cost accelerometers, the ground motion retains an almost 100% chance of staying unobserved at any given point. One may only place some limits on the peak amplitude of ground motion by observing its effects, or lack thereof. To do so, seismologists run to the mountains, looking for fragile geological features, such as precariously balanced rocks. Structural engineers take a slightly more cinematic and sinister approach. They put on their fedora hats (or tank top and shorts, for video game enthusiasts) and go tomb raiding, searching for rocking rigid bodies that may have survived or toppled in graveyards, tombs, mausoleums, churches, and temples. Yet how is one to best make sense of such low-entropy (and sometimes contradictory) uncertain information? Let’s have some fun by blowing an old problem to smithereens, perhaps needlessly bringing to bear all the tools of contemporary earthquake engineering, ranging from ground motion prediction models and correlation structures to rocking body fragilities and Bayesian analysis.
Dimitrios Vamvatsikos, Christos G. Lachanas
Mars from the InSight: Seismology Beyond Earth
When NASA’s InSight lander touched down in Elysium Planitia, Mars, in November 2018 and deployed its seismometer SEIS, it ushered in a new age for planetary seismology - more than 40 years after the first attempt to record marsquakes with the Viking missions. SEIS, an extremely sensitive instrument, has by now provided near continuous seismic records for more than 3 years. Its rich dataset shows Mars to be seismically active, with over 1,300 marsquakes detected so far, mostly with magnitudes below 4. Despite their small size, these quakes provide important and unprecedented constraints on the interior structure of the planet, from the shallow subsurface via the crust, the lithosphere, and the mantle transition zone down to the core, and allow to study Martian tectonics and thermo-chemical evolution. Single-station seismology has answered some of the big questions about the interior of our planetary neighbour, and this contribution gives an overview of results and surprises so far.
Brigitte Knapmeyer-Endrun, W. Bruce Banerdt, Suzanne E. Smrekar, Philippe Lognonné, Domenico Giardini, Caroline Beghein, Éric Beucler, Ebru Bozdağ, John Clinton, Raphael F. Garcia, Jessica C. E. Irving, Taichi Kawamura, Sharon Kedar, Ludovic Margerin, Mark P. Panning, Tom W. Pike, Ana-Catalina Plesa, Nicholas Schmerr, Nicholas Teanby, Renee Weber, Mark Wieczorek, Salma Barkaoui, Nienke Brinkman, Savas Ceylan, Constantinos Charalambous, Nicolas Compaire, Nikolaj Dahmen, Martin van Driel, Anna Horleston, Quancheng Huang, Kenneth Hurst, Balthasar Kenda, Amir Khan, Doyeon Kim, Martin Knapmeyer, Jiaqi Li, Sabrina Menina, Naomi Murdoch, Clément Perrin, Martin Schimmel, Simon C. Stähler, Eléonore Stutzmann
GMPEs for Romania’s Vrancea Intermediate Depth Seismic Source
The strong earthquakes from Romania’s Vrancea intermediate depth seismic source were felt on large areas in Europe (Bulgaria, Republic of Moldova, Serbia, Hungary, Ukraine, Republic of North Macedonia, etc.) and have induced significant damage and human losses not only in Romania, but also in neighboring countries. Vrancea source is a major contributor to the seismic hazard of Romania, Republic of Moldova, Bulgaria, and Southern Ukraine. As a fundamental component of the seismic hazard assessment in the region, Vrancea specific GMPEs have been of high interest for local and international researchers. The paper presents an overview of the almost 30 years of history of GMPEs developed for Vrancea seismic source, in relation to the available seismic events database, ground motion records database and soil categories, from the early relations predicting peak ground accelerations to the modern relations predicting spectral accelerations.
Alexandru Aldea, Radu Vacareanu, Dan Lungu, Florin Pavel, Cristian Arion
Reliability-Based Liquefaction Triggering Assessment Framework: A Unified Approach for SPT-CPT-Vs
For longer than four decades, the current practice for liquefaction triggering engineering assessments have been dominated by case history-based deterministic and probabilistic models. The predictive model proposals have been constituted based on different sets of case histories concerning in-situ test indices, namely standard penetration test (SPT) N value, cone penetration test (CPT) q, and shear-wave velocity (Vs), etc. The present study uses the databases of Cetin et al., Moss et al., and Kayen et al. together to develop a unified liquefaction triggering predictive model within a probabilistic framework. The scope concentrates on the illustrative introduction of the proposed unified reliability-based framework along with the comparative presentation of model predictions. The unified model enables a joint assessment of liquefaction performance predictions at sites, where different in-situ test indices are used individually or jointly to characterize the soil resistance against liquefaction.
K. Onder Cetin, B. Umut Ayhan, Robb Moss, Robert Kayen
Seismic Detection Efficiency of a New Inexpensive MEMS Sensor Prototype: Application to Micro-seismicity and Distant Moderate Earthquakes
We evaluate the seismicity detection capability of a new inexpensive triaxial accelerometer prototype based on micro-electro-mechanical systems (MEMS technology). Networks of MEMS sensors were installed in northern and central Italy. These devices recorded major earthquakes as well as small seismic events (1.5  < Ml < 6.3). Where possible, MEMS are here compared to the closest high‐quality seismic stations belonging to national seismic networks. Analysis was made for the micro-seismicity and distant seismic events, far ~400 km from the MEMS sensors’ arrays. The comparison, in terms of PGA and spectral responses between MEMS and high-quality stations, confirms that the signals are in good agreement. The inexpensive MEMS sensors can detect small local events and distant moderate earthquakes, providing an efficient characterization of the ground motion parameters. This confirms that the proposed accelerometer prototypes are promising tools to integrate traditional networks for seismicity monitoring.
Valeria Cascone, Jacopo Boaga

Seismic Risk Assessment and Mitigation

Earthquake and Structural Engineering Science for Civil Protection
The importance of a close relationship between civil protection organizations and scientific community is widely recognized today at international and European level. In this perspective, research projects on risks are more and more focused on the production of outcomes that are application oriented, requiring the involvement of civil protection organizations, and creating a well-structured knowledge network within a European civil protection framework.
For about forty years, the Italian civil protection has relied upon the scientific community to find the best solutions, or at least those based on the most advanced and consolidated knowledge, for activities that concern the entire disaster risk management cycle: from forecasting and prevention to the management and overcoming of the emergency, as well as for repair and reconstruction activities after major events. The interactions between civil protection and scientific community take place in Italy mostly through the so-called Competence Centers and the Major Risk Commission. They both work with an interdisciplinary, multisectoral and, when needed, multi-hazard risk approach.
This paper aims to describe how the Competence Centers, i.e. the scientific operational partners that provide products resulting from research and innovation activities that can be integrated in civil protection activities, operate in a way that has evolved over the years, as the advice of the scientific community has become increasingly fundamental in the decision-making process for civil protection. The focus will be especially on the scientific activities and some important results and products related to seismic risk and structural engineering applications.
Mauro Dolce
European Seismic Risk Model – Insights and Emerging Research Topics
A new European Seismic Risk Model (ESRM20) was recently released to the scientific community (http://​risk.​efehr.​org). This model combines the European Seismic Hazard Model (ESHM20), a regional model of site response based on proxy data (topography and geology), an exposure model describing the distribution of building classes for 44 countries, and vulnerability models for over 200 building classes, in order to estimate key seismic risk metrics at the European scale, including average annual losses and return period economic losses and loss of life. This Chapter explores some of the insights from this model, including the regions of highest risk in Europe, the building classes contributing most to the losses, and the potential impact of retrofitting those building classes. All of the models, as well as the underlying datasets, workflows and software have been openly released, thus allowing reproducibility of the results, but also providing a set of resources that can be used to kick-start additional research. Examples of how these resources can be used by researchers will be given herein, as well as new research topics emerging from the models.
Helen Crowley, Jamal Dabbeek, Venetia Despotaki, Daniela Rodrigues, Luis Martins, Vitor Silva, Xavier Romão, Nuno Pereira, Graeme Weatherill, Laurentiu Danciu
Incorporating Future Earthquake Risk in Disaster Risk Management
Factors such as the increase in the global population, economic growth, climate change, and aging infrastructure are contributing to the increase in the impact caused by earthquakes. Despite the overwhelming evidence of the dynamic nature of earthquake risk, current disaster risk management is mostly informed by static risk information. Consequently, risk reduction strategies might rapidly become obsolete, insufficient, and inadequate to properly address disaster risk. We assessed how the three main components (hazard, exposure and vulnerability) of earthquake risk are expected to evolve in the future, and how those changes will impact the trajectory of earthquake risk for the forthcoming decades. We used machine learning algorithms and remote-sensing datasets between 1975 and 2015 to perform these projections for the country of Montenegro. Such analysis allows identifying the drivers of earthquake risk, and how risk reduction measures can be designed and implemented to achieve specific risk reduction targets.
Vitor Silva, Alejandro Calderon, Lana Todorovic, Luis Martins
New Insights on the Seismic Exposure and Vulnerability of Structures in Romania
The study focuses on new insights related to the seismic exposure and vulnerability of buildings in Romania. Information collected during the national census performed in 1992 and 2011 is employed for a thorough evaluation of the seismic exposure of buildings. Damage data complied after the Vrancea 1977 earthquake, as well as the evolution of the codes employed for the design of various buildings and structures are briefly discussed in order to better evaluate the seismic vulnerability. In addition, the evolution of the construction practice in Romania is discussed, as well. Finally, the EFEHR seismic exposure and vulnerability models for Romania are analyzed.
Florin Pavel, Radu Vacareanu, Cristian Arion, Alexandru Aldea
Seismic Risk Assessment and Preliminary Intervention Cost-Benefit Analysis for the Building Stock of Istanbul
Past destructive earthquakes in highly seismic areas of the world have shown that the failure of earthquake-prone buildings endangers the lives of the inhabitants and may cause enormous financial losses. Management of the seismic risks through effective mitigation efforts requires the identification of risky buildings in our cities. However, this is a challenging task, since the building stock is generally too huge to be investigated by using detailed seismic assessment methods provided by current technical documents. On the other hand, available quick assessment methods such as street surveys may lead to remarkably erroneous estimations, particularly if the building stock is composed of substandard buildings constructed without proper engineering service and inspection. Thus, reliable rapid assessment methodologies are required for seismic risk identification and classification of buildings in big cities. In the scope of a recent campaign launched by the Istanbul Metropolitan Municipality (IMM), PERA2019 rapid assessment methodology has been employed on more than 20000 buildings from 33 different districts of Istanbul. In this study, firstly, the preliminary results obtained for those buildings by considering a Scenario-Based Earthquake case are summarized. Then, a preliminary cost-benefit analysis considering the pre-earthquake and post-earthquake intervention costs (such as retrofitting, reconstruction and structural and non-structural damage repairs) together with the secondary costs (such as interruptions on the use of damaged buildings) have been performed and discussed. The obtained results indicate that a synchronized effort orchestrating rapid assessment methodologies and intervention strategies may provide feasible and effective solutions for reduction of seismic risks in big cities like Istanbul.
Cem Demir, Mustafa Comert, Hasan Huseyin Aydogdu, Alper Ilki
Seismic Performance of Heritage Clay Brick and Lime Mortar Masonry Structures
This paper summarizes recent investigations into the structural and material response of ambient-dry and wet clay-brick and lime-mortar masonry elements, with focus on those used in heritage structures in Historic Cairo. In addition to cyclic tests on large-scale masonry walls subjected to lateral displacement and compressive gravity loads, the studies included complementary tests on small scale masonry panels and material specimens. It is shown that moisture can have a notable effect on the main material properties, including the shear and compression strengths, brick-mortar interaction parameters, and the elastic and shear moduli. The extent of the moisture effects is a function of the governing behaviour and material characteristics as well as the interaction between shear and precompression stresses and can lead to a loss of more than a third of the stiffness and strength in addition to a reduction in ductility. Simple and cost-effective strengthening techniques, using textile-reinforced mortars, for enhancing the lateral performance of low-strength heritage masonry element, are also considered in this study. The effectiveness of the strengthening approach is illustrated and quantified through additional tests on the small-scale panels and large-scale wall specimens. It is shown that simple analytical assessment methods can be reliably adapted for predicting the response of the wall specimens, in terms of the lateral stiffness, strength and overall load-deformation behaviour.
Ahmed Y. Elghazouli, Dan V. Bompa, Sherif A. Mourad, Ahmed Elyamani
Analysis Case Studies in Evaluation, Rehabilitation and Reconstruction of the Built Heritage
The conservation of the built heritage represents one of the main challenges for the future of construction in Europe and will acquire relevance in the world context. Efforts regarding retrofit, rehabilitation and reconstruction of damaged built cultural heritage have increasingly attracted attention to rescue or maintain cultural value.
Due to their complexity, heritage buildings’ safety assessment and rehabilitation carry relevant challenges concerning structural engineering skills and the required structural analysis techniques. Misleading assumptions can lead either to unsafe assessments or serious capacity underestimations, thus implying excessive costs for rehabilitation and eventually avoidable usage limitations.
The analysis of carefully chosen case studies provides helpful information that may be analogically applied in different contexts of assessment rehabilitation and reconstruction of historical buildings. In this context, two cases are presented and discussed to provide information and helpful knowledge for application to other built heritage.
Rita Bento
Urban-Scale Risk Assessment: (How) Does It Change If We Include SSI and Site Amplification Effects?
We introduce, develop, compare and apply two holistic, modular methods to include site amplification (SA) and soil-structure interaction (SSI) effects in urban scale earthquake risk assessment. We propose two methods, including a detailed and a simplified structural modeling approach. SSI and SA effects are explicitly considered in both approaches’ fragility and vulnerability calculation. The detailed method is accompanied by a significant time and effort cost, while it more elaborately captures the structural response. The simplified modeling approach facilitates the analyses procedures; however, it neglects certain aspects of the more complex nonlinear dynamic structural behavior. We applied the two approaches to the risk assessment of a block of buildings in Thessaloniki, Greece, and demonstrated each method’s advantages and disadvantages. Our main results suggest that SA effects increase fragility more than SSI. Using a detailed modeling approach may lead to a more reliable estimate of the expected losses, compromised, however, by the significantly higher modeling and computational effort.
Dimitris Pitilakis, Christos Petridis, Chiara Amendola
Implementation of Emerging Technologies in Seismic Risk Estimation
Ever increasing population in seismically active urban areas, aging building stock, and expansion of urbanization to previously agricultural lands with soft soil deposits render the protection of human lives against earthquake disasters extremely more difficult by the time. Although much effort is put in further improving the current seismic design practices for new buildings, recent earthquakes show us, again and again, that life losses occur in older and much more vulnerable structures. Finding those substandard, collapse-vulnerable buildings before a destructive earthquake is like finding a needle in a haystack. It is clear that the problem in hand cannot be addressed with the existing, and mostly old-fashioned tools anymore.
This manuscript focuses on how the emerging technologies, such as Artificial Intelligence, image processing, and data sciences in general, can be implemented as useful tools for conducting an urban scale seismic risk assessment while estimating the risk for every individual building. A review of the available technologies is given for the exposure component. Furthermore, a novel method of estimating the vulnerability of individual buildings, based on autoregressive machine learning algorithms, is presented. The manuscript discusses that the technological advancement is mature enough to radically alter how the earthquake risk is estimated.
Ihsan Engin Bal, Eleni Smyrou
Peculiarities of Seismic Risk in Hilly Regions: Topographic Effects on Hazard and Vulnerability
Many of the world’s high-seismic hazard regions are characterized by hilly topography. Topographical features pose significant problems when it comes to the seismic safety of buildings and infrastructure facilities, both with respect to the seismic impact, the structure’s vulnerability and potential secondary hazards such as slope stability-related issues. The seismic ground motion characteristics are greatly influenced by the geometry of topographical features such as slopes, hilltops, ridges and canyons and their relationship with the geologic materials partly overlying these features. Both, topography and geology lead in most cases to a significant amplification of the seismic ground motion and hence increased seismic demand to buildings located in these areas. This comes in addition to the fact that buildings located in hilly areas have a significantly lower structural capacity. Due to the limitations posed by the hill topography and the scarcity of flat building plots, many buildings are placed on hill slopes thus have highly irregular configurations, both in plan and elevation, making them highly vulnerable to seismic impact.
The manuscript focuses on selected case studies in the Indian Himalayas, which are not only the youngest mountains, but also one of the most seismic areas in the world. Influence of topography on seismic hazard and vulnerability of buildings in the study area is illustrated using extensive numerical studies. The gross effect of these two parameters is demonstrated by comparing the probabilistic earthquake loss estimates with and without considering the topographic effects.
Dominik Lang, Yogendra Singh, Sergio Molina, Mitesh Surana

Structural Earthquake Engineering

Insights on the Seismic Design of Current RC Buildings: Field Lessons, Codes and Research Needs
Recent earthquakes evidenced that many building structures may have a poor performance in future seismic events, as consequence of many factors, among of them the approach followed in their design, the irregular characteristics of the structural system, the poor detailing, and an eventual strong influence of the nonstructural elements in the structural response.
In certain design scenarios, designers declare difficulties in applying some of the seismic design rules and requirements included in the codes. Indeed, some verifications, as the ones related with the irregularities in buildings check, their impact in the behaviour factor that can be considered in design for the different structural systems, the global and local ductility checks, the detailing rules to be satisfied for each structural element, the consideration of the influence of infills in the structural response, the design of beam-column joints, among other design rules, may not be of easy adoption in certain situations by the designers. In other direction, materials, technical solutions and constructions systems, adopted in practice for the structure and nonstructural elements, continues to progress, inducing new levels of complexity in the design process.
All this justifies the continuous development of the seismic design rules and requirements included in the codes, aiming to reach rigorous design guidelines with acceptable level of complexity, avoiding misinterpretations and errors in their application by the designers.
Humberto Varum, André Furtado, José Melo
Optimum Design of Seismic Joints in Bridges
A key aspect of seismic design of bridges is the appropriate selection of joint gaps, an issue that has hardly received proper attention so far, while pertinent code provisions are far from comprehensive. End gaps define the boundary conditions of the bridge and affect its dynamic response; their proper design can lead to an improved structural performance under dynamic actions.
This contribution poses the problem, assesses the effect of gap size on the seismic response of bridges and puts forward a methodology for optimising this size, using a number of criteria such as maintaining the functionality of the bridge for moderate earthquakes, ensuring the safety of the bridge under earthquakes stronger than that used for code design, and, last but not least, optimising the cost of the bridge (as affected by joint gap size) using a life-cycle cost approach.
The idea of the ‘Dynamic Intelligent Bridge’ recently coined by the first author is revisited here, wherein current bridge joints that have a fixed width are substituted by variable-width joints and, under seismic loading, the joint gap is optimised either with a one-off adjustment, or continuously (in real time) through semi-active control. In all cases a novel device is used that permits this improved behaviour of the joints, the moveable shear key (MSK), a device for blocking the movement of the bridge deck, which has the possibility to slide, hence varying the size of the existing joint gap.
Andreas J. Kappos, Ioannis Mikes
NextGen Building Systems - S4: Seismically Safer, Sustainable and Smart - Raising the Bar to Enhance Community Resilience and Sustainability
Time for action: after decades of “lessons learnt from previous earthquakes” with severe and unacceptable socio-economic impacts, the remarkable mismatch between societal expectations and actual seismic performance of modern buildings is increasingly evident. A medium-long-term coordinated plan for the seismic retrofit of the existing building stock needs to be urgently implemented to achieve an overdue risk reduction at national scale in most of seismic-prone countries worldwide.
When designing new earthquake-resisting building, targeting Life Safety of the occupant is clearly not enough anymore for the general public, who would expect to be provided with an “earthquake-proof” building. A paradigm shift in performance-based design criteria and objective towards damage-control or low-damage design philosophy and technologies is thus urgently required, to say the least. In parallel, and of equal, if no higher, importance, a dedicated effort to improve the communication to the non-technical audience, raise awareness in terms of risk and available solutions and co-create feasible pathways has to become a high-level priority.
When dealing with the existing building stock, “Safety first” is the typically agreed top-of-the list priority. Yet, rarely - in “peace time” thus prior to an earthquake event - the desire to improve the seismic safety of a building is the main trigger for rehabilitation/refurbishment interventions.
This paper and its associated presentation will provide an overview of recent advances and unique opportunities to enhance the community resilience and sustainability, based on the developments and implementation of either: a) next generation technologies for an integrated (skeleton + non-structural elements) low-damage building systems, moving towards the concept of an “earthquake proof building” and b) unique proactive socio-economic/financial policies to sustain national-wide long-term programs for the integrated seismic-energy efficiency rehabilitation of the whole building stock.
Stefano Pampanin

Open Access

The Challenge of the Integrated Seismic Strengthening and Environmental Upgrading of Existing Buildings
The construction industry, as a main energy consumer and a foremost contributor to greenhouse gas emissions, has been undergoing a “green revolution” in the recent years. Sustainability has become a prominent issue, therefore a framework for including energy efficiency and sustainability in the design of buildings is badly needed. Sustainability is the core of the European Renovation Wave strategy and of the New European Bauhaus initiative.
A design approach, named SAFESUST (SAFEty and SUSTainability) has been proposed at the Joint Research Centre of the European Commission, able to address at the same time structural safety, energy and environmental performances. The output of this approach is a unique parameter, expressed in monetary terms, which helps in identifying the most appropriate design solution.
More recently, the Joint Research Centre, under mandate of the European Parliament, has activated a European Pilot Project named “Integrated techniques for the seismic strengthening and energy efficiency of existing buildings”. The project is expected to put forward a simplified holistic approach to improve simultaneously the seismic safety and energy efficiency of the existing European building stock and to stimulate the use of integrated solutions.
The Joint Research Centre is also conducting a Preparatory Action for the definition of a labelling strategy for the implementation of the New European Bauhaus initiative.
Paolo Negro, Elvira Romano
From Conventional to Innovative Approaches in Seismic Engineering: Buildings with Energy Dissipation Systems and the Upcoming Second Generation of Eurocode-8
Conventional approaches in seismic design dissipate most of the energy input by the earthquake through plastic deformations in regions of the main structure that also support the gravity loads. This involves important damage spread throughout the structure. Innovative approaches based on the use of energy dissipation devices (EDDs) apply a completely different strategy. The EDDs release the main structure from dissipating energy and limit its responsibility to only (or mainly) sustaining the gravity loads as the building deforms laterally. The seismic capacity of the structure is entrusted entirely (or mainly) to EDDs. Ultimately, the usefulness of EDDs is fully acknowledged, but their use in Europe is still very incipient. Two impediments to the widespread implementation of EDDs would be the lack of requirements, or else the over-conservative requirements of code provisions for the seismic design of structures with EDDs. This presentation introduces the concept of a buildings with energy dissipation systems and briefly reviews recent research on this topic. Finally, the procedures for verifying buildings with energy dissipation systems that have tentatively been adopted in the draft-new-Eurocode 8 are explained.
Amadeo Benavent-Climent
Drift Capacity Models for the New Masonry Chapter of Eurocode 8 Part 1-2
The masonry chapter of the new Eurocode 8 Part 1 contains several novelties, including new differentiation between unreinforced masonry typologies with regard to drift capacities and therefore \(q_D\)-factors. Drift capacity models for masonry walls are empirical models obtained from experimental data. This paper summarises some of the reflections that underlie the drift capacity models developed for Eurocode 8 Part 1–2 and complements analyses provided in the associated background document. It discusses the definition of drift capacity for cyclic shear-compression tests in the literature and puts forward a new, less conservative definition of the drift capacity. An analysis of data on 115 hollow core clay brick walls can identify size effects if all 115 walls are analysed together, regardless of whether they fail in shear, flexure or a hybrid mode. In line with numerical findings, the size effects are absent for walls failing in shear subjected to low axial load ratios. For high axial load ratios, for which size effects were expected, the experimental data on walls failing in shear is insufficient. Additionally, only 20 walls failed in flexure, making the data for this failure type also inconclusive. The paper confirms the drift capacity models for hollow clay walls presented in the background document.
Katrin Beyer, Ernesto Andrés Inzunza Araya, Savvas Saloustros
Hybrid Simulation Testing of Coupling Beams
Short and stiff beams coupling shear walls in RC buildings present concerns regarding their seismic response and specifically their mode of failure and their energy dissipation capacity. Although their behavior has been subject of several experimental campaigns, most of the respective specimens used were tested as elements isolated from the rest building and assumptions had to be employed regarding the proper kinematic conditions to be applied at beam end sections during testing - with the common option of choice being to free the axial degree of freedom. To offer more insight into the coupling beam-structure interaction and its effect on beam response, component-level testing on coupling beams was initially performed, followed by hybrid simulation of an eight-story RC structure. Test results make evident the effect kinematic constraints inflict on the shear capacity and failure mode of coupling beams.
Jamin Park, Alexandru Trandafir, Nikolaos Stathas, Elias Strepelias, Xenofon Palios, Oh-Sung Kwon, Boyan Mihaylov, Stathis Bousias
Large-Scale Testing for Enhancing the Resilience of Schools in Seismic Regions: Challenges and Cost-Efficient Solutions
This work presents the results of a large-scale experimental study aiming to investigate the seismic performance of a three-storey reinforced concrete school building supported on a novel, low-cost, easy-to-implement seismic base-isolation system entitled PVC ‘sand-wich’ (PVC-s). With a modest additional cost and training of builders, the PVC-s system uses locally resourced materials to achieve the intentional initiation of base sliding and the dissipation of seismic energy during earthquakes through the encapsulation of sand grains between two sheets of polyvinyl chloride (PVC) covering the area underneath the raft foundation. Given the prerequisite that the building is adequately designed as a standard earthquake resistant structure, the PVC-s system significantly enhances its seismic performance under moderate to extreme seismic events by acting as a ‘fuse’ that reduces the transfer of energy to the superstructure, while also achieving long term financial benefits by limiting the degree of seismic damage experienced during the life cycle of the structure. The effectiveness of the PVC-s system is shown experimentally and numerically through a probabilistic framework of incremental dynamic analyses (IDA) on a detailed three-dimensional finite-element model of the school building triaxially excited with a suite of 30 ground motions. Seismic demand reduction was estimated in the range of 30% to 70% for the design-level ground motion intensity and above. The analyses also contributed to optimising the length of the gap between the sliding system and the non-structural perimeter parapet wall that was not explored experimentally. The detailed experimental and numerical investigation demonstrate that the PVC-s system is a feasible, low-cost alternative for seismic isolation that can be appealing in low-income countries and beyond.
Anastasios G. Sextos, Ziliang Zhang, Nicholas A. Alexander
Seismic Design and Evaluation of Industrial Facilities
Industrial facilities must be thoroughly designed to withstand seismic actions as they exhibit an increased loss potential due to the possibly wide-ranging damage consequences and the valuable process engineering equipment. Past earthquakes showed the social and political consequences of seismic damage to industrial facilities and sensitized the population and politicians worldwide for the possible hazard emanating from industrial facilities. However, a holistic approach for the seismic design of industrial facilities can presently neither be found in national nor in international standards. The introduction of EN 1998-4 of the new generation of Eurocode 8 will improve the normative situation with specific seismic design rules for silos, tanks and pipelines and secondary process components. The article presents essential aspects of the seismic design of industrial facilities based on the new generation of Eurocode 8 using the example of tank structures and secondary process components. The interaction effects of the process components with the primary structure are illustrated by means of the experimental results of a shaking table test of a three story moment resisting steel frame with different process components. Finally, an integrated approach of digital plant models based on building information modelling (BIM) and structural health monitoring (SHM) is presented, which provides not only a reliable decision-making basis for operation, maintenance and repair but also an excellent tool for rapid assessment of seismic damage.
Christoph Butenweg
Seismic Resilience of Multi-story Dual-Steel Building Frames
Dissipative structural behavior is a common feature of seismic resistant structures. In case of multi-story steel frame structures, the dissipative behavior can be controlled by providing a favorable plastic mechanism, which involves the formation of plastic hinges at predefined locations (e.g., beam ends and/or joints), while rest of the structure behaves essentially elastic. Ensuring the requirements for the development of the plastic mechanism can lead to high strength requirements for non-dissipative elements/components. A modern approach to fulfill these requirements and control the local/global hierarchy criteria is to combine two steel grades, i.e. high strength steels (HSS) in non-dissipative members/components and mild carbon steels (MCS) in dissipative members/components. Used in combination with replaceable dissipative elements, the solution of two steels, called dual-steel solution, is also effective in the recovery phase after an extreme loading, as it eases the retrofit intervention, i.e., creates a more robust and resilient environment. The study presented in the paper is a review of reference works on the practical application of dual-steel systems in multi-story steel building frames.
Dan Dubina, Florea Dinu
Extending Analysis Capabilities of Equivalent Frame Models for Masonry Structures
The equivalent frame modeling of masonry buildings is widely used if not a real standard for the nonlinear seismic analysis of masonry buildings. Originally created to represent the in-plane behavior of the walls in the plan, it was subsequently applied for the analysis of three-dimensional models of entire buildings. In current standards and also in the new draft of Eurocode 8 this modeling technique retains a key role for the analysis of masonry structures. Recent developments and applications reflect the analysis capabilities subsequently added to this modeling technique, often derived after calibration with experimental results and/or detailed numerical models. They include pushover and time-history analysis features, inclusion of strength and stiffness contributions of the out-of-plane response of walls and floor/roof diaphragms, discretization of walls with irregular opening distributions, modelling strategies applicable to complex buildings with flexible diaphragms.
Andrea Penna, Stefano Bracchi, Christian Salvatori, Chiara Morandini, Maria Rota
Progresses in European Earthquake Engineering and Seismology
herausgegeben von
Radu Vacareanu
Constantin Ionescu
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