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About this book

This book reports on current challenges in bridge engineering faced by professionals around the globe, giving a special emphasis to recently developed techniques and methods for bridge design, construction and monitoring. Based on extended and revised papers selected from outstanding presentation at the Istanbul Bridge Conference 2018, held from November 5 – 6, 2018, in Istanbul, Turkey, and by highlighting major bridge studies, spanning from numerical and modeling studies to the applications of new construction techniques and monitoring systems, this book is intended to promote high standards in modern bridge engineering. It offers a timely reference to both academics and professionals in this field.

Table of Contents

Frontmatter

Invited Papers

Frontmatter

Numerical Investigations on the Collapse of the Morandi Bridge

Abstract
The collapse of a relevant portion of the Polcevera river viaduct, located in Genoa (Italy) and also known as Morandi Bridge, is herein object of a numerical investigation. The bridge was designed in the early 1960s by Riccardo Morandi, a well-known Italian engineer, and opened to the public in 1967. The collapsed part of the bridge essentially comprised an individual self-standing structure spanning 171 m and two simply-supported connecting Gerber beam systems, each spanning 36 m from the self-standing structure to the adjacent portions of the bridge. A previous investigation, by Calvi et al. (Calvi et al. in Struct Eng Int 29:198–217, 2019), indicated that the collapse of the bridge could have potentially been triggered by a sudden loss of effectiveness of one stay (e.g. due to the failure of either the deck-stay or the antenna-stay connections), which in turn would have induced a flexural–torsional-shear failure of the bridge deck. In the current work, therefore, the attention is turned into a more detailed study of the latter, through the employment of detailed Finite Element Analysis modelling, with a view to corroborate, or not, the results of the aforementioned previous study. As in the latter, the development of such model was based entirely on publicly available material that has so far been rendered online accessible. It is shown that should the support provided by one of the bridge stays be removed, the ensuing flexural–torsional-shear demand on the deck would be such that the latter would be led to the type of collapse observed in the field.
G. M. Calvi, M. Moratti, N. Scattarreggia, V. Özsaraç, P. M. Calvi, R. Pinho

Importance of “Heuristics” in Suspension Bridge Engineering and 1915 Çanakkale Bridge

Abstract
Suspension bridges can be regarded as masterpieces of the engineering profession. Although they are conceptually clear cut 5-piece load-bearing systems which are highly hyperstatic and their sizes are enormous. They undergo large displacements under loads, have nonlinear behavior and are sensitive to horizontal loads, especially wind loads. Suspension bridges are the most elegant, aesthetic and relatively economic structures of our civilization. The three decision methods to solve problems of engineers are “logic”, “probability” and “intuition”. Intuition, namely “heuristics” can be a vital influence in their decisions. Especially bridge designs are based on mathematical models, which take into account known patterns of physical behavior, but there are potentially a good many unknowns and uncertainties, which means heuristics is very useful and even required for short cut of the calculations and analysis. As the numbers of suspension bridges are increasing, a quite large database is becoming available for studying suspension bridges. At the same time, there has been a challenge to span longer distances, pushing the envelope of the engineering experience into new territory. This paper explores practical mathematical expressions obtained through regression analyses to predict easily key design parameters of long span suspension bridges such as main geometric dimensions, material quantities/qualities and dynamic properties for preliminary design calculations and estimations in order to satisfy. A large design parameter database matrix for 20 long span suspension bridges was collected to bring out heuristic approximations through regression analyses. Finally, these regression models are used to examine the design parameters of 1915 Çanakkale Bridge Project, which will break the longest span record with a main span length of 2023 m and the tallest tower record with 318 m (IP Point). It was observed that the dimensions, mass distributions and material qualities selected for the design of 1915 Çanakkale Bridge agree with the findings of this study.
Ersin Arıoğlu

Bridge Failures and Mitigation Using Monitoring Technologies

Abstract
The current study aims to understand the reasons for bridge failures. It considers the recent damages and collapses of in-service real bridge structures and discusses mitigation methods based on monitoring technologies. Transportation systems serve a crucial function in the strategies for mitigating bridge damages and failures. After investigating recent damages and failures in real bridges, structural bridge failures are classified in this study according to their safety and operational function. For each function, global and local level failures are also defined with two groups: major/long-span and highway bridges. In the light of this classification, structural monitoring methods are identified according to global and local failures. Along with standard Structural Health Monitoring (SHM) systems with comprehensive sensor networks, at  vision-based SHM system and developments in this area are shown to provide some opportunities for mitigation of bridge failures resulting from service loads rather than natural hazard-induced failures.
Selcuk Bas, Necati Catbas

Bridge Design

Frontmatter

1915 Çanakkale Bridge – Meeting the Challenge

Abstract
The 1915 Çanakkale Bridge is a world record 2023 m main span suspension bridge crossing the Çanakkale Strait in Turkey to connect Europe and Asia. Detailed design has been prepared in a challenging short period of 12 months. Significant design challenges for aerodynamics, ship collision, seismic and poor soil conditions have in combination with the very tight design and construction schedule significantly impacted alignment and articulation of the bridge. To accommodate the windy location, the bridge girder is designed as a twin-box steel girder for the purpose of a wind-resistant design. The dense ship traffic including the world largest ships and a massive grow rate for the strait has governed the design of the deep water tower foundations. The bridge situation in a seismically active region has further affected significant parts of the substructure design. Seismic hazard and difficult geological site conditions impose tremendous challenges to the bridge design. Finally, the tight construction schedule has conditioned the design solutions to accommodate fast track construction. The paper summarize the engineering approach, design decisions regarding alignment and articulation, design challenges and results obtained for the detailed design of the bridge.
Inger Birgitte Kroon, Henrik Polk, Kent Fuglsang

“Piccoli Angeli” Bridge Over Gorzone Canal in Cavarzere (VE)

Abstract
The “Piccoli Angeli” bridge was implemented by Zara Metalmeccanica Srl and designed by Prof. Enzo Siviero’s team. The bridge, with a 56 m span, is the synthesis of a design path that considered points of view related to culture and landscape as well as technical and economic aspects. The bridge, which has a strategic function in the countryside network context, memorializes through its name (Ponte degli Angeli) a tragic event that marked the history and now belongs to the memory of the place. The colours of the bridge (a dark gray for the scaffolding and white for the lateral bands) make it visible against the landscape, while the tapered and tense shape recalls the light curvatures that appear on the horizon. The result is a sober, elegant and economical work: the bridge was built for about 800,000 Euro.
Alessandro Stocco, Enzo Siviero

Predicting Time-Dependent Deformations of Prestressed Concrete Girders

Abstract
Camber prediction plays an important role in the construction planning of prestressed concrete girders. An accurate prediction is essential to avert unexpected cost and construction delays. The purpose herein is to compare the accuracy of the creep and shrinkage models such as AASHTO LRFD, ACI 209R-92, and fib MC 2010 on strain, curvature, and camber predictions. The experimental data were gathered from fifty-one full-scale girders including AASHTO BT-54, BT-72, and Type I and T-Beams. Compressive strengths at 28 days varied between 43 and 94 MPa. The ALCAMBER v1.0 software, utilizing a time-steps approach, was developed for the predictions and made available online. The results demonstrated that the camber growth and the growth of prestress losses were not accurately predicted and were overpredicted on average. The growth predictions up to the girder erection were most accurately predicted in terms of (i) prestress losses by AASHTO LRFD with an error of 68% and (ii) camber growth by ACI 209 with an error of 51%.
Levent Isbiliroglu, Robert W. Barnes, David M. Mante

Bridge Engineering Optimization Opportunities Through Integrated Solutions: Design – Constructive Method

Abstract
The demand for productivity and cost optimization is a common requirement of bridge construction process nowadays. Focusing on span-by-span concrete bridges, different solutions have proved to be efficient. The choice for the most adequate solution is not linear and depends on several factors of quite different nature, such as bridge geometry (curvature, transversal slope, longitudinal slope), deck section (weight, shape), span length and bridge total length, environmental conditions, site logistics, local construction and design traditions and constructor experience and preferences. Independently of the chosen solution, a fundamental factor for achieving a cost and time-efficient construction process is a timely cooperation between the bridge designer and the construction process developer, making key adaptations in bridge design in order to make it easier for construction. In this specific case, details do matter and a judicious choice may have a significant impact in construction times. In this paper, different span-by-span concrete bridge deck construction processes are presented, ranging from segmental pre-cast to cast in situ solutions. The different solutions have a common denominator – the demand for productivity. The presentation is based on real examples. Throughout the text, a reference is made to Organic Prestressing System (OPS), an actively controlled prestressing system that increases structural efficiency. In its recent applications on bridge construction equipment, OPS confirmed a positive impact in productivity. A particular focus is given to the M1-90-S, a span record holder movable scaffolding system, mainly manufactured in Turkey and currently in operation in Ankara-Sivas high speed railway.
Pedro Pacheco, Pedro Borges, Hugo Coelho, Diogo Carvalho

Load Distribution and In-Plane Superstructure Movements on Highly Skewed Steel Girder Bridges

Abstract
Highly skewed girder bridges experience modified load paths, deck diagonal and acute corner cracking, and superstructure horizontal movements caused by long-term loading. This paper presents the instrumentation and load testing of a 23-year-old, three-span, medium-span-length, steel girder bridge with a skew angle of 47° to understand the effects of existing deck cracks on bending and shear girder load distribution. Measured and predicted load distribution factors as per AASHTO LRFD Bridge Design Specifications were compared. Load testing data, consisting of bending and shear strains at multiple locations across the length and width of an exterior span, were used to validate finite element models. Bridge models under temperature loading were used to evaluate the importance of bridge skew angle on in-plane superstructure displacements. The investigation showed that skew had a major role in bridge in-plane displacements, and consequent superstructure in-plane rotation, leading to greater transverse displacements with increasing skews under thermal loading.
Mauricio Diaz Arancibia, Pinar Okumus

Soil-Structure Interaction Analysis of a Railway Bridge in Rotterdam

Abstract
Theemswegtrace bridge is a double track railway bridge located in Rotterdam, Netherlands. Total length of the bridge is 3.7 km, with a typical span length of 30 m. For these typical spans, superstructure consists of simply supported precast prestressed I girders and cast in place R/C slab. An assessment study of the original design was performed in a non-linear manner to observe the importance of soft soil conditions on rail-structure interaction. Due to soft-soil conditions, rail-structure interaction analyses according to UIC 774-3 were performed together with inclusion of barrette piles and associated soil-springs. Site specific non-linear p-y curves, t-z curves and q-z curves were developed and used in the analyses. It was found out that soils structure interaction can effect the results significantly and has remarkable importance in rail structure interaction analysis of bridges located on soft soils.
Cenan Ozkaya

Reliability Based Safety Level Evaluation of Cable Members for Cable-Stayed Bridges in Turkey

Abstract
Turkey, ranking second on investing in roads after Slovakia among the OECD countries, has recently started to design and construct long-span cable-supported bridges. In recent years, a live load model accurately representing the actual live load uncertainties prevailing in Turkey has been developed using probabilistic methods. The live load model, KGM 45, is now used in the design of short to medium span bridges in Turkey. In a previous nationally funded research, the superstructure of cable-stayed bridges has also been studied with KGM 45 live load model. The focus of this paper on extending the findings of the previous research into new cable-supported long-span bridge live load designs of Turkey. In this concept, both superstructure and cable designs have been studied by a committee formed by the Turkish Highways, KGM. In this paper, we present only the results of cable designs.
Alp Caner, Nurdan Apaydın, Yeşim Esat, Burak Kurtman

Design of Izmir Bay Crossing Bridge

Abstract
The Izmir Bay Crossing Bridge is a part of a 6.8 km fixed link between Çiğli and İnciraltı districts in Izmir. Total bridge length is 4175 m. Two platforms, each 21 m wide, will combine to carry three lanes of highway traffic and a light railway system. The cable-stayed bridge is located over the circulation channel, and has a total length of 590 m and a main span of 270 m. Pylon height is 88.7 m. The cable-stayed bridge will be constructed by free cantilever method and the rest of the bridge will be constructed by movable scaffolding system. The bridge has a post-tensioned box girder deck with a constant height of 2.5 m. It was particularly important during the design process to ensure structural performance of the bridge because of high seismicity and very poor soil conditions at the site. 2000 mm diameter steel driven piles are used for the foundations. First 20 m of the piles are assumed to be laterally unsupported by soil and pile cap stiffness and mass were considered in the global model for seismic analysis.
Burak Kurtman

Bridge Construction

Frontmatter

Al Bustan South Bridge Design and Build Project, Doha, Qatar

Abstract
This paper summarizes recent developments in the design and built Al Bustan Bridge and Highway Project as part of the Qatar Expressway Programme and the lessons learned from it.
The Al Bustan South Project comprises design and construction of an expressway to the north of Doha with grade separated junctions, four-lanes dual deck to form a 1,946 m long bridge structure, including 863 on/off ramp bridges. The project includes drainage system, extra high-voltage cables, street lighting, substations, irrigation transmission pipelines, water pipelines, foul sewer, landscape, intelligent transportation, art-scaping design and construction.
The Qatar Expressway Programme is a very large road infrastructure projects that connects Doha with other cities through a set of advanced highways, roads, and flyovers. The scope is expected to deliver about 800 km of safe and efficient roads. The programme also includes the construction and development of an integrated infrastructure network equipped with state-of-the-art, reliable underground utilities, including storm water networks, electrical services, and intelligent transport systems. Al Bustan Corridor, Orbital Highway, North Road, Al Rayyan Road and Lusail Expressway part of this programme.
Design and building of highways and bridges in urban areas with very tight schedules are always big challenges to contractors as well as to the employers. The contractor must manage the busy existing traffic to provide work zones to the bridge construction works. The existing utilities and their relocation have been major issues in the structural design to accommodate the foundations. Consideration of utility relocations and traffic diversion management may change the entire concept of bridge’s design and construction. To improve life around the city and achieve aesthetic harmony in these structures, the employer had to make important provisions.
Yousef Al Emadi, Ali Kara

Design Challenges of a River Crossing: Dim Çayı Extradosed Bridge

Abstract
Extradosed bridges are efficient and aesthetic alternatives for relatively long urban crossings with shallow decks. The first extradosed bridge in Turkey was constructed in Antalya Çallı Crossing, with an 80 m main span and 2.5 m deep post-tensioned pi-section deck. The second extradosed bridge is currently under construction over the Dim River in Alanya, as part of the new Alanya-Gazipaşa Highway. The Dim Çayı Extradosed Bridge has seven spans and consists of two parallel decks: 400 and 390 m long, with an S-shaped curve in plan. 12 m high pylons, housing two sets of six continuous cables per pylon, using the Freyssinet Saddle and Cohestrand technology, support the 100 m main span. The variable height post-tensioned pi-section deck is cast-in-place over scaffolding. Couplers and external blisters provide the continuity of the tendons. Construction stage planning of the bridge required the casting of the first half of the viaduct, and resting the 50 m half mid-span on temporary steel piers. River bed is temporarily diverted to base the temporary steel piers and its foundation. The construction of the concrete pylons and saddles are followed by stressing of the extradosed cables and removal of temporary piers. Length of the bridge, curvature in plan, variable deck geometry, number of cables and the location of riverbed, created challenges on the construction stage analysis. The deflection of the deck is monitored to check it stays within the tolerances of the theoretical results. For the seismic design, a return period of 1000 years was taken. Seismic acceleration and short piers required the use of a combination of Lead Rubber Bearings and Pot Bearings to reduce the seismic effects and lead to an economic and safe substructure solution. At time of preparing this paper, the bridge was under construction and was to allow traffic by the end of 2018.
Cemal Noyan Özel, Kamil Ergüner, Abdullah Rahman, Sema Melek Kasapgil, Hatice Karayiğit, Özgür Özkul, Kutay Kutsal

The Ethiopia Railway Viaducts: Steel Girder Launching and Permanent Bearing Design

Abstract
The Awash-Kambolcha-Hara Gebaya (AKH) Railway project is 389 km long single railway line over 54 bridges constructed in Ethiopia. The 5 m wide precast concrete composite deck rests on two built-up steel box girders side by side, supported on steel piers. The typical span is 46.4 m, formed by four 11.6 m segments using friction bolts. The construction of shallow pier and short bridges is performed using lifting cranes. For the construction of tall pier and long bridges, where the crane capacity is exceeded, incremental launching method (ILM) is used. Eight out of 51-bridges, ranging from 200 to 615 m continuous in length, are launched to provide construction ease and speed. The 11.6 m long steel box pieces are bolted at the assembly yard and launched over temporary bearings with an 18 m steel front nose. The longest bridge (B24) has 14 spans with 800 m horizontal radius, 2.42% slope and 45 m pier height. All launching equipment: back nose, pulling stick, guiding devices, temporary bearings and jack supports, are designed and manufactured locally in Turkey. The bridge design did not consider ILM method initially, so the authors worked with the already drilled existing web/flange splice bolt holes to connect the launching devices. In addition to the launching equipment, the permanent elastomeric bearings of all bridges are designed and manufactured in Turkey. The deck is supported on sliding elastomeric bearings longitudinally, to minimize seismic forces on the piers. Prestressed damping systems (PDS) are used in longitudinal direction to create a fixed point at one abutment in service state, while providing additional rigidity and damping during earthquake. The deck is fixed transversally using steel shear keys between the girders and the piers. The paper presents details about launching and bearing design of AKH railway bridges.
Kutay Kutsal, Hatice Karayiğit, Cemal Noyan Özel, Özgür Özkul

Incremental Launching by Lag-Casting: İhsaniye Viaduct

Abstract
Incremental Launching Method (ILM) is a bridge construction technique that has become an efficient alternative in Turkey in recent years. In the first phase of The Northern Marmara Motorway Project (KMO1), three viaducts were constructed using ILM. The KMO1 is followed by the second phase: KMO2. İhsaniye Viaduct is part of KMO2 on the European Side of Istanbul, located south of the Third Istanbul Airport (IGA), and constructed using the ILM. Several advantages are offered by the ILM technique, including quantity saving, enhancing the safety during construction and introducing innovative seismic design approach. This paper focuses on the deck and pier design of the İhsaniye Viaduct. The deck is constructed by lag casting of segments. First, only the bottom slab and the webs are cast. After reaching the launching strength, the U-section is pushed out-of-the formwork, where the top slab is cast simultaneously with the next segment’s U-section in the second step. This technique provided a fast launching track, optimizing the time required for strength and workforce. Detailed analysis of the construction staging, post-tensioning and rebar detailing are exhaustively studied. The pier design is governed by the seismic actions. Innovative double-wall pier shape was used to increase its flexibility in the transversal direction while providing energy dissipation through the creation of plastic hinges at double walls. Longitudinally, the deck is fixed on several piers and fluid viscous dampers are placed at the abutments to reduce the seismic displacement. The viaduct is two decks side by side, 21.5 m wide, 856 and 867 m in length with 66 m typical spans and an 80 m maximum span. The 80 m span is launched using a temporary steel pier.
Cemal Noyan Özel, Özgür Özkul, Hatice Karayiğit

Effect of Skew Angle on the Rotation of Exterior Girders During Construction

Abstract
Bridge designers tend to extend the deck slab width beyond the exterior girders, over a distance called the overhang, to increase the width of the bridge without adding extra girders. Moreover, the screed machine used in finishing the surface of the deck slab usually rests on the edges of the overhang. The machine weight combined with the weight of the fresh concrete leads to torsional moments in the exterior girder. Hence, excessive rotations in the exterior girder arise and they lead to issues such as lose of concrete cover, instability of the superstructure and non-uniform deck slab thickness. Many Departments of Transportation are facing this problem and there are no specific guidelines to compute this rotation. Contractors usually use temporary bracing systems such as timber blocks and diagonal or transverse ties to reduce the rotation. However, these methods were found to be not very effective. The bridge geometrical parameters play a significant role in this phenomenon, and one of these parameters is the skew angle. Skewed bridges are popular because of the geometrical conditions imposed by roads alignment and the geographical barriers to cross, which leads to a non-perpendicular crossing. In these cases, skewed bridges are more economical than an equivalent straight bridge. This study focuses on the effect of skew angles on the rotation in steel girder bridges. The purpose of this study is to examine different skew angles using Finite Element Analysis (FEA) of bridges subjected to construction loads. SAP2000 is used to develop the FE models of these bridges. The findings of this research will provide designers and contractors a better understanding of the effect of skew angles on the rotation of exterior girders and opens the way for future research to develop methods to reduce the rotation to satisfactory limits.
Faress Hraib, Li Hui, Miguel Vicente, Riyadh Hindi

Reconstruction of Partially Collapsed Post-tensioned Beğendik Bridge During Balanced Cantilever Construction

Abstract
Beğendik Bridge with a main span of 210 m has partially collapsed during construction in December 2017. The main reason for the partial collapse was a result of unfortunate events following each other. The collapse was simply triggered by removing a simple piece of timber support element from the scaffolding to have some space to place the unexpectedly oversize pot bearings on the abutment. No one has been injured or died during the collapse mainly due to ductile design of superstructure that allowed seven workers to escape from inside of the box girder within forty-five minutes. The focus of this paper on the description of the trigger mechanism of the partial collapse of the bridge, demolishment of damaged parts and reconstruction of the bridge. Following the collapse, a series of engineering scenarios have been evaluated to restart the construction. Reconstruction of the bridge has been started just in four months of time and bridge is still under construction.
Alp Caner, Nurdan Apaydın, Melike Cınar, Erol Peker, Mehmet Kılıc

Construction of Namawukulu Footbridge in Uganda

Abstract
For many years, Bridges to Prosperity has been trying to improve people’s lives in the isolated communities throughout the world by building footbridges. In this concept, recently Ramboll UK and IABSE Foundation has teamed up to realize a suspended footbridge project located in the eastern Uganda. A multi-national team of structural engineers travelled to site to construct the bridge together with the local community. In this paper, the suspended bridge design that enables the use of basic materials and the construction methods developed considering the available limited resources is presented.
Sercan Durukan, Xavier Echegaray

Life-Cycle Environmental Impact Assessment of Steel Bridge Deck Pavement

Abstract
To evaluate the environmental impact of steel bridge deck pavement (SBDP), based on life cycle assessment (LCA), this study quantified energy consumption and gas emission of epoxy asphalt (EA) mixture, stone mastic asphalt (SMA) mixture and guss-asphalt (GA) mixture. Firstly, the life cycle inventory of SBDP materials was established, involving the stages from raw material acquisition to end of life. Subsequently, environmental impact assessment indicators were proposed to evaluate energy consumption, climatic change and human health. Secondly, the uncertainty assessment method was investigated, and the uncertainty of inventory data and environmental factors was analyzed subsequently. Thirdly, “EA + EA” structure and “GA + SMA” structure were analyzed based on the established LCA model. Results indicate that the environment impact of “GA + SMA” is greater than “EA + EA”, and the stages with high environmental impacts of the two typical structures are the raw material acquisition, plant production, and operation and maintenance, successively. In addition, the production of epoxy asphalt binder and the plant production of GA and SMA should be optimized to reduce energy consumption and gas emission.
Xiang-fei Zhang, Zhen-dong Qian, Hui Gao

Bridge Extreme Event Loads: Earthquake, Wind and Fire

Frontmatter

Efficient Fire Hazard Mitigation for Suspension Bridge Cables

Abstract
Increasingly, large suspension bridges are exposed to fire risks as the traffic they carry increases. A truck fire on a suspension bridge may lead to main cable failure or a strength reduction that will either cause down-graded classification of the load carrying capacity or need for long lasting repairs of the main cable with large costs and traffic disruption as severe consequences. A serious fire in a truck occurred in 2013 on the New Little Belt Suspension Bridge in Denmark, and caused rapidly rising flame temperatures to above 1000 °C, somewhat similar to a hydrocarbon fire. Based on this accident and a number of other incidents with fires on roads and bridges, a risk and cost–benefit study focusing on fire risks for this bridge was carried out. Based on the result of the study, it was decided to provide fire protection to the main cables on the New Little Belt Bridge. Due to the large socio economic importance, the need for similar mitigation of fire hazards has been considered for bridges such as Älvsborg Suspension Bridge (Sweden), Great Belt East Bridge (Denmark) and A.L. MacDonald Suspension Bridge (Canada). Current status is that fire retro protection projects have been decided and are being prepared for the latter two bridges. Based on the accident on New Little Belt Bridge, a fire protection concept for main cables has been developed after detailed studies of the fire impact on this occasion. This has resulted in advanced modelling of the fire loading on a main cable and in design elaboration of an efficient fire hazard mitigation concept for main cables. This paper describes the systematic process for evaluation of the fire accident on New Little Belt Bridge and how this has evolved into a very efficient fire hazard mitigation concept for main cables. The concept may be used on existing as well as on new suspension bridges being essential elements in national road infrastructure systems.
J. Laigaard Jensen, N. Bitsch, Harikrishna Narasimhan

Seismic Performance of Bridge Systems Enhanced with Cellular-Solid Shear Walls

Abstract
Light-weight shear wall panels with deterministic cellular periodic architecture could provide the basis for vibration mitigation in large scale structural systems. In this study the behavior of shear walls with cellular solids under seismic loading is examined. An investigation to evaluate the effects of different cellular configurations is conducted, including the orientation angles and the shapes of the cells (honeycomb, re-entrant or chiral architecture). The cellular walls may be appropriately arranged between the columns of a pier of a concrete bridge system for seismic resistance enhancement in both directions. Appropriate simplified Finite Element Models are developed to predict the stiffness, strength, and energy dissipation effectiveness of shear wall panels when subjected to monotonic and cyclic shear loading, with ABAQUS software. The total column-cellular wall-deck system behavior is studied with simple stick models after the calibrated wall properties have been taken into account.
Spyridoula Μ. Papathanasiou, Panos Tsopelas, Thanasis Zisis

Wind Response of a Bridge Pylon Using Numerical Simulations of the Atmospheric Boundary Layer and Fluid Structure Interaction (FSI)

Abstract
With the current computational capabilities and the development of Computational Fluid Dynamics (CFD), it is possible to perform numerical simulations of the neutral atmospheric boundary layer (ABL) to study the effects of wind forces on civil structures, and consequently evaluate their response with the purpose of obtaining a suitable design. In this article, we present numerical simulations of the fluid–structure interaction (FSI) of a single concrete pylon of a long span cable-stayed bridge to estimate its response under wind loads. In order to carry out a proper FSI modelling, it is necessary, firstly, to simulate the features of the atmospheric boundary layer (ABL) of the site where the structure will be located. This is used as input for the CFD model, which is studied with a special software providing pressure coefficients, velocity contours, and streamlines, which are then used to estimate wind loads acting on the structure. Secondly, a finite element analysis (FEA) is performed in order to evaluate the response of the structure in terms of mechanical elements (bending moment and shear) and displacements. In this paper, we applied this methodology to study the FSI response of a real bridge pylon. We compare results from the FEA analysis with those obtained from an isolated aero-elastic pylon scaled model studied in a wind tunnel.
Raúl Sánchez-García, Roberto Gomez, J. Alberto Escobar
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