Analysis of a bridge failure due to fire using computational fluid dynamics and finite element models

Bridge fires are a major concern because of the consequences that these kind of events have and because they are a real threat. However, bridge fire response is under researched and not covered in the codes. This paper studies the capabilities of numerical models to predict the fire response of a bridge and provides modeling guidelines useful for improving bridge design. To reach this goal, a numerical analysis of the fire of the I-65 overpass in Birmingham, Alabama, USA in 2002 is carried out. The analyses are based on computational fluid dynamics (CFD) for creating the fire model, and finite element (FE) software for obtaining the thermo-mechanical response of the bridge. The models are validated with parametric studies that consider heat release rate of the spilled fuel, discretization of the fire temperature in the transition from CFD to FE modeling, and boundary conditions. The validated model is used in a study to evaluate the influence of fire scenario (CFD versus standard fires), and live load. Results show that numerical models are able to simulate the response of the bridge and can be used as a basis for a performance-based approach for the design of bridges under fire. Additionally, it is found that applying the Eurocode standard and hydrocarbon fires along the full length of the bridge does not adequately represent a real bridge fire response for medium-long span bridges such as this case study. The study also shows that live loads essentially do not influence the response of the bridge. (C) 2014 Elsevier Ltd. All rights reserved.Funding for this research has been provided by the Spanish Ministry of Science and Innovation (research project BIA 2011-27104) and the Universitat Politecnica de Valencia (Research and Development Support Program PAID-06-11). Funding has also been provided to Dr. Maria Garlock by the National Science Foundation (NSF) under award number CMMI-1068252. The authors are grateful to R. King from the Federal Highway Administration of the USA, J. Black and T. Colquett from the Alabama Department of Transportation, J. Glassman from Princeton University, J.V. Aguado from Ecole Centrale de Nantes and to J. Hidalgo from the University of Edinburgh for all the information and support provided. All opinions expressed in this paper are the authors' and do not necessarily reflect the policies and views of the sponsors.Alós Moya, J.; Paya-Zaforteza, I.; Garlock, ME.; Loma-Ossorio, E.; Schiffner, D.; Hospitaler Pérez, A. (2014). Analysis of a bridge failure due to fire using computational fluid dynamics and finite element models. Engineering Structures. 68:96-110. https://doi.org/10.1016/j.engstruct.2014.02.022S961106

Valencia bridge fire tests: Validation of simplified and advanced numerical approaches to model bridge fire scenarios

[EN] Bridge fires are a major concern and the subject of many studies that use numerical models. However, experimental studies are still required to test the validity of these numerical models and improve their accuracy. This paper uses temperature results of the Valencia bridge fire tests carried out at the Universitat Politecnica de Valencia, in Valencia (Spain) to calibrate the fire models that constitute the first step in modeling any bridge fire event. The calibration is carried out by both a simplified approach (Heskestad and Hamada's correlation) and advanced numerical models (Computational Fluid Dynamics models built with the Fire Dynamics Simulator -FDS- software). The Valencia bridge fire tests involved four fire scenarios under a composite bridge with Heat Release Rate (HRR) values between 361 and 1352 kW. The results show that applying Heskestad and Hamada's correlation gave good results when used within its limits of application (HRR < 0.764 MW) but did not work well beyond them, which means it would be suitable for planning reduced scale bridge fire tests but not in the analysis of real bridge fires. On the other hand, FDS provides good predictions of the temperatures and can be used to study bridge fire responses. This work is therefore an important step forward in the study of bridge fires and towards the improvement of the resilience of infrastructure networks vis-a-vis fire hazards. It also highlights the problems that can arise in fire tests in the open air, the influence of the wind being of critical importance.Funding for this research was provided by the Spanish Ministry of Science and Innovation (Research Project BIA 2011-27104). The authors are grateful to the Infrastructure and Safety departments of the Universitat Politecnica de Valencia and the City of Valencia Fire Department (Cuerpo de Bomberos de Valencia), which provided crucial support in conducting the tests.Alós-Moya, J.; Paya-Zaforteza, I.; Hospitaler Pérez, A.; Loma-Ossorio, E. (2019). Valencia bridge fire tests: Validation of simplified and advanced numerical approaches to model bridge fire scenarios. Advances in Engineering Software (Online). 128:55-68. https://doi.org/10.1016/j.advengsoft.2018.11.003S556812

Analysis of the influence of geometric, modeling and environmental parameters on the fire response of steel bridges subjected to realistic fire scenarios

This paper studies bridge fires by using numerical models to analyze the response of a typical girder bridge to tanker truck fires. It explains the influence of fire position, bridge configuration (vertical clearance, number of spans) and wind speed on the bridge response. Results show that the most damage is caused by tanker fires close to the abutments in single span bridges with minimum vertical clearance and under windless conditions. The paper provides new insights into modeling techniques and proves that bridge response can be predicted by FE models of the most exposed girder, which saves significant modeling and analysis times. (C) 2015 Elsevier Ltd. All rights reserved.Funding for this research was provided by the Spanish Ministry of Science and Innovation (Research Project BIA 2011-27104) and the Universitat Politecnica de Valencia (Research and Development Support Program PAID-06-11). All opinions expressed in this paper are the authors' and do not necessarily reflect the policies and views of the sponsors.Peris-Sayol, G.; Paya-Zaforteza, I.; Alós Moya, J.; Hospitaler Pérez, A. (2015). Analysis of the influence of geometric, modeling and environmental parameters on the fire response of steel bridges subjected to realistic fire scenarios. Computers and Structures. 158:333-345. https://doi.org/10.1016/j.compstruc.2015.06.003S33334515

Fire hazard in bridges: Review, assessment and repair strategies

[EN] This paper presents an overview of fire hazard in bridges. A detailed review of actual fire incidents, case studies related to fire hazards, and post-fire assessment and repair strategies in bridges is presented and summarized. In doing so, this review points to the importance of fire hazard in bridges, aids practicing engineers with practical tools for developing strategies for repairing fire damage in bridges and identifies areas where further research is needed. © 2011 Elsevier Ltd.The research presented in this paper is co-sponsored by Michigan State University (through Strategic Partnership Grant Award No. SPG-71-1452), the Spanish Ministry of Education (postdoctoral fellowship awarded to Mr. Paya-Zaforteza - Grant No. EX-2008-0669- and research project BIA 2011-27104), and the National Science Foundation (NSF) under Grant Nos. CMMI-1068252 and CMMI-1068621 awarded to Princeton University and Michigan State University. All opinions, findings, and conclusions expressed in this paper are of the authors' only and do not necessarily reflect the policies and views of Michigan State University, or the Spanish Ministry of Education. The authors also thank Dr. Khaled Mahmoud for his valuable contributions.Garlock, M.; Paya-Zaforteza, I.; Kodur, V.; Gu, L. (2012). Fire hazard in bridges: Review, assessment and repair strategies. Engineering Structures. 35:89-98. https://doi.org/10.1016/j.engstruct.2011.11.002S89983

Linkage-based movable bridges: Design methodology and three novel forms

Linkages have been widely used in machines and deployable structures, but these mechanisms have rarely been employed in the design of movable bridges. This paper explores the use of linkages both to actuate the kinematic motion and to serve as structural elements of movable bridges. First, the design methodology for these forms is presented which includes (1) physical shape-finding to develop a conceptual design, (2) generation of a parametric model and kinematic equations, and (3) multi-objective structural optimization for minimum self-weight and minimum force for operation. This optimization procedure includes shape optimization to determine the lengths and relative angles of members and sizing optimization to design the section profiles of members to meet the specifications of current American bridge design code. Heuristic algorithms, including descent local search and multi-objective simulated annealing, are employed. Three novel linkage-based forms, featuring 38. m movable spans, that were designed using this methodology are presented. This research suggests the beginning of an investigation into alternative forms for movable bridges using linkages. © 2011 Elsevier Ltd.This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-0646086. Dr. Thrall is also grateful for support from the Norman J. Sollenberger Fellowship. Dr. Paya-Zaforteza has been involved with this research project while on appointment as a Postdoctoral Fellow under the Program for Postdoctoral Stays administered by the Spanish Ministry of Education(Contract Number EX-2008-0669). The authors are grateful for the advice of Professors Maria E.M. Garlock (Princeton University), David P. Billington (Princeton University), and James K. Guest (Johns Hopkins University). The authors would also like to thank the anonymous reviewers for their helpful comments and suggestions.Thrall, AP.; Adriaenssens, S.; Paya-Zaforteza, I.; Zoli, T. (2012). Linkage-based movable bridges: Design methodology and three novel forms. Engineering Structures. 37:214-223. https://doi.org/10.1016/j.engstruct.2011.12.031S2142233

Closed-form Procedure for Predicting the Capacity and Demand of Steel Beam-Columns under Fire

[EN] During a fire, columns on the perimeter of a building will be subject to moments induced by both a thermal gradient and the restraint of axial expansion by adjacent heated beams, which themselves develop axial load. These members thus act as beam-columns because they are then subject to a combination of axial load plus moment caused by a combination of gravity plus thermal loading. This paper presents a two-pronged procedure to predict the behavior of the perimeter column as a beam-column, considering both the individual member response (including thermal gradients) and the global response (including the interactions of adjacent members). All methods discussed in the paper are closed-form (i.e., they require no iteration) and can therefore be solved by using a spreadsheet or simple mathematical algorithm. The framework is sufficiently simple for use in codified structural-fire design and could be included in a reference of performancebased analysis methods for steel structures. Although this paper specifically addresses the performance of columns on the perimeter of buildings, the proposed framework can be a blueprint for the performance-based analysis of other beam-columns, such as floor beams.The research presented in this paper is based on work that is cosponsored by the National Science Foundation (NSF) (under Grant No. CMMI-0652282) and the National Institute of Standards and Technology (NIST) (under Grant No. 60NANB7D6121). Dr. Quiel's involvement with this research project began while on appointment as a U.S. Department of Homeland Security (DHS) Fellow under the DHS Scholarship and Fellowship Program, which is administered by the Oak Ridge Institute for Science and Education (ORISE) for DHS through an interagency agreement with the U.S. Department of Energy (DOE). ORISE is managed by Oak Ridge Associated Universities under DOE Contract No. DE-AC05-00OR22750. Dr. Paya-Zaforteza has been involved with this research project while on appointment as a Postdoctoral Fellow under the Program for Postdoctoral Stays administered by the Spanish Ministry of Education (contract number EX-2008-0669). All opinions, findings, and conclusions expressed in this paper are the authors' and do not necessarily reflect the policies and views of the NSF, NIST, DHS, DOE, ORISE or the Spanish Ministry of Education.Quiel, SE.; Moreyra Garlock, ME.; Paya-Zaforteza, I. (2011). Closed-form Procedure for Predicting the Capacity and Demand of Steel Beam-Columns under Fire. Journal of Structural Engineering. 139(9):967-976. doi:10.1061/ASCE)ST.1943-541X.0000443S967976139

Direct simulation of the tensioning process of cable-stayed bridges

This paper proposes a new and innovative algorithm, the Direct Algorithm (DA), which introduces, for the very first time, the unstressed length of the stays concept into the modeling of the construction process of cable-stayed bridges. This assumption enables a fast and direct simulation of construction stages by analyzing independent Finite Element Models when time-dependent phenomena are neglected. The computational speed and the limited computer storing requirements of the DA make it especially indicated for optimization problems. Furthermore, it can be implemented in any structural analysis software. (C) 2013 Elsevier Ltd. All rights reserved.Part of this work was done through a collaborative agreement between University of Castilla-La Mancha (Spain) and Tongji University (China). This included an exchange of faculty and scholars. The financial support from Kwang-Hua Foundation from College of Civil Engineering of Tongji University and from the International Relation Office of University of Castilla-La Mancha is greatly appreciated.Lozano Galant, JA.; Xu, D.; Paya-Zaforteza, I.; Turmo Coderque, J. (2013). Direct simulation of the tensioning process of cable-stayed bridges. Computers and Structures. 121:64-75. doi:10.1016/j.compstruc.2013.03.010S647512

Modifications of the stress-state of cable-stayed bridges due to staggered construction of their superstructure

In current practice, the effects of the evolutionary erection of cable-stayed bridge superstructure are rarely included into the simulation of its tensioning process. In fact, stay forces in service are usually defined in early stages of design, when the construction process has not even been conceived in detail yet. In order to fill this gap, the effects of the evolutionary erection of cable-stayed bridge superstructure throughout the tensioning process are studied in this paper. This study is focused on steel cable-stayed bridges erected on temporary supports. For the very first time a new criterion to include the effects of the evolutionary erection of cable-stayed bridges into the definition of the stay forces in the service state is presented.The authors wish to thank the Ministerio de Economia y Competitividad, the Ministerio de Ciencia e Innovacion and the Junta de Comunidades de Castilla-La Mancha (Spain) for the funding provided through the research projects BIA2013-47290-R, BIA2009-13056 and PII2I09-0129-4085 directed by Jose Turmo and founded with FEDER funds.Lozano-Galant, JA.; Ruiz Ripoll, L.; Paya-Zaforteza I.; Turmo, J. (2014). Modifications of the stress-state of cable-stayed bridges due to staggered construction of their superstructure. Baltic Journal of Road and Bridge Engineering. 9(4):241-250. doi:10.3846/bjrbe.2014.30S24125094Aboul-Ella, F. (1991). New iterative analysis of cable-stayed structures. Computers & Structures, 40(3), 549-554. doi:10.1016/0045-7949(91)90225-bBywalski, C., & KamiIński, M. (2013). RHEOLOGICAL STRAINS IN CONCRETE MODIFIED WITH STEEL FIBRE REINFORCEMENT. Journal of Civil Engineering and Management, 19(5), 656-664. doi:10.3846/13923730.2013.803497Hegab, H. I. A. (1987). Energy Analysis of Double‐Plane Cable‐Stayed Bridges. Journal of Structural Engineering, 113(10), 2174-2188. doi:10.1061/(asce)0733-9445(1987)113:10(2174)Hegab, H. I. A. (1986). Energy Analysis of Cable‐Stayed Bridges. Journal of Structural Engineering, 112(5), 1182-1195. doi:10.1061/(asce)0733-9445(1986)112:5(1182)Kim, T. H., Kim, Y. J., & Shin, H. M. (2014). Performance assessment of precast concrete pier cap system. Computers and Concrete, 13(4), 501-516. doi:10.12989/cac.2014.13.4.501Li, L., Ma, Z. J., & Oesterle, R. G. (2010). Improved Longitudinal Joint Details in Decked Bulb Tees for Accelerated Bridge Construction: Fatigue Evaluation. Journal of Bridge Engineering, 15(5), 511-522. doi:10.1061/(asce)be.1943-5592.0000097Lin, Y.-C. (2014). CONSTRUCTION 3D BIM-BASED KNOWLEDGE MANAGEMENT SYSTEM: A CASE STUDY. JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT, 20(2), 186-200. doi:10.3846/13923730.2013.801887Lozano-Galant, J. A., & Turmo, J. (2014). Creep and shrinkage effects in service stresses of concrete cable-stayed bridges. Computers and Concrete, 13(4), 483-499. doi:10.12989/cac.2014.13.4.483Lozano-Galant, J. A., & Turmo, J. (2014). An algorithm for simulation of concrete cable-stayed bridges built on temporary supports and considering time dependent effects. Engineering Structures, 79, 341-353. doi:10.1016/j.engstruct.2014.08.018Lozano-Galant, J. A., Dong, X., Payá-Zaforteza, I., & Turmo, J. (2013). Direct simulation of the tensioning process of cable-stayed bridges. Computers & Structures, 121, 64-75. doi:10.1016/j.compstruc.2013.03.010Lozano-Galant, J. A., Payá-Zaforteza, I., Xu, D., & Turmo, J. (2012). Analysis of the construction process of cable-stayed bridges built on temporary supports. Engineering Structures, 40, 95-106. doi:10.1016/j.engstruct.2012.02.005Lozano-Galant, J. A., Payá-Zaforteza, I., Xu, D., & Turmo, J. (2012). Forward Algorithm for the construction control of cable-stayed bridges built on temporary supports. Engineering Structures, 40, 119-130. doi:10.1016/j.engstruct.2012.02.022Navrátil, J., & Zich, M. (2013). Long-term deflections of cantilever segmental bridges. The Baltic Journal of Road and Bridge Engineering, 8(3), 190-195. doi:10.3846/bjrbe.2013.24Veletzos, M. J., & Restrepo, J. I. (2011). Modeling of Jointed Connections in Segmental Bridges. Journal of Bridge Engineering, 16(1), 139-147. doi:10.1061/(asce)be.1943-5592.0000112Wang, P.-H., Tang, T.-Y., & Zheng, H.-N. (2004). Analysis of cable-stayed bridges during construction by cantilever methods. Computers & Structures, 82(4-5), 329-346. doi:10.1016/j.compstruc.2003.11.003Wong, J. C. K., Lee, Y., Lo, Y. T., Wong, K. W., Leung, A. Y. T., Fok, W. K., … Yiu, C. Y. E. (2014). The correlation between the noise and vibration induced by a bridge movement joint. The Baltic Journal of Road and Bridge Engineering, 9(2), 208-214. doi:10.3846/bjrbe.2014.2

The San Nicolas Church in Gandia (Spain) or how Eduardo Torroja devised a new, innovative and sustainable structural system for long-span roofs

This paper analyzes the structural behavior and the context of the roof designed by the Spanish engineer Eduardo Torroja for the San Nicolas Church in Gandia (Spain). The roof is an unknown, unique, elegant and sustainable thin-walled structural system made of two deep concrete beams spanning 29 m. The structure was possible because of Torroja's exceptional conceptual design, which used prestressing in a new way to counterbalance the biaxial bending and torsion problems caused by using deep beams with an open asymmetric cross section in long-span structures. The paper explains in detail the conceptual design of the roof as well as the results of a complete finite element modeling of the structure carried out by the authors, which provides a better understanding of this unknown masterpiece of Structural Art. The paper describes its original way of overcoming the major drawbacks of using open cross-section beams in long-span structural systems and points out the capabilities of simplified analysis methods to develop conceptual designs for complex structures. The authors believe the study provides inspiration for future designs and will help to give value and preserve a masterpiece of concrete construction. (C) 2013 Elsevier Ltd. All rights reserved.Funding for this research was provided by the Spanish Ministry for Science and Innovation (Research Project BIA 2011-27104) and the Spanish Ministry of Education (Collaboration Grant awarded to G. Nunez-Collado). The authors are very grateful to the architects O. Perosanz and A. Meseguer, art historian J. Paya-Zaforteza, teacher F. Carbonell and the Archivo Torroja and its librarian, I. Garcia, for all the information and support provided. The authors also want to thank the first and present parish priests of San Nicolas Church, Father J. Minana and Father R. Sala for the invaluable information they gave and for providing full access to the church.Núñez Collado, G.; Garzón Roca, J.; Paya-Zaforteza, I.; Adam Martínez, JM. (2013). The San Nicolas Church in Gandia (Spain) or how Eduardo Torroja devised a new, innovative and sustainable structural system for long-span roofs. Engineering Structures. 56:1893-1904. https://doi.org/10.1016/j.engstruct.2013.08.003S189319045

Bearing capacity of steel-caged RC columns under combined bending and axial loads: Estimation based on Artificial Neural Networks

The use of steel caging for strengthening a reinforced concrete (RC) column is an economical and common solution. However, the design of the optimum steel cage is a complex task. Artificial Neural Networks (ANN) has shown to be a useful device for engineers to solve tasks related to the modelling and prediction of the behavior of complex engineering problems. This mathematical tool can be trained from a series of inputs in order to obtain a desired output, without the need to reproduce the phenomenon under study. Based on a total of 950 results obtained with a validated finite element (FE) model, this paper presents the use of ANN to predict the axial-bending moment (N-M) interaction diagram of steel-caged RC columns under combined bending and axial loads. The data is arranged in a format of six input parameters taking into account several aspects such as the geometry of the RC column, the size of the steel cage, the concrete compressive strength, the steel yield stress and the axial load level. The output is the bending moment reached by the steel-caged RC column. Since the way of solving the beam-column joint plays a key role in the behavior of the strengthened column, four ANNs are developed in this paper, related to the beam-column connection type: using capitals, using capitals with chemical anchors, using capitals and steel bars, and without any element. The ANNs developed show excellent results, which are far better to those given by three design analytical proposals. Based on the ANNs performed, a simple mathematical expression is developed, which can be used by practitioners when facing the design of a steel-caged RC column subjected to axial loads and bending moments. (C) 2013 Elsevier Ltd. All rights reserved.The authors wish to express their gratitude for the financial support received from the Spanish Ministry of Science and Innovation under Research Project BIA 2008-06268. Also to the Generalitat Valenciana for its financial support within the GVPRE/2008/153 Project. Mr. Garzon-Roca is grateful to the Generalitat Valenciana and to the Universitat Politecnica de Valencia for the scholarship he was awarded to complete his doctorate studies. Special thanks are due to Professor Pedro A. Calderon for his support in this research.Jørgensen, C.; Grastveit, R.; Garzón Roca, J.; Paya-Zaforteza, I.; Adam Martínez, JM. (2013). Bearing capacity of steel-caged RC columns under combined bending and axial loads: Estimation based on Artificial Neural Networks. Engineering Structures. 56:1262-1272. https://doi.org/10.1016/j.engstruct.2013.06.039S126212725