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

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