Designing steel bridges for fire safety

While bridge fires can often lead to substantial losses, current codes and standards do not specify any provisions for fire resistance of load bearing structural members in bridges. In order to bridge this knowledge gap, this study presents a practical approach to overcome fire hazard in steel bridges of critical nature. The proposed approach comprises of two components namely, analytical and numerical. In the analytical component, fire risk in a steel bridge is assessed, through a specially derived fire-based importance factor that allows estimating vulnerability of a bridge to fire hazard. The second component integrates both simplified calculation method as well as highly nonlinear numerical analysis through a coupled finite element (FE) based simulation with the purpose of developing relevant strategies for mitigating fire risk and losses. The applicability of this approach is illustrated herein through a comprehensive case study on an actual steel bridge that underwent an intense fire incident. The aim of this study is first to present engineers and designers with a practical tool to identify steel bridges vulnerable to fire hazard and secondly to guide them into developing optimum solutions to mitigate large fire losses.