Factors Governing Response of Steel Bridge Girders under Fire Conditions

Abstract

This paper presents results from numerical studies on the response of fire exposed steel bridge girders. A finite element model is applied to quantify critical factors influencing the fire resistance of steel girders in bridges. The varied parameters include: fire intensity, exposure scenario, web slenderness, and span length. Results from numerical studies indicate that fire resistance and failure mode in steel bridge girders is highly influenced by fire intensity, exposure scenario, and web slenderness. A typical steel girder can experience failure in less than 20 minutes under hydrocarbon fires. Failure through web shear buckling is the most dominant failure limit state, when web slenderness of the girder exceeds 50.