Abstract
The response of a bridge under a fire scenario is an under researched topic not covered in the codes. This paper presents an approach to evaluate the fire response of the most exposed girder of a simply supported steel girder bridge designed by the Federal Highway Administration (FHWA) of the USA spanning 12.2 m under three different fire scenarios. The analyses use computational fluid dynamics (CFD) to create the fire model, and finite element (FE) software for obtaining the thermo-mechanical response of the girder. Results show that:(a) scenarios with the fire load close to the abutments are the most unfavorable, (b) it is necessary to use horizontal springs at the pinned support to appropriate model the restrain to the longitudinal movement of the bridge deck, (c) two values of the spring constant are enough to capture the response of the bridge, and (d) the value of the spring constant influences the failure time, the failure mode and the final deflections.
