RESPONSE OF COMPOSITE STEEL PLATE GIRDER BRIDGES SUBJECTED TO DEBRIS FIRES

Abstract

Bridge fires have been a serious concern for asset owners for decades. Considerable research work has been published on the assessment of bridges subjected to hydrocarbon fires and Wildland Urban Interfaces (WUI) fires like bushfires. However, the impact from fires that may have been generated due to onsite-accumulated debris, has been largely overlooked in the past. Prolonged duration of debris fires might well cause significant damage to the bridges, unless properly accounted during the design stage. The current study investigates the influence from debris-generated fires on steel girder bridges, using a reasonably validated advanced numerical modelling framework. Fire development was modelled first as a static, and then a travelling fire, using fire dynamic simulation (FDS) to capture the Adiabatic Surface Temperature (AST) development of the structure. The resulted AST was coupled with thermo-mechanical analysis using sequentially coupled thermo-mechanical analysis procedure in ABAQUS. The numerical model was used to estimate the temperature and displacement development of the bridge. The outcome from the study will facilitate asset managers for conducting necessary risk assessments incorporating the influence of onsite flammable debris for bridges.