Fire effect of steel bridge structure with consideration of leaked combustion fuel on asphalt bridge deck

Abstract

In this paper, a fire load model is introduced for steel bridge decks considering asphalt pavement layers, aimed at exploring the consequences of fire arising from fuel leakage on the bridge pavement. Temperature data, mass loss rates, and radiation measurements from the pavement during fire tests are collected. The fire process on the bridge deck is categorized into four distinct stages, based on the mass loss rate. The temperature-time model is constructed by fitting the temperature data from the first two stages on the top surface. This model is then validated by comparing the temperature data obtained from various temperature-time load inputs with the experimental data from the middle and bottom surfaces. Additionally, a finite element numerical model is developed for a steel box girder bridge, enabling a comparison of different temperature-time models to establish the rationality of the bridge deck temperature-time model. Finally, the thermal mechanical coupling method is employed to investigate the impact of fire on the bridge's mid-span, revealing a close alignment between the simulation temperatures derived from the bridge deck temperature-time curve and the experimental results.

Keywords

• Bridge deck fire
• Temperature field
• Temperature-time model
• Asphalt pavement
• Thermal-mechanical coupling