Abstract: Abstract: In order to analyze the fire resistance of suspension bridge structure, a fire resistance analysis method based on the equivalent temperature section is proposed. The temperature calculation model of cable section composed of parallel steel strands is deduced based on the heat conduction theory, and a simplified equivalent temperature calculation method is further established. Then the finite element model of the cable bridge with equivalent cable area is established, and the temperature rise curve of the main cable at the fire position is determined according to the equivalent temperature calculation method. Finally, the fire response process and fire resistance performance of the suspension bridge structure are studied through thermal coupling analysis. The results show that for the four-layer cable of the main cable of the suspension bridge, there is an obvious uneven temperature field before 50 minutes in the vehicle fire. There are obvious differences between the overall bridge structural response when considering the uneven temperature field of cable section and when not considering it. The layered cable temperature equivalent method based on equivalent area and equivalent strength can consider the uneven distribution of cable section, simplify the finite element model of cable bridge and avoid the complex heat conduction analysis of the whole cable bridge.

Key words:  suspension bridge, fire performance, equivalent temperature, numerical simulation, simplified calculation method