Bridge Fire Vulnerability Hierarchy Assessment Based on the Weighted Topsis Method

With the increasing traffic volume and gradually higher percentage of hazardous goods transport vehicles, bridge fire accidents are more frequent and the resulting losses are striking. Therefore, the assessment of fire risk in bridges has important implications. In this paper, we identify and establish a bridge fire vulnerability indicator system based on vulnerability theory from three aspects: the susceptibility to fire, its resistance to reversal, and its exposure during a fire. On the basis of grading fire vulnerability and making a description of the status of each grade, the corresponding index values of each grade were established by the method of assigning values to the qualitative indexes, and then the empowering TOPSIS method was applied to calculate the relative closeness of each indicator to the ideal status, so as to establish a bridge fire vulnerability grade evaluation model. Finally, using a bridge as an example, it was verified that the assessment method was reasonably feasible by calculating the relative proximity of the bridge to the ideal condition, resulting in a fire vulnerability grade of I for the bridge, which corresponded to its fire history.