Semiquantitative Fire Risk Grade Model and Response Plans on a National Highway Bridge

Abstract

For the last ten years, the number of cases of large-scale fires which occur on bridges, tunnels, and underpasses has increased. Such fires cause primary and secondary damage, including loss of human life, traffic congestion, and extensive financial damage. Therefore, a risk grade model and effective response plan need to be established for such cases in order to minimize the social and economic costs of bridge fires. In this study, the hazard factors contributing to bridge fires were selected to apply a risk grade model. A total of 144 bridge fire simulations were performed to calculate a surface temperature based on time by using Fire Dynamics Simulation (FDS). A risk grade in accordance with the degree of surface damage state caused by temperature of bridges was presented, and the mobilization time criteria for fire suppression were proposed. The surface temperatures based on time can be classified according to the vertical clearance and mobilization time criteria for fire suppression. Through the classified maximum surface temperatures based on time for bridges, the risk grade can be estimated according to the degree of surface damage state caused by temperature. In order to evaluate the applicability of the established risk grade model to the actual bridge, the arrival time taken from the bridge to the fire station was calculated through a Geographic Information System (GIS) network analysis, and the grades for actual bridge cases were assessed. The purpose of this bridge fire risk grade model is to establish a disaster prevention strategy based on risk grades and to minimize the subsequent social damage by determining a priori the disaster scale.

Bridge Fire Vulnerability Hierarchy Assessment Based on the Weighted Topsis Method

“…Therefore, the bridge fire vulnerability grade assessment based on the empowered TOPSIS method is a more convenient and feasible assessment method for bridge fire risk. The comparisons in [4,5] using the fuzzy comprehensive evaluation method do not need to find the right transferred membership function, as well as to prevent human subjective judgment in the process of looking for membership function, making the results more objective and reliable. In addition, we do not need to calculate the multistage evaluation result, making the evaluation process more simple and more suitable for engineering application programming.…”

“…At the same time, the fire rescue emergency response mechanism should be improved. 4 Irreversible components in the ecological environment around the bridge should be reduced and the impact of fire on the entire bridge system should be minimized.…”

“…Through the threestep risk assessment procedure of PRA, SRA, and DRA, the fire risk of bridges is assessed Sustainability 2022, 14, 14174 2 of 11 to further identify the locations of high-risk bridges, so as to formulate corresponding countermeasures. Hojune Ann [4] determined the damage degree of the bridge surface based on FDS technology, established the risk level, established the risk level model on this basis, and determined the risk level of the actual bridge through GIS, so as to formulate the corresponding plan. For cable-stayed bridges and suspension bridges, the cables and beams share the load.…”