Revising Seismic Vulnerability of Bridges Based on Bayesian Updating Method to Evaluate Traffic Capacity of Bridges

Analyzing the seismic vulnerability of bridge structures is of great significance in assessing the sustainable capacity of bridges. However, previous seismic vulnerability analysis of bridge structures was based on theoretical simulation or experimental research, which couldn’t really reflect the actual seismic damage. Therefore, this paper used Bayesian updating method to obtain a corrected vulnerability curve of bridge structures considering the theoretical simulation and historical seismic data, which overcame the shortcomings that information couldn’t be updated. Specifically speaking, the seismic demand probability function of the bridge structure was obtained through numerical simulation, and a seismic vulnerability curve of a log-normal distribution with two parameters (median value c j and log-standard deviation ξ j ) was established, which was taken as the prior information. Then, combining the historical empirical damage data, the demand information is updated to obtain the posterior probability of the structural seismic demand. The possibility of exceeding the limit damage state of the bridge structure under different ground motion intensity can be obtained by using the corrected seismic vulnerability curve. The results show that the corrected seismic vulnerability curves are closer to theoretical simulation results, which provides a new idea for the reliability analysis of the bridge structure. Moreover, based on the corrected seismic vulnerability curve of Guxigou Middle Bridge, the post-earthquake traffic capacity of the bridge was evaluated by combining with traffic flow and traffic time. The research results show that the proposed method can quickly evaluate the sustainable traffic capacity of bridges after earthquakes, which has certain practicability and scientificity and provides the theoretical basis and practical guiding significance for the relief work after earthquakes.