Seismic vulnerability analysis of typical continuous girder bridges of Chongqing-Kunming high-speed railway

In order to evaluate the seismic performance of a typical three-span continuous girder bridge of Chongqing-Kunming high-speed railway, the theoretical seismic vulnerability of the bridge is analyzed based on the method of probabilistic seismic demand analysis. The measured ground motion records along the Chongqing-Kunming high-speed railway were selected as the seismic input. Considering the uncertainty of the bridge parameters, the Latin hypercubic sampling method was used to generate the bridge finite element model samples. Based on the incremental dynamic analysis method, the seismic response peak of each component of the bridge was obtained by performing nonlinear time history analysis. The seismic demand model was established by linear regression analysis of peak response and peak acceleration of ground motion. Furthermore, the seismic vulnerability curves of the bridge structure with ordinary spherical steel bearing and hyperboloid spherical seismic isolation bearing were compared. The results show that the seismic isolation bearing can effectively reduce the vulnerability probability of the brake pier and optimize the seismic performance of irregular bridge structures with different pier heights. The research methods and conclusions can provide reference for seismic design of irregular continuous girder bridges. © 2021, Central South University Press. All rights reserved.