Seismic Reliability Analysis of Cable-Stayed Bridges Subjected to Spatially Varying Ground Motions

Abstract

To efficiently and accurately evaluate the seismic system reliability analysis (SSRA) of cable-stayed bridges subjected to spatially varying ground motions, a direct probabilistic framework was developed in this paper. First, the relevant methods for the structural seismic reliability were presented, including the multiplicative dimensional reduction method, maximum entropy method with fractional moments (FMs), and the product of conditional marginals (PCMs). Second, based on the OpenSees platform, the 3D finite element model of the cable-stayed bridge was established, along with the uncertain structural parameters, stochastic ground motions, and failure modes of each structural component under earthquake loading summarized. Third, considering the double uncertainties of the bridge and ground motions, the nonlinear time history analysis was conducted for the bridge under various scenarios. Finally, the nonlinear seismic response and fractional moment of the structural response were obtained. The maximum entropy method with FMswas used to get the probability density function (pdf) of the structural response, together with the failure probability and reliability index of each component. Considering the correlation between components, the PCMs was used to obtain the failure probability of the bridge under earthquake loadings, and some critical conclusions were drawn.