考虑墩-梁碰撞效应的连续刚构桥系统易损性与概率地震风险性分析OA北大核心CSTPCD

A continuous rigid-frame bridge was selected with a main span arrangement of(120 + 220 + 120)m to investigate the influence of the pounding effects between the main girder ends and transition pier on the seismic system fragility and probabilistic seismic risk of the bridge.The real internal force state of the completed bridge was extracted from the actual construction simulation.The dynamic analysis model of the bridge was developed based on the equivalent load method,which considers the internal force state.The Hertz-Damp model is utilized to simulate the pounding effects.A total of 90 pulse-like near-fault ground motions were selected and inputted along the longitudinal direction.The pounding process and damage mechanism were illustrated through nonlinear time-history analysis.The composite system fragility curves of the bridge,con-sidering the weight coefficients of piers and bearings,were established by incremental dynamic analysis.These curves were compared to the fra-gility curves derived from the first-order boundary method series model and the parallel model.Moreover,the site seismic hazard function was convoluted with the fragility function to establish the probabilistic seismic risk curves.Subsequently,the system fragility,probabilistic seismic risk,and the pier-beam pounding effects were investigated.The results indicated that the displacement response of the transition pier and the seis-mic risk probability could be underestimated by 3 to 5 times and 120%,respectively,when the pounding effects are ignored.The seismic damage probability of slight and moderate damage can be underestimated by 35%to 80%when the peak ground accelerations are 0.2g to 0.6g,while that of severe and complete damage can be underestimated by 13%to 68%and 15%to 59%when the peak ground accelerations are 0.6g to 1.5g,re-spectively.