地震和滑坡链式灾害作用下连续梁桥结构易损性分析OA北大核心CSTPCD

The disasters-resistant research on bridge structure mainly focuses on the mainshock-aftershock and erosion performance.Few studies are proposed on seismic fragility analysis of bridges under disaster chain.First,this paper proposes a framework of bridge performance analysis based on cumulative damage under earthquake and landslide.By using a typical three-span continuous girder bridge in the western mountain area as an example,the nonlinear finite element model was built.Then,based on the nonlinear time history analysis,the cumulative damage of bridge structure under the combined action of earthquake and landslide was analyzed by a probability-based method,and the seismic vulnerability curve was obtained to evaluate the seismic performance of bridge structure.Finally,the effect of the landslide volume and the landslide movement distance on the seismic performance of bridges was studied.The results show that the cumulative damage of bridge structure increases obviously under the disaster chain action of earthquake and landslide,and the seismic demand of structure increases greatly.The failure probability of the bridge struc-ture increases significantly when the landslide distance is 150 m,and it starts to be stable after the distance exceeds 250 m.When PGA=lg,landslide movement distance is 100 m,the landslide with the volume of 1X107 m3 has the largest damage effect on the structure,and the probability of complete damage increases by more than 60％.The existence of earthquake landslides will significantly increase the failure probability of bridge structures under different ground motion levels,which should be considered in site selection and safety fortification.