不同地震激励方向下隔震曲线梁桥易损性分析OACSTPCD

To further evaluate the seismic performance of isolated curved girder bridges under seismic excitation,the influence of seismic excitation direction on their fragility was studied.A finite element model of an isolated curved girder bridge with laminated rubber bearings was estab-lished by APDL.Near-fault ground motions in the same seismic event were selected from PEER,and horizontal bidirectional ground motions were input according to the proportion specified in the code for nonlinear dynamic time-history analysis.The seismic fragility curves of the components were calculated by combining the seismic response and damage index.Considering the change in seismic excitation direction,seismic fragility surfaces of the components(pier and bearing)and bridge system were obtained using MATLAB programming and the influence of seismic excitation direction on the fragility of the isolated curved girder bridge was analyzed and discussed.The re-sults show that under different limit states,the tangential damage probability of each pier is obvi-ously greater than that in the radial direction.The tangential fragility of each bearing is slightly greater than the radial fragility,with little difference.The tangential fragility of bridge members(pier and bearing)strongly depends on the seismic excitation direction,whereas the dependence of radial fragility is weaker;with an increasing damage level,the fragility of members becomes more sensitive to the seismic excitation direction.The fragility of the bridge system,which is in-sensitive to changes in the seismic excitation direction,is closer to that of the most vulnerable component because of the high correlation between the responses of the components.When evalu-ating the seismic performance of the isolated curved girder bridges,the influence of the seismic excitation direction on their seismic fragility should be considered to make the fragility analysis results more reasonable and reflect their actual damage state more accurately.