Vulnerability analysis of continuous girder bridges based on time dimension under mainshock-aftershock sequences
This study examines the vulnerability of continuous girder bridges based on time dimension under the action of mainshock-aftershock sequences.A three-span continuous girder bridge was taken as the research object,and the nonlinear dynamic analysis was performed based on the OpenSees finite element software.By selecting ground motions corresponding to the regional site type,the time-based mainshock-aftershock sequences were constructed through the improved Omori's law and the statistical relationship of regional mainshock-aftershock sequences.The improved Park-Ang damage index was used for the structure.The linear fitting method of di-rect regression probability was used to establish the seismic vulnerability curves of piers at differ-ent time points in a short term after the mainshock,and the influence of mainshock-aftershock sequences on the seismic performance of the continuous girder bridge in regional time domain was studied.The results show that aftershocks will bring obvious incremental damage to the bridge structure.The exceedance probability of each damage state increases with the increase of peak ground acceleration and time.The higher the level of damage caused by the mainshock,the lower the exceedance probability,and the greater the exceedance probability under the action of after-shocks.The exceedance probability shows the largest increase on the first day after the main-shock,and then,it gradually decreases over time and becomes stable on the tenth day.There-fore,the time effect of the mainshock-aftershock sequence should be fully considered when analy-zing the damage caused by the earthquake to the bridge.
万方数据
维普
