Reliability analysis of an inter-story isolated structure under a main-aftershock sequence based on the Laplace asymptotic method

After a strong mainshock, subsequent ground motion is the result of sequence multiple aftershocks, and damage to structure under these conditions more severe than from single earthquake. Most seismic studies are based on earthquake event. To explore influence main-aftershock an isolated inter-story structure, we constructed three-dimensional finite-element model such subjected it repeated sequences. The Laplace asymptotic method second-order second-moment was used calculate reliability action mainshock after at different levels. effects number location isolation layer, stiffness bearing in were analyzed. results showed that aftershocks increased failure probability each sub-structural part structure. lower had greatest influence, which about 3.89 times for alone. vs similar, but magnitude aftershock plays major role failure. reduced overall In case layer positions, placement top seventh story extremely rare level resulted reduction 6.01%. With bearings stiffness, largest decrease 7.88% when 50%.