UCLA

Structures are generally under the risk of earthquake events, especially in regions with high seismicity. However, rather than occur individually, the seismic events are tend to happen in sequence of the mainshock and the multiple aftershocks, which would cause additional damage to the damaged buildings in post-mainshock environment and increase the probability of collapse. This study mainly focuses on characterizing the seismic risk of a 4-story steel frame under mainshock-aftershock earthquake sequences. The damage of the structure are captured using the maximum story drift ratio and the energy-based damage indices, of which the performances are evaluated and compared in prior. The result shows that the energy-based damage index has higher ability to capture the potential structural damage and tend to display higher rate of collapse in the lifetime of buildings.