Seismic Loss Estimation with Consideration of Aftershock Hazard and Post-Quake Decisions

Current seismic performance methodologies already have the ability to estimate the direct loss, downtime, and fatalities of buildings because of earthquakes using performance-based earthquake engineering (PBEE). However, earthquake aftershocks that have the potential to cause additional damage to buildings are not considered in these methodologies. Conversely, previous seismic performance assessments considering aftershocks, which were on the basis of simplified models that do not have the capacity to simulate details, cannot account for various post-quake decisions (e.g., evacuation, safety evaluation, and repair). In this study, the effects of aftershocks and postquake decisions on seismic performance are discussed. An assessment procedure in accordance with other PBEE-based methods, but also with the ability to consider aftershocks, is proposed. A framework was developed according to the procedure. An illustrative case study also is presented using two nonductile reinforced concrete frame buildings. A total of 18 near-fault and 60 far-field recorded mainshock-aftershock sequences are employed in the example. The case study showed that mainshock-aftershock sequences can result in significantly more serious consequences than when only the mainshock is considered. Also, using only one aftershock instead of multiple aftershocks was found to be an acceptable balance between computational effort and accuracy. (C) 2016 American Society of Civil Engineers.