Regional seismic-damage prediction of buildings under mainshock—aftershock sequence

Abstract

Strong aftershocks generally occur following a significant earthquake. Aftershocks further damage buildings weakened by mainshocks. Thus, the accurate and efficient prediction of aftershock-induced damage to buildings on a regional scale is crucial for decision making for post-earthquake rescue and emergency response. A framework to predict regional seismic damage of buildings under a mainshock-aftershock (MS-AS) sequence is proposed in this study based on city-scale nonlinear time-history analysis (THA). Specifically, an MS-AS sequence-generation method is proposed to generate a potential MS-AS sequence that can account for the amplification, spectrum, duration, magnitude, and site condition of a target area. Moreover, city-scale nonlinear THA is adopted to predict building seismic damage subjected to MS-AS sequences. The accuracy and reliability of city-scale nonlinear THA for an MS-AS sequence are validated by as-recorded seismic responses of buildings and simulation results in published literature. The town of Longtoushan, which was damaged during the Ludian earthquake, is used as a case study to illustrate the detailed procedure and advantages of the proposed framework. The primary conclusions are as follows. (1) Regional seismic damage of buildings under an MS-AS sequence can be predicted reasonably and accurately by city-scale nonlinear THA. (2) An MS-AS sequence can be generated reasonably by the proposed MS-AS sequence-generation method. (3) Regional seismic damage of buildings under different MS-AS scenarios can be provided efficiently by the proposed framework, which in turn can provide a useful reference for earthquake emergency response and scientific decision making for earthquake disaster relief.