An investigation of the structural nonlinearity effects on the building seismic risk assessment under mainshock–aftershock sequences in Tehran metro city

Abstract

This research attempts to investigate the effects of neglecting the nonlinear behavior of structures on the estimated seismic risk assessment of buildings under mainshock–aftershock (MA) sequences. In this regard, the Tehran metro city is selected as a building site due to its high seismicity level. Three separate 5-, 10-, and 15-story buildings are considered and designed based on international design codes. The earthquake hazard scenarios containing mainshock–aftershock sequences are modeled randomly using a synthetic stochastic methodology for this region. Next, by implementing the Monte Carlo simulation method, buildings performances are obtained for a large number of different scenarios, and consequently, the lifetime direct losses imposed on the buildings are evaluated. To investigate the effect of structural nonlinearity, the described process is performed in two distinct scenarios: one of them assumes that the buildings behave linearly, while the other one allows the structures to respond nonlinearly. Finally, the level of dependency of calculated lifetime seismic risk to this parameter and also the contribution of different sources of losses, including physical damage, business interruption, and casualty losses, are investigated considering the aftershocks effect.