Influence of earthquake duration on structural collapse capacity: Application to self-centering shear walls

Abstract

This study investigates the influence of earthquake duration on the structural collapse capacity of self-centering shear walls (SCSW). The assessment process employing different response indicators is examined when considering the duration effect, including the inter-story drift ratio (IDR) and damage index (DI) quantified through a modified damage model. SCSWs with varying self-centering parameters λ are designed and modeled, and incremental dynamic analyses are performed using two record sets with distinct effective durations and equivalent frequency contents. The assessment criteria outlined in FEMA P695 are utilized to quantify the collapse capacity of SCSWs considering the duration effect. Meanwhile, the duration effect on structural performance corresponding to multiple damage states are evaluated. Results show a minimal correlation between the duration effect and collapse capacity when employing IDR during evaluations. Conversely, earthquakes with longer durations may impose higher collapse risks to SCSWs when assessing collapse capacity using DI. Meanwhile, enlarging λ can effectively mitigate damage development and reduce collapse risks for SCSWs. The results further demonstrate that damage may develop more rapidly within SCSWs under long-duration earthquakes, potentially leading to inadequate redundancy during intense seismic events. Additionally, the result suggests that the current performance assessment process only employing deformation-based response indicators may lead to inadequate evaluation of collapse risks for SCSWs, especially when accounting for the effect of earthquake duration.