Influence of ground motion’s vertical component on seismic fragility of slopes using finite element simulations

Abstract

Extensive research has been conducted on the influence of ground motion’s vertical component on slope performance. However, whether this effect was substantial remains controversial. This study investigates the effect of the vertical component of ground motion records on the seismic fragility of slopes using finite element simulations. We consider three slope models with frictional soils subjected to two sets of input motions comprising a subset of ground motion records in the Next Generation Attenuation West 2 database (Sets H and HV consist of 300 horizontal components only and 300 combined horizontal and vertical components of the records, respectively). The maximum permanent seismic slope displacements computed from Set HV are mostly greater than those from Set H, particularly at a small horizontal-component peak ground acceleration (PGAH). The seismic fragility curves of the slopes from Set HV, calculated by a probabilistic seismic demand model, are generally higher than those using Set H for three threshold values (5, 15, and 30 cm), with a pronounced distinction observed from intermediate to high levels of PGAH. This outcome indicates that including the vertical component in dynamic finite element simulations affects the seismic fragility of slopes, expected to contribute to improving seismic hazard and resilience assessments.