Effect of Mainshocks-Aftershocks Sequences on the Lifetime Performance of a Liquefiable Soil Foundation-Embankment System

Abstract

Structures should be designed to resist multiple seismic hazards during their serviceable life. However, among these hazards, the clusters events of mainshocks and aftershocks might induce structural collapse. On the other hand, it is known that the Performance Based Earthquake Engineering (PBEE) methodology presents limitations in accounting for the damage issued from multiple events. Thus, the fragility exposure of the structure cannot be determined due to the dependency of these events. 

For this purpose, this work proposes a methodology to study the response of a liquefiable soil-foundation embankment system subjected to sequences of mainshocks – aftershocks. Thus, for a given lifetime duration, the damage accumulation is calculated after mainshocks generated stochastically and aftershocks generated with the BASS (Branching Aftershock Sequence) model. Consequently, the survival probability was estimated as to evaluate the performance of the embankment. Finally, the lifetime fragility evolution of the embankment was calculated.

The results of this work show the importance of the soil history of loading that affect the future behavior of the embankment. In addition, the aftershocks can result into more damages even if they have less magnitude than the mainshocks.