Lifetime response of a liquefiable soil foundation-embankment system subjected to sequences of mainshocks and aftershocks

During their typical design working life, structures are subjected to multiple sequential earthquakes that are divided into clusters of mainshocks and aftershocks. In consequence, the induced seismic damage accumulates due to these several events in each cluster. On the other hand, the Performance Based Earthquake Engineering (PBEE) methodology presents limitations in accounting for the damage issued from multiple events and the fragility curves represent the failure probability only in one event of a given intensity. For this purpose, this work studies the response of a given structure subjected to sequences of mainshocks–aftershocks during its lifetime. The used time histories (mainshocks) were stochastically generated from a synthetic ground motion model, whereas the aftershocks were generated from the Branching Aftershock Sequence (BASS) model. The cumulative damage measure of the embankment is calculated after the tested sequences. More importantly, its lifetime distribution is estimated and compared with previous results. Finally, to be compatible with the PBEE methodology, the fragility evolution of the embankment over its lifetime was calculated as to emphasize its evolution with the loading history in the soil