Seismic performance of a hydroelectric dam under repeated earthquakes

A large mainshock that can trigger a variety of aftershocks, including larger aftershocks, within a short period can potentially increase the cumulative damage on structures. This study is devoted to analyzing the structural performance of a dam under seismic loading. Seismic sequences characterized by the repetition of moderate and strong earthquakes are categorized into two parts: near field and far field. The distance of earthquake events from the epicenter less than 20 km is categorized as near field, whereas the distance of more than 20 km is considered far field. The effect of repeated near-field and far-field earthquakes on a concrete dam is investigated. The nonlinear seismic response of the dam differs because of the aging process. Chemical factors (humidity and liquidation process) and mechanical loadings, which are responsible for degrading aged concrete, are incorporated in this study. This study analyzes the dam safety throughout its design life by considering the repeated earthquake loading and material impact on the chemical factors and mechanical loadings as the age of concrete reach up to 100 years. The performance of the concrete dam for 50 and 100 years after the construction is studied