Investigation of seismic damage index due to water level changes in reservoir through nonlinear dynamic analysis under Far-Fault and Near-Fault ground motions

In this study, reservoir water level effects on nonlinear dynamic response of concrete gravity dams are investigated. For this purpose, the nonlinear behavior of the dam concrete is captured using the concrete damage plasticity (CDP) on the non associated flow rule assumption. Water in the reservoir is represented by the Lagrangian (displacement-based) fluid finite elements. The program ABAQUS is applied for nonlinear dynamic analysis of dam-foundation-reservoir systems and employed in the response calculations. Nonlinear dynamic analysis of Shafarood concrete gravity dam subjected to three far-fault and three near-fault earthquake groundmotions are performed for three different water levels. The crest displacements, the failure element distribution in dam body and damaged Index in different conditions are presented. The results obtained from nonlinear analyses for different water levels are compared with each other. It is apparent that the reservoir water level significantly affected the dynamic response of gravity dam but under near-fault ground motions reservoir has a mitigation effecton nonlinear dynamic response of dam.