Seismic Performance Evaluation of Concrete Gravity Dam on Rock Foundation System with Shear Zone

Two-dimensional finite element analysis was performed to investigate the effect of earthquake force on a concrete gravity dam resting on the rock foundation system with shear zone. The compressive stress in the dam structure, the shear force distribution, bending moment distribution and settlement of raft and pile, and axial force within pile were studied using pseudo-static method and time-history dynamic analysis. From the results, it is observed that the maximum compressive stress under earthquake loading is more than the permissible limit within the dam body. While compressive stress is within the permissible limit in the other locations of the ground and dam. The maximum shear force and bending moment within the raft is observed to be at the nearest pile-head to the dam toe. Similarly, the shear force, bending moment, and axial force are maximum within the pile nearest to the dam heel. The results obtained from pseudo-static analysis and dynamic analysis were also compared and it is observed that both the analyses predicted results in a comparable range, except for the pile load. The dynamic analysis predicted a much higher value of pile load in comparison to the pseudo-static analysis.