A continuum damage concrete model for earthquake analysis of concrete gravity dam-reservoir systems

In this study, the earthquake damage response of the concrete gravity dams is investigated with considering the effects of dam-reservoir interaction. A continuum damage model which is a second-order tensor and includes the strain softening behavior is selected for the concrete material. The mesh-dependent hardening technique is adopted such that the fracture energy dissipated is not affected by the finite element mesh size. The dynamic equilibrium equations of motion are solved by using the improved form of the HHT-α time integration algorithm. Two dimensional seismic analysis of Koyna gravity dam is performed by using the 1967 Koyna earthquake records. The effects of damage on the earthquake response of concrete gravity dams are discussed. Comparison of the Westergaard and Lagrangian dam-reservoir interaction solutions is made. The effects of viscous damping ratio on the damage response of the dam are also studied.