The Effect of Foundation's Modulus of Elasticity on Concrete Gravity Dam's Behavior

Investigation on the behavior of dams against the seismic loads is a key factor for safety requirement. One of the most important problems in evaluation of seismic behavior of concrete gravity dams is dam-reservoir-foundation interaction. In this paper, we study the effect of dam-reservoir-foundation interaction on nonlinear behavior of concrete gravity dams, a two-dimensional approach was used including the finite element method and smeared crack approach. Effective parameters in the models are physical properties of concrete such as modulus of elasticity, tensile strength and specific fracture energy. Their importance in the nonlinear analysis was investigated in a parametric study. Different boundary conditions were used in foundation in order to determine the seismic response of concrete gravity dams. Results show that when the nonlinear analysis includes the dam- foundation interaction and the foundation's mass, flexibility and radiation damping, the seismic response of concrete gravity dam will be reduced to a realistic level. Decreasing in ratio of foundation's modulus of elasticity to dam's modulus of elasticity (EF/ES) causes increasing in dam crest displacement. The crack profile is expected to reduce due to mass of foundation and it's damping effects in massed foundation system.