Seismic Response of Concrete Arch Dams Including Dam-Reservoir- Foundation Interaction Using Infinite Elements

In the present paper, a direct time domain procedure is used for dynamic linear and nonlinear analysis of the coupled system of reservoir-dam-foundation in 3D space. The foundation is assumed massed and infinite elements are used to model the semi-infinite medium via the far-end boundary of the foundation model. The nonlinear behavior of mass concrete is modeled using the smeared crack approach in which the elements can be cracked in each Gaussian point. The reservoir is assumed to be compressible and is modeled using finite element method with appropriate boundary conditions. The coupled system is solved using the staggered displacement method. As a case study, KARADJ double curvature arch dam in Iran is chosen to investigate the effect of massed foundation on the seismic response of the system. It is found that the response of the system with massed foundation including infinite elements is the same as that when the artificial absorbing boundary on the far-end boundary of the foundation is modeled using the viscous boundary. In addition, when the foundation is assumed mass-less, the resulted seismic stresses within the dam body can be too conservative. Decreasing the crack profiles and displacements are observed in nonlinear analysis of the dam when infinite elements are used to model the semi-infinite medium via the far-end boundary of the foundation model.