Dam-foundation rock interaction effects in earthquake response of arch dams

The dynamic response of Morrow Point Dam to Taft ground motion is presented for a wide range of properties of the dam, foundation rock, impounded water, and reservoir boundary materials. Based on these response results, the effects of dam-foundation rock interaction (considering damping, inertia, and flexibility of the foundation rock) with empty reservoir are investigated. The significance of dam-foundation rock interaction effects ignored in standard analyses that consider flexibility of the foundation rock but not its inertia or damping-material and radiation-effects is then identified. Finally, the combined effects of dam-foundation rock interaction, dam-water interaction, and reservoir boundary absorption are studied.