Nonlinear dynamic analysis of concrete gravity dam-water-foundation rock systems utilizing a simplified non-associated elasto-plastic joint model

In the present study, a simplified non-associated joint model is employed to evaluate the influence of apparent friction coefficient and cohesion on earthquake response of concrete gravity dam-water-foundation rock systems. The formulation and its theoretical concepts are discussed initially. Then, a primary verification of the model is considered to control its implementation and to show its characteristics. Thereafter, the sliding behavior of Pine Flat gravity dam-water-foundation rock is studied for different ratios of foundation rock to dam elastic moduli by application of the described nonlinear joint-model. It is shown that joint opening/closing as well as sliding affects the seismic response of gravity dams significantly for rigid foundation assumption case. However, its influence reduces as foundation rock modulus decreases and radiation damping effects increases. This is observed by comparing displacement histories and envelope of principal stresses in dam body. In particular, locations and magnitudes of maximum tensile and compressive stresses occurring in the dam body are also changed when joint modeling is considered in comparison with corresponding linear cases.