STRUCTURAL SAFETY OF HIGH ARCH DAMS WITH VARIABLE WATER LEVELS BASED ON SEISMIC PERFORMANCE EVALUATION

Seismic performance evaluation of arch dams under different environmental conditions is vital for the structural safety of the existing dams. In the present paper, effects of the reservoir water in four different levels are investigated on the seismic performance of an arch dam. Dynamic equilibrium equations of the dam-reservoir-massless foundation coupled system are solved by Newmark’s time integration algorithm. Several three-component ground motions, obtained from deterministic hazard analysis of the dam site, are used for excitation of the finite element model. Seismic performance evaluation is utilized considering parameters such as crest displacement, demand capacity ratio, cumulative inelastic duration and extension of the overstressed areas on upstream and downstream faces obtained from linear elastic analyses. It is found that dewatering the reservoir leads to extension of the overstressed areas on both upstream and downstream faces and increases structural operating risk. In such a case, detailed nonlinear analyses, including joint and material nonlinearities, are required for more realistic results on crack propagation.