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.