Effects of near-fault ground motions in seismic performance evaluation of a symmetric arch dam

Near-fault ground motion effects in comparison with far-fault ground motions on seismic performance of a symmetry concrete arch dam are investigated. Various sets of near-fault and far-fault ground motions with approximately identical peak ground acceleration were used for analyses of coupled system. For this purpose the Karaj arch dam was selected as case study and two different options were considered for dam-foundation interaction. In the first case, foundation rock was assumed rigid, and in the second case foundation rock was simulated as a massless medium. The behavior of the dam and foundation was expressed in terms of displacement, and the reservoir was modelled based on fluid elements. The seismic performance evaluation of the arch dam was performed using demand-capacity ratios obtained from linear analyses.