Hydrodynamic pressures in contraction joints including waterstops on seismic response of high arch dams

In the present paper, the effects of hydrodynamic pressures in contraction joints, on seismic response of arch dams are investigated. For this purpose an algorithm for applying the hydrodynamic pressures in open contraction joints is developed. The dam body material is assumed to have linear elastic behavior and all the contraction joints are simulated as reported in as-built drawings. In addition, the reservoir medium is taken to be compressible and the rock foundation is modeled as a mass-less flexible medium. The coupled system of dam-reservoir-foundation is analyzed utilizing simultaneous approach and NEWMARK-β method is used for integration in time domain. The effects of hydrodynamic pressure during seismic excitation on joints opening/sliding, stress distribution patterns within the dam body and on the crest displacement time history are studied. It is found that for a typical high concrete arch dam, the hydrodynamic pressure in the contraction joints are not affected much by in the present of waterstops. Taking these pressures into account leads to significant consequences on the dam behavior; and it must be considered, as the joint opening in high concrete arch dams is a common phenomenon even during low to medium ground shakings.