EARTHQUAKE ANALYSIS OF ARCH DAMS .1. DAM-FOUNDATION INTERACTION

A three-dimensional boundary element technique for the earthquake analysis of arch dams is presented. The dam and the foundation rock are assumed to be viscoelastic domains, the latter being boundless. Under the assumption of linear behavior, the dam-foundation rock interaction and the traveling-wave effect are represented in a direct and rigorous way (existing finite element representations include the former effect in a very approximate way and do not consider the latter). The linear response of an arch dam (the Morrow Point dam) to harmonic P- or S-waves propagating vertically is presented for empty reservoir conditions. The importance of the dam-foundation rock interaction and the traveling-wave effect are clearly shown. The results are in contrast with some obtained using the finite-element method. The water domain and the combined dam-water-foundation rock interaction effects are included in the model in a companion paper, in which results for the same arch dam with the reservoir full of water are presented.