Simplified Earthquake Analysis of Concrete Gravity Dams

Abstract

A two‐stage procedure was proposed in 1978 for the analysis phase of elastic design and safety evaluation of concrete gravity dams: (1) A simplified analysis procedure in which the response due only to the fundamental vibration mode is estimated directly from the earthquake design spectrum; and (2) a refined response history analysis procedure for finite element idealizations of the dam monolith. The former was recommended for the preliminary design and safety evaluation of dams, and the latter for accurately computing the dynamic response and checking the adequacy of the preliminary evaluation. In this paper, the simplified analysis procedure has been extended to include the effects of dam‐foundation rock interaction and of reservoir bottom sediments, in addition to the effects of dam‐water interaction and water compressibility included in the earlier procedure. Also included now in the simplified procedure is a “static correction” method to consider the response contributions of the higher vibration modes. Thus, the design procedure proposed in 1978, which is still conceptually valid, should utilize the new simplified analysis procedure.