Two- and Three-Dimensional Dynamic Finite Element Analyses of the Long Valley Dam

Keywords: Finite Element Analysis, Soil Response, Cyclic Loading, Accelerations, and Long Valley Dam.

Abstract: Earthquake response records of the well-instrumented Long Valley Dam in the Mammoth Lake area of California are compared with numerical prediction made using finite element models. The soil response to cyclic loading is accounted for by the use of a multi-surface plasticity model. The input and output to the finite element analyses take the form of acceleration, and are compared in both the time and frequency domains. Natural frequencies have also been obtained for the finite element models and for the real structure from spectral analysis, and are in generally good agreement. The time-domain results give good agreement and high correlation in the up/down-stream direction but poor agreement in the vertical (and transverse in the case of 3-D) direction. The failure of the finite element models to capture the high-frequencies present in the vertical and transverse directions is thought to be partly due to the crude finite element discretization used. To improve the modeling in these directions, a finer 3-D mesh has been prepared for further analysis and the results will be presented in a subsequent report.