Chen, M.-T., and Harichandran, R. S. (1996). "Simplified response
analysis of earth dams to spatially varying earthquake ground motion."
Proceedings, 11th World Conference on Earthquake Engineering,
Acapulco, Mexico, Paper No. 527.
Abstract
Recent research (Harichandran and Vanmarcke, 1986; and many others) has
shown that significant variation of earthquake ground motion exists over
the base dimensions of large structures. The response analysis of an
earth dam subjected to spatially varying earthquake ground motion
(SVEGM) generally requires a 3-D finite element model in order to
accurately represent the spatially varying excitation at the base and
sides of the dam. Since SVEGM is usually characterized using
probabilistic models, the seismic analysis of the dam is best performed
using random vibration analysis, as long as linear response is assumed.
However, a 3-D finite element-based random vibration analysis can be
extremely time-consuming. This paper presents an approximate method for
obtaining "equivalent" excitations in reduced space from the general
excitation along the dam/rock interface, such that the response of the
dam may be computed reasonably accurately at locations away from the
base using a 2-D shear beam model. The maximum shear stress at the base
of the dam, which can be large due to the ground strain caused by SVEGM
and the high stiffness of the stream-bed, is largely due to the
so-called pseudo-static response of the dam. Reasonably accurate
estimates of the shear stresses at the base requires the pseudo-static
responses to be computed through a 3-D finite element model, which is
nevertheless much quicker than performing a dynamic analysis.