Effect of Seismic wave scattering on the Response of Dam-Reservoir-Foundation Systems

Traditionally the foundation in a dam is modeled by a sub-structuring approach for the purpose of seismic performance analysis. The main disadvantage of sub-structuring approach is that it cannot be used for solving nonlinear dynamic problems. Therefore, in that case seismic response analysis must be carried out in time domain. Among the different earthquake input mechanisms the deconvolved earthquake input model is a preferred method as it removes the seismic scattering effects due to artificial boundaries of the semi-infinite foundation domain. Deconvolution is a mathematical process which allows the adjustment of the amplitude and frequency contents of an earthquake ground motion applied at the base of the foundation to achieve the desired output at the dam-foundation interface. The existing procedures of deconvolution are not effective for all types of earthquake records including high-frequency and low-frequency ground motions. An improved procedure has for deconvolution been proposed here.