Development of a new equivalent linear algorithm with rate dependent soil model

Abstract

One dimensional site response analysis is widely used in estimating local seismic site effects. The soil behavior in the analysis is assumed to be independent of the rate of the seismic loading, while the laboratory results show that both the shear modulus and damping of cohesive soils are influenced by the rate of loading. The influence of the rate dependent soil behavior on ground motion propagation is not well understood. A new simplified equivalent linear analysis method is developed that approximates the rate dependence of soil behavior and is used to perform a suite of one dimensional site response analyses. The rate-dependent shear modulus has negligible influence, while rate-dependent soil damping filters out high frequency components of the motion and reduces the computed ground response. Copyright ? 2007 by The International Society of Offshore and Polar Engineers(ISOPE).