Rate-dependence of rockll behavior on propagated near fault ground motions

Equivalent linear one-dimensional site response analysis, which approximatesnonlinear soil behavior within the linear analysis framework, is widely used in estimatinglocal site eects. in this analysis, soil behavior is often assumed to be independent ofthe frequency of seismic loading. however, the large scale triaxial test results on rockllmaterial have shown that the shear modulus and, especially, the damping ratio, areinuenced by the loading frequency. a series of one-dimensional equivalent linear analyseswere performed on 30 m and 90 m thick proles of the studied rockll material to evaluatethe frequency-dependent soil behavior under several well-known near-fault ground motions.the analyses are carried out for three base acceleration levels, namely, 0.1 g, 0.35 g and 1 g,using the simple time history scaling method. results show that the frequency-dependentshear modulus and damping ratio can have a pronounced inuence on propagated groundmotion. the frequency-dependent soil behavior is also dependent on the thickness of thesoil prole, amplitude, equivalent no. of cycles at 0:65max, and frequency content of theinput ground motion