Semi-empirical model for site effects on acceleration time histories at soft-soil sites. Part 2: Calibration

摘要

A previously developed simplified model of ground motion amplification is applied to the simulation of acceleration time histories at several soft-soil sites in the Valley of Mexico, on the basis of the corresponding records on firm ground. The main objective is to assess the ability of the model to reproduce characteristics such as effective duration, frequency content and instantaneous intensity. The model is based on the identification of a number of parameters that characterize the complex firm-ground to soft-soil transfer function, and on the adjustment of these parameters in order to account for non-linear soil behavior. Once the adjusted model parameters are introduced, the statistical properties of the simulated and the recorded ground motions agree reasonably well. For the sites and for the seismic events considered in this study, it is concluded that non-linear soil behavior may have a significant effect on the amplification of ground motion. The non-linear soil behavior significantly affects the effective ground motion duration for the components with the higher intensities, but it does not have any noticeable influence on the lengthening of the dominant ground period.