Soil deposits earthquake response by means of a stochastic approach

Abstract

The analysis of the dynamic response of soil deposits under not too severe earthquake excitation by a stochastic approach is presented. The range of earthquake severity considered makes the equivalent non-linear method suitable for the earthquake response analysis. in this method the soil nonlinearity is modelled through the adequate adjustment of the stiffness and damping properties as a function of the average strain level achieved in a given soil volume. Traditionally this kind of approach is used with the time-frequency response complex method. The required statistical significance of the analysis makes it necessary to perfom several equivalent non-linear lime domain analyses.

Herein an alternative approach by means of a stochastic definition of the input excitation and of the responses is presented. A comparison between a set of one dimensional site lime analyses and their stochastic counterpart is made. 111is allows to appreciate the effectiveness of the later. The statistical modelling of the responses was achieved by a judicious choice of the exceedance statistical distribution of probability in view of the essential hypothesis that either the input and of the responses constitute narrow band processes.