Analysis of seismic records to evaluate soil-structure interaction effects on bridges

Abstract

Soil-Structure Interaction (SSI) could significantly affect the dynamic behaviour of bridge structures. The most sophisticated approaches used to model the SSI effects deal with kinematic and inertial interaction separately, being unable to consider the combined effect of both phenomena, as it happens in real cases. This supports the need of a better understanding of such effect in order to establish a better SSI modelling technique. This paper presents the results of several analyses conducted with seismic records obtained from instrumented bridges in order to determine how SSI affects their dynamic properties. The data correspond to several selected ground motions, as they were recorded by instruments located on free field, foundation piles, substructure and superstructure, corresponding to Via California bridge (Capistrano Beach, California) and Lake Crowley bridge (Mammoth Lakes, California). The results include fundamental mode properties identified for each bridge, comparison of spectral response quantities, determination of directionality effects and evaluation of signals using frequency domain techniques. The final analysis is done based on the results of the records analysis and the particular overall characteristics of each structural system. © The Society for Experimental Mechanics, Inc. 2012.