Two approaches to identify equivalent structural models from earthquake responses

Abstract

In many instances buildings are mutually connected, giving rise to complex arrays. In such cases it is difficult to assess a reliable structural scheme for the seismic analysis of a single building of the array. Two methods for interpreting the earthquake records of complex arrays are presented. The aim is to identify structural schemes of a single building or part of the array which account for the effects of the adjacent structures, in order to transform a complex system, with several parts interacting together, into a simpler one suitable for design purposes. Both methods are limited to linear behaviour and to planar systems. The structural parameters of the models are evaluated from recorded seismic responses. The equivalent models both comprise the addition, to the assessed scheme of the analysed building, of an appropriate distribution of masses and stiffnesses which represent the effect on that building of all the neighboruing connected units. In the first procedure, such a distribution is evaluated according to a predifined scheme, while in the second approach the physical characterization of the model is defined a posteriori. The two methods are applied to generated sample data in order to verify their reliability and accuracy.