MODAL IDENTIFICATION FOR A MULTI DEGREE OF FREEDOM SYSTEM USING CROSS SPECTRUM METHOD

摘要

A new system identification technique using cross spectrum of ARMA model is presented to estimate modal characteristics of buildings from microtremor records. By using this method, one can identify modal characteristics of buildings with soil-structure interaction, where mode shape and damping factors are estimated accurately from the building response record excited by wind forces as well as ground motion. Moreover, the modal characteristics are able to be separated accurately from one another. In this paper, we derive the theory of this technique, and demonstrate its applicability through numerical simulations for a SR model.