System identification of linear MDOF structures under ambient excitation

This paper introduces the eigenspace structural identification technique fo r tall buildings subjected to ambient excitations that are stationary and w here only the response time histories are measured. Based on the forward in novation model of the Kalman filter sequence, the actual response can be co nstructed as a function of the measured response time history with contamin ation of either displacement or velocity. The response time history is deco mposed into subspace matrices using QR decomposition and Quotient Singular Value Decomposition (QSVD) techniques. These are then substituted into the least-square formulation to obtain the solution which is non-unique. Simila rity transformation is applied to arrive at the desired solution employing the fact that eigenvalues of self-similar systems are identical. The advant ages of this eigenspace technique are that it is non-iterative, initial est imates of the parameters to the identified are not required, well-establish ed numerical algorithm of the decomposition techniques employed are availab le, and the method can handle MDOF systems efficiently. Copyright (C) 1999 John Wiley & Sons, Ltd.