Identification of multistory shear buildings under unknown earthquake excitation using partial output measurements: numerical and experimental studies

In practice, it may be difficult to accurately measure some structural external excitations such as earthquake excitations to structures. Therefore, it is important to study algorithms for the identification of structures under unknown earthquake excitation. Based on the extended Kalman estimator approach recently proposed by the authors, a time domain algorithm is presented in this paper for the identification of multistory shear-type buildings under unknown earthquake-induced ground motion using partial measurements of structural absolute acceleration responses. In the absolute coordinate system, the unknown earthquake excitation is applied as an unknown external input to the first floor of the building. The recursive solution for structural state vector and structural parameters above the first story is estimated by the extended Kalman estimator approach, and the unknown input to the first floor is subsequently estimated by least-squares estimation. Then, the first story stiffness is estimated based on the structural eigenvalue, and the expansion of the determinate of the structural eigen matrix. Finally, the unknown ground motion is estimated by solving a first-order differentiation equation based on the Newmark- method. Both numerical simulation and experimental investigations validate the efficiency of proposed algorithm in the identification of multistory buildings under unknown earthquake excitation with partial output measurements of structural absolute acceleration responses. Copyright (c) 2013 John Wiley & Sons, Ltd.