Integration of decentralized structural control and the identification of unknown inputs for tall shear building models under unknown earthquake excitation

Since some excitations such as earthquakes or wind forces cannot be accurately measured, it is necessary to explore algorithms which can integrate structural control and the identification of unknown excitations. In this paper, an algorithm is proposed for the decentralized structural control of tall shear-type buildings under unknown earthquake-induced ground motion. The equations of motion of a tall controlled shear building subject to unknown ground motion are established in the absolute co-ordinate system, in which the ground motion input is applied to the 1st floor of the building and treated as an unknown external excitation. A decentralized control algorithm based on the instantaneous optimal control scheme is developed with limited measurements of structural absolute acceleration responses. The inter-connection effect between adjacent substructures is treated as ‘additional unknown disturbances’ at substructural interfaces to each substructure. Instantaneous optimal control forces are obtained by sequentially utilizing a Kalman estimator for the substructural state vector and least square estimation of the ‘additional unknown disturbances’. Then, unknown ground motion is subsequently estimated by the Newmark-β method. To validate the performances of the proposed algorithm, two numerical examples of decentralized control of tall building models under unknown earthquake excitations are studied and the simulation results are compared with those by the conventional centralized control under measured earthquake excitation.