Optimum design of active/passive control devices for tall buildings under earthquake excitation

To economically enhance the performance of active/passive control devices for seismic response reduction of tall buildings, this paper investigates the optimal placement and optimal parameter of control devices using the linear quadratic performance index as an objective function. The linear relation between the increment of performance index and the change of the position matrix of control devices is first established based on the assumption that the control gain remains unchanged. The optimal placement of control devices is then determined in terms of the sequence of the calculated performance index increments and the number of control devices to be used. With the control devices at their optimal places, the seismic response of the building is finally computed using the suboptimal control gain derived using the minimum error principle, from which the equivalent optimal parameters of passive devices can be also determined. The applicability of the proposed approach and its limitation are carefully examined through numerical examples. The results from the numerical examples show that the suggested approach is quite accurate and effective in determining the optimal placement and optimal parameter of control devices if the number of removed control devices is limited to a certain range.