Reliability-based stochastic optimal control of frame building under near-fault ground motions

Most of stochastic optimal control methods were developed on the basis of Ito stochastic differential equation, which assumes that the external excitation is white Gaussian noise or filtered white Gaussian noise. However, this assumption is far from the real excitations, which hinders the applications of stochastic optimal control theory. In this paper, the reliability-based stochastic optimal control via direct probability integral method (DPIM) for building structure is proposed, which is applicable to performance-based design of general control systems of linear structures under non-stationary and non-white random excitations. Firstly, the DPIM is utilized to accurately and efficiently compute dynamic reliability of the controlled system. Then, the reliability-based objective function is suggested to optimize the parameters of the placed control devices of building structure, and reliability-based maximum story controllability index is established to determine the optimal placement of control devices, thus fulfilling the stochastic optimal control of structure. Finally, a 10-story shear frame building controlled by active tendons under random excitations of near-fault earthquake ground motions verifies the effectiveness of the proposed optimal control method. Moreover, the optimal control schemes of frame structure under near fault non-pulse and impulsive ground motions are compared, indicating that the velocity pulses of near-fault ground motions impose significant effect on structural responses, and the more control energy is needed for guaranteeing structural safety.

Automated summary

This paper proposes a reliability-based stochastic optimal control method for building structures under non-white noise excitations. By utilizing DPIM to calculate dynamic reliability and optimizing control device parameters, the optimal control of structures can be achieved effectively.