HYBRID CONTROL SYSTEMS FOR RIGID BUILDINGS STRUCTURES UNDER STRONG EARTHQUAKES

This paper deals with the efficiency of a hybrid vibration control for rigid buildings structures under earthquakes. The hybrid control consists of a base isolator and tuned mass damper (TMD) or active tuned mass damper (ATMD). The active control force is calculated within a feedback loop by the mean of the linear quadratic controller (LQR) designed to penalize the displacement and the velocity of the floor on which the ATMD is installed. A total of four cases are studied based on the placement and the type of the control system either passive TMD or active TMD. The lower and top floor alternatively carries the TMD control system. The case of a rigid six-degree of freedom base isolated frame structure illustrates the effectiveness of the hybrid control through simulations. Simulation results, obtained from real time-history data of three earthquakes (El Centro, Northridge and Loma Prieta) show that the proposed control is effective. The hybrid control system is able to reduce the vibration amplitudes especially the base isolator displacement and acceleration without affecting the super-structure response regardless of the placement of the TMD control system. Such a hybrid control system can protect high importance buildings containing sensitive equipment.