| Semi-active control has received extensive attention in recent years because it offers the best features of both passive and active control. Significant progress has been made in the field of structural control to mitigate the seismic responses of building structures with semi-active devices.; In this study, a piezoelectric friction damper (PFD) was first introduced with its clamping force regulated by piezoelectric stack actuators. A new semi-active control algorithm, which consists of Coulomb friction, viscous and non-linear Reid damping mechanisms, was proposed to drive the piezoelectric stack actuators. Fundamental properties of the proposed control strategy were investigated in detail. The proposed control strategy was applied to a 20-story, inelastic, steel moment-resisting frame building to study its seismic effectiveness under four ground motion records. For damper placement in practical applications, a sub-optimal and heuristic procedure was developed to distribute PFDs on the structure. The efficiency of the sub-optimal procedure was investigated with a 3-story benchmark building. Finally, the effectiveness of the control strategy was verified with shake table tests conducted on a ¼ scale, 3-story frame structure.; This study shows that the proposed control algorithm is quite adaptive to external loads and effective in suppressing structural responses due to multi-level earthquake excitations. The proposed sub-optimal damper placement procedure is efficient and practical in structural control design. Numerical simulations of the seismic responses of the ¼ scale, 3-story frame structure are in good agreement with the experimental results. |
