Semi-Active Control of a Steel Frame with Piezoelectric Friction Dampers

In this paper, a previously designed and fabricated friction damper with four piezoelectric actuators was installed on the first story of a 1/4 scale, 3-story steel structure. The performance of the damper and a simple control strategy was evaluated both numerically and experimentally under four modified earthquake ground motion records of various amplitudes. The seismic effectiveness and adaptability of the algorithm as well as the effect of damper saturation on structural responses were investigated. Numerical simulations of the structure agreed well with the experimental results. The proposed control strategy can not only effectively reduce the structural responses but also adapt to the varying excitations from both weak and strong earthquakes. Experimental results also indicated that a piezoelectric friction damper slightly saturated could be advantageous to the seismic mitigation of buildings. Over saturation will, however, degrade the performance of the Semi-active control strategy