Active Vibration Control of Gantry Structures Using PZT Actuators

In this paper the Active Vibration Control (AVC) of a three-story gantry type structure is designed. AVC is a viable solution to decrease drift (relative displacement between the slabs) in civil structures under seismic excitation. The structure under consideration is composed by six individual gantries. Dynamic models of these individual components are obtained using classical structural dynamic methods and include a reduction of its degree of freedom (DOF). The complete model of the three-story structure is obtained assuming a rigid diaphragm behavior of the slabs. This model is a multi-input, multi-output linear ordinary differential equation (ODE) including nine DOF. The obtained ODE equation is transformed to its equivalent multi-input MIMO state space realization. The state space format is the require representation to easily apply the proposed LQR, LQG and H∞ control techniques. In addition, this work considers the possible location of the PZT actuators within the structure. Real seismic data were used to test the system performance. The controlled system response shows a substantial improvement when compared to the non-controlled structure behavior.