Semi-active control of a building complex with variable friction dampers

Semi-active coupling control of a building complex, which consists of a main building and a podium structure, using variable friction dampers is investigated in this paper for mitigating seismic responses. The mathematical model of a building complex with variable friction dampers under earthquake excitation is first established. A clipped control strategy is then developed to allow variable friction dampers to work effectively with linear quadratic Gaussian control algorithms as a global-feedback controller. Local-feedback controllers, which include viscous and Reid friction controllers, modulated homogeneous friction controllers, and non-sticking friction controllers, are also formulated for use with variable friction dampers. A building complex of a 20-story main building and a 3-story podium structure is finally used as a numerical example to demonstrate the effectiveness of semi-active coupling control and to compare the local-feedback controllers with the global-feedback controller. The control performance of each controller for the building complex with either single or multiple friction dampers under various ground motions is examined in terms of both story drifts and acceleration responses. The numerical results show that semi-active coupling control is quite promising for reducing seismic responses of both buildings.