Composite semiactive control of a class of seismically excited structures

The paper deals with the formulation of semiactive controllers for a class of nonlinear seismically excited base-isolated structures in order to reduc e the absolute motion of the base and the inter-story drifts of the buildin g structure. The advantage of the proposed control scheme is that semiactiv e control devices are only required at the base and the first floor to adju st on-line the damping and stiffness using their displacements and velociti es as feedback information. The feedback control law is derived and analyze d via Lyapunov stability techniques. A numerical example is given to illust rate the effectiveness of the control scheme for a 10-story frictional base -isolated structure subject to seismic actions. (C) 2001 The Franklin Insti tute. Published bs Elsevier Science Ltd. All rights reserved.