Hybrid control of buildings with nonlinear base isolation

A hybrid seismic control system for buildings structures is considered, which combines a class of passive nonlinear base isolator with an active control system. The active control forces are applied to the structural base with the objective of reducing its displacements. An adaptive control law is formulated to compute the control forces in order to assure a form of stable behaviour of the system under seismic excitation and in the presence of uncertainties in the characteristics of the building of the hybrid control system. The global behavoiur of the structure-base isolator system is such that the absolute base displacement is significantly reduced, the price paid being a slight increase of the response of the structure. &nbsp