Preview Control of Base-Isolated Structures Subject to Earthquake Excitations

Active vibration control of base-isolated and fixed-base structures during earthquake is studied.Attention is given to optimal control methodology with and without preview for protection against earthquakes. A three-story building under fixed-base condition and with laminated rubber bearing base isolation system subject to the El Centro 1940 earthquake are analyzed.The responses of structure with passive, active and hybrid vibration control systems are evaluated. Accelerations and displacements responses for active systems with and with out preview sensors for fixed base and base-isolated structures are computed and the results are compared with those for the unprotected building. It is shown that the seismic protection of buildings could be achieved with passive and active vibration control techniques. Properly designed active control systems can effectively reduce the acceleration transmitted to structures during a major earthquake. It is also shown that the inclusion of the preview sensors in the active control strategy improves the system performance considerably. The hybrid use of the laminated rubber bearing isolation system with the active control strategies leads to significant improvement of the structural protection during a seismic event