SEMI-ACTIVE HYBRID SEISMIC ISOLATION SYSTEMS: ADDRESSING THE LIMITATIONS OF PASSIVE ISOLATION SYSTEMS

Passive seismic isolation systems consisting of passive isolation bearings and passive damping devices have been utilized in at least five building structures located in regions of potentially strong seismic activity. As the application of performance-based seismic design specifications becomes more widespread, it is expected that the number of such applications of hybrid structural control technology will increase. The performance of such hybrid control systems, however, may be further enhanced by modifying the passive damping devices to behave as semi-active control elements. This paper discusses the features of semi-active hybrid seismic isolation systems that address some of the limitations of passive hybrid isolation systems. In addition, some of the implementation issues related to the use of semi-active hybrid seismic isolation systems are discussed. Finally, the development of a semi-active hybrid seismic isolation system consisting of passive sliding isolation bearings and semi-active fluid damping devices is presented.