Experimental testing and analytical modeling of semi-active fluid dampers for seismic protection

The development, experimental testing, and analytical modeling of an intelligent seismic response control system is described in this paper. The control system is m the form of semiactive fluid damping devices which may be installed within the lateral bracing system of buildings or as part of a seismic isolation system for bridges or buildings. The dampers have mechanical properties which can be modified through a closed-loop feedback control system which utilizes the measured earthquake excitation and/or the response of the structural system. Further, the dampers exhibit fail-safe characteristics in that, in the event of failure to operate as semi-active devices, the dampers convert to passive high-damping devices. The dampers were extensively tested to determine the mechanical properties and the dynamic behavior of the devices. Furthermore mathematical models for describing the damper behavior were developed and utilized for analytically predicting experimental results.