PERFORMANCE ASSESSMENT OF ISOLATED STRUCTURES WITH ADDED DAMPING

Seismic isolation and use of damper technologies seen a variety of applications in the design of structures to mitigate seismic risk.Viscous Damper (VD) is used to improve the performance of a base isolation system and decreasing displacement demand. When the damping in the bearings is low, use of viscous damper is the most effective for reducing the structuralresponse. Lack of clear-cut method for selecting design parameters and the combination of these two systems and decision on how to reduce structural damage caused reluctance of clients to use these systems. Performance-based design provides a useful framework for developing the relationships among the characteristics of the ground motion, baseisolated structure and viscous damperand to evaluate the ability of design approaches to achieve targeted performance goals. The purpose of this paper is to develop methods for considering performance parameters like: mean annual frequency of limit states, mean annual frequency of collapse and collapse margin ratio (CMR) in performance assessment of base isolated structures with viscous damper. Studies showed that base isolated structure with viscous damperhave better seismic performance comparably to base isolated structures.