RETROFITTING OF REINFORCED CONCRETE FRAME BUILDING USING METALLIC DAMPERS

Abstract

Past studies have revealed that safe handling of earthquake by building structures requires reasonable amount of energy dissipation. The conventional practice is to adopt masonry infills and bracing system as lateral load resisting systems. Seismic behavior of metallic damper in reinforced concrete building is still not fully established. The study focuses on exploring methodology for design of shear yielding dampers and response of reinforced concrete building equipped with dampers, which is actually designed for gravity loads. In addition, this study attempts to explore the ambiguity in selection of stiffness ratio (SR) and response of metallic dampers. The outcome of this will help forward to explore the applicability of SR value in other type of similar building. Hence, it is an initiative towards the incorporation of the overlooked design parameter, which will yield economical use of damper and change in response of building. The study adopts energy dissipating device (EDD), which is an immediate choice nowadays particularly passive metallic damper with bracing, is currently trending in earthquake engineering community. Shear yielding damper is the recent development and adopted widely. The effectiveness of metallic damper as a device for energy dissipation during earthquake relies on various design parameters namely connection efficiency, stiffness ratio, yield strength of shear and flexure plates. The most equivocal parameter is brace stiffness to device stiffness (B/D) ratio and device stiffness to bare frame stiffness (D/F) ratio. Past studies did not suggest and justified the adoption of SR value. Adopting single value of SR for all storey may not show uniform dispersal of ductility and fully utilize intended inelastic behavior of the damper. The present study tries to explore the reasonable value of SR by adopting given methodology and variety of analysis. Thus, to optimize the dynamic response based on uniform distribution of deformation, different B/D ratio must be adopted.