Experimental study on seismic retrofit of a RC frame using viscoelastic dampers

The deformation capacity of a viscoelastic damper (VED) is generally limited by the thickness of the VE pad. In this study, a VED with fail-safe mechanism was developed and its seismic performance was evaluated by a series of experiments of full-scale two-story reinforced concrete (RC) frame before and after seismic retrofit. The VED is composed of high damping rubber viscoelastic pads and is installed vertically between stories. One bare frame and two retrofitted frames with different damper capacities were tested under cyclic loads to validate the effectiveness of the newly developed dampers. The Bouc Wen model was developed to simulate the seismic behavior of the damper, which turned out to represent the behavior of the VED accurately. As a case study, the proposed VED was applied to seismic retrofit design of a 4-story RC moment framed structure, and it was found that the proposed retrofit scheme could adequately improve the seismic performance of the structure by reducing both inter-story and residual displacements.