Experimental and numerical investigation on seismic performance of retrofitted RC frame with sector lead viscoelastic damper

Abstract

In this paper, an innovative approach of utilizing sector lead viscoelastic damper (SLVD) is proposed to retrofit destructive damaged RC frames. A pre-damage was introduced into two candidate RC frames through a pseudo cyclic load up to 2.4% inter-story drift ratio imposed on the two frames. Then, a quasi-static test was conducted to investigate the seismic performance of the retrofitted frame equipped with SLVDs in comparison with the performance of a CFRP retrofitted frame and an intact frame. Experimental results confirmed that the proposed SLVD retrofitted approach is able to properly protect the beam-column joint zone and to strengthen the horizontal bearing capacity, the initial stiffness, and the secant stiffness of the damaged RC frame. Moreover, the SLVD retrofitted RC frame had the highest ductility, about 14.01% higher than that of the intact RC frame and 15.35% higher than that of the CFRP retrofitted RC frame. As a result of the excellent hysteresis behavior of the SLVD, the equivalent viscous damping ratios of the SLVD-retrofitted RC frame were rather high and were stable between 0.12 and 0.18. Numerical investigations showed that the effective sector radius of the SLVD played an essential role in improving the seismic performance of the retrofitted frame, while both the viscoelastic layer thickness and the lead core diameter had little contribution to improve the seismic performance of the pre-damaged RC frame.