Shaking table tests and numerical simulations on RC frames retrofitted with friction-damped brace

Abstract

In this study, the dynamic response of double-story reinforced concrete (RC) space frames retrofitted with diagonally arranged friction damped-brace system was evaluated through shaking table tests. A simplified friction damper was proposed and tested under cyclic loading, later used to retrofit an RC frame. The splice of a conventional steel brace was converted into a friction damper, which requires limited technical expertise on site. Commercially available brake-pads were used as a friction material between the splice plates and bracing elements. An artificial ground motion characterized by a short period, similar to the Korean earthquake histories, was generated and used for the shaking table tests. The tested RC frame half-scaled of existing old structures in Korea. The shaking table tests results demonstrated that the dynamic response of the retrofitted RC frame was improved with reduced drift demands. Additionally, a numerical modelling method for friction damped-brace system was developed, and the dynamic responses of retrofitted RC frame with the proposed friction damper was numerically investigated using OpenSees. The numerical simulation results agreed well with the experimental observations.