Experimental study on a self-centering RCS interior joint endowed with replaceable dampers

Abstract

Reinforced concrete column and steel beam (RCS) joints are typically designed to dissipate seismic energy by the inelastic deformation of plastic hinges developed at beam ends. This design results in difficult-to-repair damage and residual drifts. In this paper, as a result, a self-centering RCS interior joint with dampers that can be easily replaced and unbonded post-tensioning (PT) strands fixed at the middle of the steel beam is proposed. The aforementioned joint is thus expected to substantially decrease residual drift under strong earthquakes. A quasi-static experimental program on nine self-centering RCS interior joints was carried out. The experiments explored the feasibility of the self-centering RCS interior joint and tested its mechanical and hysteretic behavior, energy dissipation capabilities, self-centering capabilities and replaceability of the proposed joint. The experimental results clearly showed that the proposed joint experienced minimal residual drift and performed satisfactorily in terms of moment carrying capacity and energy dissipation capabilities. Moreover, the self-centering ratio λ considerably affected the seismic behaviors of the joint. Finally, the specimens performed almost identically after the replacement of damaged dampers.