Seismic performance of RC short columns with buckling restraint reinforcement

Abstract

This paper considers the application of the buckling restraining concept in reinforced-concrete (RC) columns subjected to seismic-type loading. The main objective of the experimental study is to investigate the seismic performance of RC short columns with buckling-restrained casing provided to the main reinforcement at the critical region. The debonding of reinforcement by providing a rebar restraining collar is carried out at the plastic hinge region where maximum bending moment occurs. The columns are subjected to quasi-static cyclic lateral loading combined with a constant axial loading to simulate seismic-type loading. The performance of these columns is compared – in terms of ultimate load, ductility, load displacement envelope and energy dissipation capacity – with that of counterpart short columns designed as per Indian Standard code IS:456-2000 and ductile detailing as per IS:13920-2016. The main variables selected in this investigation are the axial load ratio and the length of the buckling-restrained casing of reinforcement. The test results indicate that the columns with buckling-restrained casings have improved performance in terms of lateral load-carrying capacity, energy dissipation characteristics and reduced stiffness degradation relative to columns without casing.