Influence of Buckling Restrained Reinforcement on Behavior of Columns

The present study proposes an alternative reinforcement material system, known as buckling restrained reinforcement (BRR), to improve the behavior of concrete columns loaded with earthquake-type loading in moderate seismic areas. BRR is made from circular steel tubes and placed in the main bars in the plastic-hinge-critical portion. Experimental investigations were carried out on half-scale models of concrete columns provided with and without BRR and loaded with a combination of axial loading and quasi-static reverse cyclic lateral loading. Performance improvement is observed in load-deformation characteristics, energy dissipation, and lower stiffness degradation for column specimens with the proposed BRR in comparison with specimens having light ductile detailing. Moreover, congestion of tie bars near the joint was also removed by providing BRR at the plastic hinge zone with wider tie spacing (>33%) than ductile detailing, thus reducing the confining reinforcement bars by 25% and reducing the construction challenges in the field. (c) 2020 American Society of Civil Engineers.