Buckling-restrained brace using round steel bar cores restrained by inner round steel tubes and outer square steel tube

Abstract

This study proposes a buckling-restrained brace (BRB) which is composed of round steel bar cores restrained by inner round steel tubes and an outer square steel tube. One advantage of using the round steel bar cores against the steel plates and tubes is that the bar-ends can be connected to the structural members using screw-joints. The cyclic loading tests were conducted on two test specimens to examine the hysteretic performance of the proposed BRBs. Test results revealed the applicability, restraining capacity, and end-coupler performance of the proposed brace. With an increase in the number of contraction allowance zones, efficacy and performance of the brace became more satisfactory. Furthermore, a theoretical method for designing the proposed BRB in a simplified and optimal way is discussed. For the creation of the design guideline, the braces were analyzed comparatively over a wide range of sections, lengths, and different load conditions, which are most suitable for low to mid-rise buildings. It was found that the design is governed by the heaviest components of the brace, and that the pin connection to the frame was a key component for optimal design.