Experimental and numerical studies of the multi-tube assembled buckling-restrained braces

Abstract

In this paper, the multi-tube assembled bolt-connected buckling-restrained brace (MT-BRB) with four internally restrained rectangular steel tubes and one externally restrained square steel tube is experimentally analyzed. This study conducted cyclic loading tests on five specimens with different parameters to investigate the effects of different loading directions of the core plate, the presence or absence of unbonded materials, the gap-to-width ratio and the width-to-thickness ratio on the mechanical properties, seismic performance and failure mode of MT-BRB. The experimental results indicated that the MT-BRB specimens made of unbonded materials had stable cyclic performance and energy dissipation capacity. Subsequently, the same numerical model as the experimental specimen was established, and the hysteresis and stress curves extracted from the finite element model were compared with the experimental results. The simulation had ideal agreement with the experiment result, demonstrating that the model was effective for performance predictions. Based on this, the working mechanism of MT-BRB was further explored through finite element analysis. Finally, parameter analysis was conducted on the constraint ratio and constraint length ratio to further investigate the energy dissipation performance of MT-BRB. This study is beneficial for promoting the application of MT-BRB in energy dissipation and vibration reduction engineering.