The effect of design parameters on mechanical performance of all-steel buckling restrained brace with double steel tubes

To explore the effect of design parameters on the mechanical performance of the proposed all-steel buckling-restrained brace (BRB), the finite element software ABAQUS is adopted. The brace consists of an inner round steel tube and an outer square steel tube to restrain its inner core, designed with both the cruciform-section core and the H-section steel core. Quasi-static tests are performed on the all-steel BRB to explore its energy dissipation capacity. The cyclic behavior of the specimen models is evaluated. The validity of the numerical model is verified by comparing the predicted results with the experimental results. Next, the effects of three parameters on the mechanical properties of the brace-the width-thickness ratio of the inner core, the clearance between the inner core and the inner round steel tube c1, and the constraint ratio-are investigated by the validated numerical model. The width-thickness ratio varies from 6 to 20, the gap value ranges from 1 to 7 mm, and the constraint ratio ranges from 0.43 to 1.03. Results show that the hysteresis curves of the two braces are full, with stable hysteretic performance and good energy dissipation capacity, which justifies the construction. Based on the parameters analysis results, the optimum values of the width-thickness ratio, gap, and constraint ratio have been recommended for steel BRBs.