Hysteretic performance of self-centering buckling-restrained braces with embedded friction spring

Abstract

This paper proposes an alternative configuration of an all-steel assembly self-centering buckling-restrained brace (FSBRB) fabricated by combining a buckling-restrained brace and friction spring. The hysteretic performance of the FSBRB is investigated using low-cycle fatigue tests, and the accuracy and applicability of the theoretical hysteretic model are verified by comparing the theoretical, test, and simulation results. The test results show that the hysteresis curve of the FSBRB exhibits a symmetric flag shape with stable hysteresis performance under cyclic loading. The recommended minimum pre-pressure of the friction spring is not less than four times the yield force of the buckling-restrained brace to achieve a full self-reset. The friction spring also has non-negligible energy dissipation capacity, which accounts for 60% of the total energy dissipation of the FSBRB under the zero residual displacement condition. The equivalent viscous damping ratio of the brace is approximately 20%. The parameter analysis results obtained by simulation show that the change in taper angle has the greatest influence on peak force and residual displacement. Moreover, the friction coefficient mainly affects energy consumption, and pre-pressure ratio has a strong relationship with the yield force of the brace. Accordingly, to achieve the self-centering capacity, the FSBRB design scheme with small taper angle, friction coefficient, and pre-pressure ratio is selected priority to attain the performance objective and reduce the force requirement of connecting parts.