A novel reinforced-concrete buckling-restrained brace for precast concrete lateral-load-resisting frames

Abstract

This paper describes a numerical investigation on the seismic design and behavior of a novel reinforced-concrete buckling-restrained brace component for use in precast concrete lateral-load-resisting frames. The design procedure aimed to develop a brace with ductile behavior under reversed cyclic loading. Nonlinear finite element analyses were conducted to investigate the following potential undesirable failure modes of the brace: global buckling of the brace, closure of the end gaps, and local translational buckling of the energy-dissipation bars. The results indicated that failure through global buckling is unlikely for practical brace designs. Closure of the end gaps can be prevented by designing a wide-enough gap at each end of the brace, but design must also ensure that local buckling of the energy-dissipation bars does not occur over their unsupported length across the end gaps. An axially decoupled steel shear dowel can be used to permit a wider end gap without triggering translational buckling of the energy-dissipation bars. Braces that are designed to prevent undesirable failure modes can provide stable behavior up to ductile low-cycle fatigue fracture of the energy-dissipation bars.