Overall buckling behavior of all-steel buckling restrained braces

One of the key requirements for the desirable mechanical behavior of buckling restrained braces (BRBs) under severe earthquake loading is to prevent global buckling until the brace member reaches sufficient plastic deformation and ductility. This paper presents finite element analysis results of the proposed all-steel buckling restrained braces. The proposed BRBs have identical core sections but different buckling restraining mechanisms (BRMs). The objective of the analysis is to conduct a parametric study of BRBs with different amounts of gap (between the core and the BRM) and initial imperfections to investigate the global buckling behavior of the brace. The results of the analysis showed that BRM flexural stiffness could significantly affect the global buckling behavior of a brace, regardless of the size of the gap. In addition, a minimum ratio of the Euler buckling load of the restraining member to the yield strength of the core, Pe/Py is suggested for design purposes. This ratio is the principal parameter that controls the global buckling of BRBs.

► In this paper, we study the overall buckling prevention condition of all-steel BRBs.
► Finite element analysis is conducted to investigate brace global buckling behavior.
► BRBs with Pe/Py ratios greater than 1.2 do not usually experience global buckling.