Global buckling prevention condition of all-steel buckling restrained braces

One of the key requirements for the desirable mechanical behavior of buckling restrained braces (BRBs) under severe lateral loading is to prevent overall buckling until the brace member reaches sufficient plastic deformation and ductility. This paper presents finite element analysis results of proposed all-steel buckling restrained braces. The proposed BRBs have identical core sections but different Buckling Restraining Mechanisms (BRMs). The objective of the analyses is to conduct a parametric study of BRBs with different amounts of gaps and cores and BRM contact friction coefficients to investigate the global buckling behavior of the brace. The results of the analyses showed that BRM flexural stiffness could significantly affect the global buckling behavior of a BRB. However, the global buckling response occurred to be strongly dependent upon the magnitude of the friction coefficient between the core and the encasing contact surfaces. In addition, the results showed that the global buckling response of BRBs with direct contact of the core and BRM is more sensitive to the magnitude of contact friction coefficient.