Influence of design parameters of buckling-restrained brace on its performance

• Core contact force and BRB performance are evaluated via refined FE analysis.
• The influences of external strength and stiffness, core length, etc. are presented.
• Suggestions for core width-to-thickness ratio, core thickness and gap are proposed.
• Equations for core half-wave length and contact force are proposed and verified.
• Core plasticity and external lateral restraint are considered in fitting equation.

The contact interaction between the core and external restraining members is a vital factor that affects the overall performance of buckling-restrained braces (BRBs) significantly. In this study, refined finite element (FE) model was employed to evaluate the contact force between the core and external restraining members and to investigate the BRB performance. Moreover, the influences of strength and stiffness of external restraining member, core length, and other geometric parameters on the BRB performance were also studied. On the basis of numerical results obtained in the study, the recommended values of core width-to-thickness ratio, core thickness and gap were proposed. By considering the core plasticity and the lateral restraint of external restraining member, some formulas for predicting the half-wave length of core buckling as well as contact force were also proposed while the core buckled in multi-wave form. These formulas were numerically verified and could be references in the design of BRB.