Critical load and application of core-separated buckling-restrained braces

• A new type of light-weight BRBs called CSBRBs is proposed.
• Explicit formulas are derived to calculate the critical loads of the CSBRBs.
• The elasto-plastic behavior under axial monotonic compression is studied.

A new type of buckling-restrained braces (BRBs), called core-separated buckling-restrained braces (CSBRBs) is presented and investigated in this study. The CSBRBs are composed of two chord members and one or several continuous web plates that connect those members longitudinally. This core-separated section improves bending stiffness, thus resulting in lightness and convenience in fabrication and erection compared with conventional BRBs. The elastic buckling performance of CSBRBs is initially investigated because such performance depends directly on the restrain ratios, which should be specified in the design of all types of BRBs. The critical loads of pin-ended and fix-ended CSBRBs are then obtained based on the equilibrium method and verified by finite element (FE) elastic buckling analysis, respectively. Subsequently, the relationship between axial compression and core compressive strain of CSBRBs with different restrain ratios is studied by using FE elasto-plastic analysis. These research achievements provide the foundation for further investigations and applications for CSBRBs.

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