Behavior and design method of pinned-pinned buckling-restrained brace.

In buckling-restrained braces (BRBs) with pinned joints, the core component near the ends have influence on both the capacity of the core segments near the ends and the overall behavior of the BRB. Based on theoretical and numerical analysis, this paper discusses the failure modes and the overall behaviors of pinned-pinned BRBs with unsupported yielding segments and strengthened segments near the ends. It is found that the unsupported yielding segments and strengthened segments of the core will bend under axial pressure, which will induce additional eccentricities at the ends of the restraining part, making the stress state more unfavorable. If the unsupported segment of the core is too long, failure may occur in the segment with too much bending. By taking the core segments near the ends out as a free body, a simplified model was obtained. Using an iterative method cooperatively, the simplified model can approximately determine the eccentricities added at the two ends of restraining parts. Finally an overall stability design method that can take the additional eccentricities into account is given. [ABSTRACT FROM AUTHOR]