Cyclic performance of a two-story reinforced-concrete frame strengthened with inverted-V buckling-restrained braces and T-shaped anchorage

Abstract

This study investigated the seismic performance of a 1/3-scale, two-story, three-span reinforced-concrete frame strengthened with inverted-V buckling-restrained braces (BRBs) and a T-shaped anchorage system. In the tested configuration, two BRBs were installed at each story, with the lower ends connected near the beam-column joints and the upper ends converging at the midspan of the beam above. A quasi-static reversed cyclic loading test and finite-element analysis were conducted to evaluate the global response, BRB behavior, connection performance, and damage evolution. Results demonstrated that the strengthened frame exhibited stable spindle-shaped hysteresis loops and increased lateral resistance and stiffness with improved energy dissipation. The T-shaped connection effectively transferred BRB axial forces while suppressing buckling, mitigating stress concentrations and ensuring robust load transfer. Additional numerical analyses compared the tested inverted-V configuration with diamond-shaped chevron and single-diagonal configurations. Among three investigated arrangements, the diamond-shaped configuration produced the most favorable beam-damage distribution. The BRB-strengthened RC frames satisfied the inter-story drift limits of GB 50011–2010 and demonstrated efficacy for structures in high-seismic regions.