Experimental study on seismic performance of double-level yielding buckling-restrained braced concrete frames

This paper focused on the seismic performance of buckling-restrained braced concrete frame. Two different systems including the single-level yielding buckling-restrained braced concrete frame (SYBRBCF) and the double-level yielding buckling-restrained braced concrete frame (DYBRBCF) were designed for comparison. Compared with the single-level yielding buckling-restrained braces which are similar to many existing types of buckling-restrained braces, the double-level yielding buckling-restrained braces (DYBRBs) have two different energy absorption mechanisms that are expected to provide energy dissipations under the frequent earthquakes and rare earthquakes. To comparatively investigate the seismic performances of the two systems, cyclic tests were performed on one DYBRBCF specimen and another SYBRBCF specimen. The seismic response including the hysteretic curves, backbone curves, ductility coefficients, equivalent damping ratios, strengths, and stiffness degradations of the two experimental specimens was compared and analyzed. The test results indicate that the properly designed SYBRBCF and DYBRBCF can both exhibit the full hysteretic curves, meet the strong-column-weak-beam design requirement, and achieve the expected seismic performance. However, it was found that the ductility coefficient and energy dissipation capacity of the DYBRBCF were 72.2% and 23.4% higher than those of the SYBRBCF. The present study also provided useful design recommendations, which were beneficial to promote the application of DYBRBs.