Seismic Testing of the Connecting Joint in a Buckling-Restrained K-Braced RC Frame

Abstract

In this study, a 12-story reinforced concrete (RC) building with buckling-restrained braces (BRBs) arranged in a zigzag configuration is proposed as a prototype building. The beam-column joint at the tenth floor selected as the sub-assemblage specimen and its details including the BRB gusset bracket and RC corbels were designed following the model building codes. The full-scale sub-assemblage of the structural system was tested using cyclic loading procedure. Test results show that the proposed BRB-to-RC connection details performed very well without failure in the steel gusset bracket or the RC corbels. In order to further study the seismic performance of the 12-story buckling-restrained braced RC frame, nonlinear response history analyses are conducted using a total of 240 (SLE, DBE and MCE) ground accelerations. Analysis results indicate that the maximum ratios of total BRB shear to base shear are about 23% (SLE), 21% (DBE) and 19% (MCE). The maximum inter-story drift ratios under MCE and DBE events are 2.32% and 1.82%, respectively. Analysis results also suggest that the high mode effect is not significant. It is found that the peak demand of the horizontal tension force on the steel gusset bracket can be estimated by considering 70% of the sum of the two horizontal force components computed from the two adjacent BRB maximum tension strengths.