Abstract
This paper evaluates the seismic performance of conventional steel composite beam-column rigid joints, and a novel buckling restrained knee-braced joint (BRKBJ), considering the impact of the floor slab. A series of quasi-static comparative tests were conducted to analyze the failure mode, load-bearing capacity, hysteresis performance, and ductility of both types of joints. Our findings revealed that the hysteretic curve of the BRKBJ exhibits a robust and shuttle-like shape, suggesting an adequate energy dissipation performance. However, its yield displacement is relatively small. Conversely, there is a marginal increase in the yield displacement of the beam and column, along with a significant rise in the yield load when compared to the rigid joint. The ultimate load-bearing capacity increases by 32.6%, and the displacement under this ultimate load decreases by 19.2%. Furthermore, the equivalent viscous damping coefficient and the ductility coefficient see an increase of 14.5% and 21.6%, respectively. When damage occurs to the joint, the buckling restrained knee brace helps shift the plastic hinge outwards, safeguarding the beam-column joint. It was also observed that the impact of the buckling restrained knee brace on the hysteretic behavior of the composite beam-column rigid connection at the beam end during the tension phase is notably more than during the compression phase. The presence of a floor has minimal effect on the BRKBJ.
Publisher
The Hong Kong Institute of Steel Construction