Design and seismic performance analysis of a novel special-shaped steel tube concrete column steel beam joint

In this study, a novel special-shaped steel tube concrete column steel beam joint is proposed. Bolt connections are used to connect the pre-welded steel beam and the special-shaped steel tube concrete column. Based on the finite element software ABAQUS, we established finite element models of the column-beam joints, and conducted a series of finite element analyses to investigate the influence of various parameters on the seismic performance of the joint. These parameters include the shape and size of the flange hole, the shape and size of the web hole, and thickness of the spliced plate on the flange. The results show that the difference between the finite element analysis and experimental results for bearing capacity and displacement is within 10%. This indicates that finite element analysis can be effectively utilized to study the seismic performance of the joint. Compared to joints with non-spliced beam, the rotational deformation capacity of the joint is reduced when using bolts and spliced plates designed by the equal-strength method. The energy dissipation capacity and ductility deformation capacity of the joints with spliced beams are significantly improved by using elliptical bolt holes in the flange, and plastic hinges are formed in the spliced region. The elliptical holes in the web with varying sizes have little effect on the seismic performance of the joint. The thicknesses of the spliced plate ranging from 6 mm to 8 mm has little effect on the seismic performance of the joint, and a thin spliced plate will reduce the seismic performance of the joint. The study presented in this paper can provide a reference for promoting the engineering application of special-shaped steel tube concrete structures.