Finite element analysis on the mechanical behaviour of a novel three-dimensional semi-rigid steel joint with a channel component under static and cyclic loading

In this study, a novel three-dimensional semi-rigid steel joint with a channel steel component is proposed, in which the channel steel component is connected to the column flange through a hybrid connection of bolts and welds along the minor axis. The design of the minor axis connection in this study had no weakening effect on the column web, and it was more convenient and easier to attach the additional channel steel component than the additional plates to the column flanges by welding. In order to investigate the static behaviour and seismic performance of the proposed novel three-dimensional semi-rigid steel joint with a channel steel component and to evaluate the interaction between both axes, numerical analyses were conducted systematically. The finite element (FE) models are firstly calibrated against the experimental results in order to get accurate results, and then the rotating characteristics, joint moment capacity, joint stiffness, ductility and energy dissipation capacity of the proposed novel semi-rigid steel joints were analysed under ten loading cases along the major and minor axes. The results indicate that the proposed novel semi-rigid steel joint has good energy dissipation capacity and deformation performance. Loading in the major-axis direction has almost no influence on the ultimate joint moment capacity but has some influence on the initial stiffness, ductility, stiffness degradation and energy dissipation ability of the proposed novel semi-rigid steel joint along the minor axis. In addition, the modified moment-rotation (M-theta) hysteretic model for the proposed novel semi-rigid steel joint is capable of effectively characterising its hysteretic behaviours, which can provide a reference for practical applications.