Experimental and Numerical Investigation of Cross-Shaped Joints with Adjustable Stiffness for Cold-formed Thick-Walled Steel Column–Column Connections

Cold-formed thick-walled steel members have a higher bearing capacity and wider applicability in the mid-rise buildings in comparison with the widely-used cold-formed thin-walled steel framing walls in low-rise buildings. To avoid the shortcomings of cold-forming effect, a structure with hinged or semi-rigid joint steel frame using cold-formed thick-walled steel and cold-formed thin-walled steel framing shear wall is one reasonable choices, and it will be very helpful to simplify the on-site assembling processes. In this paper, a cross-shaped joint with adjustable stiffness was proposed, and better seismic performance was investigated and confirmed by tests. By increasing the thickness of the web plates of the cross-shaped joint, the bearing capacity, stiffness, and ductility of the joint can be significantly improved, and the buckling deformation of the web plate will be reduced. Moreover, a strengthening stiffener, Type 2 proposed in the paper, has a significantly effect on the cross-shaped joint for seismic damage and intact specimens. Using ANSYS software and the SOLID185 element, a finite element model was established. With the increasing thickness of the end plate of the stiffener Type 2, both the stiffness and bearing capacity of the cross-shaped joint can be significantly increased.