Stiffness and Strength of Single Shear Cold-Formed Steel Screw-Fastened Connections

Results are presented from an experimental program on single shear cold-formed steel-to-steel through-fastened screw connections, including documentation of the complete load-deformation response and stiffness degradation. Ply thicknesses from 0.88mm to 2.58mm and screw diameters of 4.17mm to 5.49mm were tested to cover the practical range of applications common to cold-formed steel framing. A custom non-contact optical technique measured steel ply relative displacements and screw tilting angles. Fastener load-deformation response is presented in a format that can be incorporated into codes and standards for system level design calculations that require connection stiffness to quantify load sharing. The simplified multi-linear curves characterized from monotonic responses can also serve as nonlinear springs in cold-formed steel subsystem computational models (e.g., shear wall, floor diaphragm, roof truss) and 3D whole building cold-formed steel structural simulations.