Experimental studies on screw connections between cold-formed steel framing and sandwich sheathing

Abstract

Cold formed steel (CFS) framed wall panels with sheathing is one of the main lateral load resisting systems in light gauge structures. The nonlinear behavior of the CFS wall panel under in-plane shear loading is dictated by the nonlinear behavior of the screw connections between CFS framing and sheathing. Necessity for new and high performance CFS shear wall configurations is clearly felt by the engineering community in order to cater for the increased seismic demands in mid-rise CFS buildings. To this end the experimental studies on screw connections are essential to understand the behavior of full scale wall panels by phenomenological models. This paper presents the experimental studies on the screw connection between CFS framing and new sheathing configuration with screw subjected to shear parallel to the free edge of the sheathing. This setup mimics shear experienced by the screw as a component in full scale wall panel tests. The proposed new sheathing configuration consists of a brittle sheathing material (one of cement particle board, fiber cement board and gypsum wallboard) sandwiched between two thin steel sheets. The experiments are performed for both monotonic and cyclic loading protocols and the stiffness, ultimate strength and ductility showed a significant increase due to the sandwich steel sheets. Ultimately, the configuration with sheathing material which provides higher strength as well as ductility has been proposed for future study by full scale experiments.