Behavior of Cold-Formed Steel Frames with Varying Sheathing Panels under Lateral Loading

Abstract

This study investigates the lateral behavior of cold-formed steel (CFS) frames with different sheathing materials and coverage configurations under monotonic lateral loading. Fourteen one-bay two-story CFS frame specimens were tested using plywood and fiber cement board (FCB) panels installed at various sheathing heights of 0%, 50%, 75%, and 100% of the wall height. The experimental program evaluated the influence of sheathing type and sheathing height on failure modes, ultimate strength, stiffness, energy absorption, and ductility. The results show that plywood-sheathed frames primarily experienced ductile tearing and screw withdrawal, whereas FCB-sheathed frames failed through brittle fracture and rupture around screw connections. For the same sheathing configurations, the FCB-sheathed specimens exhibited higher strength and stiffness, compared to plywood. Increasing sheathing height significantly enhanced structural performance for both materials, with strength increasing by up to 1.9 times for plywood and up to 3.3 times for FCB compared to the unsheathed frame. Energy absorption also increased substantially with greater sheathing coverage. Despite having lower strength and stiffness, plywood-sheathed frames exhibited greater ductility due to their more flexible and less brittle behavior. Overall, the findings confirm that both the type of sheathing and the extent of sheathing coverage strongly influence the lateral resistance and deformation capacity of CFS frame systems.