UC San Diego

Cold-Formed Steel (CFS) framing has gained substantial popularity in the North American market in the recent years, particularly in mid-rise building construction. Buildings framed with closely spaced CFS members repetitively placed in the walls develop resistance to lateral loads through a variety of systems including steel sheet sheathing attached to the CFS members. Damage to walls sheathed with steel sheet largely manifests in the form of local failure of screw fasteners. To this end, in the present paper, the damage observed in fastener connections between steel sheet sheathing and CFS framing members in wall-lines subjected to quasi-static cyclic loading is systematically quantified. Four symmetric and unfinished wall-line configurations, including two each of Type I and Type II shear wall detailing systems, are evaluated at different performance levels. Tilting/bearing and sheet pullover are identified as the two predominant fastener connection failure modes and damage statistics for each failure mode demonstrate the progression of connection damage. Specimens with a larger quantity of fastener connections demonstrated 1.5-3.0 times greater hysteretic energy dissipation at similar cumulative drift. However, the number of fasteners used had no apparent effect on equivalent hysteretic damping due to the reduction in wall lateral strength developed.