Investigation of CFS shear walls with two-sided sheathing and dense fastener layout

Even though CFS framed shear walls have been the subject of many research, test data on walls sheathed with OSB panels on both sides using relatively small fastener spacing is scarce. The current investigation aims to fill this gap through an integrated experimental and numerical study on lateral load response of double side sheathed CFS-framed wall panels utilizing relatively small fastener spacing. The experimental investigation included cyclic tests on nine 1220x2440 mm wall panels. For the tested walls the predominant failure mode was buckling of boundary studs. The average maximum drift ratios of all tests were 3.2% and 3.0% in two loading directions. The corresponding average drift ratios at peak load capacity were 2.9% and 2.7%. The numerical part of the study included detailed modeling of wall panels using the OpenSees platform following the fastener-based and equivalent brace modeling approaches. In the fastener-based models, the nonlinear behavior of each screw between the CFS framing members and the sheathing panel was simulated by a nonlinear spring element. Material models used for these nonlinear spring elements were calibrated with the data from physical testing of connection screws. In the equivalent brace model, inelastic response of all connection screws was lumped into two nonlinear brace elements. Material models used for these brace elements were calibrated with the measured lateral load-drift data from wall panel testing. Good agreement was obtained between the numerical responses from both modeling approaches and the measured response.