Experimental and analytical assessment of the sheathing-to-framing connection behavior in timber frame walls with single-sided double-layered sheathing panels

Abstract

This study investigates the structural performance of sheathing-to-framing connections in timber frame walls incorporating single-sided double-layered sheathing panels. An experimental program was conducted, involving monotonic push-out shear tests on various materials and fastening combinations, with loading applied both parallel and perpendicular to the timber grain. The study assessed key performance indicators such as shear strength, stiffness, ductility, and failure mechanisms for single-and double-layered sheathing configurations using gypsum-based and wood-based panels. Results demonstrated that adding a second sheathing layer significantly enhances shear capacity and stiffness, typically resulting in an increase by a factor of 1.7-2.9, depending on configuration. However, the effect on ductility was configuration-dependent, with notable increases observed in setups using non-structural inner layers. The failure modes varied by sheathing type: gypsum panels exhibited staple punching and cracking, while wood-based panels showed staple withdrawal. Analytical predictions, derived from adapted Johansen and Bla ss models, aligned well with experimental shear capacities and expected failure modes in most configurations, particularly for those using non-load-bearing sheathing materials. Comparisons with large-scale wall racking tests validated the small-scale findings, although some discrepancies in stiffness were observed due to possible construction imperfections in the full assemblies. Ultimately, this work addresses a gap in both the current and forthcoming second generation of Eurocode 5, which currently lacks provisions for single-sided, double-layered wall systems.