Performance of Light-Frame Timber Shear Walls Produced with Weathered Sheathing

Abstract

Light-frame wood construction is the most common construction method used for single- and multifamily residential structures in the United States. Shear walls made with engineered wood structural panels are the primary lateral force resisting system in these structures. Although shear walls are expected to be protected from prolonged or severe exposure to moisture, situations such as flooding and compromised building envelopes have the potential to expose shear walls to high levels of moisture and subsequently alter their properties. The specific contribution of moisture degradation in engineered wood structural panels on shear wall performance was investigated in this study by subjecting oriented strand board (OSB) and plywood to accelerated weathering prior to shear wall assembly. Shear walls (2.44×2.44 m) were tested by using a monotonic loading protocol to compare performance between walls produced with standard sheathing and those produced after sheathing had been weathered and dried. Statistically significant losses in yield load, shear capacity, and energy dissipation from moisture degradation during accelerated weathering were determined for OSB walls, while none were present for plywood walls. In addition, localized strain in the sheathing near fasteners in the uplift corner was monitored by using digital image correlation, which showed differences in strain distribution for both OSB and plywood walls constructed with weathered sheathing.