Shear resistance of Oriented Strand Board panel sheathings in timber-framed shear walls

Timber-framed shear walls play a crucial role in providing stiffness and resistance to timber buildings subjected to horizontal forces induced by wind or earthquakes. Enhancing the load-carrying capacity of a timber-framed shear wall subjected to horizontal forces, is achieved most effectively by reinforcing the connection between sheathing and framing members. Since however, the shear resistance of such a wall is determined by the resistance of the individual wall elements, strengthening the sheathing-to-framing connection is possible only to an extent where the shear resistance is not limited by the resistance of the sheathing panel. This study presents experimental investigations of the shear resistance of OSB/3 panels, when used as sheathing material in timber-framed shear walls, which revealed that the shear resistance of the OSB/3 sheathing was reduced in comparison to the shear strength of the OSB/3 panels themselves. The reduction is attributed to additional stresses in the panel, and is accounted for in design rules specified in the German National Annex of Eurocode 5 (DIN EN 1995-1-1/NA:2013-08) and in the CEN Enquiry (ENQ) draft of Eurocode 5 (prEN 1995-1-1:2023-09). The results of the investigations confirm the reduction factor which is proposed in prEN 1995-1-1:2023-09, for wall elements with one-sided sheathings. However, the reduction factor specified for the design of wall elements with two-sided sheathings could not be confirmed. The results of this study performed with comparably massive and rigid timber framing revealed no difference in the reduction factor for timber-framed shear walls with one- or two-sided sheathings.