Racking Strength of Light-Frame Nailed Walls

Horizontal forces, such as wind, are resisted by the walls parallel to the wind direction. These forces, which lie in the plane of the wall, are known as the shear or racking loads, and are transmitted to the sheathing through the fastener system. Qualification of sheathing materials has generally been limited to performance testing of 8-ft by 8-ft (2.4-m by 2.4-m) stud wall assemblies. An analytical procedure has been developed that accurately predicts racking strength based upon the lateral resistance of the individual fasteners. The structural model is applicable to any sheathing size or geometry, so it is possible to determine the racking strength of light frame walls from simple lateral nail tests or small scale racking tests. The procedure offers a direct means for designers and code officials to predict racking strengths of panels incorporating various sheathing materials and fasteners.