Lateral Load Sharing by Diaphragms in Wood-Framed Buildings

Current analysis and design procedures for light-frame wood buildings do not give consideration to the complex three-dimensional structural response of the buildings. A full-scale single-story wood house is constructed and tested under lateral loads at various stages of loading to evaluate the structural response and load-sharing characteristics. Different sheathings, fastener arrangements, and openings are incorporated to create shear walls with varying stiffnesses. Extensive force and displacement readings are made of the building during testing to quantify the structural response. Results of the study indicate that the roof diaphragm affected the distribution of lateral load to the shear walls of the building. The roof diaphragm behaved nearly like a rigid diaphragm. Load distribution among the shear walls is a function of wall stiffness and position within the building. The walls transverse to the loading direction carried between 8% and 25% of the applied lateral load. Stiffness contributions provided by additional layers of sheathing are directly additive.