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 con structed and tested under lateral loads at various stages of loading t o evaluate the structural response and load-sharing characteristics. D ifferent sheathings, fastener arrangements, and openings are incorpora ted to create shear walls with varying stiffnesses. Extensive force an d displacement readings are made of the building during testing to qua ntify 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 wa ll stiffness and position within the building. The walls transverse to the loading direction carried between 8% and 25% of the applied later al load. Stiffness contributions provided by additional layers of shea thing are directly additive.