Utilizing diaphragm action for wind load design of timber frame and structural insulated panel buildings

Current design methodologies for timber frame structures do not formally incorporate the structural benefits of structural insulated panels (SIPs) as diaphragm elements, which contribute significantly to the ability of these buildings to resist lateral loads. Both timber frame and post-frame buildings that have not necessarily been formally designed have long histories of good performance when subjected to wind and seismic forces. Strength and stiffness tests were conducted on three 2.44-m- (8-ft.-) deep and 7.32-m- (24-ft.-) wide roof diaphragm assemblies, and two 6.10-m- (20-ft.-) deep and 7.32-m- (24-ft.-) wide roof diaphragm assemblies. Data from these tests were collected, tabulated, and analyzed according to existing methods typically utilized for post-frame diaphragm testing, which exemplified the effectiveness of SIPs as diaphragm elements and reduced the forces in timber frame members to within code-conforming levels. A sample timber frame diaphragm design was performed to provide building designers with methods for including diaphragm action when designing timber frame buildings to resist lateral loads and to develop an engineering rationale for the excellent performance of laterally loaded timber frame buildings.