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.
Results have been used to develop a methodology that allows engineers and designers to quickly and easily calculate the forces present within post-frame structural elements and account for the diaphragm action of the roof and endwalls.
Differences between typical post-frame diaphragm action and SIP diaphragm action contributed to nonlinear increases in shear strength and stiffness observed in SIP diaphragm tests.
Previously discussed test results and analyses provided ample quantification of timber frame and SIP roof system behavior to allow designers to include diaphragm action as a means of reducing forces in timber frame members, and providing sound designs for timber frame and SIP structures subject to wind loads, as presented in the following examples.
Reductions in member combined stress values as a result of including diaphragm action of SIPs are shown in Table 2 as Model 2.
Member combined stress values as a result of including diaphragm action of SIPs utilizing data from testing at the University of Wyoming are shown in Table 2 as Model 3.
2 procedures for diaphragm design allowed for the incorporation of diaphragm action of SIPs within the roof system of a timber frame building to effectively reduce member forces within timber frame components to acceptable design levels.
roof assemblies, and subsequent data analyses utilizing a typical residential timber frame building provided ample quantification of roof system behavior to allow designers to include diaphragm action as a means of reducing forces in timber frame members and providing code-conforming designs for timber frame and SIP structures subject to wind loads.
Member forces in frames were reduced to allowable NDS-01 (AF & PA 2001) design limits without increasing timber sizes, whereas without including diaphragm action, members and joints were overstressed and thus not code compliant.
Combined stress values for members of the example timber frame utilizing no diaphragm action (Model 1), assuming an effectively rigid endwall (Model 2), and utilizing preliminary test data from clad and unclad walls at the University of Wyoming.