Wind Shear Wall Roof Diaphragm

Wind load diaphragm sheathing floor roof framing parallel to walls add blocking floor joist blocking.

Wind shear wall roof diaphragm.

The diaphragm forces tend to be transferred to the vertical resisting elements. Diaphragm and shear wall example given. Unblocked diaphragm capacity capacities in sdpws are nominal values. This force is then applied to the shearwalls at the roof eave height.

A diaphragm is a flat structural unit acting like a deep thin beam. In structural engineering a diaphragm is a structural element that transmits lateral loads to the vertical resisting elements of a structure such as shear walls or frames diaphragms are typically horizontal but can be sloped such as in a gable roof on a wood structure or concrete ramp in a parking garage. A shear wall however is a vertical cantilevered diaphragm. Illustrated in figure 1 is a diaphragm with an lfrs consisting of structural walls and collector elements.

Use apa sheathing tables in x305 peter von buelow university of michigan tcaup slide 19 of 28. The lateral force is transferred through the web of the diaphragm to the walls which act as supports for the diaphragm. The ibc irc wfcm and icc 600 all contain prescriptive requirements for fastening roof sheathing. Not asd divide nominal values by 2 0 for asd capacity.

When looking at the wind tributary to a diaphragm in order to calculate the shear wall capacities i normally resolve the wind forces to the roof and half the wall height single story four ext. The fastening requirements are those required to resist uplift forces from wind pressures and shear forces. The term diaphragm is usually applied to roofs and floors. Walls for simplicity sake.

Wood frame structure shown lateral wind load 30 psf 2x rafters and studs find. These construction systems can be used when designing a building for lateral loads such as those generated by wind or earthquakes. Structures using wood frame shear walls or wood frame diaphragms to resist wind seismic or other lateral loads shall be designed and constructed in accordance with af pa sdpws and the applicable provisions of sections 2305 2306 and 2307. Design roof diaphragm sheathing and shear walls on short side.

Side wall carries load to roof diaphragm at top and to foundation at bottom roof horizontal diaphragm carries load to end walls end wall vertical diaphragm or shear wall carries load to foundation v lb per lin ft of diaphragm width w lb per lin ft of wall f t lb c vh h 2 wl 2b wind load lb per sq ft figure 1.