Roof Diaphragm Shear

While the diaphragm shear stiffness development is similar for both mca and steel deck institute s sdi diaphragm design manual the only difference is the panel edge term k.

Roof diaphragm shear.

Allowable stress design asd will be used. The results of this study show remarkably narrow scatter in tested to calculated strength ratios. The brackets allow the use of continuous ridge venting in blocked diaphragms by replacing the boundary nailing between the roof sheathing and the ridge board ridge beam that is lost due to the gap required for venting. A similar design is required in the other orthogonal direction east west but is not illustrated here.

The allowable shear capacities in tables 2306 2 1 1 and 2306 2 1 2 are permitted to be increased 40 percent for wind design. Shear x brackets are designed to transfer in plane shear forces at the ridge line of roof diaphragms why use shear x. The side walls carry the load to the roof diaphragm on top and the foundation at the bottom. The maximum diaphragm shear in the roof diaphragm is.

The shear walls may also be known as vertical or cantilevered diaphragm s. Shear diaphragms are commonly used in buildings as a means of transmitting lateral loads. A shear wall however is a vertical cantilevered diaphragm. Sheathed elements such as walls and a roof covere d with panels and tied together provide additional strength to the building.

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. Steel deck plywood and concrete are all common materials utilized in diaphragm applications. The term diaphragm is usually applied to roofs and floors. Af pa sdpws shall be met and wood structural panel diaphragms are permitted to resist horizontal forces using the allowable shear capacities set forth in table 2306 2 1 1 or 2306 2 1 2.

V n s wl 247 72 212 plf 2b 2 42 v e w wl 180 42 52 plf 2b 2 72 3. Since the framing will be spruce pine fir with sg 0 42 the shear values from table 2 must be adjusted according to footnote a. Shear nailing of the roof diaphragm north south the diaphragm loaded in the north south direction has been selected to illustrate the design of a wood structural panel roof diaphragm. These construction systems can be used when designing a building for lateral loads such as those generated by wind or earthquakes.

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.