Roof Diaphragm Unit Shear

Max shear diaphragm reaction at shearwall diaphragm unit shear reaction length of diaphragm plf.

Roof diaphragm unit shear.

Shear diaphragms are essentially planar structural systems found in roofs floors and walls of buildings. Lbs ft plf 2. This is the most common situation. Anchorage for shear transfer is also discussed in section 22 2 3.

These construction systems can be used when designing a building for lateral loads such as those generated by wind or earthquakes. Drag strut at the edge of the diaphragm it distributed the shear force from one diaphragm to another e g. Sdpws table 4 2a diaphragm allowable unit shear capacity for seismic v s asd 255 plf sdpws table 4 2a. As a wood sheathed diaphragm is loaded slip will occur between the perimeter framing member and the sheathing.

A diaphragm structure results when a series of such vertical and horizontal diaphragms are properly tied together to form a structural unit. The term diaphragm is usually applied to roofs and floors. A shear wall however is a vertical cantilevered diaphragm. A shear wall however is a vertical cantilevered diaphragm.

At the roof level these wall reactions turn the load in the roof system in the plane of the roof. Diaphragm apparent shear stiffness ga 14 kips in. A diaphragm is a flat structural unit acting like a deep thin beam. 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.

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. The major components of a diaphragm include the individual deck panels the structural members to which they are connected and the connecting devices or fasteners. They are comprised of interconnected units attached to supporting members such that the entire assembly possesses both in plane shear strength and stiffness. Fastening of the chord or chord enhancement should not inhibit this slip.

This horizontal element is known as the diaphragm. Diaphragm unit shear at the east side of line 3 and at line 9 is 136 000 160 850. The new or enhanced chord member must be anchored into the diaphragm for unit shear transfer. Blocked diaphragm all panel edges are supported by and nailed to framing member unblocked diaphragm only the short 4 ft edge is supported by framing member.

The diaphragm resists the in plane loads by acting as a large horizontal beam spanning between the supporting end walls that are known as shear walls. From floor diaphragm to shear.