Roof Diaphragm Unit Shear

Lbs ft plf 2.

Roof diaphragm unit shear.

Max shear diaphragm reaction at shearwall diaphragm unit shear reaction length of diaphragm plf. 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. A diaphragm structure results when a series of such vertical and horizontal diaphragms are properly tied together to form a structural unit. They are comprised of interconnected units attached to supporting members such that the entire assembly possesses both in plane shear strength and stiffness.

These construction systems can be used when designing a building for lateral loads such as those generated by wind or earthquakes. Shear diaphragms are essentially planar structural systems found in roofs floors and walls of buildings. A shear wall however is a vertical cantilevered diaphragm. This is the most common situation.

A diaphragm is a flat structural unit acting like a deep thin beam. The term diaphragm is usually applied to roofs and floors. 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. Diaphragm unit shear at the east side of line 3 and at line 9 is 136 000 160 850.

As a wood sheathed diaphragm is loaded slip will occur between the perimeter framing member and the sheathing. 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. Diaphragm apparent shear stiffness ga 14 kips in.

The new or enhanced chord member must be anchored into the diaphragm for unit shear transfer. This horizontal element is known as the diaphragm. Sdpws table 4 2a diaphragm allowable unit shear capacity for seismic v s asd 255 plf sdpws table 4 2a. From floor diaphragm to shear.

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. Fastening of the chord or chord enhancement should not inhibit this slip. A shear wall however is a vertical cantilevered diaphragm. A diaphragm is a flat structural unit acting like a deep thin beam.

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. At the roof level these wall reactions turn the load in the roof system in the plane of the roof.