Roof Diaphragm Unit Shear

The new or enhanced chord member must be anchored into the diaphragm for unit shear transfer.

Roof diaphragm unit shear. A shear wall however is a vertical cantilevered diaphragm. 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. These construction systems can be used when designing a building for lateral loads such as those generated by wind or earthquakes.

At the roof level these wall reactions turn the load in the roof system in the plane of the roof. 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. A shear wall however is a vertical cantilevered diaphragm.

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. Diaphragm apparent shear stiffness ga 14 kips in. A diaphragm is a flat structural unit acting like a deep thin beam. 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 term diaphragm is usually applied to roofs and floors. Shear diaphragms are essentially planar structural systems found in roofs floors and walls of buildings. This is the most common situation. Max shear diaphragm reaction at shearwall diaphragm unit shear reaction length of diaphragm plf.

Diaphragm unit shear at the east side of line 3 and at line 9 is 136 000 160 850. This horizontal element is known as the diaphragm. Fastening of the chord or chord enhancement should not inhibit this slip. 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.

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. 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. Anchorage for shear transfer is also discussed in section 22 2 3.

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.