Roof Diaphragm Action

When a rigid diaphragm is specified tekla structural designer automatically applies nodal constraints to the associated slab nodes.

Roof diaphragm action.

Managing diaphragm action in roof panels and slabs tekla structural designer forms diaphragms in every slab item of a parent slab when diaphragm option is set to rigid or semi rigid. A horizontal diaphragm element parallel and in line with the applied force that collects and transfers. This horizontal element is known as the diaphragm. The corresponding diaphragm chord forces are therefore equal to m divided by the diaphragm depth b.

The construction requirements and load capacities of wsp sheathed diaphragms are found in the american wood council s special design provisions for wind and seismic sdpws. 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. At the roof level these wall reactions turn the load in the roof system in the plane of the roof. The sheathing transfers both vertical gravity load to the regularly spaced framing members and shear loads horizontally in diaphragm action.

Once installed these sheets can also be used as a horizontal brace and therefore the steel deck acts as a diaphragm. 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. The maximum unit shear on the wall diaphragm is also equal to the roof reaction r divided by b. The maximum roof diaphragm moment m equals ww wl x l2 8.

The fluted deck is equivalent to the web of a horizontal beam of which the. Offset roof planes roof framing must keep diaphragm in plane load on diaphragms may be different due to different heights. Proportion load rationally. Diaphragm action at the roof level.

The steel deck sheets used for roofs and floors provide support for gravity loads between the joists and or beams. A roof diaphragm can be constructed of steel plywood or concrete to create the rectangular plane underlying the roof panels. A shear wall however is a vertical cantilevered diaphragm. A diaphragm structure results when a series of such vertical and horizontal diaphragms are properly tied together to form a structural unit.

A diaphragm is a flat structural unit acting like a deep thin beam.