Roof Diaphragm Openings

Except that two 3 m x 10 m openings are required in the diaphragm for architectural reasons the rest of the building is the same as in design example.

Roof diaphragm openings.

Most openings of any significant size should be checked. A gib plasterboard ceiling diaphragm is a stiff and strong horizontal element which will effectively transfer loads to connected bracing walls lines exceeding 6m or 7 5m with dragon ties to a maximum of 12m. A shear wall however is a vertical cantilevered diaphragm. 2306 2 3 double diagonally sheathed lumber diaphragms.

For shear look at the force acting on the net area. Openings in shear panels that materially effect their strength shall be fully detailed on the plans and shall have their edges adequately reinforced to transfer all shear stresses. Double diagonally sheathed lumber diaphragms shall be designed and constructed in accordance with af pa sdpws. A diaphragm is a flat structural unit acting like a deep thin beam.

Wood diaphragm on reinforced cmu shearwalls neylon et al 2013. In its most basic form i e. Tier 2 evaluation procedure. Gypsum board diaphragm ceilings shall be in accordance with section 2508 5.

It is strongly recommended that analysis for a diaphragm with an opening should be carried out. A diaphragm structure results when a series of such vertical and horizontal diaphragms are properly tied together to form a structural unit. 2306 2 4 gypsum board diaphragm ceilings. Roof chord continuity 4 5 1 4 openings at shear walls.

There are a number of openings in the diaphragm through which structures pass between the thorax and abdomen. The in plane shear transfer demand at the wall shall be calculated. For a diaphragm with openings draw a free body diagram through it. There are three large openings the aortic the esophageal and the caval opening plus a series of smaller ones.

Using this basic concept the diaphragm shear forces can be determined and generally the same principles applied even with the introduction of roof openings or irregular building geometry. Diaphragm openings immediately adjacent to the shear walls shall be less than 25 of the wall length for life safety and 15 of the wall length for immediate occupancy. You ll probably need some kind of chord element around the opening to make sure the diaphragm isn t overstressed in bending. A rectangular uninterrupted plane a diaphragm behaves primarily as if it were a short deep beam figure 1.

Similar changes to 2306 3 for shear walls. A 20 m x 30 m building has a wood diaphragm on cmu walls as shown in figure 1. The diaphragm itself does not have a bracing unit rating but is used when bracing lines exceed 6m separation.