Roof Diaphragm Chord

The force in the chord is customarily determined by dividing the moment in the diaphragm by the depth of the diaphragm.

Roof diaphragm chord.

T l shaped and other odd. At the roof level these wall reactions turn the load in the roof system in the plane of the roof. T c l b w w h v v v side wall carries load to roof diaphragm at top and to foundation at bottom. Idealizing and simplifying complicated structures.

T chord t c chord c w diaphragm reaction goes to shear walls. Discontinuities in diaphragms are often created when a portion of an exterior wall line is offset from the main wall line causing a disruption in the diaphragm chord or strut. Therefore area is for 1 2x4. The maximum unit shear on the wall diaphragm is also equal to the roof reaction r divided by b.

Even if designed for vertical loads only the beam end connections probably have some capacity to develop horizontal forces through the column. Offset roof planes. Roof diaphragm chord for the diaphragm the chords carry the moment couple and the panels carry the web shear tension generally controls. 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.

This yields an upper bound on the chord force since it assumes elastic beam. These edge mem bers are commonly called chords in diaphragm design and may be joists ledgers trusses bond beams studs top plates etc. Max chord force occurs at location of max moment chord force t or c chord force mmax diaphragm depth chord unit shear chord force length of diaphragm plf. Chords are usually the double top plates of the walls but for simple but jointed members only 1 member is acting at the joint.

Sloped roofs idealize sloped wood roof diaphragms as if they are flat. When this occurs the disrupted chord or strut force must be transferred across the discontinuity through an alternate load path. While the diaphragm edge members perform the function of flanges resisting bending stresses. The corresponding diaphragm chord forces are therefore equal to m divided by the diaphragm depth b.

This horizontal element is known as the diaphragm.