Question about special bridging to restrain bar joists tilted about their longitudinal axis

[cliff234]

What do joist manufacturers do to deal with bar joists tilted about their longitudinal axis? I know that additional bridging is required to restrain the joists, but is the additional bridging automatically designed and provided by the joist manufacturer, or does the EOR have to add a note on the drawings specifically directing the joist manufacturer to design and provide the special bridging? (See attached.) And how much “tilt” can joists accommodate before special bridging is required?

 

[BAretired]

Each joist carries P*cosθ where P is the gravity load per joist and θ is the slope of the roof. Bridging must be designed for P*sinθ. The sloping reaction from all of the bridging must be resisted by the ridge beam, the edge beam, the roof diaphragm or a combination of all three. It is the job of the EOR to design the roof structure, not the job of the joist supplier.

There is no limit to the slope of roof but joists alone are not effective in resisting a force parallel to the roof (or normal to the joist).

BA

 

[cliff234]

Thank you BAretired!

 

[BAretired]

You are welcome, cliff234.

BA