AS3990. Restraint against torsion.

[Mb87]

Mech Eng looking for clarification on structural calcs.

Have a beam (loaded on the bottom flange via pillow block)
The beam is held by 2 bolts in a cleat through the web at each end.

From what I can tell, the beam should have an le=1.2x span

From 5.9.3.1
le = span

but from 5.9.6
factor of 1.2 because the critical flange is loaded and the beam has no lateral restraint.

 

[Smoulder]

If load is downwards then bottom flange isn't critical flange.

 

[human909]

Also this sounds like a engineering problem that is better dealt with by using AS4100.