Double channel with torsional restraints
Double channel with torsional restraints
(OP)
Situation: Back-to-back 10" channel sections are joined with spacer plates which are welded to the backs of the channels. The composite double-channel beam is simply supported, and is loaded at discrete points.
The point loads are such that the spacers need to act as torsional restraints so that yielding under flexure is the critical strength limit state.
The nearest restraints to one point load are located at 18 inches one direction and 12 inches the other.
How will the torsion be distributed to the restraints?
I think that the torsion will be distributed based on geometry - the closest restraint will get the most torsion - but I'm unsure as to the correct relation, and would appreciate some guidance.
The point loads are such that the spacers need to act as torsional restraints so that yielding under flexure is the critical strength limit state.
The nearest restraints to one point load are located at 18 inches one direction and 12 inches the other.
How will the torsion be distributed to the restraints?
I think that the torsion will be distributed based on geometry - the closest restraint will get the most torsion - but I'm unsure as to the correct relation, and would appreciate some guidance.






RE: Double channel with torsional restraints
How much space is between the channels? Proper welding would require a rather large gap.
RE: Double channel with torsional restraints
BA
RE: Double channel with torsional restraints
5-inch spacing between the channels - we have verified that the welds can be physically performed and inspected.
I dug into my 1st year mechanics text and confirmed the ratios - similar to the distribution of shear on a simply-supported beam from a concentrated load.
Thanks to you both.
J
RE: Double channel with torsional restraints
RE: Double channel with torsional restraints
We are using 5"x9.5"x20mm plates as the spacers. The plates get fillet welded both sides to the backs of the channels.
J
RE: Double channel with torsional restraints
BA