Torsional capacity of built up light gage members
Torsional capacity of built up light gage members
(OP)
I'm trying to calculate the torsional capacity of a 7' long box beam light gage header that has a torque introduced by an eccentric brick veneer. Does it make sense to consider the (2) vertical stud sections and (2) horizontal track sections to be acting as a group as a "closed section" ? (Assuming, of course, that all the componets are connected appropriately)






RE: Torsional capacity of built up light gage members
RE: Torsional capacity of built up light gage members
DaveAtkins
RE: Torsional capacity of built up light gage members
I typically connect the brick/veneer angle to the web with tek screws. I also have had the luxury of having my veneer angle bearing a minimum of 4" on masonry on each side of opening, therefore I've considered my connection to the web only to aid in the resistance of excess deflection and simply to tie the two together. The fact that the angle bears on masonry each side, should eliminate the torsion, should it not?
DaveAtkins - Often the header depth will exceed the angle depth. What would you do in this case? Do you suggest that connecting to the web is not good - unless perhaps stiffened?
Another consideration - (on a slight tangent) For curtain wall situations, I have often used 10-12" track for the vertical side members and multiple 6" horizontal stud members to resist wind.
RE: Torsional capacity of built up light gage members
The angle bearing on each side wouldn't necessarily eliminate torsion because the support angle will still deflect even if it is sized to resist the entire load. A single angle will twist as well as undergo translation. Where it is fastened to the header, it will pull on the header. Depending on the actual detail you have, the header may have to resist some torsion due to the forced deformation the angle imposes on it.
I've used multiple nested studs and track for overly large headers. Others cases have worked out better with bracing to support headers for wind.
RE: Torsional capacity of built up light gage members
DaveAtkins