Eccentrically Loaded Brick Ledge with Wood Stud Backup

[enigma2]

I'm having a bit of a mental block on this on; hopefully someone can help me out...

I have brick veneer on a wood stud wall backup. At the window heads, door heads, etc. I have a steel angle as a brick ledge.

In the typical case, the architect wants an air space between the stud and the brick, so the horizontal leg of the angle is 4" and the center of the load from the veneer is almost 3.25" from the stud wall. With this eccentricity, how do I determine the maximum span of the angle if I want to use a 4" vertical leg or 6" vertical leg? The angle is fastened at each stud (16" o.c.) I know I can consider arching action for the load, but I'm also restricted to L/600 deflection at most because of the brick.

(I also have a worse case where the arch is adding insulation, so the horizontal leg is 6" and the center of the veneer is almost 5" from the stud wall, but I figure the procedure is the same.)

Any thoughts to lead me in the right direction?

 

[JAE]

Why are you connecting the angle to the wood studs?

Normally you use a loose angle lintel that simply bears on each end of the opening over the brick (enough bearing distance to keep the bearing stress under the maximum allowable).

The wood studs should just provide lateral support, not vertical.

 

[msquared48]

As an alternative here, and JAE is correct too, you might want to consider the following options:

1. Add a glulam beam below the studwall that serves as a header over the opening. Add a structural tee section that can be both bolted (one leg of the flange) to the underside of the glulam, and thru-bolted (web) to the glulam, transmitting the eccentricity from the brick to the glulam.

2. If you do not want to use a wood ledger, try a steel tube section for the lintel/header with a flat steel plate welded to the bottom to support the brick. The tube section is much better in torsion. The tube section would be supported by a pipe column at each end.

Mike McCann
McCann Engineering