How to anchor brick shelf angles to a wood building?

[MJC6125]

I have a four story wood structure with brick veneer. The veneer height exceeds 30 feet, so we are going to support the brick veneer at each level with shelf angles. I was wondering how people typically detail the connection of the shelf angle back to wood-framed buildings.

Let's say I have maximum 12' of supported brick at 39 psf = 468 plf. The center of brick veneer will have about a 3 1/4" eccentricity from the face of the sheathing, so 468x3.25 = 1521 lb-in/ft moment. I was planning on using an L5X5X3/8 angle. What's the preferred way to attach it back to the structure? (1) row of lag screws into solid blocking between the wall studs? I'm getting that I need 3/4" lag screws at 8" o.c. to take the combined shear and withdrawal loading. I was planning on locating this angle and blocking right above the wall bottom plate, so gravity loads will be transferred through direct bearing. How do you transfer the tension of the moment couple out of the blocking into the wood studs?

 

[NorthCivil]

My vote would be on through bolting the angle to the rim joist at the floor platform. a big fat washer, even custom made from 3/16" thick steel on the inside face. lag bolts only have so much thread, and if the wood gets wet its a recipe for distaster.

 

[dik]

If you have to attach it to wood, then through bolting is the way to go... Careful, your loads can be high and wood generally 'creeps'. If a cold environment, for thermal movement, keep your shelf angles 10' to 15' long... and also watch for thermal transfer and condensation on the inside.

Dik

 

[XR250]

I would not attach the lintel to wood blocking between studs - that is a recipe for disaster. Attach it to the floor band only with thru bolts if you must use this detail as NorhtCivil stated. If you are using I-joists, make sure your band is at least an LVL - may 2-ply. I despise this detail. My guess is that the wood ends up creeping and rotating in practice until the lintel bears on the brick below and so on and so on.
Seems there should be a better way of dealing with 4 stories of brick.

 

[GerryBertier]

I would consider not supporting the brick on wood and keeping everything supported by the foundation.

Estimate your wood shrinkage and brick expansion and have your architect detail their window sills for this differential at the upper levels.

I believe the 30ft limit is prescriptive, but don't have the code in front of me.

 

[dik]

I should have added that some codes exclude wood as a means of masonry support.

Dik

 

[XR250]

I would consider not supporting the brick on wood and keeping everything supported by the foundation.

Estimate your wood shrinkage and brick expansion and have your architect detail their window sills for this differential at the upper levels.

I believe the 30ft limit is prescriptive, but don't have the code in front of me.

I was told that the brick expands the most when it is young as it is very dry when it comes out of the kiln. There ought to be a way to let it acclimate to some degree which would minimize the expansion.

https://ascelibrary.org/doi/abs/10.1061/41016(314)72

 

[MJC6125]

I don't have an ASCE account in order to access that report that XR250 linked to, but the abstract for it brings up a good point. "The expected differential movement when using sawn lumber is 1.70 in. (4.32 cm) for a 30 ft. (9.1 m) exterior wall. If the floor joists are switched to LVL spruce-pine I-joists, similar differential movement (1.59 in., 4.04 cm) can be obtained by going up to a 50 ft. (15.2 m) wall." I assume that 30 foot prescriptive limit was developed based on dimensional lumber floor framing. I am using I-joists/LVLs for floor framing and have a total height of brick veneer less than 50', so I'm tempted to go GerryBertier's route of supporting all the brick off the foundation. That being said, 1.70 in. seems like a large amount of differential movement.


I found this link from the Brick Industry Association that seems to be recommending supporting brick veneer in excess of 30 feet all from the foundation:

http://www.gobrick.com/Portals/25/d...ck Veneer Above 30 Feet with Wood Framing.pdf

However, I also found the following link from woodworks that to me seems to be recommending supporting the veneer at each floor level on the upper levels:

http://www.woodworks.org/wp-content...Brick-Veneer-Wood-Solution-Paper-Oct-2015.pdf

Any issue with cross-grain bending in the rimboard/LVLs when bolting the eccentric brick load to the face?

 

[XR250]

I have never seen anywhere near 1.7" of delta in this situation. Must be expected if the lumber is not kiln dried or has been rained on for a week and the brick is fresh out of the plant.