Veneer shelf angle and large openings

[braves25]

I have a two story building with brick veneer. Arch wants a shelf angle at the top of the second floor windows. Most windows are 15' wide, so I am using a HSS header and jamb system at these openings and will connect my veneer support angle to the HSS header. However, I have some openings that are just 10' wide where I am using a typical light ga. header and jamb system (with the same veneer support angle). Distance from the outside edge of metal stud to outside face of veneer is 6.625". The studs "by-pass" the second floor slab so they are not supported vertically by the second floor framing. Questions are: 1. Where I do not have any headers (HSS or lt. ga.) and will be connecting my shelf angle directly to the stud. Is it okay to weld to 16 GA studs with a 1/8" weld? Also, any suggested details for this? I have about 11' of veneer from the top of opening to the top of parapet, giving about a 600# load to the stud. 2. At the light ga. headers (10' openings) would you screw the shelf angle to the lt. ga. header? I'm using the following boxed header: (3)-1000S162-97 with 600T200 top and bottom member. Thank you and have a great day.

 

[phamENG]

Why? How tall are the stories? What's the point of a shelf angle above the second floor windows? If you're going to have a shelf angle, the floor level is usually be best place structurally (though I realize there are architectural benefits to doing it at the windows.) But putting those loads on the studs are not fun.

You'll need lintels, of course, but it's usually best to keep those in the brick if you can and not put the gravity loads on the backup if you can avoid it. And in bypass framing, it gets even harder.

To answer your questions directly:

1) No, don't try to weld an angle to a stud. A really amazing welder might be able to pull it off, but by the time you heat up the rolled steel enough to get the weld to actually fuse with the base metal, you won't have any stud left.

2) No. Generally speaking, screws should go through thinner material into thicker.

If a loose lintel can't do the job, a structural steel jamb and header will likely be required to make the connection work. The torsion on that header will be pretty high, and that light gauge header may struggle with it.

 

[masonrygeek]

As Pham said, do you really need a shelf angle at that point? TMS 402/602 says a shelf angle at 30' for brick veneer and every floor above. Two stories sound like about 25' so you should be OK unless the floors are taller. Plus, this is cold formed framing so you don't have the differential movement issues like you would have with brick veneer/wood stud walls. By switching to loose steel lintels over the openings you don't need to attach anything to the backing.

 

[RiverBeav]

You can weld a ledge angle to light gage steel studs to support brick veneer. We usually do 16 gage studs minimum and just a vertical weld between the web side of the stud to the back face of the Ledge angle. We have done this on office buildings with ribbon windows all the way around the building.

I have never attached a ledge angle to a light gage header. Any weld you would do would be loading a web of the joist in its weak direction, so I am not confident in the ability of that web to distribute the forces from the ledge angle. You could theoretically put in stiffeners to take the load, but then you are using screws in withdrawal to resist heavy loads from welds. If I need a ledge/shelf angle at an opening, I usually bite the bullet and put an HSS header in (either hung from the slab above or with full HSS Jambs each side of the opening).

If you can use loose lintels, that would be preferred.

 

[braves25]

The overall height of the veneer is about 38'. FiverBeav, what type of connection detail do you use for your HSS header/jamb connection? I have done this in the past and am going to go this route for this project.

 

[jerseyshore]

Definitely try to use loose lintels for all of the openings, even if you have to use bent plates instead of book angles that's way better.

I've very rarely done the angle off the light gauge header thing. When I did do this, it was either bolted or screwed together, can't remember which. I've probably never specified welds for LGMF. When I do this I will always add blocking or kickers to prevent any torsion on the metal stud header.

The 30 ft limits for wood are mainly for fire issues, with consideration for shrinkage and stud shortening. You don't have the same concerns with metal studs, although they can weaken during a fire.

Whenever I spec relief angles and say to put them at a window level, they put them at the floor level instead. When I say to put them at the floor level, well, you get where I'm going with this.

Just go with whatever is preferred right now. If they want it at the windows, see how many screws you need to make it work.

 

[Enable]

For all that is holy on this earth do not specify welds from a hot rolled angle to a light gauge stud. There are better ways to skin this cat (many given above - screws are excellent, use them).

 

[RiverBeav]

https://www.eng-tips.com/viewthread.cfm?qid=376253

Dave Atkins' advice on this thread is similar to my understanding of what a standard detail for supporting brick ledge angles on office buildings. The brick veneer is supported by a ledge angle that is welded to each stud with a vertical weld running on the web side of the stud.

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https://www.mutualmaterials.com/wp-content/uploads/2022/01/AnchoredBrickVeneerOSD.pdf

Figure 2.6 in this document talks about welding the ledge angle to the brick veneer supports.

 

[braves25]

Many thanks, RiverBeav. The document looks to be very helpful. Thank you!