Brick Lintel 1

[jonathanwilkins]

I have a customer who wants to reinforce the brick above a garage door header with 3/16" wire as opposed to a big steel lintel or tying a regular lintel to the garage door header. It's a 16' door w/ approx 30" of brick above it. He's been doing this forever (as long as I've been alive if not longer) just now the building inspector has asked him to have it engineered. I've scoured all the books I have + the internet looking for resources. Any books, papers, direction? One that I can't find is the BIA Tech Notes 17h. Seems to be referenced in a lot of areas but I can't find it. Thanks.

 

[Ron]

Just because he has been doing it forever doesn't mean it's right. Not only do you have 30 inches of brick above it, you have a roof bearing on it and loads that it must be designed for but might not ever feel.

Not sure how you intend to use the 3/16" wire, but unless it is high strength and being used as pre-stressing or post-tensioning in some fashion, it isn't nearly enough.

Look as some of his other projects that have been in place for a while. I'd be surprised if they are all performing.

If you are doing the engineering on this, I can't imagine how you can get 3/16" wire to work with normal loading.

 

[msquared48]

Without more information, I will have to defer to Ron's comment.

Does your client have a detail of the proposed installation you caqn post that we can review?

I will have to admit though that I, too, am skeptical of the wire. I have used wire ties to hold the brick to the wall, resisting horizontal loads, but never vertical loads. That is the purpose of the steel lintel.

Mike McCann
MMC Engineering

 

[kslee1000]

jo:

Please let us know if you find anything that even touches this tech only scanty. I would like to try it on my bay windows, which requires the lintel replaced.

 

[jonathanwilkins]

The lintel isn't actually carrying any roof load - that's carried by the garage door header. It's only a lintel carrying the 30" of brick veneer - approx 100plf.

I'm very aware that because he's been doing it forever doesn't make it right - hence my research. His experience is that this performs much better than lagging the lintel to the garage door header and that it's much more economical than having a lintel sized appropriately.

He doesn't have a detail - what he does is take truss-type reinforcement and lay it in the mortar joint every-other course. The brick does sit on a 5x3-1/2x5/16" lintel and that is shored while the mortar cures.

Thanks for all comments. Jonathan

 

[JStructsteel]

I would worry long term the beam creeping and the bottom bricks wanting to fall out, the only thing holding them would be the mortar in tension. I would sacrifice a piece of angle for the piece of mind.

 

[jonathanwilkins]

The brick will sit on a 5x3-1/2"x5/16" lintel - bricks won't fall out

 

[kslee1000]

So the wire reinforcing allowed him to reduce the size of lintel, otherwise would be more bulky. Is this what you menat?

 

[jonathanwilkins]

The reinforcing will carry the load - the lintel is only there to help w/ installation though it obviously will contribute some load-carrying ability.

Client got this idea from a brick industry publication years ago. He's currently trying to find it so I can look at it.

 

[Ron]

jonathanwilkins....now I understand what you are doing. Your first posting led me to believe something else. I thought you were trying to create a load bearing header using brick with ladder wire!

What he's proposing is common, provided the bricks are appropriately tied as Mike noted. For only the brick load, with ties, the angle picks up most of the load...not the bottom course of brick.

 

[jonathanwilkins]

Ron - thanks. Sorry for any confusion. How do you decide how much the reinforcing carry's vs. how much the steel angle carries?

Any references on how to design? I can't find any. He brought me the paper he's been using & it is for gable ends w/ a minimum height of the brick of at least 13" at the ends of the header. This seems to me that this design is relying on the arching of the brick much more than the reinforcing wire. This makes me a little concerned so I'd like to find a design reference so I can run the numbers on everything. Thanks. Jonathan

 

[beton1]

I think what is happening is that the angle (lintel) is undersized, especially from the building inspector's perspective. The wire which is embedded in the mortar joints is creating a more rigid brick construction, reducing flexing or deflection of the lintel. Trying to prove this capacity and making it meet the code is the difficult task. With only 30" brick height, and a 16' span, arching action is minimized. An interesting question, I'd like to see if it can be proven, maybe post the paper?

 

[JAE]

Is this what you are looking for?

http://www.gobrick.com/html/frmset_thnt.htm

This isn't 17H but it does show the brick spanning vertically between supports (see the third paragraph under DESIGN CONSIDERATIONS). Also see the design example at the end of the page.

 

[hokie66]

With a 16' opening, neither the angle or the wire reinforcing is sufficient. If his solution has served well in other installations, it is because the angle and brick are acting compositely. I wouldn't want to depend on composite action without some shear connectors.

 

[RacingAZ]

That is a common detail. The angle gets screwed to the header every so often (depend on your calcs) and you just check the angle for the span between the screws. The angle and the screws will transfer the load to the header which may now be subject to L/600 deflection criteria.

 

[BAretired]

It is not surprising that your client has been successful with his method of reinforcing brick lintels. The load is trifling and the brick beam is 30" deep spanning only 16 feet. But the strength of the beam relies on the strength of mortar.

It is not clear why he does not want to attach the steel angle to a header. Is that a big cost item? If it is, ask him to grout in #3 vertical ties, hooked top and bottom, through the holes in the brick at, say 24" centers. And, maybe a #3 bar horizontal top and bottom wouldn't hurt. The top bar should extend two feet beyond the edge of opening.


BA

 

[msquared48]

BaRetired:

This is interesting... Maybe he doesn't want to tie the brick to the garage header because the deflection seen by the header is different than that seen by the brick/steel angle combination, if I understand the concept correctly. In other words, maybe the brick combination sees less deflection or movement with live load than the continuous dead load of the brick/steel lintel combo.

Am I making myself clear here? Maybe he has found less cracking of the brick veneer if this method is used. Just thinking out loud.

Mike McCann
MMC Engineering

 

[hokie66]

I sort of retract my previous statement that the wire reinforcement is not sufficient. If he has say four 3/16" wires in the bottom two courses, it should work for bending, provided the mortar can be considered acting monolithically with the brick. But I still believe the angle and brickwork would be working compositely.

 

[jonathanwilkins]

BaRetired & msquared48 - He does not want to lag the lintel to the header because he worries about the header shrinking/expanding at a different rate from the brick causing cracks.

We've detailed this connection many times but he doesn't like that due to experience.

Thanks again to everyone for your help.

 

[BAretired]

I agree with Mike McCann. The brick beam would be stiffer than the header and free of load fluctuation. It should be held together by more than just mortar, though.

A positive connection to the steel angle would be a good start. Also, for wind pressure, wouldn't he need brick ties?



BA