Smart questions
Smart answers
Smart people
Join Eng-Tips Forums
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Member Login




Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips now!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

Join Eng-Tips
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

jonathanwilkins (Civil/Environmental) (OP)
8 Apr 09 11:49
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 (Structural)
8 Apr 09 13:13
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 (Structural)
8 Apr 09 13:22
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 (Civil/Environmental)
8 Apr 09 13:26
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 (Civil/Environmental) (OP)
8 Apr 09 13:44
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
jrisebo (Structural)
8 Apr 09 13:53
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 (Civil/Environmental) (OP)
8 Apr 09 13:55
The brick will sit on a 5x3-1/2"x5/16" lintel - bricks won't fall out
kslee1000 (Civil/Environmental)
8 Apr 09 14:17
So the wire reinforcing allowed him to reduce the size of lintel, otherwise would be more bulky. Is this what you menat?  
jonathanwilkins (Civil/Environmental) (OP)
8 Apr 09 14:20
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 (Structural)
8 Apr 09 14:42
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 (Civil/Environmental) (OP)
8 Apr 09 14:50
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 (Civil/Environmental)
8 Apr 09 16:31
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 (Structural)
8 Apr 09 17:43
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 (Structural)
8 Apr 09 18:19
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 (Structural)
8 Apr 09 19:19
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 (Structural)
8 Apr 09 20:45
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 (Structural)
9 Apr 09 2:03
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 (Structural)
9 Apr 09 7:36
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 (Civil/Environmental) (OP)
9 Apr 09 8:08
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 (Structural)
9 Apr 09 9:28
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

CTSeng (Structural)
9 Apr 09 13:10
Reinforced brick is possible, BIA Tech notes 17 and 17B. Done some small lintels with exposed brick 3 sides and joint space between for rebar and grout.  Shoring and pointing these for appearnce isn't easy.

Not sure joint wire in a bed joint is permitted nor would I count on it as flexural reinforcement.
BAretired (Structural)
9 Apr 09 14:05
Wire reinforcement is used in masonry walls and is counted upon as reinforcement, usually for wind loads.  The attached file shows an example of three continuous wires, two in the block and one in the brick.

It might be a good idea to cut a shallow channel in alternate bricks in the bottom course to improve the bond.

 


BA

jonathanwilkins (Civil/Environmental) (OP)
9 Apr 09 14:24
Talked w/ an engineer for the Brick Industry Association - he gave me this detail which will supposedly be in the 2009 IRC.  They tried to get in this version of the code but were a few votes short.   
jonathanwilkins (Civil/Environmental) (OP)
9 Apr 09 14:24
PS - it's on page 19.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!

Back To Forum

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close