# Brick arches



## rktect 1 (Jan 4, 2010)

Just wondering if anybody knows at what point a brick arch no longer requires a steel lintel and becomes a structural brick arch.

I have a garage door opening 16 feet wide (please no input on header sizes) that will have brick veneer around it including a gable ended roof to a height of 21 feet.  On each side is 1'-9" wide of brick horizontally up the sides of the garage door opening until we have the beginnings of the arch (single brick soldier course), which is 7 feet high.  At the max. height of the arch is 8 feet high.  Very low radius.  So I was just wondering at what point do we go from needing a steel lintel to not needing one.  It looks like it would require a steel lintel.


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## vegas paul (Jan 4, 2010)

Re: Brick arches

Sounds more like big radius, not a low (small) one!  Actually the radius is 32.5 feet.  Here's one for the engineers:  the radius = the sum of [the square of half the chord length (8' squared) + the sagitta squared (ha! look that one up! = 1' squared)], divided by twice the length of the sagitta (2).

See?  And no discussions about 16' header calculations...


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## Architect1281 (Jan 4, 2010)

Re: Brick arches If It was Easy There would be a Chart

http://www.gobrick.com/BIA/technotes/t31.htm

Ther is no easy answer to Arch without header support you are applying a "Spring Arch Theory"

which relies mostly on Mass ans Resistance of what you land on and the angle you approach at

to do so in a veneer is really sketchy

The Romans understood and the Greeks understood

todays Masons would not want the death peanalty if it dosent hold


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## brudgers (Jan 4, 2010)

Re: Brick arches



			
				rktect 1 said:
			
		

> Just wondering if anybody knows at what point a brick arch no longer requires a steel lintel and becomes a structural brick arch.I have a garage door opening 16 feet wide (please no input on header sizes) that will have brick veneer around it including a gable ended roof to a height of 21 feet.  On each side is 1'-9" wide of brick horizontally up the sides of the garage door opening until we have the beginnings of the arch (single brick soldier course), which is 7 feet high.  At the max. height of the arch is 8 feet high.  Very low radius.  So I was just wondering at what point do we go from needing a steel lintel to not needing one.  It looks like it would require a steel lintel.


The bricknotes show a curved steel angle.

http://www.gobrick.com/BIA/technotes/t31.htm\

Otherwise you will have the thrust also in the veneer.

If I were reviewing the plans, I'd say put in an angle or show me calcs.


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## conarb (Jan 5, 2010)

Re: Brick arches

Architect 1281:

Glad to see you made it over here, we need your voice of reason.


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## RickAstoria (Jan 5, 2010)

Re: Brick arches



			
				rktect 1 said:
			
		

> Just wondering if anybody knows at what point a brick arch no longer requires a steel lintel and becomes a structural brick arch.I have a garage door opening 16 feet wide (please no input on header sizes) that will have brick veneer around it including a gable ended roof to a height of 21 feet.  On each side is 1'-9" wide of brick horizontally up the sides of the garage door opening until we have the beginnings of the arch (single brick soldier course), which is 7 feet high.  At the max. height of the arch is 8 feet high.  Very low radius.  So I was just wondering at what point do we go from needing a steel lintel to not needing one.  It looks like it would require a steel lintel.


The_Design_of_Masonry_Structures_and_Fou.pdf

Starting on Page 138 of this PDF file: This may or may not answer your explicit question but might give you some food for thought in the design of structural arch framing. The book dates back to when this was common. (ie. 1922) It is dated but can be useful when you apply modern knowledge on top of this. This also sounds like something needing engineered judgment.

PS: Send me Email address via PM so I can send the big ugly file. It might be too big to send over the forum. 15+ Megabytes.


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## rktect 1 (Jan 5, 2010)

Re: Brick arches

Thanks for the replies.

I have read the t31.pdf as well as the t31a.pdf and t17.pdf.  These all give some good info.  I have also sent an email to the technical services at BIA which is what I was told to do when I phoned them if I had specific questions regarding a design.  So we shall see what they have to say if anything at all.

I think I have to ask the question on this one to the architect to either supply the calcs or add the steel lintel as required by IRC 703.7.3

Anybody have some good verbage for this comment regarding what calcs I want?

From what I have read about low rise (f/L = .2 or less) major arches ( 6 feet or longer), I am to calculate the load of brick above as L/4.  So 16/4=4 feet highx16 feet x about 26#/sq. ft. = 1650 pounds.  Not much but the abutment is only 1'-9" being held together by mortar and maybe a metal tie or two which is not supposed to be used for loading.


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## Heaven (Jan 5, 2010)

Re: Brick arches

If I was reviewing I'd say submit an engineered plan.


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## brudgers (Jan 6, 2010)

Re: Brick arches



			
				rktect 1 said:
			
		

> Anybody have some good verbage for this comment regarding what calcs I want?


1. Please provide calculations or manufacturer's literature demonstrating the ability of the 16'-0" brick veneer arch to be self supporting.

2. Please provide calculations or manufacturer's literature demonstrating the ability of the brick veneer piers to withstand inplane thrust loads from 16'-0" brick arch.


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## RickAstoria (Jan 6, 2010)

Re: Brick arches



			
				brudgers said:
			
		

> rktect 1 said:
> 
> 
> 
> > Anybody have some good verbage for this comment regarding what calcs I want?


1. Please provide calculations or manufacturer's literature demonstrating the ability of the 16'-0" brick veneer arch to be self supporting.

2. Please provide calculations or manufacturer's literature demonstrating the ability of the brick veneer piers to withstand inplane thrust loads from 16'-0" brick arch.

That is an interesting one. I would have done this as "reinforced" structural brick masonry NOT veneer. I have more docs for doing it that way then veneer brick work.

At least the portion around this arch.


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## rktect 1 (Jan 6, 2010)

Re: Brick arches

Well, this architect wants to do an unreinforced structural brick veneer arch with standard corrugated sheet metal ties spaced about 24" horiz. and 16" vert. with an abutment of 21".  I think that means about 1 tie every 16" vert.


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## Pcinspector1 (Jan 6, 2010)

Re: Brick arches

Arch1281,

Thax for the brick website info, really good information!


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## kilitact (Jan 6, 2010)

Re: Brick arches

Heaven;



> If I was reviewing I'd say submit an engineered plan.


I would agree with Heaven (didn't mean this in a religious way     )


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## JBI (Jan 6, 2010)

Re: Brick arches

A reply that was truly 'Heaven sent'? :lol:


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