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RE: Concrete Masonry Arch[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: <seaint(--nospam--at)seaint.org>
- Subject: RE: Concrete Masonry Arch
- From: "Randall Moore PE SE" <ranmoo(--nospam--at)ec.rr.com>
- Date: Thu, 19 Jun 2008 21:37:26 -0400
This is not specifically what you asked for, but I would think perhaps some of the info could be applicable to CMU arches. In the past when I have designed and detailed brick arches, I used the technical guides on the Brick Institute of America’s website – http://www.gobrick.com/html/frmset_thnt.htm .
Here are some technical guides that have some nice rules of thumb for brick arches (especially with regard to arch rise to span ratios), that I think might be applicable to CMU arches as well.
Brick Masonry Arches 31A [Oct. 1967] (Reissued July 1986)
Structural Design of Brick Masonry Arches - 31B Rev [Nov./Dec. 1981] (Reissued May 1987)
Structural Design of Semicircular Brick Masonry Arches 36 Rev [July/Aug. 1981] (Reissued Jan. 1988)
If the arch rise to span is appropriate, then it would seem that the masonry should principally be in compression, and no reinf. steel required; unless there are perhaps other considerations like minimum reinforcing requirements for seismic design category.
Hope that helps.
Randall Moore PE SE
From: Rich Lewis
I’m looking for detailing tips and insight in concrete masonry arch construction. I have a project where the architect has shown several masonry arches. The wall construction is 8” CMU and a brick veneer. I have seen many brick arches built but I have never seen a concrete masonry wall arch built. I have some opening in the 15 feet span range.
I have NCMA TEK 14-14 which states the arch should be made of solid CMU or the CMU should be grouted solid. I see the steps to construct the arch as being:
1. Install arch form
2. Create the first row of the arch using brick, either clay or concrete. The architect will determine that.
3. Build the brick veneer arch as a typical brick arch.
4. Build the CMU backup arch using cut block. I would assume hollow block.
5. Grout the arch solid up to the crown height
6. Put in a bond beam course directly above the crown.
7. Build the wall above the arch as a typical wall.
I’m wondering if I should put some steel bars in that follow the arch curve, directly above the first row of bricks. I know this area is in compression so I don’t see much use of the steel. I’m also wondering if I should have some vertical steel in the arched section of wall, between the bond beam and the first row, above the spring line.
I open to suggestions for detailing CMU arches.
- Concrete Masonry Arch
- From: Rich Lewis
- Concrete Masonry Arch
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