origin of the term jack arch
origin of the term jack arch
(OP)
I had first heard the term "jack arch" during college, while doing some intern work on the NYC subway system. And I've recently been hearing the term (somewhat blindly) thrown around on a job in Philadelphia. I have a general working knowledge of what a "jack" arch is, but like everything else in the engineering world, it seems to have a very vague definition and the origin of the term are sketchy, at best.
The best reference for a possible origin of the term is from a book that I stumbled over:
jack arch. A flat masonry arch, specifically flat terra-cotta floor arches. One explanation for the origin of this term is the resemblance of the center "keystone" arch block to the crown on the Jack in a deck of playing cards. (Friedman, Historical Building Construction, 2010)
Can anyone offer a definition and/or origin for a "jack" arch?
Cheers...
The best reference for a possible origin of the term is from a book that I stumbled over:
jack arch. A flat masonry arch, specifically flat terra-cotta floor arches. One explanation for the origin of this term is the resemblance of the center "keystone" arch block to the crown on the Jack in a deck of playing cards. (Friedman, Historical Building Construction, 2010)
Can anyone offer a definition and/or origin for a "jack" arch?
Cheers...






RE: origin of the term jack arch
RE: origin of the term jack arch
Mike McCann, PE, SE (WA)
RE: origin of the term jack arch
Mike McCann, PE, SE (WA)
RE: origin of the term jack arch
something that supports or holds in position: as
a : an iron bar at a topgallant masthead to support a royal mast and spread the royal shrouds
b : a wooden brace fastened behind a scenic unit in a stage set to prop it up
Where I hear this is a "jack rafter", with the term being used in a little different sense from normal structural use.
When you draw things, you can call it "Item X" or "Arch per Detail C" but the guys out building it are going to give it a name if it doesn't have one, and trying to guess where that came from 500 years later might be difficult.
RE: origin of the term jack arch
"Jack" is often used in the context of small; see first entry in bibliography: https://www.nh.gov/dot/org/projectdevelopment/envi...
TTFN

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RE: origin of the term jack arch
Logically applying the term, a jack arch is one having less arch or rise than other arches, as in a flat configuration
Mike McCann, PE, SE (WA)
RE: origin of the term jack arch
Aitken, T. Road Making and Maintenance: A Practical Treatise for Engineers, Surveyors, and Others.
Philadelphia: J.B. Lippincott Company, 1900.
https://archive.org/details/roadmakingandma00aitkgoog
(Click "All Files: HTTPS" - on the left - to find the PDF version)