Bridge Components Technical Terms Stringer vs Girder
Bridge Components Technical Terms Stringer vs Girder
(OP)
Can someone explain to me the difference between stringers and girders? I've got a project involving a concrete bent railroad bridge with multiple steel stringers/girders for the super structure framing. It appears the terms "Girder" and "Stringer" in the bridge industry are used intermittently to describe the same framing component. Appears "Girder" is more universally used term, please explain any defined differences in the engineering/construction industry.






RE: Bridge Components Technical Terms Stringer vs Girder
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Bridge Components Technical Terms Stringer vs Girder
RE: Bridge Components Technical Terms Stringer vs Girder
I'd probably lean toward calling it a stringer if less than ~30" deep, or a girder if it's a larger member.
RE: Bridge Components Technical Terms Stringer vs Girder
While we're talking about bridge terms, can I go on record to say that the term "bent" has always sounded like a misnomer to me. There's nothing "bent" about them (yes, I know the etymology is probably from historic usage or non-English languages). Maybe it's just me but I've always tried to refer to bridge supports are "piers" rather than "bents".
Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries
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RE: Bridge Components Technical Terms Stringer vs Girder
I've heard of the vertical bents being referred to as piers also.
It appears this bridge could be labeled as having either girders or stringers. The member size is W36x150 and there are six (6) of them.
RE: Bridge Components Technical Terms Stringer vs Girder
All said, I think you could call it a girder or a stringer and the intent would be clear, as long as you were consistent.
Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries
www.americanconcrete.com
RE: Bridge Components Technical Terms Stringer vs Girder
W36 would be a stringer; beams between stringers or girders are diaphragms.
RE: Bridge Components Technical Terms Stringer vs Girder
A bridge "bent" usually has been used to refer to one "line" of supports for the superstructure. This could be one large pier, perhaps two, three, or more smaller piers that share a common foundation, or a row of piling, as in a "pile bent".
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RE: Bridge Components Technical Terms Stringer vs Girder
I am unsure of the differences in the terms "Pier" and "Bent", both are used intermittently. However, I'm under the impression that a pier is a continuous member that is both the deep foundation and structural vertical framing member. While a bent, may not be. I am unsure of this though.
RE: Bridge Components Technical Terms Stringer vs Girder
If you're in the US, look at your state DOT's bridge inspection manual for the local terminology.
RE: Bridge Components Technical Terms Stringer vs Girder
For example, a drilled shaft/caisson foundation that extends as a continuous member above grade as the structural vertical framing member, would be labeled a pier.
Similarly, a driven pile or group of piles in a row that extends continuously above grade with a cap beam, would be labeled a pier.
RE: Bridge Components Technical Terms Stringer vs Girder
RE: Bridge Components Technical Terms Stringer vs Girder
The link below doesn't give an origin either, but comes up with some suggestions:
http://www.madsci.org/posts/archives/2002-05/10203...
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/