Shear Connection Design
Shear Connection Design
(OP)
I was reviewing some general note sheets produced by another engineer, and came across this note regarding connections:
"Shear connections shall be designed for 1/2 of the allowable uniform loads table in Part 2 of the AISC (ASD)"
The note sheet was based on ASD 13th Edition, and when I asked the signing engineer what table he was referring, he referred me to a client specification that requested the note be used for the design basis. I still use my LRFD 2nd Edition, so I have a little trouble finding things in ASD 13th.
Does anyone know which table the note could be referring?
"Shear connections shall be designed for 1/2 of the allowable uniform loads table in Part 2 of the AISC (ASD)"
The note sheet was based on ASD 13th Edition, and when I asked the signing engineer what table he was referring, he referred me to a client specification that requested the note be used for the design basis. I still use my LRFD 2nd Edition, so I have a little trouble finding things in ASD 13th.
Does anyone know which table the note could be referring?






RE: Shear Connection Design
The ASD table, in the 13th edition, that would be applicable would be Table 3-6 (for wide flanges).
Note that this table has values for both LRFD and ASD and simply provides the maximum uniform load that a particular beam can support for various spans...all assuming that Lb = 0.
If the unbraced length is greater than 0, then the maximum load the beam can take is LESS that that given. So if a fabricator designs the connection for a beam at Lb=0, they are always going to have a connection that is at least as strong, if not stronger, than the beam.
RE: Shear Connection Design
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RE: Shear Connection Design
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Unfortunately, change will not be easy. "We've always done it that way..." Contractors say that and we get upset, but we're guilty of it, too.
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Here's another thought. I know of one fabricator that likes to use single angle connections. It's a lot easier to get these to work with reasonable reactions.
And another: Fabricators rightfully gripe about EORs who specify reactions using part of the max unif load because they sometimes end up with insane requirements. For example, say you have a W10x12, 5' long around a mech. opening. Good luck getting a reasonable connection to work for half the uniform load--75 kips. (Remember that at least the top flange will get coped in most cases like this.) I've used about a zillion beams like that, all with Ru = almost nothing written on them.
Sorry, but it's just plain old lazy to use this old method and needs to die.
RE: Shear Connection Design
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With spreadsheets, etc. that you can develop, it's really easy to verify standard AISC shear connections. We use single plate shear connections mostly - sometimes double angle.
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27128's point about short beams at mechanical openings is the most obvious example of this requirement leading to ridiculous connection design. We ran into an EOR that absolutely refused to back off of it, and we had to haunch both ends of a W8x10 that was 3' long. That does cost more than a bolt or two. Unfortunately for the fabricator, it was his cost, not the owner's. Who's going to figure super-reinforced connections for beams at mechanical openings at bid time?
"Lazy" is the nicest word I can use to describe this.
RE: Shear Connection Design
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RE: Shear Connection Design
I have also seen drawings that have shown the reaction on the plan, and one number was covered up by a beam so it looked like something else (example; R=111kips was shown but looked like R=11kips because of cluttering). Obviously dangerous.