CJP Beam Splice In-Place
CJP Beam Splice In-Place
(OP)
I specified a CJP field weld, and the detailer has pointed out that it requires a backing tab which can't be installed because there is an existing metal deck and slab above. Does anyone have a solution for this?






RE: CJP Beam Splice In-Place
RE: CJP Beam Splice In-Place
Jayrod's approach sounds reasonable. Maybe a non-starter but they could do selective demo/core drill of the deck over the connection to get a backer bar in place.
RE: CJP Beam Splice In-Place
RE: CJP Beam Splice In-Place
RE: CJP Beam Splice In-Place
@ Celt, I would use the metal deck as backing. I just don't know if that is acceptable. The article states that this is problematic for fatigue at the tension flange, and this is a beam at the compression flange.
@ azcats, I don't if they can demo a tiny piece. They would probably have to core drill like Celt said.
@ DETstru, I can specify B-P8 (J weld with 1/8" land). Does this develop the full flange force since it is always in compression?
RE: CJP Beam Splice In-Place
Only thing to watch out for, is to avoid excessive concrete heating on top of the decking.
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RE: CJP Beam Splice In-Place
Thanks All!
RE: CJP Beam Splice In-Place
I'm not sure that a zero root approach is advisable here, simply for the fact that I'm not sure it's achievable. The root will be involved in the takeup of your length tolerance and, more importantly, angular tolerance for the new beam. It's hard to imagine that you'd manage both the zero root and proper fitup.
It sounds crude but could you bevel the edge of backup plate and just bash it under the deck as a wedge of sorts? You might compromise a deck weld locally which surely isn't a big deal.
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: CJP Beam Splice In-Place
B-P8 is prequalified with R = 0. Wouldn't a PJP weld be better for fit-up than a CJP?
And I'm open to bashing in a backing bar. How do I determine the minimum thickness?
RE: CJP Beam Splice In-Place
I speculate not as any rotational tolerance would involve a gap forming at one or more of the welded joints.
There's a table for this in AWS. Depends on your particulars as you can imagine.
I've got an alternate idea but it'll take some sketching. Get your checkbook ready.
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: CJP Beam Splice In-Place
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: CJP Beam Splice In-Place
RE: CJP Beam Splice In-Place
Thanks!