inspection of CJP at moment connection vs prequalified joint
inspection of CJP at moment connection vs prequalified joint
(OP)
RE: inspection of CJP at moment connection vs prequalified joint
connectegr, I need some of that CWI support for a field welding/bolting issue...question: On a CJP beam to column moment connection, the prequalified joint designation shown is TC-U4a, but have a situation where the column appears to have cut a little short resulting in the bottom of the top beam flange being actually equal to the top of column cap plate. Not exactly the prequalified joint...
What should be the proposed fix on this?
connectegr, I need some of that CWI support for a field welding/bolting issue...question: On a CJP beam to column moment connection, the prequalified joint designation shown is TC-U4a, but have a situation where the column appears to have cut a little short resulting in the bottom of the top beam flange being actually equal to the top of column cap plate. Not exactly the prequalified joint...
What should be the proposed fix on this?






RE: inspection of CJP at moment connection vs prequalified joint
There are a couple of simple "fix's", like extending the column. But those are WAY above your level of authority and authorization. You have done your job as the CWI: you found a significant erection problem that renders a Moment Connection useless. Now the Engineer [and probably the Fabricator] have to give the Erector a plan on how to fix this problem.
RE: inspection of CJP at moment connection vs prequalified joint
How many sides of the column have moment connections?
Is the cap plate fillet welded to the column? They can arc gouge the fillet and replace the cap plate with a thicker plate. Remember if full moment is required the plate should be grade 50 to match the flange.
Does the moment force require the full thickness of the beam flange? If the bottom of the flange aligns with the top of the cap plate, a fill plate could be welded to the cap plate, with fillet welds in the direction of the load. The flange could then be welding with B-U4a weld. Note that the seam between the cap plate and fill with probable not fuse and show and defect in UT testing. If less than the full thickness is required and effective weld thickness can be given. This is basically a partial penetration weld.
If a plate on top is a problem. Two plates can be welded to the cap plate under the beam flange and on both sides, with CJP welds. The plates can be fillet welded to the toes of the beam flange. Note that these fillet welded have some eccentricity.
If the intent was to weld to the cap plate the weld should have been a B-U4a. The cap plate should have extended beyond the column, which would have allowed easier access for welding. This also allows a fillet weld for the column to cap plate. The bottom flange to the column flange is a TC-U4a.
Hope this helps...
http://www.FerrellEngineering.com
RE: inspection of CJP at moment connection vs prequalified joint
connectegr: B-U4a at top flange, correct.
See attached sketch for other answers. Curiously the beam on the uphill side has correct fit up. Top of column cut at incorrect angle perhaps...
Also, what would you do if one end of a beam has the flanges beveled upside down?
RE: inspection of CJP at moment connection vs prequalified joint
I agree that RFI's can be a none productive exercise. And I second your approach of suggesting a repair. In my experience EOR's can be short on imagination. However, the easy answer to your conservative suggestion, is usually YES. They won't suggest anything less. Ultimately this does require EOR involvement whether in a direct conversation, non-conformance report, or RFI.
I know just the right firm, if you need official help. Good luck
http://www.FerrellEngineering.com
RE: inspection of CJP at moment connection vs prequalified joint
http://www.FerrellEngineering.com
RE: inspection of CJP at moment connection vs prequalified joint
I have attached a sketch of two options. I wish I could have drawn these with my iPad or iPhone. A picture is worth a thousand words. Does this satisfy your technically curiosity?
http://www.FerrellEngineering.com
RE: inspection of CJP at moment connection vs prequalified joint
It is easier [and faster] to get forgivness than to get permission
RE: inspection of CJP at moment connection vs prequalified joint
Thanks
Respectfully, "easier and faster" can be a dangerous approach. I have spent many client's money fixing what they thought was a conservative field repair. Just saying...
Both details can be developed to match the moment capacity of the beam. But, they are incomplete as shown. And there are pros-cons to each. If the moments are given, then a real solution can be developed. However, the erector rarely has enough information.
http://www.FerrellEngineering.com
RE: inspection of CJP at moment connection vs prequalified joint
RFI transmitted...
Pencil sharpened...
Severe and intense analysis of numbers...
Much cogitation...
More severe and intense analysis of numbers...
Conclusion drawn...
Papers shuffling...
RFI returned...
MC = deleted
Dang.
RE: inspection of CJP at moment connection vs prequalified joint
http://www.FerrellEngineering.com
RE: inspection of CJP at moment connection vs prequalified joint
When I get "incredible" RFI answers, I usually send the Cover My A--, RFI. Again I am not a big fan of the RFI process, but they do serve a liability purpose.
http://www.FerrellEngineering.com