moment welds.
moment welds.
(OP)
Doing a three story red iron bldg, they are hanging this week. Its loaded with moment welds, every connection. The weld is a B-u4a which is basically a groove butt weld unlimited thickness with a 45 degree and a 1/4 inch root, with backing. My question is, since the whole bldg is moment, how are they going to maintain the 1/4 root. I'm on the betting side that they are not going do it. Start complaining like contractor do and say its not possible. I'm asking because I can already see the fighting begin.If one column is out of measurement, then the 1/4 be out. please advise
master ICC inspector, AWS CWI





RE: moment welds.
A good detailer/fabricator will have paid some attention to any tolerance buildup, plus or minus, in a string of beams and columns. He knows their shop practice and tendencies from experience. And, the erector should a thinking a column or two/three ahead as he erects that grid line of beams and columns. Obviously, the columns should be properly located and plumbed and the beams be fit btwn. them, with minor adjustments as they move down the line. The welding detail would seem to allow enough throat/root variation for this fit-up and for a good welder to do a good weld. A slightly larger root will only cost them some time and weld filler, it shouldn’t make for an inferior weld. You could always spec. 3.5" wide backer bars to give them a little extra leeway.
RE: moment welds.
Let us know what happens.
RE: moment welds.
RE: moment welds.
SHouldn't happen, but you have to look at your field supervision, field weld inspector, and field engineer to make the joints properly. .
RE: moment welds.
AWS D1.1 includes as fit up tolerances that should be adequate to accommodate the contraction, i.e., the erector can open the root slightly in anticipation of the contraction.
The bottom line, the detail assumes a 1/4 inch root opening while detailing the connection. The erector opens the root to about 5/16 inch with the assumption he will loose that extra 1/16 inch once the weld is completed and cools to ambient temperature. The 1/16 contraction is an assumption that works for joints that are up to about 3/4 inch thick. More allowance should be considered for joints that are thicker.
The allowance can be adjusted once a few joints are welded. If the erector knows what he's doing, he will monitor the first few joints to make the necessary corrections in his root fit up allowance.
Best regards - Al
RE: moment welds.
master ICC inspector, AWS CWI
RE: moment welds.
Stupid is as stupid does. Some people learn from their mistakes, others never do.
Best regards - Al
RE: moment welds.
RE: moment welds.
There are provisions in D1.1 for root openings in excess of the dimensions shown in figures 3.3 and 3.4. The issue is the erector would actually have to have a copy of D1.1 and read it to find out how to address the situation correctly.
The other side of the coin is when the root openings are too tight. The erector can open the root up, but a little care and expertise is required so as not to gouge the heck out of the column flange.
The third party inspector should not get involved in telling the erector how to erect steel, how to weld the joints, or how to correct a deficiency. The TPI should simply report the nonconformance to the Engineer. The TPI is not the erector's consultant. The TPI represents the Owner. Ultimately, directing the erector only gets the TPI into very hot water.
Best regards - Al