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RE: Welding Failures[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: seaint(--nospam--at)seaint.org
- Subject: RE: Welding Failures
- From: "Harold Sprague" <spraguehope(--nospam--at)hotmail.com>
- Date: Wed, 12 Apr 2006 19:08:06 +0000
OK. Going further back into my history when I was a welder, we would take a piece of welding rod and weld it to a fitted stiffener. We would slide the stiffener into the end of the HSS (modern lingo) and hold it in place while we welded it inside of the HSS. We would use 2 welding stick electrodes (welded end to end to make a 2' electrode) and we could weld inside the HSS about 8 or 10 inches from the end fairly easily. Obviously they were one sided fillet welds, or partial pen welds if we bevel ground the stiffener edges. Old ironworkers taught me that trick.
WARNING, DIGRESSION ALERT ---> Back when I welded in the shop, we still had rivet heaters that we would use to keep the welding electrodes hot and dry. We would also use the rivet heaters to warm food in the winter. I am not old enough to have used real structural rivets.
There are ways to weld internal stiffeners in HSS. Welding 2 channels toe to toe gave rise to an impractical butt weld. It was not an impossible weld, but very impractical.
Regards, Harold Sprague
From: "Gary Hodgson & Associates" <ghodgson(--nospam--at)bellnet.ca> Reply-To: <seaint(--nospam--at)seaint.org> To: <seaint(--nospam--at)seaint.org> Subject: RE: Welding Failures Date: Wed, 12 Apr 2006 08:26:05 -0400 Harold, I read somewhere once that if there had been internal stiffeners in the built-up tube that the welds might not have mattered so much and the tubes probably would not have failed. That's my recollection, but it makes some sense. I always get comments that you can't weld stiffeners inside HSS but you can if you use a little ingenuity. In the Hyatt case, it would have been relatively simple. Gary On 9 Apr 2006 at 6:25, Harold Sprague wrote: > Let me first offer an example of one welding issue:> The Hyatt Regency Walkway collapse resulted from a bad detail. One of the > issues seldom mentioned was that the channels were welded toe to toe with an > inappropriate welding symbol. The intent was for a CJP weld. The symbol> shown on the contract drawings and on the shop drawings was a butt weld.> The butt weld on the contract drawings was not the correct symbol for a CJP > weld. It was incorrect because of the limitations on thickness for the butt> weld. The weld was further inappropriate because of the contour of the > surfaces that were opposite of the arrow. The weld provided was just> whatever fusion that could be provided using a one sided weld with no bevel > on the access side of the weld. At best there was about 1/4" of effective> weld along the seam that joined the 2 channels. >> Under load, the stresses in the connection caused the web of the constructed > tube to buckle and caused bending and tension in the meager 1/4" weld. The> weld fractured and the entire walkway collapsed. > > From my soap box:> The proper way for any CJP weld to happen is that the proper CJP weld should> be shown on the contract drawings. The shop drawings should then be> prepared indicating the "detail" weld symbol, or the "detail" weld procedure> should have been prepared for the shop. I prefer any CJP weld to be> properly detailed and submitted to the ENR on the shop drawings. Otherwise,> I reject the shop drawings. > > Personally, I expect the detailed weld symbol to show the procedure, the> bevel, the preparation, the heat, the filler metal, etc. And I check them.> Maybe I am a bit particular, but I have worked in about every area of > structural steel and I am more than a bit cautious. > > The problem is that not many engineers understand how to read a properly> submitted detailed CJP welding procedure. Then the appropriate inspections > have to occur. I am qualified to do visual inspections, but not for CJP. I> do, however, know how to verify the qualifications of the NDT welding > inspector. Put it all together and you have a good weld. >> Few engineers know how to properly specify or verify CJP welds. For that > matter, few engineers are taught how to properly interpret the confirmation> cylinders of concrete mix design submittals. > > Formal training on how to properly interpret and review shop drawing> submittals should be mandatory, but I am not aware of any training in this> area. > > Regards, > Harold Sprague > > > > > > >From: "jascopac" <jascopac(--nospam--at)pacbell.net> > >Reply-To: <seaint(--nospam--at)seaint.org> > >To: "Seaint@Seaint. Org" <seaint(--nospam--at)seaint.org> > >Subject: Welding Failures > >Date: Fri, 7 Apr 2006 10:25:46 -0700 > >> >I am having a heated argument with a welder on welding symbols. It is a > >long story but basically my advise is if there is any doubt don't just weld> >it check with the engineer. > >> >To prove my point I would like to find reference to major failure caused by> >poor welding practice or misunderstanding the welding symbols. > > > >Can anyone refer me to articles or references on this subject? > > > >Thanks > > > > > >James A. Sadler, SE > >Jasco Pacific, Inc. > >550-D Industrial Way > >Fallbrook, CA 92028 > >1-760-723-8135 > >1-760-723-8136 Fax > >jascopac(--nospam--at)pacbell.net > > > >
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