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RE: Welding Failures

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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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