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RE: Welding Failures

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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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