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Re: Welding Failures

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Harold, 
 
Do you think that a good CJP weld would have helped in this case? 
 
 
Have a good Sunday.
 
Steve Gordin SE
Irvine CA
----- Original Message -----
Sent: Saturday, April 08, 2006 11:25 PM
Subject: RE: Welding Failures

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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