Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Welding Failures

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Steve,
A proper CJP weld would have helped, but not much. At best it would have raised the failure load. There were many other problems with the design of the connection. The section desired for aesthetics was a box section with sharp 90 degree corners. The proper materials would have been a box section fabricated from plate. The only way channels could be used would be to grind a bevel on the toes to allow a CJP from the outside, tack on a backer bar, and then weld the channel sections together. By the time you do all that, you may not have a thick enough web for the compression loads.

There were many things wrong with the connection. The weld was just one of them.

Regards,
Harold Sprague





From: "S. Gordin" <mailbox(--nospam--at)sgeconsulting.com>
Reply-To: <seaint(--nospam--at)seaint.org>
To: <seaint(--nospam--at)seaint.org>
Subject: Re: Welding Failures
Date: Sun, 9 Apr 2006 10:16:49 -0700

Harold,

Do you think that a good CJP weld would have helped in this case?

Info on the case can be seen at http://www.eng.uab.edu/cee/REU_NSF99/hyatt.htm#Causes.

Have a good Sunday.

Steve Gordin SE
Irvine CA
  ----- Original Message -----
  From: Harold Sprague
  To: seaint(--nospam--at)seaint.org
  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
  >
  >
  >
  >******* ****** ******* ******** ******* ******* ******* ***
  >*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
  >*
  >*   This email was sent to you via Structural Engineers
  >*   Association of Southern California (SEAOSC) server. To
  >*   subscribe (no fee) or UnSubscribe, please go to:
  >*
  >*   http://www.seaint.org/sealist1.asp
  >*
  >*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
  >*   send to the list is public domain and may be re-posted
  >*   without your permission. Make sure you visit our web
  >*   site at: http://www.seaint.org
  >******* ****** ****** ****** ******* ****** ****** ********

  _________________________________________________________________
Express yourself instantly with MSN Messenger! Download today - it's FREE!
  http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/


  ******* ****** ******* ******** ******* ******* ******* ***
  *   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
  *
  *   This email was sent to you via Structural Engineers
  *   Association of Southern California (SEAOSC) server. To
  *   subscribe (no fee) or UnSubscribe, please go to:
  *
  *   http://www.seaint.org/sealist1.asp
  *
  *   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
  *   send to the list is public domain and may be re-posted
  *   without your permission. Make sure you visit our web
  *   site at: http://www.seaint.org
  ******* ****** ****** ****** ******* ****** ****** ********

_________________________________________________________________
Express yourself instantly with MSN Messenger! Download today - it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/


******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* * This email was sent to you via Structural Engineers * Association of Southern California (SEAOSC) server. To * subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
* Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you * send to the list is public domain and may be re-posted * without your permission. Make sure you visit our web * site at: http://www.seaint.org ******* ****** ****** ****** ******* ****** ****** ********