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RE: Butt-welding a gap

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Michael,

I am not sure I would want to go this route but AWS does have similar requirements.  The required root openings in AWS, and also shown in AISC, are like concrete form and rebar clear distances.  You have a minimum but the code allows a plus or minus construction tolerance (note that sometimes the plus or minus might be zero).  The root opening construction tolerances are shown in AWS 2002 Figure 5.3 and in most cases ranges from 1/16 inch to 1/4 inch for groove welds.  However, (as pointed out to me in a private e-mail from Dave Evans) AWS section 5.22.4.3 "Corrections" has the following:

Root openings greater than those allowed in 5.22.4.1, but not greater than twice the thickness of the thinner part or 3/4 inch, whichever is less, may be corrected by wielding to acceptable dimensions prior to joining the parts by welding.

The commentary to this section reads:

Root openings wider than those allowed by Table 5.5 may be corrected by building up one or both sides of the groove faces by welding.  In correcting root openings, the user is cautioned to obtain the necessary approvals from the Engineer where required.  The final weld is to be made only after the joint has been corrected to conform to the specified root oping tolerance, thus keeping shrinkage to a minimum.

Thomas Hunt, S.E.
ABS Consulting




"Michael Bryson" <mbryson(--nospam--at)NYASE.com>

10/03/2003 09:23 AM

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RE: Butt-welding a gap





This was ruled out because it was felt that two welds so close together
might cause some kind of stress concentration / notch effect. Is there
some requirement in AWS or CSA for a minimum clearance between welds? I
thought it was something like 4 times the base thickness?

Could you fill in the gap by depositing a 3/4" weld one side, then 3/4"
on the other, and then finally filling the remainder in after letting it
cool?

-----Original Message-----
From: Gary Hodgson & Associates [mailto:ghodgson(--nospam--at)vaxxine.com]
Sent: Friday, October 03, 2003 3:53 AM
To: seaint(--nospam--at)seaint.org
Subject: Re: Butt-welding a gap

Michael, I don't know about the AWS specs but there is a requirement
in the Canadian welding code that says if the gap exceeds 5/8", you
have to build up the end by some means before closing the gap, i.e.
you sould add a piece of steel by full strength weld to the free end
and then do your final weld.  This minimizes shrinkage and attendant
built-up stresses.  As the two codes are similar, I am sure there is
a similar req't in the AWS spec.

Gary Hodgson


On 2 Oct 2003 at 16:27, Michael Bryson wrote:

Subject:                         Butt-welding a gap
Date sent:                       Thu, 2 Oct 2003 16:27:43 -0700
From:                            "Michael Bryson" <mbryson(--nospam--at)NYASE.com>
To:                              <seaint(--nospam--at)seaint.org>
Send reply to:                   <seaint(--nospam--at)seaint.org>
Organization:                    http://www.seaint.org

> I am reviewing a welding procedure to "fill-in" a gap for a beam
> flange moment connection. The gap is about 2" and it will filled in as
> a butt-weld. They are claiming this is a pre-qualified weld
> (BU-4a-GF), but I'm not sure that is correct.
>
> I am wondering if some time should be allowed between passes to allow
> the weld to cool? I can't find anything in the AWS for this.
>
> (Note the connection is NOT for a seismic application.)
>
>  TIA
>
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