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RE: RE: Fillet Weld Reinforcement of Flare Bevel Groove Welds (Specifically HSS Connections)

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Bill,

The size limitation of T1/4, need not exceed 3/8" is primarily for fatigue
applications. It is optional for static applications. We revised the
provision in Section 2 on Design for D1.1:2002, for static applications, but
Section 3 does not reflect this change. The new provision in in  2.6.5
"Corner and T-Joint Surface Contouring" which simply states that the
contouring fillet need not exceed 5/16", and there is no minimum size.

What you have is a reinforcing fillet, and you should look at D1.1:2002
section 2.3.2.7. You must determine the "shortest distance from the joint
root to the weld face of the diagrammatic weld". Because of the
configuration of a reinforced flare-bevel groove, the fillet weld becomes
very large to become truly effective, as the root along the curved tube wall
is close to the toe of the fillet, hence close to the fillet face.

Don't worry about any maximum fillet size. The 3/8" (or 5/16") limit was put
in there to keep people from specifying huge fillets to transition T- and
corner-joints to reduce stress concentrations at the weld toes. At the sizes
noted, the stress concentrations at the fillet toes are about the same
whether you have a 5/16" fillet or a 1" fillet.

The Canadians have incorporated this into their new welding code W59-03.

See http://www.cwbgroup.com/tal/35147865076111631953.asp

Bob

Robert E. Shaw, Jr., PE
President
Steel Structures Technology Center, Inc.
24110 Meadowbrook Rd., Suite 104
Novi, MI 48375-3406
(248) 893-0132
fax (248) 893-0134
www.steelstructures.com



-----Original Message-----
From: Bill Swanson [mailto:bswanson(--nospam--at)clarkpac.com]
Sent: Thursday, December 18, 2003 8:01 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: RE: Fillet Weld Reinforcement of Flare Bevel Groove Welds
(Specifically HSS Connections)


Bob,

Thank you for your response.

For reference, my specific welding process is SMAW and the Joint
Designation is BTC-P10.

I have been directed in another forum to Note 7, pg. 72 of the AWS
D1.1.:2002:

"7. If fillet welds are used...to reinforce...groove welds in corner and
T-joints, these shall be equal to T1/4, but need not exceed 3/8 in."

I wonder if this is where the passage in the aforementioned HSS Ex. 5.4 is
referencing. As far as the HSS Example, If the above note is accurate ( I
assume it is), I can see a possible misinterpretation in that the author of
the example is using a direct .25 wall thickness addition to the effective
thickness of the flare bevel as opposed to a calculated measure of the SRSS
of the original flare bevel width and the .25T "leg" of the fillet
reinforcing.  The actual increase in weld strength is then closer to 8% ,
not 40%.

Beyond the example problem, I still have an unresolved issue with this
note, in that it specifically states a size of fillet reinforcement of
T1/4. I know what T1 is, and I understand as T1/4 exceeds 3/8", the fillet
reinforcement need not.

However, I need more build out than T1/4 to reach my effective width size
for my desired weld strength. Am I restricted to T1/4? This note does not
state T1/4 as a max or min., rather as 'shall be equal to'.

So, if I were to build up a flare bevel weld on a 1/4"(.233") wall
rectangular tube with a 1/4" fillet and use the shortest distance from the
face of build up back to the start of the flare bevel to measure my
effective width, and then use this width to calculate my weld strength-it
sounds like I would be at variance with the code. (Obviously a 1/4" build
out is greater than T1/4=.233/4.=.05825)

If I were to need more weld strength for this joint and one that is still
pre-qualified, is my only solution thickening the tube wall? Thus flare
bevel weld size and fillet reinforcement size is larger. Or can I build out
the fillet reinforcement greater than T1/4 and calculate the effective
width?...........Which personally is what I would, of course, prefer.

Thanks again for any assistance on this topic.



At 06:27 PM 12/18/2003 -0500, you wrote:
>Bill,
>
>Welcome.
>
>My best guess is that someone misunderstood section 2.14.3 of AWS
D1.1-1996,
>upon which the HSS Manual is based. I sit on D1 SC1 on Design, and that
>interpretation does not ring a bell with me, either under previous or
>current code language.
>
>There has been some effort in this regard. The Canadians have a different
>approach, and AISC has new research, that we are studying for possible
>inclusion in a future D1.1.
>
>Bob Shaw
>
>Robert E. Shaw, Jr., PE
>President
>Steel Structures Technology Center, Inc.
>24110 Meadowbrook Rd., Suite 104
>Novi, MI 48375-3406
>(248) 893-0132
>fax (248) 893-0134
>www.steelstructures.com
>
>
>-----Original Message-----
>From: Bill Swanson [mailto:bswanson(--nospam--at)clarkpac.com]
>Sent: Thursday, December 18, 2003 3:47 PM
>To: seaint(--nospam--at)seaint.org
>Subject: Fillet Weld Reinforcement of Flare Bevel Groove Welds
>(Specifically HSS Connections)
>
>
>Hello, New to Forum.
>
>In following a design example in AISC's Hollow Structural Sections
>Connection Manual, I have come across a passage that refers to criteria for
>reinforcing a flare bevel groove weld with a fillet weld. The example
>problem (Ex. 5.4, page 5-22) addresses the weld of a WT section to an HSS
>Column. The passage,..."Note that if the weld [flare bevel] is reinforced
>with a fillet weld, the effective throat could be increased by 0.25 times
>the wall thickness per AWSD1.1 which would increase the weld strength by 40
>percent"....seems to imply a limit to the reinforcement of a flare bevel
>for the HSS Section more restrictive than simply building up the effective
>throat thickness to the HSS shear and/or tension rupture strength.
>
>I have combed through the AWS D1.1:2002 to the best of my ability over the
>last couple of days and have found nothing specifically regarding this
>issue with flare bevel groove welds. With deadlines approaching,
>well,...you've all been there.
>
>Can anyone cite the AWS code section that addresses this topic? Or, would
>anyone be willing to share knowledge of effective strength limits of fillet
>reinforced flare bevel welds?
>
>Any assistance in this matter would be greatly appreciated.
>
>Thanks in advance,
>William P. Swanson, P.E.
>
>
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