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Up Topic Welding Industry / Inspection & Qualification / New take on an old subject.
- - By waynekoe (**) Date 03-15-2006 18:44
Back in June , there was some debate on the subject of whether or not a T joint fillet was considered as prequalified. I've done some exploration into this subject, and this is what I've found.

1. Prequalified Skewed T fillet, welded both sides, to max. obtuse angle of 135*, min. acute angle of 60* [fig.3.11 (a)] no joint prep and two root gaps.

2. Prequalified Skewed T joints [fig. 3.11 (b)],same angles and welded both sides, but with joint prep and one consistent root gap.

3. Prequalified Skewed T joint, welded on the obtuse side only with the obtuse angle greater than 100* (this is the key)

4. Prequalified Skewed T joint, welded on the acute side only, with acute angle bewteen 60* and 30* inclusive.

All this comes down to whats not covered in the above four items. That will be the the 20* between 80* and 100* (acute/obtuse), which , according to the definitions in annex K, would be a T joint and not (my opinion) considered as prequalified.I'm guessing that this is due to the available effective weld area, or, lack there of. Does this make any sense to anyone else?

Parent - - By Quality0537 (*) Date 03-16-2006 08:38
I wasn't in the original discussion , (but would like to read it), just off the cuff I would say YES a Standard T- joint is a prequalified joint. What you describe are all skewed joints, and only apply to skewed joint s in and of themselves and the exclusion of a "standard 90 deg" t-joint from that section wouldn't surprise me.

However t-joints are shown for many of the prequalified joints, and the note #10 for figure 3.3 and 3.4 reads - the orientation of the two members in the joints may vary from 135 to 180 for butt joints, or 45 to 135 for corner joints, or 45 to 90 for t-joints.

I think I just figured part of the original argument ---- did it have anything to do with all the shown " prequalified designated t-joints" showing a groove weld and not an true T-joint and fillet weld as we would expect??

that is an interesting point - that I would like to know more about - when / where did the original discussion take place - how can I find those posts???
Parent - By jwright650 (*****) Date 03-16-2006 12:23
http://www.aws.org/cgi-bin/mwf/topic_show.pl?id=7252#33657

Here's a link to the old discussion I believe he was talking about.
John Wright
Parent - - By waynekoe (**) Date 03-16-2006 16:53
Bill, Granted, joints in 3.3 & 3.4 do indicate some T joint configurations, but, they are intended for full and partial pen welds and don't include fillets unless they're referencing reinforcing fillets. Section 3.9.1 points the way to the discription of "limitations of prequalified fillet welds" and not "prequalified fillet welds in lap joints". 3.11 is indeed for skewed T joints, and covers every angle between 30* acute and 100*obtuse as prequalified. So what's left? Skewed angles less that 30* until you hit the parallel plane have to be qualified by test, as do the welders, and, T joints between 100* and 80*. I can find more information to say they're not prequalified then I can to say they are. I'm not overly thrilled about this myself. I myself have enough paper out there stating they're prequalified to stretch from Anchorage to Russia. But, the facts are the facts. If you can point me in another direction, I would appreciate it.
Wayne
Parent - - By swnorris (****) Date 03-16-2006 17:17
Skewed T joints with angles less than 30 degrees are not prequalified. It is extremely difficult to recover the Z loss dimension and maintain the effective throat when angles less than 30 degrees are required in a T joint.

Whenever we have skewed T joints less than 30 degrees, we change them to a fillet welded or shop bolted open bent plate connection with the EOR's approval. Then, there's nothing to get qualified.

As for 3.3 and 3.4, when you take a standard shear bar in a T joint (90 degrees w/fillet weld) and skew it, the base turns into a PJP groove weld, and is subject to the restrictions of note j (note 10 in 2004 code) as it applies to 3.3 and 3.4. The Z loss dimension still needs to be considered, as well as the other requirements indicated in 2.2.5.1 PJP Groove Welds, 2.2.5.2, and Fillet Welds and Welds in Skewed T Joints, items (1) and (2). Z loss is the dimension from the root of the joint to the area where full fusion can be assumed to have started. See Tables 2.2 and 2.8. The table shows that at 45 degrees, the loss factor could be 0 or it could be 1/8, depending on the process and the position. So, with that being said, in my mind, the prequalified welds in 3.3 (why worry about 3.4 because complete penetration welds are usually not needed for shear bars) can be used if the Z loss factor is zero. If the angle becomes tighter, the loss factor could be as much as 1/4" or 3/8", so this starts to become a significant measurement to deduct from the effective throat of welds.
Parent - - By waynekoe (**) Date 03-16-2006 19:58
As I see it, the use of fig. 3.3 as justification to prequalify T joint fillet welds takes you into dangerous territory, bringing issue with the use of partial pen welds. To name a few, use of a partial pen in lieu of a fillet would take you out of conformance with project specs, plus the fact that only welders certified for groove welds would be able to weld them.
A shear lug T joint, if skewed 10* which is excessive, no longer a T joint, and a crappy fit up, could have two different sized welds depending on which side it was welded, taking more time to weld and creating more stresses then necessary.
I think more attention has to be paid to the angle side of the joint is welded on. A T joint, even with a small skew, should be welded with only the thinnest of root opening, i.e. 0"-1/16" or the weld size has to be increased. I'm not trying to sound condesending here, we all know the code requirements, its just the more I discuss this subject, the more convinced I am that T joints are not prequalified. Somebody help me here, I think I'm becoming obsessed with this.
Parent - - By swnorris (****) Date 03-16-2006 21:12
Wayne,

With all due respect, how will the use of PJP in lieu of fillets take us out of conformance with project specs when the project specs state that we are responsible for the design of the connections? The fact of the matter is, when the skew stays within a certain range, the welds remain fillet welds. When it doesn't, say, for the 45 degree skewed shear bars, which are very common, a groove is created, and must then be filled using either a CJP or a PJP joint detail. We simply use the BTC-P4-GF, which is for a PJP weld. To stretch the use of this joint designation a little further, as we often do on this and other prequalified joints by using the notes, Note 10 (2004 D1.1, but changed to Note j in 2006 D1.1) can be used along with this joint designation, and this note states that the orientation of the two members in the joint may vary from 45 degrees to 90 degrees for T joints.

The groove welds would not be a problem either because our (and probably most) structural welders are qualified to weld them.

To answer your question in your initial post "All this comes down to whats not covered in the above four items. That will be the the 20* between 80* and 100* (acute/obtuse), which , according to the definitions in annex K, would be a T joint and not (my opinion) considered as prequalified.I'm guessing that this is due to the available effective weld area, or, lack there of. Does this make any sense to anyone else?:

The 20 degrees between the 80 and 100 degrees that's not covered is covered in 2.2.5.2, Fillet Welds and Welds in Skewed T joints. Item (1) indicates that surfaces meeting at an angle between 80 and 100 degrees are in fact fillet welds, and the shop drawings must show the fillet weld sizes. 5.22.1 indicates that if separation in the joint exceeds 1/16", the leg of the fillet weld is to be increased by the amount of the root opening, but the root opening cannot exceed 3/16". I don't think a 10 degree swing either way would open up beyond 1/16" in the 80 to 100 degree range. But; whether or not it was poor fitup that caused a 10 degree variance, its still a prequalified fillet as long as it is between 80 and 100 degrees. Using Note 10 in conjunction with the BTC-P4-GF joint designation, a skewed T joint will still be prequalified if the shear bar is set between 45 and 90 degrees.

This is a very interesting discussion! John, Bill, Wayne, what do you think?
Parent - - By waynekoe (**) Date 03-16-2006 22:20
Scott, I'm not sure just what your shop situation is, but it sounds like for the most part your detailing the connections. That fine. Not every shop out there has the privilage of control over details. Not every shop has all their welders qualified for groove welds, and not every ironworker has 3/4G certs. As Special Inspector, I am required by the IBC-03, section 1704.3.2, to verify compliance with the approved contract documents, the "proper application of joint details at each location". If I walk into your shop and your using partial pen welds where fillets are called out, without EOR approval you're in non compliance, period.
But, that's beside the point. D1.1 Section 2.2.5.2 has nothing to do with the qualification or prequalification of welds, and note j is in reference to T joint GROOVE welds, not fillets. It's the apples and oranges thing.
I just don't see where what your telling me defines prequalified T joint fillets. I feel that 4.11.2 actually makes it clear (now). That word "SHALL" there in the first sentence. Wayne

your right about the interesting part-
Parent - - By vonash (**) Date 03-17-2006 04:04
This is boring!
Parent - By ssbn727 (*****) Date 03-17-2006 07:03
WELL EXCUSE US THEN for being interesting!!!
GO WATCH THE STEELERS DVD IF YOU WANT EXCITEMENT!!!

Respectfully,
SSBN727
Run Silent... Run Deep!!!
Parent - - By Ariel D C (**) Date 03-17-2006 08:42
Vonash,

To me, the topic is not boring. I support the discussion. Its interesting!!!

I also enjoy reading some of your feedback…If you will create a comic book about inspection / construction and distribute it to those guys working in offshore or middle east, I believe you will help to ease their homesickness…this is not to offend you but it’s a compliment.

Ariel D C
Parent - - By swnorris (****) Date 03-17-2006 12:23
Vonash,

On behalf of ssbn727, Ariel D C, Bill, Wayne, and John, I’m sorry that we bore you so much. If you’re that easily bored, why don’t you try jumping up and down on your bed, making sure that you jump high enough to repeatedly bang your head on the ceiling until you knock yourself unconscious? Then, when you wake up, if you’re still bored, you could start an argument between the four walls and leave the ceiling to settle it. While the ceiling is settling the argument, you could go outside in your underwear and point a hairdryer at passing cars to see if they slow down. Make sure to use the high heat setting, because the lower heat settings are ineffective. If you’re still bored after that, you could stand on the curb and smash some of those little packets of catsup. Remember to take your shoes off because you wouldn't want to mess them up. When you go back in the house, turn your tv upside down and stand on your head to watch it. These are just a few of the things I do to remedy boredom, but, my personal favorite when I’m bored is to get out my collection of 33 1/3 rpm records and play them at 78 rpm speed. It’s necessary due to my superior thought processing capabilities. I’m sure that you have the same superiority complex.
Parent - By yorkiepap (***) Date 03-18-2006 01:33
Hey Scott,
:>))))) Now, that's some of the best reading I've done in months....got any more ?......Denny
Parent - By waynekoe (**) Date 03-17-2006 22:35
If you can't find the remote, then you have to drag your dead ass off the couch and turn the channel by hand!
Parent - - By jwright650 (*****) Date 03-17-2006 13:31
I'm thinking I should qualify my fillet welded T-joint WPSs per 4.11 & 4.8.4. I haven't taken the time to read all of the posts and replies in this thread(yet). I think the code is pretty clear that the clips welded on for standard framing or welded in the webs are prequalified (lap joints), but to weld the stiffeners in, requires a T-joint and I'm thinking you need to qualify(document and prove) that your max single size fillet and your multi-pass fillets are do-able(hense the macros in 4.84) per your WPS.
John Wright
Parent - - By swnorris (****) Date 03-17-2006 14:10
Here's a good article about skewed T joints:

http://www.jflf.org/pdfs/papers/design_file102.pdf
Parent - - By vonash (**) Date 03-17-2006 23:32
I am definitely not bored anymore; thanks guy's, for all your kind responses.
Best regards,
Me
Parent - By texredneck (**) Date 03-18-2006 07:30
Well Vonash glad you aint bored no more :D
Up Topic Welding Industry / Inspection & Qualification / New take on an old subject.

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