Driven Pipe Pile Splice Weld

[PEinc]

Any thoughts, comments, words of wisdom, warnings, etc. about using a B-U4b weld to splice a driven pipe pile where R = 0, f = 0, and it is not possible to get access for back gouging or making the square weld?

 

[ishvaaag]

If I uderstand well you plan to do a head to head weld where there's no access to the exterior. If not, excuse me for my english is imperfect.

Were such the case, and truly unavoidable, but if inner access is feasible as to weld from within, I would plan inner stick lingitudinal welded elements of continuity. In short, sew the two parts. I would think more about this but, very likely, I wouldn't weld along the rim weld the sticks, but beyoud up and down. And may be I would complete rings or other inner devices coming to the sticks and as well welded to the inner face of the pipe if I'd find it convenient to the transfer of the forces or to make fabrication cozier.

Evaluation of the stresses may also be of help, for in compression bearing just nominal welds should suffice. The piles entering in tension by whatever the cause and in whatever the frequency would better be analyzed with disregard of at least part of the pipe and weld section, as if it was not present, and was not thus effective. This way you can check where by your assumptions the tensile stresses place you respect failure.

 

[CWIC]

PEinc:
I am going to make the assumption these are the ASTM A 252 piles you inquired about earlier.

First, if you are not backgouging, then you are no longer welding an AWS D1.1 prequalifed joint (B-U4b) in which backgouging is required as noted in the joint detail and in Note 4.

Option 1: Backing rings can be used if access to both sides of the joint is not possible (D1.1:2002, B-U4a). The backing ring is tack welded to one section of the pile, the abutting section slides over the backing ring. The root opening can then be set using spacers, the pile sections are tack welded and the spacers then removed for the circumferential welds.

Option 2: You can perform CJP tubular groove welds - welded from one side without backing (D1.1:2002, 4.12.2 and Figure 4.24), but you do have to qualify a WPS which I believe you were trying to negate previously. This method would require experienced welder(s) who have performed open-root CJP welds using the welding process you intend to use on your project. This is not easy on the thicknesses you mentioned in your other post. The groove angle will play an important factor in the feasibility of this weld.


IMHO: Based on the method in which you are trying to join these sections, at some point you will have to get the EOR to waive certain code requirements, or simply comply with the code.

 

[PEinc]

CWIC,

Yes, these are the same piles. I received backup from the pipe manufacturer that the A252 steel meets the requirements of A36. It appears that the EOR will accept A252 for prequalified welds now.

If aiming for a B-U4b weld with R=0 and f=0, is the back gouge really required or needed?

I understand that back rings could be used with a B-U4a weld and with proper root opening BUT, the contractor had already made several test pile splices (and drove the piles) with a 45 degree bevel, R=0, f=0, no backing ring, and no back gouging. The welds were inspected visually and with ultra-sound. The welds showed no discontinuities. The inspector seems happy but the EOR keeps having questions. The contractor's splicing problem is two-fold, already installed splices and future splices.

I am not familiar with CJP tubular groove welds. Is there enough time in the day for you to briefly explain what they are or provide a reference?

I agree with your final comment. I need to make the EOR comfortable with the previously made splices without setting up a massive testing program.

 

[CWIC]

PEinc:
1.) There are numerous materials which are similar in chemical, mechanical and physical properties of A 36. This is why the former D1.1 chairperson issued the memeo stating "...if it is not listed in Table 3.1, then it is not prequalifed..."

2.) It is not a matter of "is it needed" as opposed to backgouging is required, otherwise your weld is not in compliance with the B-U4-b prequalifed joint. The EOR rightfully has questions on how you are proceeding, I would have numerous questions myself. If I were the Engineer I would ask for the WPS used to perform these [technically] noncompliant welds. You say you are using a specific prequalified D1.1 detail, but the reality is - you are not.

3.) I referenced the code sections and figures applicable to the complete joint penetration (CJP) tubular (pile section) groove welds.

 

[PEinc]

CWIC,
Thank you for your timely responses to my questions. I do appreciate the time you have spent trying to guide me through my client's problem. However, with all due respect for your considerable experience and training, you do seem to be a bit too rigidly fixed to specifications and prequalifications. Based on your background, I understand where you are coming from. But, just because a weld is not a prequalified weld, it does not mean that the weld will not be sufficient for a particular application.

It is easy to say, "You can't do this because ......." It is harder to find the proper reasons why you CAN do something. Then you are solving the problem, not writing it off just "because."

I understand the reason and need for prequalified welds and procedures. However, sometimes we need to use a "recipe" that's just not in the "prequalified" cookbook. Just because it's not in the cookbook, it doesn't mean the recipe will not be delicious.

If I had your welding knowledge and experience, I would probably have an easier time solving my client's problem rather than telling him he can't do something because it's not prequalified for general use. Sometimes you gotta think outside the box! Thanks again.

Respectfully,
PEinc

 

[sayee1]

PEinc
CWIC is not "a bit too rigidly fixed to specs and prequals" as you put it. I have had too many discussions in the past with CWIC on code issues, and you need to understand that you either comply to the specs or get a waiver from your client. In this case if you carefully read CWICs response,"It is not a matter of "is it needed" as opposed to backgouging is required, otherwise your weld is not in compliance with the B-U4-b prequalifed joint. The EOR rightfully has questions on how you are proceeding, I would have numerous questions myself. If I were the Engineer I would ask for the WPS used to perform these [technically] noncompliant welds. You say you are using a specific prequalified D1.1 detail, but the reality is - you are not." What he is saying here is if in any way you deviate from the standard pre-qualified joint(which you are!), it doesn't mean that the WPS is not applicable for use. Only since it no longer meets the prequalified WPS requirements, you will have to qualify out a procedure unless your client agrees to using the prequalified WPS. If I were in your clients place I wouldn't agree to your proposal unless you had a damn good technical backup to demonstrate the variance from AWS D1.1 is still ok without a procedure qualification!!

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
email: sayee_prasad@yahoo.com
The black holes of nature are the most perfect macroscopic objects there are in the universe: the only elements in their construction are our concepts of space and time.

 

[CWIC]

PEinc:
I think you may be reading more into my reply than I intended.

I do not have a problem of using non-prequalifed welds, joints or processes. It is simply in black and white that materials, welds, technique or workmanship that are not prequalifed or code approved are subject to WPS and personnel qualification.

About 90% of my projects involve non-prequalifed welds. This means I have to develope a production process, QC system, a testing program and criteria. I often have to think out of the box to pull this off. BUT, the criteria which I specify for the non-prequalifed welds or materials must satisfy the the Owner and be approved by the EOR and the local Building Official. This is why my services are retained. Most of my clientele contact me for this very reason, an alternative solution must be sought.

Another point from my perspective, I earn a living verifying if welding activities are performed in accordance with various codes, standards and specifications. I am not trying to rub it in, but your weld is technically noncompliant with a the prequalfied joint you say it is being performed to. No it is not always cut and dried, but there are procedures to confirm if your welds are satisfactory for the intended service.

Sayeeprasadr noted we discuss many welding-related subjects in this forum. He apparently has many clients much like my own. While we don't always see eye to eye on some topics, I respect that he does not waive code requirements. He often performs non-standard and non-prequalifed welds also, but, he also notes his rational and testing criteria to confirm his methodology of verifying the minimum quality. In other words, he is showing his work on paper (via WPS, PQR and/or WPQR's).

In your original post, you asked for "...thoughts, comments, words or wisdom, warnings, etc..." My post was not of wisdom, simply my thoughts accompanied by a warning.
My personal feeling is the EOR for your project is being subjected to apprehension and doubt about how you are perfoming the work using a weld joint that you are telling him is prequalifed. I'll let sleeping dogs lie at this time and give others a chance to express their views and opinions.

 

[pipewelder1999]

1) If you are referring to a B-U4b of AWS D1.1 one then you cannot make that weld without backgouging. As an inspector, the weld is rejected along with all previous welds made that were not per the joint designg.

2) If you are wondering if it is possible to get a cjp weld with that is fit for service using the dimensions allowed for the subject AWS joint design in my opinion as a welder it would be VERY difficult and the fitness for service decision would be made by the engineer.

The reasons are related to the included angle of the joint in conjunction with the root opening. This type of joint would be highly restrained since its "Jammed up" and would be very difficult to get complete penetration with NORMAL welding techniques. UT of these could be tricky. If the inspector is noting reflections at the root and indicating they are related to the surface of the root, I would be suspect.

One think I have done in the past on a complete weld that was questionable is to cut an area out of the weld and examine it as you go,. This could be done with a grinder or arc gouger and opbserved by the engineer. In my opinion the weld should be closely examined. Have you reviewed the UT procedure used and verified that all of the requirements of AWS D1.1 were met?

Some spot radiography may help your case if ou feel the welds are good. Another thing to consider is whether the "Tested Weld" was treated the same as the previous weld. As an inspector I would question these if any "special precations" had been taken on this tested weld.

I have made UT test plates for people before using the as fitup conditions you describe above. These joints consitantly provide incomplete penetration without too much effort. Dont get me wrong, a person skilled with a 6010 or 6011 could put a root in that was fine.

Well, there is my opinion.

Have a nice day


Gerald Austin
Iuka, Mississippi

http://www.weldinginspectionsvcs.com

 

[PEinc]

CWIC & pipewelder1999,

Two good posts. Thank you.

 

[JTMcC]

PEinc,
You are correct the contractor has two problems, driven piles, and piles to be driven in the future.
The future problem is easily fixed, use a chill ring (backing bar) and ensure that all parties will accept the procedure prior to dropping the hammer.
The driven pile problem is more difficult, if you can't come to a mutual agreement with everyone involved, you may end up pulling those piles, or driving additional piles as replacements.
In my experience on welded steel piles, I believe the EOR is correct to have questions.

regards,
JTMcC.

 

[Buzzer1]

PEInc:
Is there anyway to get the exact loading on the pile? If so then you may be able to prove to the EOR that a CJP weld is not necessarily needed at this particular location. What you have may be closer to a BTC-P4. Based on past experience, sometimes a CJP is specified when a partial penetration would be sufficient. We did a job several years ago, where the columns were W14x730 sections and the engineer called for CJP welds at the flange splices. We asked for the loading at these columns and proved that partial penetration welds were sufficient, saving the contractor a ton of money and at the same time kept the EOR happy.

 

[JTMcC]

But did they take a pile hammer and drive those those columns into the earth?

JTMcC.

 

[PEinc]

I'm certain that no one will tell me the exact loads on the piles. It's a very large building with many pile caps. I'm sure there are many different "exact" pile loads.

A few of the test piles have been driven. There was no damage to the splices with driving at or slightly below 90% of yield.

The engineer let those initial splices remain as installed. So far, two piles have also been successfully load tested both vertically and laterally. It was decided that the contractor must use a splice ring with a B-U4a weld for the remaining splices.

Case closed (for now). Thanks for the comments and ideas.

 

[CWIC]

PEinc:
Many users of the forum ping for information or advice, but most of the time those trying to provide valid suggestions never know the outcome of the query. At least this post has closure.

Good luck on your project.