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Pre Approved Welds

Pre Approved Welds

Pre Approved Welds

(OP)
I am looking to find out if there are any pre approved welds (within AWS D1.1)for welding .375 straight seam pipe? The welding will be for pile casing and has to be performed on site? Any ideas?

RE: Pre Approved Welds

I just went through this for a job where my client had to splice pipe piles.  He bought pipe pile splice rings from the pipe pile supplier and then used a B-U4a, single bevel-groove weld butt joint (complete-penetration groove weld).  The splice ring acts as the backing plate so that back gouging is not required.  See AISC, 9th Edition, Page 4-161 for details of this prequalified weld.

RE: Pre Approved Welds

(OP)
Do you rember how man passes you had to perform? I was guessing it would be 5 but I want to try and confirm without having to Pay AWS to read their spec. Thnaks for the info though!

RE: Pre Approved Welds

Are you welding steel pipe pile or "rejected oil-well casing"?  

If you are using steel pipe pile material, ASTM 252 grade 2 or 3, you can use any prequalified weld type listed in D1.1.  You will have trouble conforming to CJP welds since most require back-gouging or backer bars.  You might be able to use PJP welds like BC-P2, or BC-P8.  Both assume "Stick-welding" or SMAW

It is my understanding the rejected oil-well casing has a high carbon content which makes it difficult to weld.

Why are you welding the piles.  Can you use a splicer, similar to "associated Pile & Fitting Corp", Drive-on Pipe Pile Splicer.  Refer to: www.associatedpile.com for additional info.

 

RE: Pre Approved Welds

(OP)
I am unable to use a drive on splicer because of headroom resrictions I have a 65'-0' pipe and less than 20' of headroom and there isnt even room to swing a hammer let alone seat it properly.

RE: Pre Approved Welds

When is the splice ring installed?  I saw no mention of this in the question.  

If you are installing a splice ring, you could use a CJP weld.  However, B-U4a as do the other welds require a "gap" or root opening between the two materials.  The root opening  varies with the prep angle, but is usually about 1/4" (+1/16"/-0")for a 45(+10 degree/-0 degree) degrees or 3/8" (+1/16"/-0")for a 60 (+10/-0) degree angle.  These root opening dimensions are as detailed.  Knowing what field conditions are, you are allowed to deviate from the root opening dimensions, usually by +1/4" or -1/16".  The deviation from the detailed dimension is refered to as "Fit-up".  Assuming a 45 degree angle, the root opening may vary between 3/16" to 9/16" and the angle can vary from 40 degrees to 65 degrees.  Regardless, what the angle is , you still need to provide a root opening.  

Now the fun part......how do you "hold" the pile in place and still maintain the opening while the welder is welding the pile?  

It is an expensive process to have a welder or multiple welders on site waiting to weld installed piles.  Try using shorter pile with the splicer, it might be less expensive in the long run.

  

RE: Pre Approved Welds

Splice rings already have little 1/4 inch thick metal nubs which act as the spacers for the root opening.  They get welded into the joint.

After driving the first pile section, you level off the top of the pile and then set the splice ring over the top of the driven pile.  A crane lifts the next pile section into place and the pile is guided into the top of the splice ring.  The pile is plumbed (or aligned if a battered pile) while still being held by the crane.  Then the weld is made while the crane is still supporting the pile.

If the piles are designed for any tension from uplift or bending, you probably need a welded splice, not a compression splice ring.

Yes, pile splices are expensive, especially in low headroom situations.

RE: Pre Approved Welds

Thanks for the info...I don't believe I ever used a splice ring.  Based on how you discribed it, then you should be OK to use the B-U4a CJP weld.

RE: Pre Approved Welds

We have welded quite a few pipe piles but rarely with the crane supporting the pile while welding.
At least in my experience, the pile is tacked, or welded just enought to hold it securely in position, and the crane moves on to the next pile which is tacked, crane moves on, ect, ect.
The welders at this point have a set of pile splices ready to weld. This keeps the welders welding. By the time they are finished with one set, another set has been driven, and the splices are tacked up and ready to weld.

JTMcC.

RE: Pre Approved Welds

JTMcC is correct.  A crane holds the pile until enough weld is placed to support the weight of the added pile section.  That way, the pile driving crane can move on to drive other piles if desired.  Sometimes a service (second) crane will work with the pile splice crews.

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