Cutting and Rewelding of Flange plate of I beam

• Feb 23, 2022

• #1

Nidgeo

Structural

Jan 26, 2021

5

OM

Hello,
As per the image below, it is difficult to perform complete welding of the pipe with beam's web plate, hence the client is recommended to cut some portion of the top and bottom flange and complete the welding of the pipe with the web plate of the I beam, then re-weld the portion again (CJP) on the top side and bottom side of the flange.

So the concern is we do not want to do as per the recommendation, we have carried out the welding as per the below image. so I need to justify why client recommendation is not technically possible.

Please advise.

Thank You.

 

• Feb 23, 2022

• #2

LittleInch

Petroleum

Mar 27, 2013

21,253

GB

A drawing or sketch would help, but is the web still complete - i.e. is the pipe butted up to the web or does it go through it?

Where is the bending or forces?

Doing your welding won't be good if there is a bending moment on the joint.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

• Feb 23, 2022

• #3

Enable

Structural

Jan 15, 2021

755

CA

I agree with LittleInch in that we really need to know more about the loading characteristics. What is this used for exactly?

One thing for the complete pen weld is that you would need a backing bar near the web face since you wont be able to access the area to back-gouge (in order to be a pre-qualified weld anyways). And I don't really see how you could do that since you'd be right up against the weld you just made around the pipe.

 

• Feb 23, 2022

• #4

KootK

Structural

Oct 16, 2001

18,043

CA

In general, I do think that what your client proposed would have been technically possible so long as:

1) The beam is load relieved prior to welding which would have been necessary for your approach anyhow and;

2) There would have been physical space for the weld between the top of the pipe and the underside of the the flange. Or a slot in the flange to permit that somehow.

 

• Feb 23, 2022

• #5

KootK

Structural

Oct 16, 2001

18,043

CA

Is that existing weld between the pipe and beam flange actually weld standard compliant? Those are some tough welding angles and positions I would think. To your credit, they look great visually.

 

• Feb 24, 2022

• #6

r6155

Mechanical

Jan 12, 2010

2,696

AR

The repair should have been done after an agreement with the Client.

Regards

 

• Feb 24, 2022

• #7

r6155

Mechanical

Jan 12, 2010

2,696

AR

Is this pipe under internal pressure? If so, this is not a good solution.

Regards

 

• Feb 24, 2022

• #8

kingnero

Mechanical

Aug 15, 2009

1,748

BE

I think the solution you have executed is a valid alternative, and I agree with Koot, it sure is visually pleasing.
However, we don't know the loads.

r6155 said:

Is this pipe under internal pressure? If so, this is not a good solution.

Click to expand...

Is it because there is (4 times) a weld longitudinally, so potentially enforcing hoop stress fracture? If not, could you elaborate?

 

• Feb 24, 2022

• #9

r6155

Mechanical

Jan 12, 2010

2,696

AR

@ kingnero
My point is inspection.
1) How is the inspection of the original weld, now hidden with the pad, during service?
2) I cannot see the threaded hole in the pad to perform a pneumatic test, or to check for any leaks under the pad during service.
3) I don't know if PWHT (thickness of welds?) is required.

We don't have more information from (OP)

Regards

 

• Feb 25, 2022

• #10

kingnero

Mechanical

Aug 15, 2009

1,748

BE

It strikes me as odd if that pipe were used for medium transport, because it is welded (fully moment-fixed) to a structural beam. I'd guess it is a structural hollow section. If indeed it is a pipeline, I'd fully agree with you!
We need more info, OP!