Pipe shoe installed off axis 2

[mkkarpin]

I've got a few pipe shoes where they appear to have been welded off axis from the pipe in the spooling shop. Both shoes are about 6" and are 5 and 10mm off the vertical at the bottom of the shoe. I know I've seen plenty of shoes off the vertical, but have never been asked on the acceptability criteria and would prefer not to have my EP firm run FEA to ensure it's good. This is on an emulsion pipe in thermal operations, and the piping is not misaligned. Anyone have some practical advice? I would prefer not to replace the shoe as the system has been hydro tested already.

pdf of pictures attached.

http://files.engineering.com/getfil...ac7e-206f0bf76e0d&file=Shoe_Installation_.pdf

Thanks in advance.

 

[mk3223]

It's a bad workmanship. It looks that the pipe section was rotated slightly when butt welded together. The base plate of the shoe might not be flat totally as rested on the steel beam. Have the welder to redo the shoe if needed to comply with the piping construction tolerance of the project.

 

[saplanti]

I think the pipe moved sideway under thermal/dynamic loads but the lower section of the shoe did not follow the pipe movement due to high friction force, and plastically (I just assumed it, when you lift the pipe at the support location the deformation may disappear, if you are lucky, so the deformation is elastic) deformed.

In case the pipe moves more for some reason under thermal/dynamic loading and the web of the shoe cannot take the load anymore it will fail under bending and axial load. This type of shoes are for the displacements in line with only longitudinal direction of piping, sideway move of the pipe may cause failure. If the pipe moves longitudinal and sideway, the shoe is to be selected should include gusset against side loads. It seems either the shoe was not in accordance with the pipe stress analysis results or the analysis does not include all the load conditions. Another tough is more problematic; there is no stress analysis.

 

[mkkarpin]

Saplanti
The system has not been put in service.

 

[mkkarpin]

Mk3223
I agree it's bad workmanship. I'm looking for input on whether the stress at the pipe weld due to the moment induced by the off axis pipe shoe is excessive. The system is not in a vibration service and once it reaches operating temperature there would snot be any additional forces outside of pipe and fluid weight.

I think calculating the moment induced stress in the weld to ensure it doesn't fail is the first step and easily completed. If the calculated stress in the weld is below the pipe yield, then it should be on to leave as is.

 

[BigInch]

Bad piping fabrication or bad support installation? Doesn't look like a pipe problem to me.
What's with those supports. Why does it look like the columns are cut, offset and rewelded?
Are you in melting permafrost? Supports stuck into permafrost will melt it and the supports will sink. What kind of support and foundations?

Bad supports for one reason or another.


Technology is stealing American jobs. Stop H1-Bs for robots.

 

[KevinNZ]

I would not be so concerned. The off centre installation is not as bad using a design with a single plate taking sideways friction loads in the weak axis. If the loads and local stresses are at all high then a different shoes design is required.

 

[mkkarpin]

BigInch
Surveyors messed up and located the piles incorrectly. Pile caps had to be offset. I assume that's what you are referring to.

Ended up cutting the shoes of and rewelding with MPI testing. It would have been fine, but operations would have complained. If it looks stupid, it probably is.