For rest support only can clamp act as a RF pad /saddle ?
--------------------------------------------------------------
In case say 54" line with thickness 9.27 mm , if as per thumb rule R-pad is required (welded shoe with R-Pad) , and situation is that , client ask for clamp shoe in case of welded shoe to ease construction in cold Russian environment , the question is can clamp thickness act as reinforcement pad helping the pipe. Its 2 clamp shoe support.

This question is valid only for rest supports. as for axial stopper we are going with welded support only.

In rest support the concern is , can pipe maintain its circularity against loads at support if we use clamp.

In other word , at rest support , case 1 is welded support with r-pad, case 2 is clamp support ( say clamp is of same thickness of R-pad) , will both cases have same effect on pipe circumferential stresses ?
Thank you.

You can try performing FEA using the two cases:

1) Rpad ----> Pipe/Pad welded at the edge of pad.
2) Clamp----> Pipe/Clamp in Contact but not welded.

But I'm not sure if case 2 will run in FEA since the boundary condition is not well defined and may not generate the stiffness matrix for the whole assembly. I am thinking, due to high loads there might be some portion of clamp which will not be in contact with pipe due to ovalization. This will be a non-linear scenario.

The D/T for this case is 148 and with high concentrated loads at the corner junction of shoe/pipe may cause localized buckling or ovalization. You can check this using ASME VIII Div. 2 Design By Analysis for buckling and stresses.

In lieu of FEA, maybe there are proven standards already used for this size and working successfully. I'm not sure if physical testing will be costly for this case.

The pipeline folks may have a bunch of experience regarding this matter and may give you a more practical and not so complicated approach.

Just correct me if any wrong statement is made above.

Cheers!!!

Hi there,

Just a short opinion.

Clamped shoe support analysis by FEA would be extremely complex and require performant software (ansys, abaqus etc.) to handle contact elements' based non-linear analysis. In addition, clamp bolting load should be modelled suitably.
As far as I know, I don't think at this time FE Pipe software, for instance, may be used to achieve all the assessments described above...or, maybe, it can be, but definitely not based on typical templates, and rather using advanced capabilities which cannot be easily found.

So, Borzki opinion is fair enough.

Unfortunately, there are a lot of "specialists" whose FEA "knowledge" are based on nice-graphics brochures' presentations/advertisements, instead of actual modelling work experience, but claim everywhere that clamped shoe supports may (or must!) be evaluated by FEA!

Cheers!

The clamp need to be very wide. Imagine a long shoe with a single clamp but as wide as a pad. In this way the load will be distributed over a large surface. Something like criogenic support or preinsulated support.

Regards

Totally agreed with Danb point of view.

Moreover, even if guiding restraints are not present, but lateral movement is present and no friction-reduction PTFE sliding plates are provided, transversal reinforcing plates/ribs are required, to reduce bending stresses at central-longitudinal rib/plate weld/joint with the wide-clamp wall.

Such transversal reinforcing ribs/plates is often omitted by many standard pipe support drawings for NPS 2" ... 6"(8") range. Actually, in the absence of detailed demonstrating calculations, such reinforcements should miss.

In addition, if vertical forces and corresponding friction forces are deemed as significant, shear lugs are required on longitudinal direction, on the both sides of the clamp, to be welded on pipe wall surface, to avoid clamp-pipe relative slippage.

Regards,