Critical Buckling Force

[SubseaEng10]

Hi all,

Does anyone know how to calculate the critical buckling force for a buried subsea pipeline for a given imperfection?

Just to be clear, I don't mean the effective axial force that is generated in the pipeline because of the Temp,Pressure. I mean the minimum force which causes to buckle a buried pipeline. (upheaval buckling). So it is independent to Temp./Press.

As far as I know it depends on the uplift soil resistance, download coefficient and wave length coefficient and I know all the equations!...but don't know how to find the critical buckling force for a given imperfection.

Many thanks in advance.

 

[Eyeoftheneedle]

DNV-RP-F110 - GLOBAL BUCKLING OF SUBMARINE PIPELINES is a good place to start to explain how it all works.

If, as you say, you have all the equations then I'm guessing you have the already looked at Hobbs R. E. (1984): “In-Service buckling of Heated Pipelines”, ASCE Journal of Transportation Engineering,vol. 110, pp 175-189 as this will give you the basis of your critical buckling force for a certain prop-type...if not, a very old scanned copy is attached.

 

[SubseaEng10]

Thanks very much for the attahcment.

By the way I could get the answer just by using MathCAD to solve the equations.

Cheers

 

[Eyeoftheneedle]

Not a problem.

Don't forget to keep in mind that whatever equations you are using are based on very specific shapes for the imperfections.