Palmer Upheaval Buckling Equation

[mecheng1t0]

As per the Palmer paper (link below) following is the equation for the required downward force w to avoid upheaval buckling:

w [1.16 - 4.76 (EI*Wo/cS )^(1/2)/P]P( cS*Wo/EI)^(1/2)

where
Wo is the installation submerged weight;
EI is the flexural rigidity;
cS is the imperfection height;
P is the effective axial force in operation.


The pipeline I am working on is an onshore gas pipeline with a 1 earth cover. Following are my questions:

1) It seems that the above equation was developed for offshore upheaval buckling, I am guessing that it is still applicable for onshore. Is this right ?
2) What is meant by installation submerged weight? ie should I take Wo as
a) (Weight of Pipe + Content - Buoyancy Force on Pipe) OR
b) (Weight of Pipe + Content) OR
c) (Weight of Pipe + Content -Buoyancy + Weight of Earth Cover)

http://www.engr.mun.ca/~spkenny/Cou...eading_List/1990_Palmer_Upheaval_Buckling.pdf

Thanks everyone.

 

[DSB123]

If you are onshore then Buoyancy forces do not come into the equation. For pipelines onshore you need to check not only for upheaval buckling but also at horizontal bends the pipe has a tendency to come out of the ground. Where the terrain is not exactly flat then you must check the sag-bends, overbends and horizontal bends. By the way the cover is you say 1. One what ft/metre/yard ???

 

[mecheng1t0]

Sorry missed the m, the cover is 1 m. Buoyancy will be a factor as the pipeline traverses through ROW sections that have high water table.