Hints on stress analysis of buried subsea pipeline

[KernOily]

Guys do you have any hints on stress modeling of a buried subsea pipeline. The line goes from a floating marine unloading terminal to an onshore facility, buried the entire way, about 20 miles. Analysis will include wave action/dynamic effects on the downcomer. Inlet T=4° C, commodity is pipeline gas (methane, vapor phase). We will use Pipephase to generate a thermal profile since there will be a nonuniform temperature distribution along the length of the line. I've not done one of these before, and I'm pretty sure I can handle it, but I'd appreciate it if you guys know of any "gotchas" that I need to watch out for on an analysis of this type. For example, how do I adequately account for the buoyancy effect? I think I know, but...

Thanks ! ! ! ! ! ! Thanks!
Pete

 

[MJCronin]

74,

20 miles of burried piping!!???.......The engineering cost of this line is insignificant compared to installation.

I would suggest subcontracting this task to a firm that does dynamic analysis of offshore structures.

This sounds like such a unique anlysis, it would be best left to a PhD in ocean structures.....

MJC

 

[KernOily]

Mike thanks for your comments. I've done a bit of searching and there are specialists who regularly do this kind of thing, e.g. J P Kenny. I'm thinking about subbing it out to them. Haven't decided yet. I'm pretty sure I can do it but I have to satisfy myself first that I'm not practicing outside my area of competency, and I've not done that quite yet.

Actually construction cost-wise, it's not as bad as you might think. There are special techniques and contractors that do this sort of thing all the time so they have it down pat.
Pete Thanks!
Pete