C2 Analysis of steel pipe laid on ground

[CC88]

Can anyone offer suggestions of how to model the supporting of a pipe that is laid on the ground? Even though we are solely interested in the expansion case, I need to properly input the weight and the ground support/friction to get realistic results for the expansion displacements. I have tried vertical supports every 15m, but with a total length of ~1km, the number of vertical supports cause C2 not to find a solution.

 

[richay]

I presume you've modeled this as a long series of +Y supports with friction? Try adjusting the friction-stiffness in the configuration to improve convergence.

Richard Ay
Intergraph CAS

 

[DSB123]

How do you "actually" know the load distribution ? Answer - you don't. Any analysis you perform is guesswork for such a system as yours. You cannot predict how the pipeline will "snake" over the years unless you actually place enough physical guides to "control" the pipeline.

 

[CC88]

Richard: Yes, that is what I have done as there seems to be no way to model a continual support along the length. OK, thanks, I will try the friction stiffness.

 

[CC88]

DSB: Yes, as I haven't analyzed this type of system, I was concerned about how realistic my modelling is. As this is steel, I don't think there would be 'snaking' typical of HDPE movement. But, our line is not guided other than the end anchors. Is this typical for steel pipe laid on the ground? Note we have 3 pipes side by side and are concerned about the clearances between the pipes when one is operational and the others remain cold.

 

[DSB123]

ccraigen,
You say "Pipeline" which to me suggest the system/line is long. Long lines, even steel, do "snake" I can assure you. I worked in a petrochemical site which was built in the early 1960's and most of the "ambient" lines were routed without guides and there were many instances of the lines snaking. It was the main reason why these lines actually functioned as long straight sections subjected to ambient temperature changes and solar gain (when empty) meant that the only flexibility they had was to "snake".

 

[CC88]

Thanks for the feedback. Our line is almost 1 km, with bends (<45 deg) approx. every 200m.