Pipeline Load Reduction Due to Trenching

[atedionyahoo]

Ref.: DNV-RP-F109 (Oct 2007), sec 3.4.5 (EQs 3.21 & 3.22)

My case: modeling of subsea pipeline in a trench

Question: I understand in case distance of pipeline from either trench sides/walls is more than 3D (D is pipe outside diameter) the load reduction due to trenching is not considered. Is it correct?

 

[robb4]

Yes, it's correct.
In this case you've three different options:
- don't consider the trench (very conservative approach)
- use another standard like Danish Submarine Pipelines Guidelines (very old standard)
- use a software to simulate hydrodinamic flow inside tranch (like AGA).