Upheaval Buckling Analysis of a Flexible Pipeline

Our client, who was installing a flexible pipeline as a step-out from an existing manifold, was looking for expert finite element analysis to predict potential upheaval buckling and to look for solutions.

The pipeline needed to be trenched to provide protection from interaction with fishing gear. Our client held concerns about potential upheaval buckling so the purpose of our report was to determine the rock dump heights required to prevent this and to identify alternative methods of mitigation.

This included:

• Developing a finite element model of the flexible pipeline to predict the upheaval behaviour
• Performing a range of analyses to understand the sensitivity to a range of heights and profiles as the imperfections on the seabed are unknown

Our recommendations detailed the amount of rock to order to avoid upheaval, and included the option of pre-tensioning the line before trenching to reduce the amount of rock to dump.