Upheaval Buckling

Pipelines in service are often subject to high compressive axial forces. These forces are due to temperature and pressure induced axial expansion, which is resisted by the friction force generated between the pipe and the seabed. For upheaval buckling to occur, the pipeline must first have an initial imperfection. Imperfections are typically due to the pipeline being laid over a boulder or due to irregularities in the seabed profile.

The object of the Upheaval Buckling (UPBK) module is to carry out a simplified upheaval buckling analysis based on idealised pipeline imperfections. The UPBK module is suited to the conceptual design stage in order to determine whether upheaval buckling problems exist for a given pipeline.

The UPBK module is used to:

Determine whether the pipeline is susceptible to upheaval buckling;

Evaluate the required height of backfill to prevent upheaval buckling.

Pipeline buckling is very sensitive to the size and shape of the initial imperfection. Small diameter pipelines are particularly susceptible to upheaval buckling problems for the following reasons:

The Pipeline is trenched for protection, therefore preventing lateral movement;

Submerged weights are low since concrete is often necessary for stability;

The contents temperatures are high and Pipeline flexibility is high.

The UPBK module enables the engineer to quickly and easily carry out upheaval buckling calculation. This in turn allows flexibility in conceptual design and assessment of the pipeline for a range of operational and environmental conditions.

Reference

http://www.penspen.com/Services/Software/Modules/Pages/UPBK.aspx