Introduction

Pipeline expansion is an evaluation of the pipeline in-place analysis to determine maximum pipeline expansion at the two terminations and the maximum associated axial load in the pipeline. Both results are used in managing the expansion of the pipeline in end expansions spools design, global buckling (lateral and upheaval buckling), and pipeline walking analysis.

Notable Projects

Project Name	Project Number	Notes
West DON & DON South West	KW 1009

 

Codes & Standards

Company	Title	Doc Number / Date
DNV	Submarine Pipeline Systems (Strain Based Limit State)	DNV-OS-F101

 

Course Notes

Author	Title	Notes
C. Sicilia	Lateral Buckling Assessment and Mitigation Design
Trevor Gee IBC	Pipeline Course

 

Books

Author	Title	Chapter
Young Bai	Pipelines and risers

 

Related Subjects

Upheaval Buckling

Lateral Buckling

Walking

Basic Formula
The effective axial force that determines the global response of a pipeline is denoted S. Counting tensile force as positive:

• In the as-laid condition, when the pipe temperature and internal pressure are the same as when the pipe was laid,

• Effective axial force of a totally restrained pipe in the (if it can be idealised as thin walled):

Where:

S = Effective axial force
N = Steel force
H = Effective (residual) lay tension
Δpi = Internal pressure difference relative to as laid
ΔΤ = Temperature difference relative to as laid

If a pipeline is buried and operates at a temperature higher than the temperature during installation, it wants to expand axially due to internal pressure and temperature changes, but is restrained by the surrounding soil friction and so compressive loads are generated.

The thermal expansion analysis is not simple and FEA (finite element analysis) tools are commonly used to design mitigation of thermal expansion problems. Snaking (lateral displacement) or upheaval buckling (vertical displacement) can occur due to excessive elongation, or the pipeline may experience walking (pipeline walking).