DNV-RP-F110 Global Buckling of Submarine Pipelines

DNV RP F110
Design: Limit State
Edition: 2007

"Global buckling implies that buckling of pipe as a bar in compression. It is a response to compressive effective axial force and not a failure mode."

Objective

1. To prevent global buckling for burried pipelines.
2. Allow exposed pipelines to buckle in controlled condition.

Scope

1. Design of 10" - 42" rigid pipelines.
2. ONLY limited to local bukling check.
3. Scenarios covered are exposed pipelines on even seabed and uneven seabed and burried pipelines.
4. Trawl interference only limited to lateral buckling.

Design

Effective Force wil be limited to residual lay tension, N after pipeline installation. During operation, temperature and pressure will increase contributed to maxinum compresive/restrained effective force, S0 .

Global buckling will occur if the restrained effective axial force (compression), So reach the initial effective axial force, Seff .

Introduction: Global Buckling

Global Buckling ( Pipe buckles due to compressive force in a fully restrained pipeline )

There are two types of Global Buckling:

1. Lateral Buckling: pipe buckles horizontally
2. Upheaval Buckling: pipe bucles vertically

Fig 1: Lateral Buckling

Fig 2: Upheaval Buckling

Global Buckling is a load response mode due to compressive effective axial force but NOT a failure mode. Ultimate failure mode of Global buckling includes:

Fatigue.
Fracture.
Local Buckling.

In general, effective axial force, S exists in pipelines (OMAE 2005). If pipeline is fully restrained (especially for HP/HT), this will contribute to restrained effective force, S0 (compressive). As long as effective axial force needed to trigger buckle, Seff is greater than S0 , the pipe is safe from buckle globally. The level of axial force depends on soil resistance, environmental and trawling effects, cross section and out of straightness of pipe.