Introduction
The cyclic assessment of a pipeline considers the possibility of both pipeline walking (ratchetting) and fatigue damage due to cyclical start-up and shut-downs of the system.
The phenomenon occurs due to the dynamic thermal gradient in the system during the operationall cycles. As the system cools during a shutdown, if the fluid is single phase, then a uniform cooling rate will occur. However, during start-up, the pipeline will heat up at one end first. It is this difference in transition that can cause pipeline walking in pipelines that are not fully restrained (shorter pipelines). This is usually considered using finite element analysis.
Fatigue damage occurs in the pipeline due to the cyclical stresses (stress range). A simple Miner's sum is used in conjunction with the appropriate code to determine the allowable number of cycles.
Notable Projects
Project Name |
Project Number |
Notes |
BAOBAB |
Notable due to the Pipe in Pipe nature |
|
Greater Plutonio |
Deep Water, using SAFEBUCK | |
Qatar Gas |
KW |
Large Diameter Pipe |
Other Projects
Project Name
|
Project Number | Notes |
EPC2B |
KW 0728 |
Controlled Buckles on Existing Pipeline Crossings |
Algeria Pipeline |
KW 1071 |
Onshore |
Deep Panuke |
Codes & Standards
Company |
Title |
Doc Number / Date |
SAFEBUCK JIP |
Safe Design of Pipelines with Lateral Buckling - Design Guideline |
|
DNV |
Global Buckling of Submarine Pipelines |
DNV-RP-F110 |
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 |
Mikael Braestrup |
Design and Installation of Marine Pipelines |
6.5 |
Papers
Author |
Title |
Notes |
Hobbes, R. E. |
In-service Buckling of Heated Pipelines, Journal of transportation Engineering, ASCE, Vol. 110, No.2, March 1984, pp. 175-189 |
Approximate method for determining propensity for lateral buckling |
Taylor, N. and Gan, A. B |
Submarine pipeline Buckling – Imperfection Studies, Jour. Of Thin-walled Structures, Vol. 4, 1986, pp 295-323 |
A developed version of ‘Hobbs’, including the effects of initial OOS |
Prepared Calculations
Title / Software |
Description |
Owner / Athor |
Hobbs / Excel |
Predicts the onset of buckling |
KAJW / CSG |
Cyclic Assessment