Vertical buckling of heated offshore pipelines

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:398012

Raoof, M ^[1]; Maschner, E ^[2]

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1. Loughborough Univ. of Technology (United Kingdom)
2. South Bank Univ., London (United Kingdom)

Trenched, small diameter pipelines subjected to high pressures and temperatures much higher than the ambient seawater sometimes suffer form thermal buckling instabilities leading to eventually breakout. Re-stabilizing and/or repair to such lines is both difficult and expensive. To understand the real behavior of trenched pipelines, and, therefore, check the validity of currently available theories, a program of testing is being carried out on 7m long, 16 mm diameter, copper/nickel pipes. This paper reports on the vertical buckling tests, carried out on unburied pipes, encountering point irregularities of varying sizes on an otherwise flat rigid bed, when subject to both gradual and rapid heating. The rapid heating involved a sudden release of preheated oil through the unheated pipe and was intended to simulate the conditions in the field when a delivery of hot oil from the well head is started after a long period of shut-down. The symmetrical nature of the growing buckle forms coupled with the observed apex plasticity, are described and compared with a recently proposed theoretical model, which has in itself been adapted for the effects of the end restraints in the present experiments.

• OSTI ID: 398012
• Report Number(s): CONF-940409--; ISBN 1-880653-10-9
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CALCULATION METHODS
MATHEMATICAL MODELS
OFFSHORE SITES
PIPELINES
SOIL-STRUCTURE INTERACTIONS
THERMAL EXPANSION