Analytical study of distributed buoyancy sections to
control lateral thermal buckling of subsea pipelines
Z.K. Wang, Y.G. Tang & G.H.M. van der Heijden
Unburied subsea pipelines operating under high temperature and high pressure
(HT/HP) conditions tend to relieve their axial compressive force by forming
lateral buckles in an uncontrolled manner. In order to control lateral
buckling, a distributed buoyancy section is often employed. In this study,
analytical solutions are deduced for lateral buckling of unburied subsea
pipelines with a distributed buoyancy section. An energy analysis is employed
to investigate the stability of the buckled pipeline. The influence of the
length and weight of the distributed buoyancy section on pipeline buckled
configurations, typical lateral buckling behaviour and the minimum critical
temperature difference is illustrated and analysed. The results are shown to
be in good agreement with experimental data in the literature. The effect of
imperfections is also discussed and an error analysis is conducted for one of
the main assumptions of the proposed analytical method. The results show that
increasing the length or decreasing the weight of the distributed buoyancy
section can both be used to decrease the minimum critical temperature
difference. The maximum compressive stress will decrease with decreasing
weight of the distributed buoyancy section. However, the influence of the
length of the distributed buoyancy section on the maximum compressive stress
is complicated.
keywords: subsea pipelines, lateral buckling, beam-column, distributed
buoyancy method, buckle initiation technique
Marine Structures 58, 199-222 (2018)