Analytical study of third-mode lateral thermal buckling
for unburied subsea pipelines with sleeper
Z.K. Wang, G.H.M. van der Heijden & Y.G. Tang
Unburied subsea pipelines operating under high-temperature and high-pressure
conditions tend to relieve their axial compressive force by forming lateral
buckles. In order to manage lateral buckling, a sleeper is often employed as
a buckle-initiation technique to ensure pipeline integrity. In this study,
analytical solutions of third-mode lateral buckling for unburied subsea
pipelines with sleeper are derived. The analytical solution is compared with
experimental data in the literature and shows good agreement. The stability
of the buckled pipeline is investigated by means of an energy analysis and
it is found that third-mode lateral buckling has lower energy than first-mode
buckling, which means that third-mode buckling is more likely to happen in
practice. The influence of sleeper height and sleeper friction on lateral
post-buckling behaviour is illustrated and analysed, with particular
attention paid to the minimum critical temperature difference, lateral
displacement amplitude and maximum stress. Our results show that increasing
the height of the sleeper or decreasing the friction between pipeline and
sleeper can both be used to decrease the minimum critical temperature
difference, but their influence on the maximum stress is opposite.
keywords: subsea pipeline, lateral buckling, sleeper, beam-column, buckle
initiation method
Engineering Structures 168, 447-461 (2018)