Subsea pipelines are commonly subjected to high compressive axial loads that may result in various types of displacements. The majority of deformations for non-buried pipelines occurs in the form of lateral buckling. Uncontrolled lateral buckling may cause serious problems for pipeline stability, pigability, and structural integrity. Subsea pipelines occasionally are installed on sloping regions, consequently a probable lateral slope throughout the pipeline route contributes to its buckling behavior. The current design practice in industry ignores the effect of lateral slopes on the buckling behavior. It is shown in this study that the impact of the sloping seabed may become significant and needs to be considered in the current design guidelines. An analytical study is performed in this paper by utilizing MATLAB software to investigate pipeline behavior on sloping seabed and the proposed methodology is validated against existing case studies in the literature. It is then used to validate FE models in ABAQUS software. Critical buckling force as well as pipeline lateral deformation are evaluated for a pipeline on sloping seabed areas. Moreover, it is investigated that the operational startups and shutdowns can considerably increase the buckle size on the sloping seabed. The result shows how hydrodynamic forces of steady-state currents may displace a HP/HT pipeline significantly. The results presented in this paper can provide a better understanding of lateral buckling characteristics in sloping seabed situations. Based upon the outcomes, sloping seabed conditions need to be considered for appropriate design to ensure that the pipeline stays safely in place and deformations are predicted as to prevent uncontrolled lateral buckles.
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