This study aims to ensure the lateral and vertical stability of submarine pipelines (elevated, surface and buried pipelines) under the functional and environmental loads and yield an optimum dimensions of artificial weights covering pipes laid on the alternative routes. Optimisation process depending on the iterative procedure requires an analysis considering each of extreme conditions on the internal and external pipe flow. The stabilization of the pipeline on sea-bottom exposed to wind-generated wave and uniform-steady current action is achieved by utilize artificial concrete weights and sliding resistance between pipe and soil. Wave parameters are calculated by the Airy's Linear Theory and modified by considering the effect of sea bed such as shoaIing, refraction and breaking. Then the computation of hydrodynamic forces are based on the two-term Morison equation and the Froude-Krylov theory. The required force coefficients are taken in accordance with the experimental outputs of the Det Norske Veritas. Additionally, the vortex shedding induced dynamical analysis and geotechnical studies are taken into consideration. These analytical processes are carried out the developed computer program, SUPLID, and examined for an example.
In recent years, the size, number, and applications of offshore pipelines have been steadily increasing. The energy crisis has caused increased exploitation of oil and gas reserves under the continental shelf, and the most economical means of transporting this oil and gas to shore from offshore platforms is through submerged pipelines which are also used widely in the fields of municipal and industrial wastewater outfalls, cooling water intakes and outlets, and submarine power and communication cables. The importance of offshore pipelines will be continue to increase in the near future. It is anticipated that more than one-third of petroleum supply will be from offshore oil and gas fields at the end of this decade. (Lundgren,1982)
