Pipeline On Bottom Stability

Pipeline On Bottom Stability

On bottom stability analysis is performed to ensure the stability of the pipeline when exposed to wave and current forces and other internal or external loads. The requirement to the pipeline is that no lateral movements at all are accepted, or alternatively that certain limited movements that do not cause interference with adjacent objects or overstressing of the pipe are allowed.

Hydrodynamic stability is generally obtained by increasing the submerged weight of the pipe by concrete coating. There are other ways such as increasing the steel wall thickness, placing concrete blankets or bitumen mattresses across the pipeline, anchoring or covering it with gravel or rock. Alternatively, the hydrodynamic forces may be reduced by placing the pipeline in a trench on the seabed, prior or subsequent to installation. The natural backfilling of a pipeline depends on the environmental conditions and the seabed sediment at the location.

A pipeline on the seabed forms a structural unit where displacement in one area is resisted by bending and tensile stresses. The real situation most probably involves a great variety of pipeline-seabed interface conditions. Pipeline self lowering may result in some sections of a pipeline being embedded to a larger degree than determined by soil characteristics and phenomena such as scour, sediment transport and other seabed instabilities. In other sections the pipe may be slightly elevated above the seabed due to seabed undulation or scour processes. For both conditions, the hydrodynamuc forces are reduced relative to the idealized on bottom condition.


Daftar Pustaka :
http://www.efka.utm.my/thesis/IMAGES/3PSM/2007/JSB/PARTS5/mohdridzaba030064d07ttt.pdf