MARINE PIPELAYING AND HANDLING OF RIGID PIPELINES

摘要

A support element (12) for supporting a rigid pipeline (10) during plastic bending of the pipeline has a transverse cross-sectional configuration such that, in use, a pipeline supported by the support element contacts said support element at at least first and second points (14, 16) disposed substantially symmetrically on either side of the plane of bending, the points of contact being arranged such that resultant forces between the pipeline and the support element act at points which are disposed substantially symmetrically about the plane of bending and which are spaced apart by an angle a greater than 90 DEG and less than 180 DEG around the cross-sectional circumference of the pipeline. The angle a is selected so as to minimise ovalisation for a pipeline of given material, diameter and wall thickness, and for a given bend radius and pipeline tension, or to provide useful modification of ovalisation over ranges of these parameters. For most practical applications, the optimal angle a will be greater than 90 DEG and less than or equal to 150 DEG . In preferred embodiments of the invention, the angle a is greater than 90 DEG and less than or equal to 110 DEG .