Prestressed steel tube, in particular for making anchor lines for taut line type production platforms, a method of handling and installing such a tube, and a platform including such a tube

摘要

According to the invention a steel tube is prestressed longitudinally. This prestress is advantageously exerted by cables (20) extending along the tube (10) either inside the tube or outside the tube, and prevented from moving transversely relative to the tube, said cables being constituted by fibers (of glass, of carbon, or of other inorganic materials), having a breaking strength which is greater than that of steel. Such a structure is particularly applicable to anchoring a taut line type oil production platform (200) at sea. In this case, the advantages of inorganic fibers and of steel are combined, thereby taking advantage of the very high breaking strength in traction of the fibers in order to prestress the steel which can then be subjected to much lower stress than the fibers, thus considerably reducing the elongation of the anchor lines.