Caisson shield for arctic offshore production platform

Abstract

Abstract A caisson shield for the protection of an offshore production platform and, more particularly, a caisson shield for use in an arctic environment for the protection of the offshore structure in iceberg-infested waters which is capable of absorbing the destructive forces of an impact produced by a large iceberg. The caisson shield consists of an essentially annular concrete structure encircling at least the submerged support section of the offshore production platform including vertically upstanding concentrically spaced, annular side walls, a horizontal slab base resting on the marine bottom on which the side walls are supported, and a slab top supported on the side walls, and including annularly spaced internal radial partition walls whereby the entire overall caisson shield structure provides a generally toroidal configuration incorporating a plurality of closed compartments. In one enbodiment of the invention, located along the outer annular wall is a plurality of arcuate wall sections forming a series of arches and enclosed compartments between each arcuate wall section and the outer annular wall, which impart a "scallop-like" configuration to the outer circumference of the caisson shield. The "scallop-like" outer walls are capable of resisting and absorbing extremely high ice loads by being adapted to progressively crush the leading edge of an impacting iceberg and to thereby minimize the crush of the iceberg against the caisson shield before coming to rest against the shield.

Inventors

• 👤 John D. Clinton
• 👤 Gerhard H. Reusswig

Bibliographic Details