Abstract: An offshore platform structure of the gravity type intended to be installed on a sea bed in artic or corresponding waters. The platform structure comprises a substructure intended to be completely submerged and supported by the sea bed when in installed position, a superstructure extending up from the substructure and up above the sea bed and a deck superstructure supported by the superstructure above the sea level. A fender is provided intended to protect the superstructure against drifting ice and icebergs, the substructure being provided with a preferably horizontal top support slab supporting the fender, the fender being movably arranged on said support slab and comprising a preferably compartmented cylindrical ring-shaped body with a large weight resting preferably freely on the substructure, intended to be arranged apart from the superstructure when in normal position.

Abstract: An offshore platform structure, particularly intended to be installed in waters where drifting iceberg frequently appear, the platform structure being intended to be founded in a sea bed and comprises a substructure, a superstructure rigidly affixed to the substructure and extending vertically up above the sea level supporting a deck superstructure at its upper end. The horizontal cross-sectional area of the substructure is substantially greater than that of the superstructure. The substructure rigidly supports a fender structure, the fender structure comprising an outer peripherally arranged wall and an inner cylindrical wall the inner and outer wall being rigidly interconnected by means of a plurality of vertical and/or horizontal partition walls, dividing the fender structure into a plurality of cells or compartments. The fender structure is arranged in spaced relation with respect to the superstructure.

Abstract: A method for constructing an offshore platform structure having a plurality of supporting legs inclined inwardly towards each other is disclosed. The entire structure may be constructed in a dry dock, or optionally the lower raft may be constructed in the dry dock and then towed out to a deep water site where the structure is completed. The platform foundation includes a plurality of foundation footings and the lower end of the inclined supporting legs are built in the dry dock. The legs are cast in vertical position using conventional slip forms. Subsequent to the termination of the casting of the inclined legs the supporting legs are tilted towards each other and permanently interconnected at their upper ends. At their lower ends the legs are permanently anchored to the foundation footings. Remaining sections of the legs, if any, may then be cast in any conventional manner, preferably using slip forming.

Abstract: An offshore structure for the production of hydrocarbons is constructed and arranged to rest on a base over predrilled wells in a sea bed. A moveable base plate closes the base. Attached to the base plate are a plurality of conductors which are placed in fluid communication with the predrilled wells. During positioning of the structure on top of the predrilled wells, the base plate is moveable to facilitate mating of the base plate with the predrilled well. After the base plate is in place, the base is lowered into engagement with the base plate.

Abstract: Marine structure having a base and a foundation means projecting downwardly from the base for pressing into the sea bed. The foundation comprises a wall system with pile means on both sides of the wall(s).

Abstract: A means and a method for protecting a sea bottom surface or an installation positioned on same, for instance a pipeline, which means comprises a plurality of pliable concrete plate elements which are flexibly interconnected one after the other and thereby forming a chain-like unit, which chain-like unit is positioned along the sea bottom surface, its flexible characteristics both longitudinally and transversally enabling the unit to adapt itself to transverse and to longitudinal level variations in the course of the laying.

Abstract: A multi-purpose marine structure intended to be submerged and installed on a sea bed. The structure comprises an outer peripheral body and a tapered inner section. The outer peripheral body is intended to be founded on a sea bed and comprises a tubular ring-formed body of concrete, the base of which is constructed and arranged to rest on a sea bed along its entire base periphery. The inner section is also of concrete and is formed as a cone or polyhedron having a lower end which is fixed to the outer peripheral body, the inner section tapering upwardly and inwardly from its lower end. The inner section and outer body together form a monolithic integral concrete unit, the inner section being fixed to the outer body along the inner periphery of the outer body.

Abstract: A marine structure includes a base which is to be founded upon the sea bed. An elastic pre-stressed column is rigidly fixed to and extends upwardly from the base. A buoyant, rigid structure is fixed to the upper end of the upstanding elastic column. The buoyant, rigid structure includes a submerged part and a part projecting up above the sea level to support a deck superstructure. The pre-stressed elastic column is designed to deflect in a curved manner when the buoyant, rigid structure is subjected to environmental forces. In particular, the first nautral period of the installed structure is longer than the significant exciting wave periods. Accordingly, the main structure will oscillate about its vertical equilibrium when subjected to waves and wind thereby behaving as an articulated column.

Abstract: A method is provided for mounting a deck superstructure, comprising at least one concrete girder and/or beam, on a supporting structure intended to operate in marine surroundings. The supporting structure comprises at least one column which extends above sea level and the method comprises the steps of bringing the deck superstructure, either as a unit or in sections, in position relative to the column, hoisting the deck superstructure up to the final position thereof using cables and a jacking system, and tensioning the cables upon the arrival of the deck superstructure in its final position. The lower ends of the cables are permanently anchored to the deck superstructure while the upper ends of the cables are connected to hoisting and tensioning devices arranged on top of the column.

Abstract: An offshore structure is provided for handling cryogenic fluids such as liquefied natural gas. The structure comprises a lower section of concrete and an upper section which projects up from the lower section above the sea level to support a deck superstructure. The lower section is formed of a plurality of cells and at least one of the cells houses an insulated tank for the storage of low temperature fluids. The tank or tanks are completely submerged when in operation and are rigidly supported by the associated cell. Each tank comprises a primary and secondary barrier with insulation associated therewith and the tank(s) communicates with the deck superstructure through an access tunnel system.

Abstract: A floating offshore platform is provided which, in operation, is anchored to the sea bed by an anchoring device. The platform includes an elongate column-like structure which, in operation, floats in an upright position. An anchoring device is connected to the elongate structure by at least one vertically extending cable or the like which is tensioned to restrain vertical displacement of the structure, and a plurality of generally horizontally extending members which interconnect the lower end of the structure with the anchoring device so as to restrain lateral displacement of the lower end of the structure. With this arrangement, the column-like structure behaves as a floating column pivoted to the sea bed.

Abstract: A method of construction on natural or artificial soils subject to liquefaction involves the provision of one or more permeable wells penetrating the soil supporting a structure, such that excess water pressures induced by cyclic loads on the structure can be relieved. Pumps can be used to maintain the water pressure in the wells lower than the natural water pressure in the surrounding soil. The wells may be filled with water-permeable material. Structures in accordance with the invention can be of various forms, wherein drainage may be through one or more dowels or through a cushion on the lower section of the structure or structures.