Abstract: A method and apparatus for installation of heavy, ballastable, gravity fundament structures on the sea bottom at large depths. In accordance with the invention, there is utilized air, water, and a liquid lighter than water in various proportions and combinations to provide the structure with the required buoyancy and submerged weight during the sequential phases of the transport and descent operations in order to finally position the structure in a selected location on the sea bottom. Various modes can be used to accomplish the descent and the structure may in a final stage be penetrated down into the sea bottom to a sufficient degree.

Abstract: A method for fabricating and installation of a floating bridge or the like provides that a bridge superstructure is supported by a number of pontoons and has opposite ends anchored to shore fundaments. Prefabricated pontoons are positioned successively at mutually spaced locations on the water surface along a center line of a part of the bridge superstructure being formed. Such pontoons are suitably ballasted. Further bridge superstructure is fabricated successively in sections in a production unit positioned on a barge or on a platform stationarily positioned by the shore. Such sections are being pushed outwardly of the production unit one after the other, with a new section being made as a continuation of a preceding section. The fabricated part of the bridge superstructure, formed of several interconnected sections which gradually are protruded from the barge or platform, is slid or pushed out onto the pontoons that are positioned one after the other, and are mounted thereon.

Abstract: A large, curved or spherical shell of reinforced concrete is cast without utilization of supporting framework. A casting formwork is in the form of a thin, suspended membrane that is reinforced with a collar. During construction and transport, the membrane is preliminarily equipped with a reinforcing compression ring.

Abstract: An oil storage system for an offshore platform having at least one submerged storage cell in which oil is stored on top of a water volume. In fluid communication with the submerged storage cell is another submerge cell containing water, the water storage cell is in fluid communication with ambient water outside the system.

Abstract: A tension leg platform for drilling and/or production, processing and transporting hydrycarbons from sub sea wells or installations, and methods for installation of such platform. The platform comprises in operational position the following: a working platform which has position above the sea level, a buoyant body (1) which is connected with the underside of the platform and has substantially position below the surface, and a number of tension legs (13) which connect the buoyant body (1) with a fundament anchored to the sea bed. The invention is characterized in that the lower parts of the tension legs (13) in per se known fashion are anchored to the fundament (14) and at their upper ends are controlled in guides (20, 21) on the outside of the buoyant body and are attached to the buoyant body (1) above or just below the water line.

Abstract: A method of installing a floatable or buoyant body on the sea floor includes towing the body to an installation site at the sea surface and subsequently submerging the body towards the sea floor by supplying ballast to the buoyant body. The supply of ballast is discontinued when the buoyant body reaches a preselected sinking velocity and the vertical movement of the buoyant body is discontinued at a predetermined level above the sea floor by a floating vessel or the like which is floating at the sea surface. One end of the vessel is connected to the buoyant body by a connector system, the length of which is smaller than the sea depth at the installation site. The buoyant body is displaced laterally to a preselected final location, whereafter the buoyant body is further submerged towards the sea floor until the same is positioned on the sea floor at a preselected installation site.