Topside modules are fabricated at a production site using as a foundation for installation a gravity-based structure (GBS), which can stay afloat during water transportation. Modules fabrication includes: Stage I, fabrication of components; Stage II, fabrication of nodes from the components; Stage III, fabrication of sub-assemblies from the nodes; Stage IV, shotblasting and painting of assemblies; and Stage V, assembling modules from the assemblies. Then modules transportation, movement to their seats on the GBS and their integration include: Stage VI, moving the modules to an area near the dock using self-propelled vehicles. Stage VII, moving each module onto guides of a lifting system installed in a dry dock. Stage VIII, lifting each module until lifting system guides are connected with GBS top slab guides. Stage IX, moving each module to its seat on the GBS, installed on the GBS and integrated with other modules and the GBS.

Topside modules are fabricated at a production site using as a foundation for installation a gravity-based structure (GBS), which can stay afloat during water transportation. Modules fabrication includes: Stage I, fabrication of components; Stage II, fabrication of nodes from the components; Stage III, fabrication of sub-assemblies from the nodes; Stage IV, shotblasting and painting of assemblies; and Stage V, assembling modules from the assemblies. Then modules transportation, movement to their seats on the GBS and their integration include: Stage VI, moving the modules to an area near the dock using self-propelled vehicles. Stage VII, moving each module onto guides of a lifting system installed in a dry dock. Stage VIII, lifting each module until lifting system guides are connected with GBS top slab guides. Stage IX, moving each module to its seat on the GBS, installed on the GBS and integrated with other modules and the GBS.

A gravity base (1) for supporting a superstructure (2), comprising a base structure (100), wherein the base structure is configured to be arranged on a supporting media (3) and is configured to be connected to the superstructure (2) or to a support structure (300) which is configured to be arranged between the superstructure and the base structure, and wherein the support structure is configured to be connected to the superstructure; a ballast confiner (200), wherein the ballast confiner is configured to be filled with a ballast material (250), wherein the ballast confiner (200) is configured to confine the ballast (250) on the base structure (100), wherein the base structure and the ballast confiner are structurally independent.

A foundation having a central vertical pedestal, a plurality of radial reinforcing ribs extending radially outward from the pedestal. The pedestal and ribs forming a continuous monolithic structure. An anchoring system under the ribs with anchoring the foundation to the ground by anchoring elements connected to rock anchors, soil anchors, piles or the like. The foundation design reduces the weight and volume of materials used, reduces cost, and improves heat dissipation conditions during construction by having a small ratio of concrete mass to surface area thus eliminating the risk of thermal cracking due to heat of hydration.

This application discloses a new type of suction leg, an offshore caisson, a sit-on-bottom supporting platform. The suction leg includes a sealing long pile, this sealing long pile including a tubular pipe and a top head connected tightly to the tubular pipe to form cylindrical integral structure with sealing top and opening bottom. The top head has at least one opening to be able to open or close. The sealing long pile can be penetrated into the seabed by a gravity penetration method or/and a suction pile penetration method, or pulled out from the seabed by a buoyancy uplift method or/and a suction pile uplift method.

A self-installing offshore platform includes a top deck that supports an offshore facility, a column having a top end and a bottom end, the top end connected to the top deck, the column that supports the top deck to maintain the top deck above water in a water body in both the deployed state and the undeployed state of the self-installing offshore platform, a skirt connected to the bottom end of the column, the skirt residing above a floor of the water body in the undeployed state of the self-installing offshore platform and residing on the floor of the water body in the deployed state of the self-installing offshore platform, and a ballastable float positioned between the top deck and the skirt, the ballastable float floating in the water when the self-installing offshore platform transitions from the undeployed state to the deployed state.

A steel plate and concrete composite tank unit, tank groups and offshore platforms with new type of tank units are disclosed. The tank unit comprises an outer concrete tank that comprises an outer tank shell, two heads and ring shell connections at both ends, an inner steel tank that comprises an inner tank shell, epitaxial structures at both ends of the inner steel tank. Inner tank shell is connected to the outer tank shell by epitaxial structures, and an isolation layer that is formed from the gap between the outer concrete tank and the inner steel tank where it is filled with isolation medium.

The subject matter of the invention is a gravity structure intended for a marine civil-engineering construction, comprising a slab configured so as to be placed on a sea bed and secured to a shaft directed in a principal direction substantially orthogonal to said slab, characterized in that the gravity structure comprises at least one anchoring tie rod extending in said shaft and in the slab, the gravity structure being configured so that, in a service position of the gravity structure, said at least one anchoring tie rod is anchored in the sea bed.

A method for the autonomous anchoring of foundations for offshore structures consisting of a self-floating concrete caisson manufactured in a floating dock, capable of being towed to their final location, provided with internal vertical cells, which are divided into cells that are interconnected with each other and equipped with emptying and filling devices that allow the regulation of the ballast level for anchoring when they are filled with seawater. This method comprises the following stages: constraining the foundation, fastening and mooring by at least three tugboats pulling radially on the foundation to be anchored from at least 3 different directions; connecting the different sensors needed for controlling the operation with a control unit; gradual and controlled sinking of the foundation until it reaches its position of installation on the seabed; and final ballasting of the foundation.

A gravity-based foundation for the installation of offshore wind turbines, manufactured in a floating dock for towing to the final destination thereof, where it is anchored and finally completely submerged below sea level, comprising a concrete floating caisson, in the shape of a prism, with a hexalobular base, divided into several cells by at least one partition with a significantly circular cross section, concentric with a central cell, determining inner vertical cells interconnected with each other and with the exterior, which is closed at the top by a cover or covers that are removed once the foundation is anchored before being filled with a ballast material.