A precast concrete gravity-base foundation is provided that is both floatable and submersible in water, and is suitable for mounting the shaft of an offshore wind turbine. The foundation comprises a bottom slab, four cylinders positioned at each corner, a centrally located cylinder, and a top slab covering each of the corner cylinders and having a central opening that receives the top portion of the centrally located cylinder. The foundation's configuration and positioning of the corner cylinders provide maximum stability, and once the corner cylinders are filled with sand, stone, or the like, the corner cylinders further bolster the overall mass and stability of the foundation. The foundation is produced on land, rolled onto a submersible jack-up barge, and transported to either a predetermined storage location or an installation site. The foundation's buoyancy and versatile storage options allow contractors to work year-round with fewer ships, cranes, equipment, and workers at the job site, making it a valuable addition to the offshore wind industry.

A gravity based foundation for an offshore installation includes a caisson of concrete and a hollow shaft. The caisson has a bottom slab, a roof and a side wall extending between the bottom slab and the roof. The roof having a passage for the shaft into the caisson. The shaft support has embedded tensioning bars vertically projecting from the upper side of the shaft support. The shaft is mounted on the shaft support by the tensioning bars. A method of manufacturing includes providing a concrete bottom slab, arranging a full-length formwork onto the bottom slab, arranging a slip formwork onto the bottom slab, providing the tensioning bars and mounting the tensioning bars in a fixed position to the full-length formwork, and concrete pouring of the sidewall and shaft support while raising the slip formwork.

A wind turbine foundation comprising a concrete support slab having a horizontal rebar grid therein, a concrete pedestal integral with the support slab and having vertical post tensioning elements therein and a plurality of concrete ribs on top of and integral with the support slab and integral with the pedestal, the ribs having rebar therein and extend outwardly from the pedestal, the pedestal, slab and ribs are connected to each other to form a monolithic foundation. The foundation design reduces the 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.

A wind turbine foundation comprising a concrete support slab having a horizontal rebar grid therein, a concrete pedestal integral with the support slab and having vertical post tensioning elements therein and a plurality of concrete ribs on top of and integral with the support slab and integral with the pedestal, the ribs having rebar therein and extend outwardly from the pedestal, the pedestal, slab and ribs are connected to each other to form a monolithic foundation. 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.

A wind turbine foundation comprising a concrete support slab having a horizontal rebar grid therein, a concrete pedestal integral with the support slab and having vertical post tensioning elements therein and a plurality of concrete ribs on top of and integral with the support slab and integral with the pedestal, the ribs having rebar therein and extend outwardly from the pedestal, the pedestal, slab and ribs are connected to each other to form a monolithic foundation. 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.

A wind turbine foundation comprising a concrete support slab having a horizontal rebar grid therein, a concrete pedestal integral with the support slab and having vertical post tensioning elements therein and a plurality of concrete ribs on top of and integral with the support slab and integral with the pedestal, the ribs having rebar therein and extend outwardly from the pedestal, the pedestal, slab and ribs are connected to each other to form a monolithic foundation. 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.

A fatigue resistant gravity based spread footing under heavy multi-axial cyclical loading of a wind tower. The foundation having a central vertical pedestal, a substantially horizontal continuous bottom support slab, a plurality of radial reinforcing ribs extending radially outward from the pedestal. The pedestal, ribs and slab forming a continuous monolithic structure. The foundation may have a three-dimensional network of post-tensioning elements that keep the structural elements under heavy multi-axial post compression with a specific eccentricity intended to reduce stress amplitudes and deflections and allows the foundation to have a desirable combination of high stiffness and superior fatigue resistance. 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.

The present invention relates to a gravity based structure 5 with a topside 2 on at least one hollow concrete platform leg 1 with a platform leg wall and a circular cross section. The at least one platform leg, includes an upper leg portion (4) cut off from a lower leg portion 3. The lower leg portion 3 has an upper sloped cut surface 10 inclined at an angle in the range of 1-10 off a horizontal axis. The upper leg portion 4 has an upper leg sloped cut surface inclined at the same angle as the lower leg sloped cut surface 10 of the lower leg portion 3 whereby the angles are complementary, the sloped cut surfaces forming an inner and an outer obtuse cone with a common vertical longitudinal axis. Furthermore, the invention relates to method of forming a conical cut through a concrete platform leg of a GBS.

The invention relates to a boat landing structure suitable for being used in a marine construction, wherein said marine construction comprises, essentially, a concrete shaft intended for being installed anchored at a depth level with respect to the water level, and wherein said boat landing structure comprises two substantially vertical and parallel ribs, integrated in the shaft of the marine construction and projecting out from same, wherein said ribs are made partially or entirely of concrete. Likewise, the space comprised between said ribs houses an access ladder suitable for being used by personnel accessing the marine construction from an operation boat. The invention also relates to a marine construction and a segment comprising the mentioned boat landing structure.

The present disclosure discloses a combined offshore wind power foundation with duct piles and a bucket, which comprises duct piles and a bucket foundation; the bucket foundation includes a steel bucket skirt, a bucket top cover, main beams, ring beam and a transition section. A top of the steel bucket skirt and the bucket top cover are integrally formed into a semi-closed structure. The bucket top cover is provided thereon with main beams uniformly arranged in a circumferential direction. The ring beam are arranged at an edge of the bucket top cover. Each duct pile includes a duct, a steel pile, duct supports and high-strength mortar, each main beam is provided at its outer side end with one of corresponding. The duct support is connected with the main beam and the ring beam, and integrated with the bucket top cover, the main beams and the ring beam.