Gantry platform for large offshore wind turbines and method of construction

Abstract

A portal platform for large offshore wind turbines and a method of construction, comprising at least three tubular legs and a horizontal deck, said tubular legs being free of horizontal or diagonal bracing members between them, said horizontal deck comprising at least three circular sleeves. Said portal platform is normally in an in-service power generation mode of operation with the tubular legs' tops connected concentrically to the horizontal deck above waterline and extending vertically downwards to the seabed; said portal platform has a temporary floating installation mode of operation comprising two barges connected to the horizontal deck above waterline on both sides of the wind turbine, the tubular legs' bottoms being concentrically located within the circular sleeves and extending vertically upwards; said method of construction is used to carry out the assembly of said portal platform and foundation piles onshore at a dock, and the integration with the wind turbine, the offshore towing and self-installation of the whole, using a cable and winch system arranged on both barges, the lowering and extension of the tubular legs through the circular sleeves to the seabed, and the completion of the transition of said portal platform from the floating installation mode to the in-service power generation mode of operation.

Description

[0001] This application claims priority to the invention filed on September 9, 2022, entitled "Portal Frame Platform and Construction Method for Large Offshore Wind Turbines", application number US17 / 941,775. Technical Field

[0002] This invention relates to a technology in the field of marine engineering structures, specifically a gantry platform for large offshore wind turbines and its construction method. Background Technology

[0003] Currently, most installed offshore wind turbines are located in waters less than 30 meters deep, with a power generation capacity typically less than 10 megawatts, supported by fixed foundations. With increasing demand for offshore wind power, there is a growing trend towards deploying large wind turbines with a power generation capacity exceeding 10 megawatts in waters deeper than 30 meters. The numerous shortcomings of existing monopile and jacket foundation technologies are the root cause of the severe bottlenecks faced by the offshore wind power industry in deploying large turbines in waters deeper than 30 meters, including high costs, complex offshore installation, and long project cycles. To reduce costs and improve project schedules, there is an urgent need for a new, efficient, and low-cost foundation structure and an installation method that does not require large crane installation vessels. Summary of the Invention

[0004] This invention addresses the aforementioned shortcomings of existing technologies by proposing a gantry platform and its construction method for large offshore wind turbines. This platform allows for assembly at the dock and integration with the wind turbine system, as a whole, towing, and self-installation without the need for large crane installation vessels, overcoming the problems of existing monopile and jacket foundations. The gantry platform includes at least three elongated tubular legs extending vertically downwards from the top above the waterline to the seabed, without any horizontal or diagonal bracing members in between, and a horizontal deck comprising at least three circular sleeves concentrically connected to the top of the elongated tubular legs, for supporting the wind turbine system in in-situ power generation mode. The wind turbine system includes a wind turbine tower, whose bottom is vertically connected to the center of the horizontal deck above the waterline, and whose top is connected to the nacelle and rotor blades. The bottom of each elongated tubular leg is connected to a foundation pile embedded in the seabed.

[0005] This invention is achieved through the following technical solution:

[0006] This invention relates to a gantry platform for large offshore wind turbines, comprising: four vertical elongated tubular legs, each located at a corner of a square pattern; four foundation piles, the upper end of each pile connected to the bottom of each elongated tubular leg; a horizontal deck comprising four circular sleeves equidistant from their geometric centers, wherein: each circular sleeve is concentrically connected to the top of each elongated tubular leg; a base structure located at the geometric center of the horizontal deck is vertically connected to the bottom of the wind turbine tower; and four horizontal beams radially connect the base structure and the circular sleeves.

[0007] The circular sleeve includes a circular outer shell whose height matches that of a horizontal beam, a plurality of uniformly and symmetrically arranged internal guide units vertically connected inside the circular outer shell, and an inner annular plate horizontally connected to the lower end of the circular outer shell, wherein the inner diameter of the inner annular plate is approximately equal to the diameter of the circle formed by the internal guide units.

[0008] Each elongated tubular leg comprises an upper section, a lower section, and a middle section. The upper section includes a top watertight cover, a circular tube, multiple external guide units vertically connected to the outside of the circular shell and symmetrically arranged, and an outer annular plate horizontally connected to the circular tube, located below the top watertight cover, with its vertical distance matching the diameter of the circular sleeve. The size of the outer annular plate of the upper section of each elongated tubular leg matches the size of the inner annular plate of the circular sleeve.

[0009] The inner diameter of the inner annular plate of the circular sleeve of the horizontal deck is at least 1 inch larger than the outer diameter of the elongated tubular leg with an external guide unit, wherein the elongated tubular leg can move vertically up and down concentrically within the circular sleeve through the opening of the inner annular plate, moving from the lower section to the upper section until it stops at the outer annular plate near the top of the upper section.

[0010] The gantry platform is located in an offshore wind farm at a water depth of approximately 60 meters and is in in-situ power generation mode. The upper part of each extended tubular leg is rigidly connected to a circular sleeve on a horizontal deck above the waterline, while the bottom of each extended tubular leg is rigidly connected to a foundation pile embedded in the seabed. The rigid connection methods include welding and cement grouting.

[0011] The gantry platform is located on the shore in relatively shallow water and is in the dock assembly mode, wherein the lower part of each extended tubular leg is concentrically placed inside the corresponding circular sleeve of the horizontal deck above the waterline, while the foundation piles stand vertically on the seabed on the shore.

[0012] In the in-situ power generation mode, the circular sleeve of the horizontal deck of the gantry platform is concentrically connected to the upper section of the extended tubular leg, wherein the gap between the outer shell of the circular sleeve and the outer shell of the upper section of the extended tubular leg is rigidly connected by grouting.

[0013] In the in-situ power generation mode, the upper end of the extended tubular leg of the gantry platform includes a vertical web plate, the upper end of which is connected to a top horizontal extension plate, and the lower end of which is connected to an upper horizontal watertight cover plate with an outer ring plate. The dimensions of the outer ring plate of the upper horizontal watertight cover plate of the extended tubular leg match the dimensions of the inner ring plate connected to the lower end of the circular sleeve of the horizontal deck. The extended tubular leg is rigidly connected to the corresponding parts of the horizontal deck by bolts through the top horizontal extension plate, the vertical web plate, and the outer ring plate.

[0014] The gantry platform is in a floating installation mode, with two floating barges connected to both sides of the horizontal deck supporting the wind turbine system. Extending tubular legs extend vertically upwards from the bottom, passing through concentric circular sleeves on the horizontal deck above the waterline. The two floating barges are equipped with deck connection support structures, as well as steel cables and winch systems, forming a catamaran. During towing and installation at sea, they provide buoyancy and stability to the integrated whole consisting of the gantry platform, wind turbine system, and pile foundation. Lateral guide devices mounted on top of the extended tubular legs are compressively connected to the wind tower via spring units.

[0015] This invention relates to a method for constructing the aforementioned gantry platform for large offshore wind turbines, comprising: first, the gantry platform is in a dock assembly mode, wherein the extended tubular legs extend vertically upward from the bottom above the waterline and are vertically integrated with the wind turbine system at the dockside via circular sleeves on the horizontal deck; second, it is in a floating installation mode, wherein two floating barges are connected to both sides of the horizontal deck to form a catamaran system that provides buoyancy and stability for offshore towing and self-installation; third, the extended tubular legs with foundation piles are lowered to the seabed via a cable and winch system, the foundation piles are embedded into the seabed, and the two floating barges are released and pulled apart to complete the offshore installation, thereby converting the gantry platform from the floating installation mode to the in-situ power generation mode.

[0016] The preferred option for the foundation piles is a suction caisson type, which allows for a one-time overall installation with the gantry platform and wind turbine system during the assembly and integration at the wharf and offshore installation operations.

[0017] The foundation piles of the gantry platform are driven piles, used for seabed soil conditions unsuitable for suction caisson piles. Driven piles are pre-installed on the seabed using a pile hammer. The gantry platform is assembled at the shore dock and installed at sea using a self-installation process similar to the construction method described above. Each driven pile has an intermediate section above the seabed, which is connected to the corresponding part of the lower part of the extended tubular leg by grouting.

[0018] Technical effect

[0019] The gantry platform of this invention has distinctive features and provides a feasible and low-cost solution to the problems existing in the monopile and jacket foundation technologies, especially for large wind turbines in water depths exceeding 30 meters.

[0020] First, gantry platforms can withstand greater bending moments than monopiles of the same steel weight, especially in water depths exceeding 30 meters. Second, the structural components of gantry platforms can be manufactured more efficiently and at a lower cost than large-diameter monopiles or jacket structures of the same steel weight due to their simple design with only three or four small-diameter tubular legs and no horizontal or diagonal bracing members. Third, gantry platforms can be assembled and integrated with wind turbine systems and foundation piles at shore docks, whereas existing monopiles and jacket structures cannot. Fourth, large specialized transport vessels are not required to transport gantry platforms from the manufacturing plant to the offshore wind farm site, whereas monopiles and jacket structures require large transport vessels. Fifth, gantry platforms can be installed at sea along with foundation piles and wind turbine systems, requiring only two low-cost conventional deck barges for a single offshore installation operation, while monopiles and jacket structures require at least two offshore installations using large specialized crane vessels. Therefore, given the severe shortage of large crane installation vessels, adopting gantry platforms can significantly reduce costs and shorten project cycles. It is estimated that the cost of a gantry platform can be 30% to 50% lower than that of a monopile and jacket, especially for large wind turbines in water depths greater than 30 meters.

[0021] In addition to the advantages mentioned above, the present invention is feasible for economical manufacturing, assembly, transportation and installation using local resources and existing port facilities and barges, without the need for imports from overseas, thereby creating new employment opportunities and other economic benefits for the local community. Attached Figure Description

[0022] Figure 1A This is a schematic diagram of an exemplary monopile foundation supporting a large wind turbine according to the prior art;

[0023] Figure 1B This is a schematic diagram of an exemplary jacket foundation supporting a large wind turbine according to the prior art;

[0024] Figure 2 A schematic diagram of a gantry platform supporting a large wind turbine according to an exemplary embodiment of the present invention;

[0025] Figure 3A A three-dimensional diagram of an exemplary embodiment of a gantry platform having four tubular legs;

[0026] Figure 3B A three-dimensional diagram of an exemplary embodiment of a gantry platform with three tubular legs;

[0027] Figure 4AA detailed side view of an exemplary embodiment of the in-situ power generation mode of the gantry platform;

[0028] Figure 4B A detailed side view of an exemplary embodiment of the assembly mode of a gantry platform dock;

[0029] Figure 5 A detailed schematic diagram of an exemplary embodiment of a circular sleeve for a horizontal deck of a gantry platform;

[0030] Figure 6 A detailed schematic diagram of an exemplary embodiment of the upper part of the tubular leg of a gantry platform;

[0031] Figure 7 This is a schematic diagram of the upper part of the circular sleeve and the tubular leg with grouting connection in an exemplary embodiment;

[0032] Figure 8 A schematic diagram of a horizontal beam connecting a circular sleeve to the horizontal deck of a gantry platform;

[0033] Figure 9 An exemplary detailed view of the upper part of a tubular leg having a vertical web and a top horizontal extension plate;

[0034] Figure 10A A detailed three-dimensional view of an exemplary embodiment of bolting to the upper part of the elongated tubular leg;

[0035] Figure 10B A detailed top view of an exemplary embodiment of the bolted connection to the upper part of the elongated tubular leg;

[0036] Figure 11A A three-dimensional schematic diagram of an exemplary embodiment of a gantry platform with four tubular legs, including two barges in a floating installation mode;

[0037] Figure 11B A three-dimensional schematic diagram of an exemplary embodiment of a gantry platform with three tubular legs, comprising two barges in a floating installation mode;

[0038] Figure 12 A detailed schematic diagram of the spring unit and the lateral guide device that are compressed at the top of the tubular leg onto the wind tower in an exemplary embodiment;

[0039] Figure 13 An exemplary three-dimensional schematic diagram of two barges equipped with deck connection support structures and cable and winch systems connected to the sides of a horizontal deck of a gantry platform in a floating installation mode;

[0040] Figure 14This is a schematic diagram of an exemplary embodiment of the construction method for assembling and supporting a gantry platform for a large wind turbine according to the present invention, in which multiple foundation piles are connected to form a sub-component system and placed vertically on the seabed of the wharf.

[0041] Figure 15 This is a schematic diagram of an exemplary embodiment of a construction method following step 1, in which a horizontal deck, including a circular sleeve, is temporarily connected to the upper part of the foundation pile to form a new sub-component system.

[0042] Figure 16 This is a schematic diagram of an exemplary embodiment of the third step of the construction method following the second step, in which two tubular legs are connected to two distal foundation piles via a circular sleeve on a horizontal deck at the wharf shore.

[0043] Figure 17 This is a schematic diagram of an exemplary embodiment of the fourth step of the construction method following the third step, in which the wind tower is vertically connected to the base portion of the horizontal deck.

[0044] Figure 18 This is a schematic diagram of an exemplary embodiment of the fifth step of the construction method following step 4, in which two tubular legs are connected to two proximal foundation piles via a circular sleeve on a horizontal deck at the quay shore.

[0045] Figure 19 This is a schematic diagram of an exemplary embodiment of the sixth step of the construction method following step 5, in which the wind turbine nacelle and rotor blades are connected to the top of the wind tower.

[0046] Figure 20 A schematic diagram of an exemplary embodiment of a floating installation mode in which two barges are connected to both sides of a horizontal deck to form a gantry platform in step 7 of the construction method following step 6;

[0047] Figure 21 A schematic diagram illustrating an exemplary embodiment of a tugboat towing a gantry platform with a wind turbine system and foundation piles in the floating installation mode, for step 8 of the construction method following step 7;

[0048] Figure 22 In step 9 of the construction method following step 8, the gantry platform is converted from floating installation mode to in-situ power generation mode by lowering the tubular legs using a cable and winch system.

[0049] Figure 23 In step 10 of the construction method following step 9, the tubular leg is lowered using a cable and winch system to bring the foundation pile into contact with the seabed.

[0050] Figure 24In step 11 of the construction method following step 10, foundation piles are embedded into the seabed soil while maintaining the horizontal deck of the gantry platform connected to the two barges.

[0051] Figure 25 To complete the transition of the gantry platform from the floating installation mode to the in-situ power generation mode in step 12 of the construction method following step 11, the two barges were separated from the horizontal deck.

[0052] Figure 26 This is a schematic diagram of an exemplary embodiment of the portal platform with elongated tubular legs according to the present invention, in the in-situ power generation mode, where the bottom pile leg connecting section of the tubular legs is concentrically connected to the driven pile foundation.

[0053] Figure 27 Detailed schematic diagram of an exemplary embodiment of a gantry platform without connection to a driven pile foundation for a dock assembly mode;

[0054] Figure 28 This is a schematic diagram of an exemplary floating installation mode of a gantry platform without connection to a driven pile foundation, which includes two barges connected to both sides of a horizontal deck to form a catamaran.

[0055] Figure 29 This is a schematic diagram illustrating an exemplary embodiment of the self-installation process of a gantry platform with bottom pile leg connection sections transitioning from floating installation mode to in-situ power generation mode, and its docking with pre-installed driven piles on the seabed. Detailed Implementation

[0056] This invention relates to a gantry platform for supporting large offshore wind turbines and a construction method that does not use large crane vessels. Before explaining the invention in detail, it should be understood that the invention is not limited to the disclosed embodiments and can be implemented or deployed in various other ways. Furthermore, although the disclosed gantry platform and construction method are generally used to support large offshore wind turbines located in water depths of 30 to 100 meters, it can be used in any body of water without depth limitations and can support any type of top system, not limited to offshore wind turbines. In this document, unless specifically stated otherwise, relational terms such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “deeper,” “shallower,” “upper,” “lower,” “side,” etc., are used only for illustrative purposes to clarify specific references and are not intended to limit the scope of the invention or the claims.

[0057] Preferred embodiments of the present invention are as follows: Figures 2 to 29 As shown, the specific implementation method is described below.

[0058] like Figure 2As shown, the gantry platform 2 of the wind turbine system includes a wind tower 4, a nacelle 6, and rotor blades 8. Its support includes multiple elongated tubular legs 12, a horizontal deck 14 above the waterline 101, and multiple foundation piles 16 embedded in the seabed 201. The multiple elongated tubular legs 12 extend vertically downwards from above the waterline 101 to the seabed 201. There are no horizontal or diagonal support members between the elongated tubular legs 12. Each elongated tubular leg 12 is connected at its top to the horizontal deck 14 and rigidly connected at its bottom to its corresponding foundation pile 16. The center of the horizontal deck 14 is connected to the bottom of the wind tower 4. The gantry platform 2 has a preferred operating water depth range from 30 meters to 100 meters. The wind turbine systems 4, 6, and 8 have a preferred power generation capacity range from 10 MW to 20 MW. The elongated tubular legs 12 are preferably designed as steel structures with inner ring reinforcing ribs, with a preferred diameter range of 3 meters to 7 meters.

[0059] like Figure 3A A gantry platform 2 supporting a wind turbine system comprising a wind tower 4, a nacelle 6, and rotor blades 8 includes four elongated tubular legs 12, each vertically positioned at a corner of a square pattern, with no horizontal or diagonal support members between the elongated tubular legs 12; a horizontal deck 14 and four foundation piles 16, each with a top connection to the bottom of the corresponding elongated tubular leg 12. The horizontal deck 14 includes four circular sleeves 14A with a diameter larger than that of the elongated tubular legs 12, arranged radially at equal intervals from the center of the horizontal deck 14 and forming a concentric rigid connection with the upper part 12A of each corresponding elongated tubular leg 12; a base structure 14B located at the center of the horizontal deck 14 and vertically connected to the bottom of the wind tower 4; and four horizontal beams 14C, each horizontal beam radially connecting the base structure 14B to the corresponding circular sleeve 14A.

[0060] like Figure 3B The gantry platform 2, supporting the wind turbine system with a wind tower 4, nacelle 6, and rotor blades 8, includes three elongated tubular legs 12 vertically positioned at the corners of an equilateral triangle pattern. There are no horizontal or diagonal support members between the elongated tubular legs 12. A horizontal deck 14 includes three circular sleeves 14A, a base structure 14B vertically supporting the wind turbine systems 4, 6, and 8 at the center of the horizontal deck 14, and three horizontal beams 14C. Each elongated tubular leg 12 is concentrically connected at its upper part 12A to the corresponding circular sleeve 14A and at its bottom to the top of the corresponding foundation pile 16.

[0061] like Figure 4AThe gantry platform 2 is in in-situ power generation mode, located at a water depth of approximately 60 meters. It includes multiple elongated tubular legs 12, each at least 60 meters long, extending vertically downwards from above the waterline 101A to the seabed 201A. A horizontal deck 14 has multiple circular sleeves 14A with a diameter larger than that of the elongated tubular legs 12, and multiple foundation piles 16 embedded in the seabed 201A. Each elongated tubular leg 12 is concentrically rigidly connected to its corresponding circular sleeve 14A at its upper part 12A, and rigidly connected to the top of its corresponding foundation pile 16 at its lower part 12B by welding or cement grouting. The horizontal deck 14 includes a base structure 14B located at its center, vertically connected to the bottom of the wind tower 4, and multiple horizontal beams 14C, each connected from one side of the base structure 14B to one side of each corresponding circular sleeve 14A. The multiple foundation piles 16 are horizontally connected together at the top above the seabed 201A via connecting rods 18. The foundation pile 16 shown in the figure is a suction caisson type, which is relatively short in length and relatively large in diameter, and its diameter is larger than that of the extended tubular leg 12. It is embedded into the seabed 201A by suction.

[0062] like Figure 4B As shown, the gantry platform 2 is in the dock assembly mode, located at a water depth of approximately 8 meters near the dock shore. It includes multiple elongated tubular legs 12 extending vertically upwards, with their upper parts 12A significantly higher than the waterline 101B. A horizontal deck 14 includes multiple circular sleeves 14A concentrically positioned above the waterline 101B at a similar height to the lower parts 12B of the elongated tubular legs. Multiple foundation piles 16 stand on the seabed 201B near the dock shore, with the top of each foundation pile 16 rigidly connected to the bottom of the corresponding lower part 12B of the elongated tubular leg 12 by welding or cement grouting. The horizontal deck 14 also includes a base structure 14B located at its center, vertically connected to the bottom of the wind tower 4, and horizontal beams 14C each horizontally connected from one side of the base structure 14B to one side of the corresponding circular sleeve 14A. The multiple foundation piles 16 are horizontally connected together at the top by connecting rods 18, which are located above the waterline 101B.

[0063] The following provides further details regarding the rigid connection between the upper part 12A of the extended tubular leg 12 of the gantry platform 2 and the circular sleeve 14A of the horizontal deck 14. This rigid connection can be either grouted or bolted; a grouted connection, such as... Figures 5 to 7 As shown, bolted connections are as follows Figures 8 to 10B As shown in the figure. Alternatively, a welded connection can also be used, with a detailed structural layout similar to that of a bolted connection, which will not be described here.

[0064] like Figure 5The circular sleeve 14A includes a circular outer shell 32 with a certain diameter and height, a plurality of internal guide units 34 vertically connected to the inner side of the circular outer shell 32, and an inner annular plate 36 horizontally connected to the lower end of the circular outer shell 32, wherein the inner diameter of the inner annular plate 36 is approximately equal to the diameter of the circle formed by the internal guide units 34.

[0065] like Figure 6 In some embodiments, the upper segment 12A of the elongated tubular leg 12 includes a circular housing 32A with a diameter equal to that of the upper segment 12A. A plurality of external guide units 34A are attached to the outer side of the circular housing 32A. An outer annular plate 36A is horizontally connected to the bottom of the circular housing 32A and a watertight cover plate 38 located at the top. The vertical distance from the outer annular plate 36A to the watertight cover plate 38 is approximately equal to... Figure 5 The height of the circular sleeve 14A shown.

[0066] like Figure 7 In some embodiments, the inner diameter of the inner annular plate 36 of the circular sleeve 14A is at least 1 inch larger than the outer diameter formed by the upper segment 12A of the elongated tubular leg 12 and the outer guide unit 34A. This allows the elongated tubular leg 12 to freely and vertically pass through the inner diameter of the inner annular plate 36 of the circular sleeve 14A until the outer annular plate 36A of the upper segment 12A contacts the inner annular plate 36. The size of the outer annular plate 36A of the upper segment 12A of the elongated tubular leg 12 is approximately equal to the size of the inner annular plate 36 of the circular sleeve 14A. The diameter of the circular outer shell 32 of the circular sleeve 14A is larger than the diameter of the circular shell 32A of the upper segment 12A of the elongated tubular leg 12, forming an annular space 33 between them. Cement grouting material fills the annular space 33, forming a rigid connection between the circular sleeve 14A and the upper segment 12A of the elongated tubular leg 12.

[0067] like Figure 8 The circular sleeve 14A includes a circular outer shell 42 with a certain diameter and height, multiple internal guide units 44 vertically connected to the inner side of the circular outer shell 42, and an inner annular plate 46A horizontally connected to the lower end of the circular outer shell 42. The inner annular plate 46A has a diameter approximately equal to the diameter of the circle formed by the internal guide units 44, and a T-shaped unit 48A vertically connected to the inner side of the circular outer shell 42. The circular outer shell 42 of the circular sleeve 14A is connected to the top flange plate 52A, vertical web plate 54A, and bottom flange plate 56A of the horizontal beam 14C.

[0068] like Figure 9The upper section 12A of the elongated tubular leg 12 mainly includes an upper part with a top horizontal extension plate 52B, a middle vertical web plate 54B and a vertical side plate 48B, and a lower part, including a circular shell 62 with a diameter equal to the outer diameter of the upper section 12A. Multiple external guide units 64 are attached to the outside of the circular shell 62. An outer annular plate 46B and a watertight cover plate 66 are at the same height and horizontally connected to the top of the circular shell 62. The vertical distance from the outer annular plate 46B to the top horizontal extension plate 52B is slightly greater than the height of the horizontal beam 14C.

[0069] like Figure 10A and Figure 10B The inner diameter of the inner annular plate 46A of the circular sleeve 14A is more than 1 inch larger than the outer diameter of the upper section 12A of the elongated tubular leg 12 with the external guide unit. This allows the elongated tubular leg 12 to pass concentrically and freely perpendicularly through the circular opening of the inner annular plate 46A of the circular sleeve 14A until the outer annular plate 46B of the upper section 12A contacts the inner annular plate 46A. The size of the outer annular plate 46B of the upper section 12A of the elongated tubular leg 12 is approximately equal to the size of the inner annular plate 46A of the circular sleeve 14A. Multiple steel bolts 68A, 68B, and 68C are used to provide a rigid connection between the upper section 12A of the elongated tubular leg 12 and the circular sleeve 14A and the horizontal beam 14C. Specifically, the top flange plate 52A of the horizontal beam 14C is connected to the top horizontal extension plate 52B of the upper section 12A of the elongated tubular leg 12 by steel bolts 68A, the T-shaped unit 48A is connected to the vertical side plate 48B by steel bolts 68B, and the inner annular plate 46A is connected to the outer annular plate 46B by steel bolts 68C.

[0070] like Figure 11A In some embodiments, the gantry platform 2 supporting the wind turbine systems 4, 6, and 8, with four elongated tubular legs 12, is in a floating installation mode. The elongated tubular legs 12 extend vertically upwards, with their upper sections 12A above the horizontal deck 14 and their lower sections 12B concentrically located inside the circular sleeve 14A, connected to the foundation piles 16. Two floating barges 72 are connected to both sides of the horizontal deck 14 via a deck support structure 74, forming a catamaran. These barges provide buoyancy and stability to the integrated system of the gantry platform 2 with the wind turbine systems 4, 6, and 8 and the foundation piles 16 during towing and installation at sea. Four lateral guide devices 76 are provided, each with one end horizontally connected to the top of the corresponding upper section 12A of the elongated tubular leg 12, and the other end contacting the wind tower 4.

[0071] like Figure 11BIn some embodiments, the gantry platform 2 supporting the wind turbine systems 4, 6, and 8 includes three elongated tubular legs 12 in a floating installation mode, wherein the elongated tubular legs 12 extend vertically upward, with their upper sections 12A above the horizontal deck 14 and their lower sections 12B concentrically located inside the circular sleeve 14A and connected above the foundation piles 16. Two floating barges 72, each with one or two deck support structures 74 connected to corresponding sides of the horizontal deck 14, form a catamaran, providing buoyancy and stability to the integrated system of the gantry platform 2 with the wind turbine systems 4, 6, and 8 and the foundation piles 16 during towing and installation at sea. Three lateral guide devices 76 are provided, each with one end horizontally connected to the top of the corresponding upper section 12A of the elongated tubular leg 12 and the other end contacting the wind tower 4.

[0072] like Figure 12 In some embodiments, each lateral guide device 76 includes a housing structure 76A, a length-adjustable hydraulic cylinder 76B, and a spring unit 76C, one end of which is connected to the hydraulic cylinder 76B and the other end of which contacts the wind tower 4, providing lateral support for each extended tubular leg 12. The length of the spring unit 76C can vary with the compressive force.

[0073] like Figure 13 In some embodiments, each of the two floating barges 72 is equipped with two deck support structures 74 and two cable and winch systems, each cable and winch system having a cable 84A and a winch 84B. Each deck support structure 74 is rigidly connected at one end to the top of the deck of the corresponding floating barge 72 and at the other end to the horizontal deck 14, while being configured with a quick release device 82 having a mechanism to separate the floating barge 72 from the horizontal deck 14 in a short time (typically a few seconds). One end of each cable 84A is connected to the winch 84B, passes through a pulley 86 connected to the horizontal deck 14 and extends downward to a second end connected to an ear plate 88 located on top of the foundation pile 16.

[0074] The following details the construction methods for gantry platforms with wind turbine systems, including dock assembly, offshore towing, and self-installation at sea. For example... Figures 14 to 25The construction method comprises twelve steps in sequence. Specifically, throughout the construction process, the gantry platform 2 has three different modes, including: First, forming the wharf assembly mode (steps 1 to 6), for the vertical assembly of the gantry platform 2 at the wharf shore and its vertical integration with the wind turbine systems 4, 6, 8 and the suction caisson foundation piles 16, in which the elongated tubular legs 12 extend vertically upward from the horizontal deck 14 above the waterline; Second, by connecting two floating barges 72 to both sides of the horizontal deck 14 in the wharf assembly mode and providing them with... The buoyancy and stability are provided to form a floating installation mode for towing and self-installation at sea (steps 7 and 8); third, an in-situ power generation mode is formed (steps 9 to 12), wherein the extended tubular leg 12 with suction caisson foundation pile 16 is lowered to the seabed 201 by using cable and winch systems 84A and 84B, the suction caisson foundation pile 16 is embedded in the seabed 201, the two floating barges 72 are released and pulled apart, and the transformation of the gantry platform 2 from the floating installation mode to the in-situ power generation mode is completed.

[0075] It is assumed here that the components of the gantry platform 2, including the extended tubular legs 12, the horizontal deck 14, and the foundation piles 16, as well as the components of the wind turbine system, including the wind tower 4, the nacelle 6, and the rotor blades 8, are prefabricated.

[0076] like Figure 14 In some embodiments, step 1 of the construction method is to connect multiple vertical suction caisson foundation piles 16 together at the top by multiple connecting rods 18 to form symmetrical sub-assemblies 301 on land according to the design, and to hoist the sub-assemblies 301 into the water at the dock shore and make them stand on the seabed 401, while their tops are above the waterline 501.

[0077] like Figure 15 In some embodiments, step 2 of the construction method involves hoisting the horizontal deck 14 onto the top of the sub-assembly 301, which is erected on the seabed 401, wherein each circular sleeve 14A is directly located on the corresponding suction caisson foundation pile 16, and the base structure 14B of the horizontal deck 14 is located at the center of a symmetrical arrangement. The horizontal deck 14 is temporarily connected to the sub-assembly 301 by a plurality of marine fasteners 92 above the waterline 501.

[0078] like Figure 16 In some embodiments, step 3 of the construction method involves vertically hoisting at least one elongated tubular leg 12F onto the top of the subassembly 301 via at least one circular sleeve 14A on the horizontal deck 14, which is located away from the pier, and rigidly connecting the bottom of the elongated tubular leg 12F to the top of the suction caisson pile 16 located away from the pier. The rigid connection may be achieved by welding or grouting.

[0079] like Figure 17In some embodiments, step 4 of the construction method involves vertically hoisting the wind tower 4 and rigidly connecting the bottom of the wind tower 4 to the top of the base structure 14B of the horizontal deck 14. The rigid connection described herein includes welding or bolting.

[0080] like Figure 18 In some embodiments, step 5 of the construction method involves vertically hoisting at least one elongated tubular leg 12N onto the top of the subassembly 301 via at least one circular sleeve 14A on the horizontal deck 14 near the pier, and rigidly connecting the bottom of the elongated tubular leg 12N to the top of the suction caisson pile 16 near the pier. The rigid connection may be achieved by welding or grouting.

[0081] like Figure 19 In some embodiments, step 6 of the construction method involves installing each lateral guide device 76 onto the top of each corresponding elongated tubular leg 12, hoisting the nacelle 6 and connecting it to the top of the wind turbine 4, and then hoisting the rotor blades 8 and connecting them to the nacelle 6. At this point, the dock assembly mode of the gantry platform 2 is complete, and the gantry platform 2, wind turbine systems 4, 6, 8, and foundation piles 16 are integrated into a single platform system. At this time, the entire platform system is in a fixed, standing state.

[0082] like Figure 20 In some embodiments, step 7 of the construction method involves rigidly connecting two floating barges 72 to both sides of the horizontal deck 14 to form a catamaran. By reducing the ballast water of the floating barges 72, the overall platform system is transformed from a fixed, standing state to a floating installation state, i.e., a floating installation mode. The catamaran provides buoyancy and stability for the floating installation mode of the gantry platform 2 at the dockside. Both floating barges are equipped with deck support structures 74 and cable and winch systems 84A and 84B. This is achieved by connecting one end of each of the deck support structures 74 to the horizontal deck 14 using a quick-release device 82, while each cable 84A passes through a pulley connected to the horizontal deck 14 from one end of the winch 84B (not shown in this figure for clarity, see [link]). Figure 13 ), and extends downwards to connect to the ear plate located on top of each corresponding foundation pile 16 (not shown in this figure for clarity, see [link]). Figure 13 At the other end of the line, the floating installation mode of the entire platform system, consisting of the gantry platform 2, the wind turbine systems 4, 6, and 8, and the foundation piles 16, is now complete.

[0083] like Figure 21In some embodiments, step 8 of the construction method involves towing the entire system of the gantry platform 2, which is in a floating installation mode and includes wind turbine systems 4, 6, 8 and suction caisson foundation piles 16, from the assembly dock to the offshore wind farm site using a tugboat 601. Two floating barges 72 are rigidly connected to opposite sides of the horizontal deck 14 to provide buoyancy and stability during towing at sea.

[0084] like Figure 22 In some embodiments, step 9 of the construction method involves a self-installation process to convert the gantry platform 2 with wind turbine systems 4, 6, and 8 from a floating installation mode to an in-situ power generation mode. This self-installation process includes releasing marine fasteners (not shown for clarity) between the horizontal deck 14 above the waterline 101 and the suction caisson foundation piles 16. Figure 22 (As shown) and allows the elongated tubular leg 12 and suction caisson foundation pile 16 to be lowered toward the seabed 201 under gravity via the circular sleeve 14A of the horizontal deck 14, and the speed of the lowering movement to be controlled by the cable and winch systems 84A and 84B. Two floating barges 72 connected to opposite sides of the horizontal deck 14 provide buoyancy and stability to the overall system of the gantry platform 2. Meanwhile, the lateral guide device 76, which moves downward together with the elongated tubular leg 12, remains in contact with the wind tower 4 during self-installation, providing lateral support for the elongated tubular leg 12.

[0085] like Figure 23 In some embodiments, step 10 of the construction method involves further lowering the elongated tubular leg 12 and the suction caisson foundation pile 16 connected thereto to the seabed 201 using cable and winch systems 84A and 84B. Meanwhile, two floating barges 72 connected to opposite sides of the horizontal deck 14 above the waterline 101 provide buoyancy and stability to the overall system of the gantry platform 2 with wind turbine systems 4, 6, and 8 during the self-installation process.

[0086] like Figure 24 In some embodiments, step 11 of the construction method involves embedding the suction caisson foundation piles 16 into the seabed 201 by suction. The upper part 12A of each elongated tubular leg 12 is concentrically positioned in the circular sleeve 14A of the horizontal deck 14, forming an annular space. At the same time, two floating barges 72 connected to opposite sides of the horizontal deck 14 above the waterline 101 provide buoyancy and stability to the overall system of the gantry platform 2 with wind turbine systems 4, 6, and 8 during the self-installation process.

[0087] like Figure 25In some embodiments, step 12 of the construction method involves filling the annular space between the upper part 12A of each extended tubular leg 12 of the gantry platform 2 and each corresponding circular sleeve 14A of the horizontal deck 14 with cement grout, thereby forming a rigid connection between the extended tubular leg 12 and the horizontal deck 14 supporting the wind turbine systems 4, 6, and 8. Then, by activating the quick release device 82, the two floating barges 72 are disconnected and pulled apart, completing the transformation of the gantry platform 2, which supports the wind turbine systems 4, 6, and 8 on the upper part and is connected to the suction caisson foundation piles 16 on the lower part, from the floating installation mode to the in-situ power generation mode.

[0088] In such Figures 26 to 29 In some of the embodiments shown, driven piles are used for seabed soil conditions that are unfavorable to suction caisson piles.

[0089] like Figure 26 The gantry platform 3, in its in-situ power generation mode, includes a wind turbine 4, a nacelle 6, and rotor blades 8. The platform's support includes: multiple elongated tubular legs 12 and corresponding connecting sections 13 connected to the bottom of the elongated tubular legs 12; a horizontal deck 14 above the waterline 101; and multiple driven piles 17 embedded in the seabed 201. The elongated tubular legs 12 extend vertically downwards from the horizontal deck 14 above the waterline 101 and are rigidly connected via connecting sections 13 to the upper sections of the driven piles 17 above the seabed 201. There are no horizontal or diagonal support members between the elongated tubular legs 12. Each elongated tubular leg 12 is rigidly connected at its top to the outside of the horizontal deck 14 by grouting or bolting. The bottom of the wind turbine 4 is vertically connected to the center of the horizontal deck 14. In some embodiments of the gantry platform 3, the driven piles 17 typically have a smaller diameter than the elongated tubular legs 12, and the diameter of the upper section of the driven piles 17 above the seabed 201 is more than 2 inches smaller than the diameter of the connecting sections 13. Each driven stake 17 has multiple shear keys attached to its upper outer side (not shown for clarity). Figure 26 (As shown in the diagram), each connecting segment 13 has multiple shear keys attached to its inner side (not shown in the diagram for clarity). Figure 26 (As shown in the image), the two are connected above the seabed 201 by cement grouting. The connecting section 13 can be as follows: Figure 26 The concentric connection shown is to the bottom of the elongated tubular leg 12, or it can be connected to the lower section of the elongated tubular leg 12 in a similar eccentric connection method as the jacket skirt pile.

[0090] like Figure 27As shown, the gantry platform 3 is in the dock assembly mode, standing on the seabed 201B at a water depth of approximately 8 meters near the dock. It includes multiple elongated tubular legs 12 extending vertically upwards, with their upper parts 12A significantly higher than the waterline 101B. A horizontal deck 14 includes multiple circular sleeves 14A concentric with the lower parts 12B of the elongated tubular legs 12 at a similar height above the waterline 101B. Multiple connecting sections 13 connect at their tops to the bottoms of the elongated tubular legs 12 and at their bottoms to a horizontal anti-sinking plate 19 located on the seabed 201B. The horizontal deck 14 also includes a base structure 14B located at its center, vertically connected to the bottom of the wind tower 4, and multiple horizontal beams 14C each connecting from one side of the base structure 14B to one side of the corresponding circular sleeve 14A.

[0091] In some embodiments, the portal frame platform 3 includes at least three elongated tubular legs 12, at least three connecting sections 13, at least three driven piles 17, a horizontal deck 14 including at least three circular sleeves 14A, a base structure 14B, and at least three horizontal beams 14C connecting the circular sleeves 14A and the base structure 14B to form a symmetrical pattern in a horizontal plane, wherein the base structure 14B is located at the center and is vertically connected to the bottom of the wind tower 4.

[0092] like Figure 28 In some embodiments, the gantry platform 3 is in a floating installation mode, including the lower section of the extended tubular leg 12 at a similar height to the horizontal deck 14 and extending vertically upward from the waterline 101, wherein the lower end of the extended tubular leg 12 is connected to the upper end of the connecting section 13 just above the waterline 101, the lower end of the connecting section 13 being connected to the horizontal anti-sinking plate 19. It also includes two floating barges 72 connected to the corresponding sides of the horizontal deck 14 via at least one deck support structure 74 to form a catamaran, which provides buoyancy and stability to the gantry platform 3 with wind turbine systems 4, 6, 8 during towing and installation at sea. It also includes a plurality of lateral guide devices 76, one end of each lateral guide device 76 being horizontally connected to the top of the corresponding extended tubular leg 12 and the other end contacting the wind tower 4 to provide lateral stability to the extended tubular leg 12.

[0093] like Figure 29 As shown, the gantry platform 3, equipped with wind turbine systems 4, 6, and 8, transitions from a floating installation mode to an in-situ power generation mode during a self-installation process at an offshore wind farm. This process includes using a cable and winch system 84 to lower the elongated tubular leg 12, which has a connecting section 13 and a horizontal anti-sinking plate 19, to a driven pile 17 pre-installed on the seabed 201. The leg 12 is then rigidly connected to the driven pile 17 concentrically via the connecting section 13 and cement grouting. Simultaneously, two floating barges 72 are connected to the corresponding sides of the horizontal deck 14 via a deck support structure 74 and a quick release device 82, providing buoyancy and stability to the gantry platform 3.

[0094] It is easy to see that, such as Figures 26 to 29 The described gantry platform 3 with driven piles 17 can be assembled at the dockside and integrated with the wind turbine, then vertically towed to the offshore wind farm as a whole, and adopts the same method as described above in this invention. Figures 14 to 25 The construction method described uses similar steps to complete the self-installation at sea without the need for a large crane installation vessel.

[0095] The above description and accompanying drawings illustrate exemplary embodiments of the present invention and the main features of the gantry platform and construction method for supporting large offshore wind turbines. The gantry platform is typically a steel structure, with a preferred operating water depth range of 30 to 100 meters. The preferred diameter of its extended tubular legs is typically significantly smaller than the diameter of the supported wind turbine tower. For large wind turbines, the tower diameter is 6 to 10 meters; the larger the turbine power, the larger the tower diameter. However, the gantry platform is not limited to the above water depth range and can be deployed in water depths below 30 meters or above 100 meters. Furthermore, the gantry platform is not limited to supporting wind turbines but can also be used to support other types of superstructures, such as substation equipment in offshore wind farms. It is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Variations, modifications, substitutions, and modifications made to the above embodiments by those skilled in the art should be covered within the spirit and scope of the present invention.

Claims

1. A gantry platform, characterized in that, include: Multiple vertically arranged elongated tubular legs, including upper, middle and lower sections; A horizontal deck includes multiple circular sleeves arranged radially equidistantly from its center, a base structure located at its center, and multiple horizontal beams. Each horizontal beam is connected at one end to a corresponding circular sleeve and at the other end to the base structure. The inner diameter of the circular sleeve is larger than the outer diameter of the elongated tubular leg. Each elongated tubular leg is concentrically located inside the corresponding circular sleeve, with an annular space in the middle. A wind turbine system includes a base structure at the bottom of a wind tower vertically connected to a horizontal deck, a nacelle connected to the top of the wind tower, and multiple rotor blades connected to the nacelle. Multiple foundation piles, the top of each foundation pile being vertically connected to the bottom of the corresponding elongated tubular leg, wherein the foundation piles are suction caisson piles and their diameter is larger than the diameter of the elongated tubular leg; Multiple foundation pile connecting rods, with both ends horizontally connected to the top of two foundation piles; Multiple lateral guide devices, one end of which is horizontally connected to the top of the corresponding elongated tubular leg; When the gantry platform is in the in-situ power generation mode in the water of the offshore wind farm, more than half of the length of the extended tubular legs extends vertically downward to the seabed below the waterline. There are no horizontal or diagonal support components between the extended tubular legs. The horizontal deck is located above the waterline. The upper section of the extended tubular legs is concentrically located inside the circular sleeve of the corresponding horizontal deck and is rigidly connected. The bottom of the wind turbine tower is vertically connected to the base structure of the horizontal deck. The foundation piles are embedded in the seabed, and their upper ends are located above the seabed and are vertically rigidly connected to the lower section of the extended tubular legs. When the gantry platform is in the quay assembly mode in the shallow water at the quay shore, more than half of the length of the extended tubular legs extends vertically upwards into the air above the waterline. There are no horizontal or diagonal support components between the extended tubular legs. The horizontal deck is located above the waterline. The lower section of the extended tubular legs is concentrically located inside the circular sleeve of the corresponding horizontal deck. The bottom of the wind turbine tower is vertically connected to the base structure of the horizontal deck. The foundation piles stand vertically on the seabed, with their upper ends located above the waterline and rigidly connected vertically to the lower section of the extended tubular legs. When the gantry platform is in floating installation mode, towing and offshore installation are achieved through a catamaran floating system consisting of two floating barges. The horizontal deck is located above the waterline and is rigidly connected to the two floating barges on opposite sides to form the catamaran floating system. More than half the length of the extended tubular legs extends vertically upward into the air above the waterline. There are no horizontal or diagonal support components between the extended tubular legs. The lower section of the extended tubular legs is concentrically located inside the circular sleeve of the corresponding horizontal deck. The bottom of the wind turbine tower is vertically connected to the base structure of the horizontal deck. The upper end of the foundation pile is located above the waterline and is rigidly connected vertically to the lower section of the extended tubular leg, while its lower end is located above the seabed.

2. The gantry platform according to claim 1, characterized in that, There is a concentric annular space between the outer side of the upper section of each elongated tubular leg and the inner side of the corresponding circular sleeve of the horizontal deck, which forms a rigid connection through cement grouting. Each circular sleeve includes a circular outer shell, multiple internal guide units vertically connected to the interior of the circular outer shell, and an inner annular plate horizontally connected to the lower inner side of the circular outer shell, the inner diameter of which matches the diameter of the circle formed by the internal guide units.

3. The gantry platform according to claim 1, characterized in that, The upper section of the elongated tubular leg includes a circular shell with a diameter equal to the outer diameter of its upper section, multiple external guide units connected to the outside of the circular shell, an outer annular plate horizontally connected to the bottom of the circular shell, and a watertight cover plate connected to the top of the circular shell, wherein the vertical distance from the bottom outer annular plate to the top watertight cover plate matches the height of the circular sleeve of the horizontal deck. The inner diameter of the inner annular plate of the circular sleeve is larger than the outer diameter of the upper section of the elongated tubular leg with the external guide unit. The elongated tubular leg extends downward perpendicularly through the opening circle of the inner annular plate of the circular sleeve until the outer annular plate of its upper section contacts the inner annular plate of the circular sleeve. The size of the outer annular plate of the upper section matches the size of the inner annular plate of the circular sleeve. The diameter of the circular outer shell of the circular sleeve is larger than the diameter of the circular outer shell of the upper section of the elongated tubular leg, forming an annular space between the two. Cement grout fills the annular space, forming a rigid connection between the circular sleeve of the horizontal deck and the upper section of the elongated tubular leg.

4. The gantry platform according to claim 1, characterized in that, The rigid connection between the upper section of the elongated tubular leg and the horizontal deck is bolted, consisting of multiple steel bolts connecting each part of the upper section of the elongated tubular leg to the corresponding circular sleeve and horizontal beam of the horizontal deck. The upper section of the elongated tubular leg includes an upper part consisting of a top horizontal extension plate, a vertical web plate and a vertical side plate, and a lower part consisting of a circular shell, an outer annular plate, a watertight cover plate and multiple external guide units. The diameter of the circular shell is equal to the diameter of the upper section of the elongated tubular leg. The outer annular plate and the watertight cover plate are horizontally connected to the top of the circular shell, and the multiple external guide units are connected to the outside of the circular shell.

5. The gantry platform according to claim 1, characterized in that, Each circular sleeve of the horizontal deck includes a circular outer shell whose diameter and height match the height of the upper part of the extended tubular leg. A T-shaped member and multiple internal guide units are vertically connected to the inside of the circular outer shell. An inner annular plate is horizontally connected to the lower end of the circular outer shell, wherein the inner diameter of the inner annular plate is equal to the diameter of the circle formed by the T-shaped member and the internal guide units. The circular outer shell is connected to the top flange, vertical web and bottom flange of the horizontal beam of the horizontal deck. The top flange of the horizontal beam of the horizontal deck is bolted to the top horizontal extension plate of the upper section of the extended tubular leg. The T-shaped member and inner annular plate of the circular sleeve of the horizontal deck are bolted to the vertical side plate and outer annular plate of the upper section of the extended tubular leg, respectively.

6. The gantry platform according to claim 1, characterized in that, The dock assembly mode includes at least three lateral guide devices, wherein one end of each lateral guide device is connected to the top of the corresponding elongated tubular leg, and the other end is in contact with the wind tower; The lateral guide device includes a housing structure, an adjustable-length hydraulic cylinder connected to the housing structure, and a spring unit, one end of which is connected to the hydraulic cylinder and the other end of which contacts the wind tower under pressure. Its length changes with the pressure.

7. The gantry platform according to claim 1, characterized in that, Each of the two floating barges is equipped with at least one deck support structure and a cable and winch system, wherein the deck support structure is connected at one end to the top of the floating barge and at the other end to the horizontal deck, wherein the deck support structure is equipped with a quick release device having a mechanism to separate the floating barge from the horizontal deck within seconds. The cable and winch system consists of a winch and a cable, one end of which is connected to a winch located on top of the floating barge, passes through a pulley on a horizontal deck and extends down to the other end, which is connected to a lug plate located on top of the foundation pile.

8. A method for constructing a gantry platform, characterized in that, The gantry platform includes: Multiple vertically extending elongated tubular legs, the elongated tubular legs including an upper section, a middle section and a lower section; A horizontal deck comprises multiple circular sleeves arranged radially at equal intervals from the center. A centrally located base structure and multiple horizontal beams, each horizontal beam being connected at one end to the base structure and at the other end to a corresponding circular sleeve, wherein the diameter of the circular sleeve is larger than the diameter of the elongated tubular leg; A wind turbine system includes a wind tower, nacelle, and multiple rotor blades; Multiple suction caisson foundation piles; Multiple foundation pile connecting rods; Multiple lateral guide devices; The construction method includes: Step 1: Connect the tops of multiple suction caisson foundation piles that are standing upright on land horizontally together using multiple foundation pile connecting rods to form a symmetrical foundation pile assembly. Hoist the foundation pile assembly into the water at the dockside so that it stands on the seabed with its top above the waterline. Step 2: The horizontal deck is hoisted onto the top of the foundation pile assembly that stands upright on the seabed. The circular sleeve of each horizontal deck is directly located on the corresponding suction caisson foundation pile. The base structure of the horizontal deck is located at the center of the symmetrical arrangement. The horizontal deck is temporarily connected to the foundation pile assembly by multiple marine fasteners above the waterline. Step 3: Vertically hoist at least one elongated tubular leg onto the top of the foundation pile assembly via at least one circular sleeve on the horizontal deck, far from the quay, and rigidly connect the bottom of the elongated tubular leg to the top of the suction caisson foundation pile on the far side of the quay, wherein the rigid connection is made by means of welding or cement grouting. Step 4: Vertically hoist the wind tower and rigidly connect the bottom of the wind tower to the top of the base structure of the horizontal deck. The rigid connection can be achieved by welding or bolting. Step 5: Vertically hoist at least one elongated tubular leg onto the top of the foundation pile assembly using at least one circular sleeve on the horizontal deck away from the quay side, and rigidly connect the bottom of the elongated tubular leg to the top of the suction caisson foundation pile on the quay side. The rigid connection can be achieved by welding or grouting. Step 6: Install the lateral guide device on the top of each corresponding extended tubular leg, hoist the nacelle and connect it to the top of the wind tower, and then hoist the rotor blades and connect them to the nacelle. At this point, the dock assembly mode of the gantry platform is completed. The gantry platform, wind turbine system and suction caisson foundation piles are integrated into a platform system. At this time, the platform system is in a fixed standing state.

9. The construction method according to claim 8, characterized in that, The gantry platform also includes: multiple pulleys connected to the horizontal deck, multiple lugs connected to the top of the corresponding suction caisson foundation piles, and two floating barges, wherein: multiple deck support structures are respectively connected to the top of each floating barge, multiple quick release devices are respectively connected to each corresponding deck support structure, and multiple cable and winch systems. The construction method described above further includes, after step 6: Step 7: Rigidly connect the two floating barges to the corresponding sides of the horizontal deck to form a catamaran system. By reducing the ballast water of the floating barges, the overall platform system changes from a fixed standing state to a floating state, i.e., the floating installation mode. The catamaran system provides buoyancy and stability for the floating installation mode of the gantry platform at the dock. Both floating barges are equipped with deck support structures and cable and winch systems. This is achieved by connecting one end of each of the deck support structures to the horizontal deck with a quick release device. At the same time, each cable extends downward from one end of the winch through a pulley connected to the horizontal deck to the other end of the ear plate located at the top of each foundation pile. This completes the floating installation mode of the overall platform system, which integrates the gantry platform, the wind turbine system, and the suction caisson foundation piles. Step 8: The entire platform system, including the wind turbine system and suction caisson foundation piles, which is in floating installation mode, is towed from the assembly dock to the offshore wind farm by tugboats, with two floating barges connected on opposite sides of the horizontal deck to provide buoyancy and stability during the towing at sea. Step 9: A self-installation process is used to convert the overall platform system of the gantry platform, which includes the wind turbine system and suction caisson foundation piles, from the floating installation mode to the in-situ power generation mode. The self-installation process includes disconnecting the marine fasteners connecting the horizontal deck above the waterline and the suction caisson foundation piles, allowing the extended tubular legs to move downwards to the seabed under their own weight through the circular sleeves of the horizontal deck. The lowering speed is controlled using a cable and winch system. At the same time, the lateral guide device, which moves downwards with the extended tubular legs, always maintains pressure contact with the wind tower to provide horizontal lateral support for the extended tubular legs during the self-installation process. Two floating barges connected to opposite sides of the horizontal deck provide buoyancy and stability to the overall platform system. Step 10: Further lower the extended tubular leg using a cable and winch system until the suction caisson foundation pile is lowered to the seabed; Step 11: The suction caisson foundation piles are embedded into the seabed by suction, wherein the upper section of each elongated tubular leg is concentrically located in the corresponding circular sleeve of the horizontal deck, forming an annular space between them. Step 12, forming a rigid connection between the upper section of the elongated tubular leg and the circular sleeve of the horizontal deck, specifically involves filling the annular space with cement grout and disconnecting the two floating barges from the horizontal deck by activating the quick release device and pulling the two floating barges apart.

10. A gantry platform, characterized in that, include: Multiple vertically arranged elongated tubular legs, including upper, middle and lower sections; A horizontal deck includes multiple circular sleeves arranged radially equidistantly from the center, a base structure located at the center, and multiple horizontal beams, wherein each horizontal beam is connected at one end to a corresponding circular sleeve and at the other end to the base structure. The inner diameter of the circular sleeve is larger than the outer diameter of the elongated tubular leg. Each elongated tubular leg is concentrically located inside the corresponding circular sleeve, with an annular space in the middle. A wind turbine system includes a base structure at the bottom of a wind tower vertically connected to a horizontal deck, a nacelle connected to the top of the wind tower, and multiple rotor blades connected to the nacelle. Multiple driven piles, specifically: circular pipes; Multiple connecting transition sections, specifically: a circular tube body, concentrically or eccentrically connected to the lower section of the corresponding elongated tubular leg; Multiple anti-sinking plates are horizontally connected to the bottom of the corresponding connecting transition sections; Multiple lateral guide devices, one end of which is horizontally connected to the top of the corresponding elongated tubular leg; When the gantry platform is in the quay assembly mode in the shallow water near the quay shore, more than half of the length of the extended tubular legs extends vertically upwards into the air above the waterline. There are no horizontal or diagonal support components between the extended tubular legs. The horizontal deck is located above the waterline. The lower section of the extended tubular legs is concentrically located inside the circular sleeve of the corresponding horizontal deck. The bottom of the wind turbine tower is vertically connected to the base structure of the horizontal deck. The connecting transition section and the anti-sinking plate located below it stand vertically on the seabed. Its upper end is located above the waterline and is vertically rigidly connected to the lower section of the extended tubular legs. At the same time, it is connected to the horizontal deck through temporary fasteners. When the gantry platform is in the in-situ power generation mode in the water of the offshore wind farm, more than half of the length of the extended tubular legs extends vertically downward to the seabed below the waterline. There are no horizontal or diagonal support components between the extended tubular legs. The horizontal deck is located above the waterline. The upper section of the extended tubular legs is concentrically located inside the circular sleeve of the corresponding horizontal deck and is rigidly connected. The bottom of the wind turbine tower is vertically connected to the base structure of the horizontal deck. The lower part of the driven pile is embedded in the seabed, and its upper part above the seabed is concentrically and vertically rigidly connected to the connecting transition section.

11. The gantry platform according to claim 10, characterized in that, When the gantry platform is in floating installation mode, towing and offshore installation are achieved through a catamaran floating system consisting of two floating barges. The horizontal deck is located above the waterline and is rigidly connected to the two floating barges on opposite sides to form the catamaran floating system. More than half the length of the extended tubular legs extends vertically upwards into the air above the waterline. There are no horizontal or diagonal support components between the extended tubular legs. The lower sections of the extended tubular legs are concentrically located inside the circular sleeves of their corresponding horizontal decks. The bottom of the wind turbine tower is connected to the base structure of the horizontal deck. The vertical connection is as follows: the upper end of the connecting transition section is above the waterline and is rigidly connected vertically to the lower section of the extended tubular leg; the lower end is above the seabed and is horizontally connected to the anti-sinking plate; each of the two floating barges is equipped with at least one deck support structure and quick release device, as well as at least one set of cable and winch system; driven piles are pre-installed on the seabed of the offshore wind field, with an outer diameter smaller than the inner diameter of the connecting transition section; the upper part of the driven pile is above the seabed, and multiple shear keys are connected to the outer side of its circular tube; multiple shear keys are connected to the inner side of the circular tube of the connecting transition section.

12. The gantry platform according to claim 10, characterized in that, When the gantry platform is in the self-installation process, the lower section of each extended tubular leg with a connecting transition section and a horizontal anti-sinking plate is lowered using a cable and winch system and concentrically connected to the upper part of the corresponding driven pile pre-installed on the seabed. The connecting transition section is rigidly connected to the upper part of the driven pile by cement grouting. Then, the upper section of each extended tubular leg is rigidly connected to the corresponding circular sleeve on the horizontal deck by cement grouting or bolts. During the self-installation process, two floating barges are rigidly connected to both sides of the horizontal deck through the deck support structure and quick release device to provide buoyancy and stability for the gantry platform. Finally, the quick release device is activated to disconnect the two floating barges from the horizontal deck, completing the transformation of the gantry platform from the floating installation mode to the in-situ power generation mode.

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