Floating structures and offshore wind power facilities

Abstract

To provide a floating structure and an ocean wind power generation facility capable of suppressing heaving.SOLUTION: A floating structure 100 installed on ocean including an annular floating body 10 which is an annular shape having a through hole extending in the vertical direction and having the ranges divided into the environment and an inside range 12 surrounded by the annular floating body 10 by the annular floating body 10 has a communication unit 18 connected to the environment and the inside range 12 and functioning as a flow path for the water.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a floating structure used as a foundation for, for example, an offshore wind power generation facility and an offshore wind power generation facility.

Background Art

[0002] Conventionally, offshore wind power generation facilities are mainly classified into two types: fixed type and floating type. The fixed type is a method of installing wind power equipment on a foundation fixed to the seabed, and the floating type is a method of installing wind power equipment on a floating structure floating on the sea. Fixed-type offshore wind power generation facilities have problems with the feasibility of the structure and a sharp increase in cost when the water depth increases. Therefore, the practical application of floating-type offshore wind power generation facilities is required. In particular, in Japan, unlike in Europe, there are many coastal areas where the water depth increases rapidly rather than being shallow, so the scope of application of the floating type is wide. The floating structures used in the floating type are mainly classified into four types: barge type (also called pontoon type), TLP type, semi-submersible type, and spar type (see, for example, Non-Patent Document 1). Each floating type is used by being moored on the sea with an anchor and a mooring cable installed on the seabed. As structural materials for manufacturing the floating structure, there are steel, reinforced concrete, and a composite structure (hybrid structure) using both.

[0003] Currently, demonstration experiments are being conducted on each of the above floating types in Japan and Europe for floating-type offshore wind power generation facilities (see, for example, Non-Patent Document 2). Each floating type has characteristics, and the applicability varies depending on the scale of the power plant, the location, the sea area conditions, and the manufacturing location.

[0004] For example, the barge type has a flat-bottomed box-boat shape and a structure that increases stability by increasing the contact surface with the water surface. This barge type has a large waterplane area and a large restoring force against the inclination of the floating body, so there is an advantage that the floating body dimensions can be reduced. However, there are problems that the wave force acting is large because the projected area near the sea surface where the wave force is large is large, and the fluctuation period of the wave and the floating body is close, and the sway becomes intense when the wave becomes intense.

[0005] As an example of a barge-type motion reduction measure, a known example is a ring-shaped floating structure with a through-hole in the center when viewed from vertically above (see, for example, Non-Patent Document 3). In this configuration, stabilization is achieved by utilizing the vibration of water confined within the ring-shaped floating structure. However, in this structure, in certain frequency bands, the water mass within the moonpool has an out-of-phase effect on suppressing the vertical motion (heave) of the floating structure, and it has been observed that this actually increases the vertical motion. Similarly, in certain frequency bands, it has been pointed out that the water mass within the moonpool causes sloshing, which increases the motion of the rotational system (pitch in forward waves, roll in transverse waves) (see, for example, Non-Patent Document 4). [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Ministry of Land, Infrastructure, Transport and Tourism, Ports and Harbors Bureau website, "Study Group on the Ideal Form of Base Ports for Achieving Carbon Neutrality by 2050 (1st Meeting), May 18, 2021, Document 3, p. 37," [online], [Accessed March 15, 2022], Internet<URL:https: / / www.mlit.go.jp / common / 001404624.pdf> [Non-Patent Document 2] National Research and Development Agency, New Energy and Industrial Technology Development Organization (NEDO) website, "Floating Offshore Wind Power Generation Technology Guidebook Supplementary Materials, National Research and Development Agency, New Energy and Industrial Technology Development Organization, March 2018, p. 129," [online], [Accessed March 15, 2022], Internet<URL:https: / / www.nedo.go.jp / content / 100891425.pdf> [Non-Patent Document 3] "Study on the motion characteristics of various floating body types," Yuka Kikuchi et al., Wind Energy Utilization Symposium, Vol. 39, pp. 315-318, 2017. [Non-Patent Document 4] "A Study on the Effect of Moonpools on the Motion Characteristics of Pontoon-Type Floating Bodies," Hayato Moritsu et al., Proceedings of the 2019 Academic Conference of the College of Science and Technology, Nihon University, pp. 669-670, 2019. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] As mentioned above, the conventional floating structure described in Non-Patent Document 3 may experience significant vertical oscillation in certain frequency bands. Therefore, a structure capable of suppressing vertical oscillation was needed.

[0008] The present invention has been made in view of the above, and aims to provide a floating structure and an offshore wind power generation facility that can suppress vertical swaying. [Means for solving the problem]

[0009] To solve the above-mentioned problems and achieve the objective, the floating structure according to the present invention is a floating structure installed on the ocean, comprising an annular floating body having a vertically extending through hole, wherein the area is divided by the annular floating body into the outside world and an internal area surrounded by the annular floating body, and is characterized by having a communication section that connects to the outside world and the internal area and functions as a water channel.

[0010] Furthermore, another floating structure according to the present invention is characterized in that, in the above-described invention, the annular floating body comprises a plurality of island-like portions projecting vertically upward from the waterline in an island-like manner, and connecting portions connecting the island-like portions underwater, wherein the connecting portion is located vertically above the connecting portion.

[0011] Furthermore, another floating structure according to the present invention is characterized in that, in the above-described invention, the annular floating body further comprises a bridge section that connects the island-like sections in the water located vertically above the connecting section.

[0012] Furthermore, another floating structure according to the present invention is characterized in that, in the above-described invention, the annular floating body further comprises a bulkhead connecting the connecting portion and the bridge portion, extending in the vertical direction and in the penetrating direction of the connecting portion.

[0013] Furthermore, another floating structure according to the present invention is a floating structure installed on the ocean, comprising an annular floating body having a vertically extending through hole, wherein the annular floating body divides the area into the outside world and an internal area surrounded by the annular floating body, characterized in that the annular floating body has a shape that forms a single cross section in at least one horizontal cross section in the water, and has a shape that has multiple cross sections scattered in at least one horizontal cross section in the surface cross section.

[0014] Furthermore, the offshore wind power generation facility according to the present invention is characterized by comprising the floating structure described above and a wind power generation facility installed on the floating structure. [Effects of the Invention]

[0015] The floating structure according to the present invention comprises an annular floating body having a vertically extending through hole, and the annular floating body divides the area into the outside world and an internal area surrounded by the annular floating body. The floating structure is installed on the ocean and has a connecting section that connects to the outside world and the internal area and functions as a water channel. By allowing some of the waves and water flow acting on the annular floating body to escape through the connecting section, it is possible to reduce the wave force acting on the annular floating body. Therefore, it has the effect of reducing the vertical swaying of the floating structure.

[0016] Furthermore, according to another floating structure of the present invention, in the above-described invention, the annular floating body comprises a plurality of island-like sections projecting vertically upward from the waterline, and connecting sections that connect the island-like sections underwater. Since the connecting sections are located vertically above the connecting sections, it is possible to reduce the wave force acting on the annular floating body by allowing some of the waves and water currents acting on it to escape through the connecting sections. Therefore, it has the effect of reducing the vertical swaying of the floating structure.

[0017] Furthermore, according to other floating structures of the present invention, in the above-described invention, the annular floating body further comprises a bridge section that connects the island-like sections in the water located vertically above the connecting section, thus providing the effect of allowing easy movement between the island-like sections.

[0018] Furthermore, according to other floating structures of the present invention, in the above-described invention, the annular floating body is further provided with a bulkhead that extends along the vertical direction and the penetrating direction of the connecting portion, connecting the connecting portion and the bridge portion, thereby ensuring rigidity at the connecting portion and reducing vertical sway of the floating structure.

[0019] Furthermore, according to another floating structure of the present invention, there is a floating structure installed on the ocean that comprises an annular floating body having a vertically extending through hole, and the area is divided into the outside world and an internal area surrounded by the annular floating body, wherein the annular floating body has a shape that forms a single cross section in at least one horizontally extending cross section in water, and has a shape that has multiple cross sections scattered in at least one horizontally extending cross section on the water surface, so that some of the waves and water currents acting on the annular floating body can escape through the connecting part, thereby reducing the wave force acting on the annular floating body. Therefore, it has the effect of reducing the vertical swaying of the floating structure.

[0020] Moreover, according to the offshore wind power generation facility of the present invention, since it includes the above-described floating structure and the wind power generation equipment provided on the floating structure, it is possible to provide a floating type offshore wind power generation facility with reduced vertical sway, which has the effect of achieving such an effect.

Brief Description of Drawings

[0021] [Figure 1] FIG. 1 is a schematic perspective view showing Embodiment 1 of the floating structure according to the present invention, (1) is a view seen obliquely from above, and (2) is a view seen horizontally from the waterline. [Figure 2] FIG. 2 is a schematic perspective view showing Embodiment 2 of the floating structure according to the present invention. [Figure 3] FIG. 3 is a schematic perspective view showing Modification 1 of the floating structure according to the present invention. [Figure 4] FIG. 4 is a schematic perspective view showing Modification 2 of the floating structure according to the present invention. [Figure 5] FIG. 5 is a plan view showing an example of the installation work of a wind turbine on a quay wall.

Modes for Carrying Out the Invention

[0022] Hereinafter, embodiments of the floating structure and the offshore wind power generation facility according to the present invention will be described in detail based on the drawings. Note that the present invention is not limited by this embodiment.

[0023] (Embodiment 1) First, Embodiment 1 of the present invention will be described. As shown in Figure 1, the floating structure 100 according to this embodiment 1 is a barge-type structure with a shallow draft and a flat bottom, and consists of an annular floating body 10 with a through hole in the center when viewed from vertically above. The annular floating body 10 has a square (quadrilateral) shape when viewed from vertically above, and the outer and inner contours of the annular floating body 10 are concentric squares. In other words, the annular floating body 10 divides the area into the outside world and the internal area 12 enclosed by the annular floating body 10. In this specification, "draft" refers to the distance from the lowest end of the floating structure 100 floating on water to the water surface in the vertical direction, and "waterline" refers to the line of intersection between the floating structure 100 floating on water and the water surface.

[0024] Furthermore, the offshore wind power generation facility 1 according to Embodiment 1 of the present invention includes a wind power generation facility 2 installed on a corner portion 10A of an annular floating body 10. The wind power generation facility 2 has a wind turbine tower 3, a wind turbine (not shown) installed at the top of the wind turbine tower 3, and a generator. In the example shown in the figure, the wind turbine tower 3 is shown to be placed on one corner portion 10A (an island-shaped portion 14 described later) of the annular floating body 10, but the present invention is not limited to this.

[0025] The annular floating body 10 has four island-shaped sections 14 that protrude vertically upward from the waterline WL (water surface), and connecting sections 16 that connect the four island-shaped sections 14 underwater. The annular floating body 10 has a square shape when viewed from vertically above, and the outer and inner contours of the annular floating body 10 are concentric squares. In other words, when viewed from vertically above, the annular floating body 10 has approximately L-shaped island-shaped sections 14 at the four corner sections 10A, and approximately I-shaped connecting sections 16 that connect two of the corner sections 10A. Therefore, a communication section 18 is formed between two of the island-shaped sections 14, that is, above the connecting section 16. Therefore, the annular floating body 10 is shaped such that, in a cross-sectional view of any horizontally extending section in water, it has a single annular cross-section, and in a cross-sectional view of any horizontally extending section above water, it has a shape in which multiple cross-sections are scattered.

[0026] The materials constituting the annular floating body 10 (island-shaped portion 14, connecting portion 16) may be, for example, steel, reinforced concrete, fiber-reinforced concrete, or a composite structure using these materials.

[0027] The connecting section 18 connects the outside of the annular floating body 10 to the internal region 12 surrounded by the annular floating body 10, and functions as a channel that allows water to pass through. In other words, the annular floating body 10 is shaped by cutting out the corner sections 10A at the four corners, leaving island-shaped sections 14 and connecting sections 16 that connect to the two island-shaped sections 14, and forming groove-shaped connecting sections 18 in the annular floating body.

[0028] The width of the connecting section 18 should, in total, be at least 10% of the width of the annular floating body 10 on one side (the length of one side of the square-shaped outer contour), and preferably less than 80%. If the width of the connecting section 18 is less than 10% of the width of the annular floating body 10, the wave force reduction effect of the connecting section 18 may not be sufficiently obtained. Also, if the width of the connecting section 18 is 80% or more, the annular floating body 10 itself may become larger in order to secure the second moment of the waterline plane necessary to ensure the stability performance of the floating structure 100, and the advantage of the barge type, which allows for a more compact floating body size compared to the semi-submersible type, may not be fully obtained.

[0029] The surface 18A of the connecting portion 16 facing the communication portion 18 may be a surface that inclins to protrude vertically upward as it moves from the outside to the inside of the annular floating body 10, and may have an inclination gradient of, for example, 30° to 60° with respect to the horizontal plane. Furthermore, the side wall 18B of the island-shaped portion 14 facing the communication portion 18 is not limited to a vertical wall extending in the vertical direction as shown in Figure 1, but may also be an inclined wall inclined with respect to the vertical direction. In addition, the width of the communication portion 18 in the horizontal direction may be set to gradually widen or narrow as it moves from the outside to the inside of the annular floating body 10. By setting the cross-sectional shape of the communication portion 18 to a shape that rapidly widens, gradually widens, rapidly narrows, or gradually narrows in this way, it is possible to change the flow velocity due to waves passing through the communication portion 18, thereby creating a phase difference with the sloshing period and adjusting to reduce the motion caused by sloshing. The shape and inclination angle of the connecting section 18 are preferably optimized for the oceanographic conditions of the area where the floating structure 100 is installed.

[0030] Since the floating structure 100 in this embodiment is of the barge type, it has the advantage of being able to have a shallow draft. However, if the draft is made too shallow, the bottom of the annular floating body 10 may be subjected to impact loads from waves due to slamming. For this reason, it is desirable that the distance from the bottom surface of the annular floating body 10 to the stationary draft when in service be at least half of the design significant wave height under normal sea conditions (expected return value over one year) in the installation area. On the other hand, making the distance from the bottom surface of the annular floating body 10 to the stationary draft when in service is made difficult to construct, so it is desirable that this distance be 2.5 times or less of the design significant wave height under extreme sea conditions set for the service life of the floating structure 100.

[0031] The operation and function of the above configuration will now be explained. In this embodiment, the annular floating body 10 is provided with a communication section 18, which reduces the external force that the annular floating body 10 receives from waves. In addition, a portion of the water flow caused by the vertical movement of water within the internal region 12 surrounded by the annular floating body 10 is released to the outside of the annular floating body 10 through the communication section 18. Therefore, the annular floating body 10 according to this embodiment, while having an annular barge-type floating body structure, can reduce the vertical swaying (heave) of the floating structure in a specific frequency band caused by synchronization with waves. Furthermore, vertical swaying can also be suppressed by reducing the waterline area. In other words, the floating structure 100 is shaped in a way that can reduce the swaying of the floating structure 100.

[0032] Thus, according to this embodiment, although it is a barge type, the restoring force can be reduced by decreasing the waterline area that governs the restoring force of vertical oscillation, and the oscillation damping effect of the floating body can be achieved by setting the natural period of vertical oscillation to the longer period side. This effect is particularly noticeable when the oscillation period of the floating structure is low.

[0033] Furthermore, according to this embodiment, since it is a barge-type floating structure, the draft at the time of installation is small, and it can be applied to relatively shallow sea areas (for example, water depth of about 40m to 80m). In addition, because the draft at launch is small, the required water depth during wind turbine assembly and temporary placement sites is small, and there is a high degree of freedom in selecting the area of ​​use.

[0034] By setting the stationary draft of the floating structure 100 during its operational period within an appropriate range, the impact load caused by slamming of the floating structure 100 in waves is mitigated, and the shape also contributes to the ease of construction of the floating structure 100.

[0035] In the above embodiment, the floating structure 100 was described as having a square shape when viewed from vertically above. However, the present invention is not limited to this, and any shape is acceptable as long as the outer shape includes an annular floating body 10, an internal region surrounded by the annular floating body 10, and a connecting portion 18 that functions as a flow path allowing water to pass through. For example, the outer shape when viewed from vertically above may be a polygon such as a triangle or rectangle, or a circle.

[0036] In the above embodiment, an annular floating body 10 is used as the base of the wind power generation equipment 2, such as a large wind turbine (for example, the base of the tower 3), and the base of the wind power generation equipment 2 is provided at the corner portion 10A, more specifically at the island-shaped portion 14.

[0037] Furthermore, as shown in Figure 5, when the construction to mount the wind turbine tower 3 on one of the corner sections 10A of the annular floating body 10 is carried out at the quay G, it is preferable to arrange the two annular floating bodies 10 so that the island-shaped sections 14 on which the wind turbine towers 3 are mounted are adjacent to each other. In this way, the towers 3 and wind turbines can be mounted on each of the two annular floating bodies 10 using a single crane C on the quay G. By arranging the annular floating bodies 10 in appropriate positions in this way, it becomes possible to simplify the construction work to mount the towers 3 and wind turbines from the quay G, thereby improving construction efficiency and reducing construction costs.

[0038] In the above embodiment, a floating structure 100 in which an annular floating body 10 is applied to the foundation of a floating offshore wind power generation facility 1 was used as an example for explanation. However, the floating structure of the present invention is not limited to foundations for floating offshore wind power generation facilities. Any equipment may be mounted on the floating structure of the present invention as long as it is suitable for its purpose.

[0039] (Embodiment 2) Next, Embodiment 2 of the present invention will be described. As shown in Figure 2, the floating structure 200 according to this second embodiment differs from the first embodiment in that it has a bridge section 20 that connects the island-shaped sections 14 on the water, located vertically above the connecting section 16. In other words, in the floating structure 100 according to the first embodiment, the island-shaped sections 14 are left at the corner sections 10A at the four corners, and groove-shaped connecting sections 18 are formed on the annular floating body. On the other hand, the shaped floating structure 200 according to this embodiment differs in that, in parts other than the corner sections 10A at the four corners, connecting sections 18, which are through holes that connect the outside of the annular floating body 10 to the internal region 12 surrounded by the annular floating body 10, are provided on the annular floating body.

[0040] Therefore, the through-hole communication section 18, like the groove-shaped communication section 18 in Embodiment 1, connects the outside of the annular floating body 10 to the internal region 12 surrounded by the annular floating body 10, and functions as a flow path that allows water to pass through. In this way, the annular floating body 10 is made capable of reducing the external forces it receives from waves by being provided with the communication section 18. In addition, some of the water flow caused by the vertical movement of water within the internal region 12 surrounded by the annular floating body 10 is released to the outside of the annular floating body 10 through the communication section 18. For this reason, the annular floating body 10 according to this embodiment, while having an annular barge-type floating body structure, can reduce the vertical swaying (heave) of the floating structure in a specific frequency band caused by synchronization with waves. Furthermore, vertical swaying can also be suppressed by reducing the waterline area. In other words, the floating structure 200 is shaped in a way that can reduce the swaying of the floating structure 200. Thus, Embodiment 2 differs from Embodiment 1 only in that it further includes a bridge section 20. Therefore, the effects of water flow and waves are no different from those in Embodiment 1, and the same motion reduction effect as in Embodiment 1 can be obtained.

[0041] In addition, the floating structure 200 is constructed without any steps between the bridge section 20 and the island section 14, allowing for easy movement between the island sections 14 by crossing the bridge section 20 during maintenance and other work. Furthermore, by providing an appropriate bridge section vertically above the connecting section 16 and, consequently, the connecting section 18, it is possible to reduce the bending moment acting on the connecting section 16 below the bridge section 20. This allows for sufficient strength to be maintained in the vicinity of the connecting section 16.

[0042] The bridge section 20, like the island section 14 and the connecting section 16, can be constructed of, for example, steel, reinforced concrete, fiber-reinforced concrete, or a composite structure using these materials. To prevent damage caused by a phenomenon called slamming, where the bridge section 20 is subjected to impact loads from waves under wave action, it is desirable that the lower surface of the bridge section 20 be positioned at a clearance of at least 1 / 4 of the design wave height under normal sea conditions relative to the stationary draft of the floating structure 200 when it is in service. By setting the height of the bridge section 20 at a distance from the stationary water surface of the floating structure 200 when it is in service, the wave impact pressure is reduced, and the effect of preventing damage is obtained. In addition, the bridge section 20 may be shaped to partially extend up to the upper part of the depth (upper deck) of the annular floating body 10 in order to adequately bear the load on the connecting section 16 below it.

[0043] In this second embodiment, the tower 3 may be placed at any corner 10A of the annular floating body 10, as in the first embodiment, or it may be installed near the center of the bridge section 20 on one side of the annular floating body 10. Installing it near the center of the bridge section 20 makes it easy to satisfy the restoring performance required by the design rules and suppresses excessive torsional moments. Installing it at any corner 10A of the annular floating body 10 limits the increase in the area of ​​the bridge section 20 that accompanies the reinforcement of the lower part of the tower 3.

[0044] (Variation 1) Next, a modified example 1 of Embodiment 2 of the present invention will be described. As shown in Figure 3, the floating structure 300 according to Modification 1 is provided with a partition wall 22 in the connecting section 18 of Embodiment 2. The partition wall 22 is a wall that connects the bridge section 20 and the connecting section 16, extending in the vertical direction and in the direction from the outside to the inside of the annular floating body 10, that is, the direction in which the connecting section 18 penetrates. Therefore, the partition wall 22 is configured to face the side wall 18B of the island-shaped section 14. Since the partition wall 22 is a member that supports the bridge section 20, it is advantageous in ensuring the structural strength of the bridge section 20. In the example in Figure 3, two partition walls 22 are shown arranged at equal intervals in the width direction of the connecting section 18, but the present invention is not limited to this, and there may be one partition wall 22 or three or more partition walls 22 provided in the connecting section 18.

[0045] (Modification 2) Next, a modified example of Embodiment 2 of the present invention will be described. In Modification 1, a communication section 18, which is a through-hole connecting the outside of the annular floating body 10 and the internal region 12 surrounded by the annular floating body 10, is provided on an annular floating body having one through-hole that penetrates vertically, and this communication section 18 is made into multiple through-holes by a partition wall 22. However, it is not limited to this, and the floating structure 400 may be made using a grid-like floating body as the annular floating body 10, which has multiple through-holes that penetrate vertically, as shown in Modification 2 in Figure 4. In other words, in Modification 2, when viewed from vertically above, the internal region 12 surrounded by the annular floating body 10 of Modification 3 is divided into four parts by arranging a cross-shaped partition wall 24.

[0046] From a different perspective, the modified form 2, when viewed from vertically above, has island-like sections 14 located at the four corner sections 10A, as well as partition walls 24 that can also be called island-like sections 14, projecting vertically upward from the cross-shaped waterline WL (water surface). The annular floating body 10 has a roughly I-shaped connecting section 16 that connects the corner sections 10A and the partition walls 24. Therefore, the annular floating body 10 is configured to have four corner sections 10A and eight connecting sections 16.

[0047] As described above, the floating structure according to the present invention comprises an annular floating body having a vertically extending through hole, and the annular floating body divides the area into the outside world and an internal area surrounded by the annular floating body. The floating structure is installed on the ocean and has a connecting section that connects to the outside world and the internal area and functions as a water channel. Therefore, by allowing some of the waves and water flow acting on the annular floating body to escape through the connecting section, it is possible to reduce the wave force acting on the annular floating body. Consequently, it has the effect of reducing the vertical swaying of the floating structure.

[0048] Furthermore, according to another floating structure of the present invention, in the above-described invention, the annular floating body comprises a plurality of island-like sections projecting vertically upward from the waterline, and connecting sections that connect the island-like sections underwater. Since the connecting sections are located vertically above the connecting sections, it is possible to reduce the wave force acting on the annular floating body by allowing some of the waves and water currents acting on it to escape through the connecting sections. Therefore, the vertical swaying of the floating structure can be reduced.

[0049] Furthermore, according to another floating structure of the present invention, in the above-described invention, the annular floating body further includes a bridge section that connects the island-like sections in the water located vertically above the connecting section, so that it is possible to easily move between the island-like sections.

[0050] Furthermore, according to other floating structures of the present invention, in the above-described invention, the annular floating body is further provided with a bulkhead that extends along the vertical direction and the penetrating direction of the connecting portion, connecting the connecting portion and the bridge portion, thereby ensuring rigidity at the connecting portion and reducing vertical sway of the floating structure.

[0051] Furthermore, according to another floating structure of the present invention, a floating structure installed on the ocean comprises an annular floating body having a vertically extending through hole, and the annular floating body divides the area into the outside world and an internal area surrounded by the annular floating body. The annular floating body is shaped to have a single cross-section in at least one horizontal cross-section in the water, and a shape with multiple interspersed cross-sections in at least one horizontal cross-section above the water. Therefore, by allowing some of the waves and water currents acting on the annular floating body to escape through the connecting parts, the wave force acting on the annular floating body can be reduced. Consequently, the vertical swaying of the floating structure can be reduced.

[0052] Furthermore, the offshore wind power generation facility according to the present invention comprises the floating structure described above and a wind power generation facility installed on the floating structure, thereby providing a floating type offshore wind power generation facility that reduces vertical swaying.

[0053] Furthermore, since the offshore wind power generation facility according to the present invention comprises the floating structure described above and wind power generation equipment installed on the floating structure, it is possible to provide a floating type offshore wind power generation facility that reduces vertical swaying. [Industrial applicability]

[0054] As described above, the floating structure and offshore wind power generation facility according to the present invention are useful for the foundation of floating offshore wind power generation facilities, and are particularly suitable for suppressing vertical swaying. [Explanation of Symbols]

[0055] 1. Offshore wind power generation facilities 2. Wind power generation facilities 3. Wind turbine tower 10 Ring-shaped floats 10A Corner 12 Internal area 14 Islands 16 Connecting part 18 Communication section 18A floor 18B Side wall 20 Bridge section 22 Bulkhead 24 Partition Wall 100-400 Floating structures C Crane G Wharf WL (Waterline)

Claims

1. A floating structure installed on the ocean, comprising an annular floating body having a vertically extending through hole, wherein the annular floating body divides the area into the outside world and an internal area surrounded by the annular floating body, It has a connecting section that connects to the external environment and the internal region and functions as a water channel, The annular floating body comprises a plurality of island-like sections projecting vertically upward from the waterline, connecting sections that connect the island-like sections underwater, a bridge section located vertically above the connecting sections in the water that connects the island-like sections, and a bulkhead extending in the vertical direction and the direction through which the connecting sections penetrate, connecting the connecting sections and the bridge section. The aforementioned connecting portion is located vertically above the aforementioned connecting portion. In the aforementioned interior area, a cross-shaped partition wall is arranged when viewed from vertically above, and the interior area is divided into four sections by this cross-shaped partition wall. A floating structure characterized by the following features.

2. A floating structure according to claim 1, Wind power generation equipment installed on the floating structure, An offshore wind power generation facility characterized by having the following features.

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