Construction method for motion suppression members and floating structures

Abstract

To propose a swinging suppression member enabling suppression of swinging due to oscillation in lateral direction derived from waves and wind.SOLUTION: Oscillation suppression members 4 are formed on a bottom surface of a floating body and each include a plate member 41 erected underwater. A construction method for an aquatic structure 1 including these oscillation suppression members 4 includes: a construction step of constructing the aquatic structure 1 by installing an upper structure on a foundation 3; a movement step of moving the aquatic structure 1 to a prescribed position; and a mooring step of mooring the aquatic structure 1 to a prescribed position. In the construction step, air is reserved in a space 5 surrounded by plate members 41 and the air in the space 5 is discharged in the movement step, at a stage when the aquatic structure reaches, due to a tow, a position with great water depth.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present invention relates to a sway suppression member for a moored water structure and a construction method for a water structure.

Background Art

[0002] In the foundation of a floating water structure, in order to reduce sway caused by waves and wind, a sway suppression member may be installed on the foundation (floating body). For example, Patent Document 1 discloses a sway suppression wing installed on the outer peripheral portion of the bottom surface of a floating body. Further, Patent Document 2 discloses a sway suppression device including an annular member inserted through the outer periphery of a columnar floating body, a first cable connecting the annular member and the floating body portion, and a second cable connecting the annular member and an estimation. The sway suppression wing of Patent Document 1 aims to control sway in the vertical and rotational directions of the floating body. That is, when a sway suppression wing is provided on the floating body, vortices are generated by fluid motion around the sway suppression wing, and the vibration of the floating body is attenuated, so that the sway of the water structure can be reduced. On the other hand, horizontal (lateral) vibrations caused by waves and wind act on the water structure. When the water structure vibrates horizontally, it becomes a factor for increasing the tension of the mooring cable, so it is desirable to suppress horizontal vibrations. However, a sway suppression member for suppressing horizontal vibrations has not been established. Further, in the sway suppression device of Patent Document 2, since the annular member can float independently of the floating body, when a force acts on the floating body to move the annular member, the water pressure acting on the annular member becomes a resistance, and the sway of the floating body can be suppressed. On the other hand, the application target of the sway suppression device of Patent Document 2 is limited to a floating body having a columnar shape. <​​​​​​​​​​​​​​​​​​ [Problems that the invention aims to solve]

[0004] The present invention aims to propose a motion suppression member and a construction method for floating structures that can suppress motion caused by lateral vibrations such as waves and wind. [Means for solving the problem]

[0005] The motion suppression member of the present invention, which solves the aforementioned problems, is for suppressing lateral vibrations of a floating body moored on the water. The floating body comprises a center column, a plurality of side columns arranged at intervals around the center column, and a beam connecting the center column and the side columns. The first motion suppression member is fixed to the lower surface of the beam in water and has a plate-like portion that extends perpendicular to the lower surface. hand The plate-like portions are arranged in a continuous manner along the periphery of the lower surface of the beam, forming an endless loop. Therefore. By using the space enclosed by the plate-like section as an air chamber, the buoyancy of the floating structure can be increased. Furthermore, the second motion suppression member comprises a plurality of linear members (e.g., wires or chains) suspended from the beam, weights fixed to the lower ends of the linear members, and a plate-like portion fixed across the plurality of linear members in the water and extending vertically. In addition, if a sea anchor is provided, the plate-like portion is arranged in a direction intersecting the water flow, thereby improving the motion suppression effect. With such a vibration suppression member, the plate-shaped portion erected in the water provides resistance, thereby reducing horizontal vibrations caused by external forces such as waves and wind acting on a structure on the water. A construction method for a floating structure equipped with such motion-suppressing members comprises a construction step of constructing a floating structure by installing a superstructure on a floating body, a moving step of moving the floating structure to a predetermined position, and a mooring step of mooring the floating structure to the predetermined position. In the construction step, air is sealed and held in the space enclosed by the plate-like part, and in the moving step, when the water depth reaches a predetermined value or higher by towing, the air in the space is exhausted. [Effects of the Invention]

[0006] According to the motion suppression member and construction method for floating structures of the present invention, it is possible to suppress motion caused by lateral vibrations such as waves and wind. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view showing a floating structure according to the first embodiment. [Figure 2] This is a cross-sectional view showing a beam of a floating structure according to the first embodiment. [Figure 3] This diagram shows the construction status of a floating structure, with (a) being the construction phase and (b) being the mooring phase. [Figure 4] This is a cross-sectional view showing the beam during the construction process. [Figure 5] This is a perspective view showing a floating structure according to the second embodiment. [Figure 6] This is a cross-sectional view showing a beam of a floating structure in the second embodiment. [Figure 7] This is a front view showing the vibration suppression member of the second embodiment. [Modes for carrying out the invention]

[0008] <First Embodiment> This embodiment describes a floating structure 1 that is moored on the water. Figure 1 shows the floating structure 1 of this embodiment. The floating structure 1 is an offshore wind power generation facility and comprises a superstructure 2 having a wind turbine 21 and a support column 22 that supports the wind turbine 21, and a foundation 3 that supports the superstructure 2. The superstructure 2 is located above the water surface via a foundation (floating body) 3 that is moored on the water. The wind turbine 21 is rotatably mounted on the upper end of the support column 22. The support column 22 is erected on the foundation 3. The foundation 3 of this embodiment includes a center column 31 that supports the support columns 22 of the wind turbine 21, three side columns 32, 32, 32 arranged at intervals around the center column 31, and beams 33, 33, 33 that connect the center column 31 and the side columns 32.

[0009] As shown in Figure 1, the center column 31 is cylindrical in shape and is positioned in the center of the base 3. The side columns 32 are cylindrical in shape and three are arranged around the center column 31. The spacing between adjacent side columns 32 is the same. The side columns 32 are connected to the center column 31 via beams 33. The beam 33 connects the center column 31 and the side column 32. One end of the beam 33 is connected to the center column 31, and the other end of the beam 33 is connected to the side column 32. Figure 2 shows the beam 33. The beam 33 in this embodiment has the shape of a rectangular prism turned on its side, and as shown in Figure 2, it has a top plate 331, a bottom plate 332, and left and right side walls 333, 333.

[0010] The beam 33 is provided with a vibration suppression member 4 to suppress lateral vibrations. The vibration suppression member 4 in this embodiment includes a plate material (plate-shaped part) 41 fixed to the lower surface of the beam 33. The plate material 41 is erected in water. The upper end of the plate material 41 is connected to the lower surface of the beam 33. That is, the plate material 41 is fixed in a direction perpendicular to the lower surface of the beam 33. In this embodiment, a plurality of plate materials 41 are arranged endlessly (connected) around the periphery of the lower surface of the beam 33. The plate materials 41 may be connected with their end faces abutting against each other, or they may be connected with their ends overlapping.

[0011] The construction method for the floating structure 1 of this embodiment will now be described. The construction of the floating structure 1 comprises a construction step of constructing the floating structure 1 by installing the superstructure 2 on the foundation (floating body) 3, a moving step of moving the floating structure 1 to a predetermined position, and a mooring step of mooring the floating structure 1 to the predetermined position. Figures 3 and 4 show the construction status of the floating structure 1. In the construction process, first, the foundation 3 is constructed on land or in the dock. A motion suppression member 4 is attached to the bottom surface of the foundation 3 (beam 33). Next, the foundation 3 is moored to the quay in a floating state in the dock, and the superstructure 2 is formed on the foundation 3. The superstructure 2 is placed on the foundation 3 using a crane or the like which is positioned on the quay. As shown in Figure 3(a), when installing the superstructure 2 on the foundation 3, it is necessary to make the draft of the foundation 3 smaller than the water depth of the quay. In this embodiment, as shown in Figure 4, the space 5 surrounded by endlessly arranged plate material 41 on the underside of the foundation 3 is made into an air chamber, and by accumulating air in the air chamber, the buoyancy of the foundation 3 is increased and the draft is reduced.

[0012] During the moving process, the floating structure 1 is towed to a predetermined location. Once towed to a deep area outside the harbor, the air from the air chamber is discharged. One method for discharging air from the air chamber is to install a valve facing the air chamber in advance and discharge the air through this valve. In the mooring process, as shown in Fig. 3(b), the floating structure 1 towed to a predetermined position is moored. At this time, the amount of the ballast 6 in the foundation 3 is adjusted to ensure stability.

[0013] The floating structure 1 of this embodiment can reduce horizontal vibrations by the anti-vibration member 4 formed on the bottom surface of the foundation 3. That is, the horizontally erected plate members 41 resist the lateral sway caused by external forces such as waves and wind acting on the floating structure 1, thereby reducing horizontal vibrations. In addition, since the plurality of plate members 41 are arranged endlessly on the bottom surface of the foundation 3, the space 5 surrounded by the plate members 41 can be used as an air chamber. Therefore, in a shallow water area, by storing air in the air chamber, the buoyancy of the floating structure 1 can be increased.

[0014] <Second Embodiment> In this embodiment, the floating structure 1 moored on the water will be described in the same manner as in the first embodiment. Fig. 5 shows the floating structure 1 of this embodiment. The floating structure 1 is an offshore wind power generation facility, and includes an upper structure 2 having a wind turbine 21 and a support column 22 supporting the wind turbine 21, and a foundation 3 supporting the upper structure 2. Since the details of the upper structure 2 and the foundation 3 are the same as those of the floating structure 1 in the first embodiment, detailed descriptions are omitted. <000009​​​​​​In this embodiment, the plate-shaped portion 44 is fixed to the linear member 42 in an upright position in the water above the weight 43. In this embodiment, one plate-shaped portion 44 is provided spanning multiple linear members 42. The sea anchor 45 is made of a flexible membrane material and is fixed to the plate-shaped portion 44 via a wire or other wire 451, as shown in Figure 7.

[0016] In this embodiment, the floating structure 1 can reduce horizontal vibrations by the motion suppression member 4 formed on the bottom surface of the foundation 3. That is, the plate material 41 erected in the water can reduce horizontal vibrations by resisting lateral swaying caused by external forces such as waves and wind acting on the floating structure 1. The weight 43 causes the linear member 42 to hang vertically, so the plate-shaped portion 44 fixed to the linear member 42 is positioned upright in the water. Furthermore, since the sea anchor 45 is fixed to the plate-shaped portion 44, the sea anchor 45 is pulled by the water flow, causing the plate-shaped portion 44 to be oriented perpendicular to the water flow. As a result, the plate-shaped portion 44 resists lateral swaying, thereby suppressing vibration. In addition, the resistance force is increased by the sea anchor 45, further enhancing the vibration suppression effect. Furthermore, since multiple linear members 42 are attached to the plate-shaped portion 44, the plate-shaped portion 44 is difficult to rotate.

[0017] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and each of the above-mentioned components can be modified as appropriate without departing from the spirit of the present invention. For example, in each of the embodiments described above, the case in which the floating structure 1 is an offshore wind power generation facility was explained, but the floating structure 1 is not limited to an offshore wind power generation facility. Furthermore, although the above embodiments described the case where the floating body is a semi-submersible type foundation 3, the structure of the floating body is not limited, and for example, it may be a barge type. Furthermore, the number of side columns 32 that constitute the base 3 is not limited; for example, there may be four or more. Also, the support columns 22 of the wind turbine 21 may be erected on the side columns 32. When fixing the plate material 41 to the foundation 3, the plate material 41 may also be fixed to the bottom surface of the center column 31 or the bottom surface of the side column 32. Furthermore, when installing the plate-shaped portion 44 via the linear member 42, the sea anchor 45 may be provided as needed. Furthermore, when the plate-shaped portion 44 is installed via the linear member 42, a weight 43 may be fixed to the plate-shaped portion 44. In this case, the plate-shaped portion 44 may have the linear member 42 fixed to its upper end and the weight 43 fixed to its lower end. [Explanation of symbols]

[0018] 1 floating structures 2 Superstructure 21 Windmill 22 Posts 3 Basics 31 Center Column 32 Side Columns 33 Beams 4. Vibration suppression member 41 Board material 42 Linear members 43 Weight 44 Plate-like part 45 Sea Anchor 5 Space

Claims

1. A motion suppression member for suppressing lateral vibrations of a floating body moored on the water, The floating body comprises a center column, a plurality of side columns arranged at intervals around the center column, and a beam connecting the center column and the side columns, It is fixed to the lower surface of the beam in water and has a plate-like portion that extends in a direction perpendicular to the lower surface, A vibration suppression member characterized in that the plate-like portions are arranged in a continuous manner along the periphery of the lower surface of the beam, forming an endless closed loop.

2. A motion suppression member for suppressing lateral vibrations of a floating body moored on the water, The floating body comprises a center column, a plurality of side columns arranged at intervals around the center column, and a beam connecting the center column and the side columns, Multiple linear members suspended from the beam, A weight fixed to the lower end of the linear member, A motion suppression member characterized by comprising a plate-like portion that is fixed across a plurality of linear members in water and extends in the vertical direction.

3. The motion suppression member according to claim 2, characterized by being equipped with a sea anchor.

4. The construction process involves installing a superstructure on a floating body to construct a structure on the water, A moving step of moving the floating structure to a predetermined position, A method for constructing a floating structure, comprising a mooring step of securing the floating structure to a predetermined position, The lower surface of the floating body is provided with the motion suppression member described in claim 1, In the construction process described above, air is sealed and held in the space surrounded by the plate-like portion. A method for constructing a floating structure, characterized in that, during the movement process, when the water depth reaches a predetermined value or higher by towing, the air in the space is exhausted.

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