Floating structure

Abstract

To reduce energy of waves working on a floating body structure regardless of wavelength of incident waves.SOLUTION: Parapet units 3a, 3b of a floating body structure 1 projects sideways from a body unit 2 above a water surface. A plurality of sets of irregular structures 5a, 5b respectively penetrating the water surface are provided on a side surface of the body unit 2. The irregular structure 5a includes two protrusions 51a arranged side by side in a horizontal direction and a recess 52b positioned in a space formed in between the two protrusions 51a by the two protrusions 51a lined up in the horizontal direction. The irregular structure 5b includes two protrusions 51b and a recesses 52b. The recesses 52a, 52b have a width in a plan view becoming smaller as approaching the center of the body unit. The plurality of parapets 3a, 3b are respectively superposed with the recesses 52a, 52b in the plurality of sets of irregular structures 5a, 5b above in the plan view. Thus, wave energy working on the floating body structure 1 is capable of being reduced regardless of a wavelength of incident waves.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a floating structure.

Background Art

[0002] Conventionally, in floating structures such as floating pontoon bridges, it has been required to reduce fluctuations caused by waves and the like to improve safety, riding comfort, etc. Also, weight reduction of floating structures has been demanded.

[0003] For example, in the large floating body 1 of Patent Document 1, a wave dissipating member 4 is provided, which is composed of a vertical plate 5 located at the front end portion on the wave upper side and a submerged horizontal plate 6 extending horizontally from the lower end of the vertical plate 5. Thereby, since the fluctuating pressure acting on the submerged horizontal plate 6 and the fluctuating pressure acting on the bottom surface of the front end portion of the large floating body 1 are out of phase and cancel each other out, the fluctuation of the large floating body 1 is reduced. In the large floating body 1, by providing an extended deck 7 above the submerged horizontal plate 6, the deck area of the large floating body 1 is increased. Note that, unlike the wave dissipating member 4, the extended deck 7 does not have a wave dissipating action, and thus can be omitted.

[0004] In the floating body of Patent Document 2, a vertical plate is provided on the side surface of the main body of the floating body, and a horizontal plate extending horizontally from the lower end of the vertical plate is provided, thereby reducing the horizontal swing of the floating body. Also, in the floating body shown in FIG. 7 of Patent Document 2, the main body 1 has a shape in which two corner portions in a plan view of a rectangular parallelepiped are cut off by vertical surfaces (vertical plates 4). Among the main body 1, the portion between the two vertical plates 4 is a convex portion region 18'. Since the waves incident on the main body 1 are reflected horizontally by the vertical plates 4 on both sides of the convex portion region 18' and move away from the main body 1, the drift force (horizontal fluctuating force) acting on the main body 1 is reduced.

[0005] On the other hand, the artificial island of Patent Document 3 is formed by creating a cylindrical body 4 having a regular hexagonal cross-section using thinned wood, immersing a honeycomb-shaped floating body 1 in which a large number of cylindrical bodies 4 are joined in the sea, and then installing a building on the floating body 1. Since the floating body 1 is completely submerged in the sea and does not rot, and is lightweight, a large buoyancy is realized.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] By the way, in the case of the large floating body of Patent Document 1, when waves with a relatively short wavelength are incident, the reduction of the sway of the large floating body is possible as described above. However, when waves with a relatively long wavelength are incident, the cancellation of the above-mentioned fluctuating pressure does not substantially occur, and there is a risk that the sway will not be reduced. Similarly, in the case of the floating body of Patent Document 2, when waves with a relatively long wavelength are incident, there is a risk that the horizontal sway of the floating body will not be reduced. In addition, in the artificial island of Patent Document 3, since the honeycomb-shaped floating body is completely submerged, it does not have a wave-dissipating action like the above-mentioned wave-dissipating member.

[0008] The present invention has been made in view of the above problems, and an object thereof is to reduce the energy of waves acting on a floating structure regardless of the wavelength of the incident waves.

Means for Solving the Problems

[0009] Aspect 1 of the present invention is a floating structure, comprising a main body portion that floats on the water surface in a state of penetrating the water surface, and a plurality of wave-returning portions that protrude laterally from the main body portion above the water surface. On the side surface of the main body portion, a plurality of sets of concave-convex structures that each penetrate the water surface are provided. Each set of concave-convex structures includes two convex portions that each protrude in a direction away from the center of the main body portion, which is the center in the plan view of the main body portion, and are arranged side by side in the horizontal direction, and a concave portion that is located in the space formed between the two convex portions by the two convex portions arranged side by side in the horizontal direction and whose width in the plan view becomes smaller as it approaches the center of the main body portion. Each of the plurality of wave-returning portions overlaps with the concave portion in the plurality of sets of concave-convex structures in the plan view.

[0010] Aspect 2 of the present invention is the floating structure of Aspect 1, wherein the shape of the main body portion in the plan view is rectangular. The plurality of sets of concave-convex structures include one or more sets of concave-convex structures provided on one side of the main body portion in the plan view, and one or more sets of concave-convex structures provided on the other side adjacent to the one side of the main body portion in the plan view.

[0011] Aspect 3 of the present invention is the floating structure of Aspect 1 or 2, wherein the plurality of sets of concave-convex structures are provided over the entire circumference of the side surface of the main body portion in the plan view.

[0012] Aspect 4 of the present invention is the floating structure of Aspect 1 or 2 (which may be any one of Aspects 1 to 3), wherein in one or more sets of the plurality of sets of concave-convex structures, the shape of the tip portions of the two convex portions in the plan view is angular.

[0013] Aspect 5 of the present invention is the floating structure of Aspect 1 or 2 (which may be any one of Aspects 1 to 4), wherein in one or more sets of the plurality of sets of concave-convex structures, the shape of the concave portion in the plan view is triangular.

[0014] Aspect 6 of the present invention is a floating structure according to Aspect 1 or 2 (which may be any one of Aspects 1 to 5). In one or more sets of the uneven structures among the plurality of sets of uneven structures, the shape of the concave portion in plan view is a trapezoidal shape in which the opening of the concave portion is one base and the end portion on the back side of the concave portion is the other base. The length of the other base is 50% or less of the length of the one base.

[0015] Aspect 7 of the present invention is a floating structure according to Aspect 1 or 2 (which may be any one of Aspects 1 to 6). The main body portion has a honeycomb structure in which a plurality of main body portion elements having a hexagonal cylindrical shape extending in the vertical direction are joined to each other on the outer surfaces.

[0016] Aspect 8 of the present invention is a floating structure according to Aspect 1 or 2 (which may be any one of Aspects 1 to 7). Each of the plurality of wave return portions overlaps with the entire concave portion in the plurality of sets of uneven structures in plan view.

[0017] Aspect 9 of the present invention is a floating structure according to Aspect 1 or 2 (which may be any one of Aspects 1 to 8). The floating structure further includes a top plate portion that constitutes the upper surface of the main body portion. The plurality of wave return portions are the end portions of the top plate portion.

[0018] Aspect 10 of the present invention is a floating structure according to Aspect 1 or 2 (which may be any one of Aspects 1 to 9). The floating structure further includes a lower protruding portion that protrudes laterally from the main body portion below the water surface. The lower protruding portion overlaps with the concave portion in plan view in one or more sets of the uneven structures among the plurality of sets of uneven structures.

Advantages of the Invention

[0019] In the present invention, the energy of the waves acting on the floating structure can be reduced regardless of the wavelength of the incident waves.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0021] FIG. 1 is a perspective view showing a floating structure 1 according to one embodiment of the present invention. FIG. 2 is a plan view of the floating structure 1. The floating structure 1 is a structure that floats on the water in a state of penetrating the water surface. When the floating structure 1 is installed in the sea, the water surface is the sea surface. The floating structure 1 is, for example, a structure that does not self-navigate. The floating structure 1 is used while being moored to a predetermined facility such as the bottom of the water or a quay wall in a floating state on the water. The floating structure 1 is, for example, a floating jetty provided in a port facility or the like.

[0022] In FIGS. 1 and 2, three directions orthogonal to each other are shown by arrows as the X direction, the Y direction, and the Z direction. The Z direction is parallel to the direction of gravity (that is, the vertical direction). The same applies to other figures described later.

[0023] FIG. 3 is a perspective view showing a state in which a top plate portion 23 (described later) of the floating structure 1 is omitted. In FIG. 3, the position of the top plate portion 23 is indicated by a broken line. FIG. 4 is a plan view showing an enlarged view of the end portion on the (-X) side of the floating structure 1. FIG. 5 is a cross-sectional view of the floating structure 1 cut at the position V-V in FIG. 4. FIG. 6 is a cross-sectional view of the floating structure 1 cut at the position VI-VI in FIG. 4.

[0024] The floating structure 1 includes a main body portion 2, a plurality of wave return portions 3a and 3b, and a plurality of lower protruding portions 4a and 4b. The main body portion 2 constitutes the main part of the floating structure 1 and floats on the water surface 91 in a state of penetrating the water surface 91. In the examples shown in FIGS. 1 and 2, the main body portion 2 is a substantially rectangular parallelepiped structure that is long in the X direction. In other words, the shape of the main body portion 2 in plan view is a substantially rectangular shape that is long in the X direction. The rectangle is the smallest rectangle that circumscribes a plurality of main body portion elements 21 (described later) that constitute the main body portion 2 in plan view. The long side of the main body portion 2 in plan view extends substantially parallel to the X direction, and the short side in plan view extends substantially parallel to the Y direction.

[0025] The length of the main body portion 2 in the X direction is, for example, 20 m to 30 m, and the length in the Y direction is, for example, 10 m to 15 m. The height of the main body portion 2 in the Z direction is, for example, 1 m to 5 m, and the draft is, for example, 0.5 m to 3.5 m. The main body portion 2 is formed of, for example, reinforced concrete, iron, or the like. Note that the shape, size, material, and the like of the main body portion 2 may be variously changed.

[0026] The main body part 2 includes a plurality of main body part elements 21, a top plate part 23, and a bottom plate part 24. Each main body part element 21 is a cylindrical member that penetrates the water surface 91 and extends in the Z direction (i.e., the vertical direction). In the example shown in FIG. 3, each main body part element 21 is a substantially hexagonal cylindrical member, and the respective shapes of the outer circumference and the inner circumference of each main body part element 21 in plan view are substantially regular hexagons. The plurality of main body part elements 21 have substantially the same shape and substantially the same size. The plurality of main body part elements 21 are arranged adjacent to each other at substantially the same position in the Z direction so as to be substantially rectangular in plan view. The outer surface 221 of each main body part element 21 is joined in a state of being in contact with the outer surface 221 of the adjacent main body part element 21 over substantially the entire surface. In other words, the main body part 2 has a honeycomb structure in which a plurality of substantially hexagonal cylindrical main body part elements 21 are joined by their outer surfaces 221 to each other.

[0027] The bottom plate part 24 is a member that forms the bottom surface of the main body part 2 below the water surface 91. The bottom plate part 24 is, for example, a substantially flat plate-shaped member that extends substantially perpendicular to the Z direction. The shape of the bottom plate part 24 in plan view is a substantially rectangle in which the long side and the short side are substantially parallel to the X direction and the Y direction, respectively. The bottom plate part 24 covers the bottom surfaces of the plurality of main body part elements 21 that constitute the honeycomb structure and is joined to the lower end parts of the plurality of main body part elements 21. Thereby, water is prevented from entering the internal space (i.e., the space inside the cylinder) of each main body part element 21 from below.

[0028] The top plate portion 23 is a member that constitutes the upper surface of the main body portion 2 above the water surface 91. The top plate portion 23 is, for example, a substantially flat plate-shaped member that extends substantially perpendicular to the Z direction. The shape of the top plate portion 23 in plan view is a substantially rectangular shape in which the long side and the short side are substantially parallel to the X direction and the Y direction, respectively. The shape of the top plate portion 23 in plan view is substantially the same as the shape of the bottom plate portion 24 in plan view, and overlaps with the bottom plate portion 24 over substantially the entire surface in plan view. The top plate portion 23 covers the upper surfaces of the plurality of main body portion elements 21 that constitute the honeycomb structure, and is joined to the upper end portions of the plurality of main body portion elements 21. Thereby, it is possible to prevent water from entering the internal space (that is, the space inside the cylinder) of each main body portion element 21 from above. That is, the internal space of each main body portion element 21 is a watertight space (void) that is sealed from above and below by the top plate portion 23 and the bottom plate portion 24.

[0029] On the side surface of the main body portion 2 on the (-X) side (that is, one short side in plan view), a plurality of sets of concavo-convex structures 5a formed by the outer side surfaces 221 of the plurality of main body portion elements 21 are provided. Also, on the side surface of the main body portion 2 on the (+X) side, a plurality of sets of concavo-convex structures 5a formed by the outer side surfaces 221 of the plurality of main body portion elements 21 are provided. Each set of concavo-convex structures 5a is composed of two convex portions 51a adjacent to each other in the horizontal direction and a concave portion 52a located in the space formed between the two convex portions 51a and arranged side by side in the horizontal direction. Note that the two convex portions 51a adjacent to each other in the horizontal direction mean two convex portions 51a arranged side by side in the horizontal direction without sandwiching another convex portion 51a therebetween. The same applies to the convex portion 51b described later. Also, the concave portion 52a can be regarded as the space itself (that is, the space) formed between the two convex portions 51a.

[0030] In the example shown in FIGS. 1 to 3, two concavo-convex structures 5a are provided on the side surface of the main body portion 2 on the (-X) side and on the side surface of the main body portion 2 on the (+X) side, respectively. The two concavo-convex structures 5a include three convex portions 51a and two concave portions 52a that are alternately arranged in the Y direction. The convex portion 51a located at the center in the Y direction among the three convex portions 51a is shared by the two concavo-convex structures 5a.

[0031] The positions of the plurality of sets of concavo-convex structures 5a in the Z direction are substantially the same as each other. The lower ends of each set of concavo-convex structures 5a are located at substantially the same position in the Z direction as the lower ends of the plurality of main body elements 21 that constitute the concavo-convex structure 5a. The upper ends of each set of concavo-convex structures 5a are located at substantially the same position in the Z direction as the upper ends of the plurality of main body elements 21 that constitute the concavo-convex structure 5a. Each set of concavo-convex structures 5a penetrates the water surface 91 and extends substantially parallel to the Z direction.

[0032] Each convex portion 51a of the concavo-convex structure 5a is formed by two outer side surfaces 221 adjacent to each other in the Y direction in one main body element 21. Each convex portion 51a is a substantially triangular prism-shaped portion that extends substantially parallel to the Z direction. Each convex portion 51a protrudes in a direction away from the center of the main body portion 2 in a plan view (hereinafter, also referred to as the "center C of the main body portion"). The center C of the main body portion is spaced apart from the (-X)-side side surface and the (+X)-side side surface of the main body portion 2 by the same distance in the X direction, and is also spaced apart from the (-Y)-side side surface and the (+Y)-side side surface of the main body portion 2 by the same distance in the Y direction.

[0033] Each concave portion 52a of the concavo-convex structure 5a is formed by one outer side surface 221 adjacent to each other in the Y direction in two main body elements 21 adjacent to each other in the Y direction. In other words, the concave portion 52a is constituted by the (-Y)-side outer side surface 221 of the convex portion 51a adjacent to the (+Y) side of the concave portion 52a and the (+Y)-side outer side surface 221 of the convex portion 51a adjacent to the (-Y) side of the concave portion 52a. Each concave portion 52a is a substantially triangular prism-shaped space that extends substantially parallel to the Z direction. Each concave portion 52a is recessed in a direction approaching the center C of the main body portion in the X direction from the tips of the two convex portions 51a adjacent to both sides of the concave portion 52a in the Y direction.

[0034] In each of the uneven structures 5a located on the side surface on the (-X) side of the main body portion 2, the two convex portions 51a are each a substantially triangular portion protruding in the (-X) direction in a plan view. The tip on the (-X) side of the convex portion 51a that is the farthest from the center C of the main body portion in the X direction corresponds to one vertex of the substantially triangular convex portion 51a in a plan view and is substantially linear extending substantially parallel to the Z direction. In other words, the shape of the tip portion of the convex portion 51a in a plan view is angular formed by the contact of the tips of two straight lines inclined at different angles with respect to the X direction and the Y direction. Note that the angular tip portion of the convex portion 51a may be a so-called chamfered shape (for example, a chamfered shape by an R surface or a C surface) in a plan view. The width in the Y direction of the convex portion 51a at the draft line of the floating structure 1 (that is, the width in a plan view) is approximately 0 at the tip on the (-X) side of the convex portion 51a and gradually increases as it goes in the (+X) direction from the tip.

[0035] In each of the uneven structures 5a located on the side surface on the (-X) side of the main body portion 2, the concave portion 52a is a substantially triangular space recessed in the (+X) direction in a plan view. The tip on the (+X) side of the concave portion 52a that is the closest to the center C of the main body portion in the X direction corresponds to one vertex of the substantially triangular concave portion 52a in a plan view and is substantially linear extending substantially parallel to the Z direction. In other words, the shape of the tip portion (hereinafter, also referred to as the "inner portion") of the concave portion 52a in a plan view is angular formed by the contact of the tips of two straight lines inclined at different angles with respect to the X direction and the Y direction. Note that the angular inner portion of the concave portion 52a may be a so-called chamfered shape (for example, a chamfered shape by an R surface or a C surface) in a plan view.

[0036] The width in the Y direction (i.e., the width in plan view) of the recess 52a at the draft line of the floating body structure 1 gradually decreases as it approaches the center C of the main body portion in the X direction. Specifically, the width in the Y direction of the recess 52a is approximately 0 at the tip on the (+X) side of the recess 52a, and gradually increases as it goes from the tip in the (-X) direction. The width in the Y direction of the opening 521a located at the end on the (-X) side of the recess 52a (the width at the draft line of the floating body structure 1, hereinafter also referred to as the "opening width") is substantially the same as the width in the Y direction of one main body portion element 21. The opening 521a of the recess 52a is located at the tips of the two convex portions 51a located on both sides in the Y direction of the recess 52a and at the same position in the X direction.

[0037] In each uneven structure 5a located on the side surface on the (+X) side of the main body portion 2, the two convex portions 51a are each a substantially triangular portion protruding in the (+X) direction in plan view. The tip on the (+X) side of the convex portion 51a that is the farthest from the center C of the main body portion in the X direction corresponds to one vertex of the substantially triangular convex portion 51a in plan view and is substantially linear extending substantially parallel to the Z direction. In other words, the shape of the tip of the convex portion 51a in plan view is angular formed by the contact of the tips of two straight lines inclined at different angles with respect to the X direction and the Y direction. The angular tip of the convex portion 51a may be a so-called chamfered shape (for example, a chamfered shape by an R surface or a C surface) in plan view. The width in the Y direction (i.e., the width in plan view) of the convex portion 51a at the draft line of the floating body structure 1 is approximately 0 at the tip on the (+X) side of the convex portion 51a, and gradually increases as it goes from the tip in the (-X) direction.

[0038] In each of the concavo-convex structures 5a located on the (+X)-side surface of the main body portion 2, the concave portion 52a is a substantially triangular space that is concave in the (-X) direction in plan view. The tip on the (-X)-side of the concave portion 52a that is closest to the center C of the main body portion in the X direction corresponds to one vertex of the substantially triangular concave portion 52a in plan view and is substantially linear and extends substantially parallel to the Z direction. In other words, the shape of the tip portion (i.e., the inner portion) of the concave portion 52a in plan view is angular, formed by the contact of the tips of two straight lines that are inclined at different angles with respect to the X direction and the Y direction. Note that the angular inner portion of the concave portion 52a may be a so-called chamfered shape (e.g., a chamfered shape by an R surface or a C surface) in plan view.

[0039] The width in the Y direction (i.e., the width in plan view) of the concave portion 52a at the draft line of the floating structure 1 gradually decreases as it approaches the center C of the main body portion in the X direction. Specifically, the width in the Y direction of the concave portion 52a is approximately 0 at the tip on the (-X)-side of the concave portion 52a and gradually increases as it goes from the tip toward the (+X) direction. The width in the Y direction (i.e., the opening width) of the opening 521a located at the end on the (+X)-side of the concave portion 52a is substantially the same as the width in the Y direction of one main body portion element 21. Note that the opening 521a of the concave portion 52a is located at the same position in the X direction as the tips of the two convex portions 51a located on both sides in the Y direction of the concave portion 52a.

[0040] On the (-Y)-side surface (i.e., one long side in plan view) of the main body portion 2, a plurality of sets of concavo-convex structures 5b formed by the outer surfaces 221 of a plurality of main body portion elements 21 are provided. Also, on the (+Y)-side surface of the main body portion 2, a plurality of sets of concavo-convex structures 5b formed by the outer surfaces 221 of a plurality of main body portion elements 21 are provided. Each set of concavo-convex structures 5b includes two convex portions 51b adjacent in the horizontal direction (i.e., arranged side by side in the horizontal direction) and a concave portion 52b located in the space formed between the two convex portions 51b by the two convex portions 51b arranged in the horizontal direction. The concave portion 52b can also be regarded as the space itself formed between the two convex portions 51b (i.e., the said space).

[0041] In the examples shown in FIGS. 1 to 3, three concavo-convex structures 5b are provided on the side surface of the main body 2 on the (-Y) side and the side surface on the (+Y) side, respectively. The three concavo-convex structures 5b include four convex portions 51b and three concave portions 52b that are alternately arranged in the X direction. Among the four convex portions 51b, the second convex portion 51b from the (-X) side is shared by the first and second concavo-convex structures 5b from the (-X) side. Also, among the four convex portions 51b, the third convex portion 51b from the (-X) side is shared by the second and third concavo-convex structures 5b from the (-X) side.

[0042] The positions of the plurality of sets of concavo-convex structures 5b in the Z direction are substantially the same as each other. The lower end of each set of concavo-convex structures 5b is located at substantially the same position in the Z direction as the lower ends of the plurality of main body elements 21 that constitute the concavo-convex structures 5b. The upper end of each set of concavo-convex structures 5b is located at substantially the same position in the Z direction as the upper ends of the plurality of main body elements 21 that constitute the concavo-convex structures 5b. Each set of concavo-convex structures 5b penetrates the water surface 91 and extends substantially parallel to the Z direction.

[0043] Each convex portion 51b of the concavo-convex structure 5b is formed by three outer side surfaces 221 adjacent to each other in the X direction in one main body element 21. Each convex portion 51b is a substantially trapezoidal columnar portion that extends substantially parallel to the Z direction. Each convex portion 51b protrudes in a direction away from the main body center C in the Y direction.

[0044] Each concave portion 52b of the concavo-convex structure 5b is formed by one outer side surface 221 adjacent to each other in the X direction in three main body elements 21 adjacent to each other in the X direction. In other words, the concave portion 52b is formed by the outer side surface 221 on the (-X) side of the convex portion 51b adjacent to the (+X) side of the concave portion 52b, the outer side surface 221 of the main body element 21 located on the main body center C side of the concave portion 52b in the Y direction, and the outer side surface 221 on the (+X) side of the convex portion 51b adjacent to the (-X) side of the concave portion 52b. Each concave portion 52b is a substantially trapezoidal columnar space that extends substantially parallel to the Z direction. Each concave portion 52b is recessed in a direction approaching the main body center C in the Y direction from the tip surfaces of the two convex portions 51b adjacent to both sides of the concave portion 52b in the X direction.

[0045] In each concavo-convex structure 5b located on the (-Y)-side surface of the main body portion 2, the two convex portions 51b are each a substantially trapezoidal portion protruding in the (-Y) direction in plan view. The front end surface on the (-Y) side of the convex portion 51b that is farthest from the center C of the main body portion in the Y direction corresponds to the shorter base (i.e., the short base) of the substantially trapezoidal convex portion 51b in plan view, and is a substantially flat surface that extends substantially perpendicular to the Y direction. That is, the shape of the front end surface of the convex portion 51b in plan view is substantially linear and substantially parallel to the X direction. The width of the convex portion 51b in the X direction (i.e., the width in plan view) at the draft line of the floating structure 1 gradually increases as it goes from the front end surface on the (-Y) side of the convex portion 51b in the (+Y) direction.

[0046] In each concavo-convex structure 5b located on the (-Y)-side surface of the main body portion 2, the concave portion 52b is a substantially trapezoidal space that is concave in the (+Y) direction in plan view. The front end surface on the (+Y) side of the concave portion 52b that is closest to the center C of the main body portion in the Y direction corresponds to the short base of the substantially trapezoidal concave portion 52b in plan view, and is a substantially flat surface that extends substantially perpendicular to the Y direction. That is, the shape of the front end surface of the concave portion 52b in plan view is substantially linear and substantially parallel to the X direction. The width of the concave portion 52b in the X direction (i.e., the width in plan view) at the draft line of the floating structure 1 gradually decreases as it approaches the center C of the main body portion in the Y direction.

[0047] In the concavo-convex structure 5b, at the draft line of the floating structure 1, it is preferable that the width in the X direction of the front end surface on the (+Y) side of the concave portion 52b is 50% or less of the width in the X direction of the front end surfaces on the (-Y) side of the two convex portions 51b and the width in the X direction of the concave portion 52b at the same position in the Y direction. In other words, it is preferable that the width in the X direction of the inner portion (hereinafter also referred to as the "inner width") of the concave portion 52b on the (+Y) side is 50% or less of the width in the X direction of the opening 521b located at the end portion on the (-Y) side of the concave portion 52b (hereinafter also referred to as the "opening width"). In the concavo-convex structure 5b illustrated in FIG. 4, the inner width of the concave portion 52b is approximately 50% of the opening width.

[0048] In each of the uneven structures 5b located on the side surface of the main body 2 on the (+Y) side, the two convex portions 51b are each substantially trapezoidal portions protruding in the (+Y) direction in a plan view. The front end surface on the (+Y) side of the convex portion 51b that is farthest from the center C of the main body in the Y direction corresponds to the short base of the substantially trapezoidal convex portion 51b in a plan view and is a substantially flat surface that extends substantially perpendicular to the Y direction. That is, the shape of the front end surface of the convex portion 51b in a plan view is substantially linear and substantially parallel to the X direction. The width of the convex portion 51b in the X direction (i.e., the width in a plan view) at the draft line of the floating structure 1 gradually increases as it goes from the front end surface on the (+Y) side of the convex portion 51b toward the (-Y) direction.

[0049] In each of the uneven structures 5b located on the side surface of the main body 2 on the (+Y) side, the concave portion 52b is a substantially trapezoidal space that is concave in the (-Y) direction in a plan view. The front end surface on the (-Y) side of the concave portion 52b that is closest to the center C of the main body in the Y direction corresponds to the short base of the substantially trapezoidal concave portion 52b in a plan view and is a substantially flat surface that extends substantially perpendicular to the Y direction. That is, the shape of the front end surface of the concave portion 52b in a plan view is substantially linear and substantially parallel to the X direction. The width of the concave portion 52b in the X direction (i.e., the width in a plan view) at the draft line of the floating structure 1 gradually decreases as it approaches the center C of the main body in the Y direction.

[0050] In the uneven structure 5b, at the draft line of the floating structure 1, it is preferable that the width in the X direction of the front end surface on the (-Y) side of the concave portion 52b is 50% or less of the width in the X direction of the front end surfaces on the (+Y) side of the two convex portions 51b and the width in the X direction of the concave portion 52b at the same position in the Y direction. In other words, it is preferable that the width in the X direction of the inner part on the (-Y) side of the concave portion 52b (i.e., the inner part width) is 50% or less of the width in the X direction of the opening 521b located at the end on the (+Y) side of the concave portion 52b (i.e., the opening width). In the present embodiment, the inner part width of the concave portion 52b is approximately 50% of the opening width as described above.

[0051] In each of the concavo-convex structures 5b located on the (-Y) side and the (+Y) side of the main body portion 2, in a plan view, the opening 521b of the substantially trapezoidal concave portion 52b corresponds to one base (i.e., the long base), and the end portion of the inner part of the concave portion 52b corresponds to the other base (i.e., the short base). As described above, it is preferable that the length of the short base is 50% or less of the length of the long base. Also, the length of the short base is greater than 0% of the length of the long base. Note that the length of the short base may be greater than 50% of the length of the long base.

[0052] As shown in FIGS. 3, 5, and 6, the outer peripheral portion of the bottom plate portion 24 of the main body portion 2 extends partially outward from the outer peripheral surfaces of the plurality of main body elements 21 constituting the honeycomb structure (i.e., in a direction away from the center C of the main body portion). Specifically, a part of the end portion of the bottom plate portion 24 extends outward from the two outer side surfaces 221 constituting the concave portion 52a below the concave portion 52a of each concavo-convex structure 5a, and at least partially overlaps the concave portion 52a in a plan view. Also, a part of the end portion of the bottom plate portion 24 extends outward from the three outer side surfaces 221 constituting the concave portion 52b below the concave portion 52b of each concavo-convex structure 5b, and at least partially overlaps the concave portion 52b in a plan view.

[0053] In the following description, the portion of the bottom plate portion 24 that overlaps the concave portion 52a in a plan view is referred to as the "lower protruding portion 4a". Also, the portion of the bottom plate portion 24 that overlaps the concave portion 52b in a plan view is referred to as the "lower protruding portion 4b". Note that the above-described outer peripheral surface is constituted by a plurality of outer side surfaces 221 that are not joined to the outer side surfaces 221 of other main body elements 21 and are in contact with the surrounding water surface 91 in the plurality of main body elements 21 arranged on the outer peripheral portion of the honeycomb structure.

[0054] As shown in FIG. 5, the lower protruding portion 4a protrudes laterally from the lower end of the outer surface 221 of the main body portion 2 below the water surface 91 (i.e., in the water). The lower protruding portion 4a is a substantially flat plate-shaped portion that extends substantially perpendicular to the Z direction. In the example shown in FIG. 3, the lower protruding portion 4a overlaps substantially the entire concave portion 52a in plan view. The shape of the lower protruding portion 4a in plan view is substantially the same as the shape of the concave portion 52a in plan view and is substantially triangular. The leading edge of the lower protruding portion 4a (i.e., the edge that is farthest from the center C of the main body portion in the X direction) is located at substantially the same position as the opening 521a of the concave portion 52a in the X direction. In other words, the leading edge of the lower protruding portion 4a is located at substantially the same position as the tips of the two convex portions 51a located on both sides of the concave portion 52a in the Y direction. The width of the lower protruding portion 4a in the Y direction gradually decreases as it approaches the center C of the main body portion in the X direction, similar to the opening width of the concave portion 52a.

[0055] As shown in FIG. 6, the lower protruding portion 4b protrudes laterally from the lower end of the outer surface 221 of the main body portion 2 below the water surface 91. The lower protruding portion 4b is a substantially flat plate-shaped portion that extends substantially perpendicular to the Z direction. In the example shown in FIG. 3, the lower protruding portion 4b overlaps substantially the entire concave portion 52b in plan view. The shape of the lower protruding portion 4b in plan view is substantially the same as the shape of the concave portion 52b in plan view and is substantially trapezoidal. The leading edge of the lower protruding portion 4b (i.e., the edge that is farthest from the center C of the main body portion in the Y direction) is located at substantially the same position as the opening 521b of the concave portion 52b in the Y direction. In other words, the leading edge of the lower protruding portion 4b is located at substantially the same position as the front end surfaces of the two convex portions 51b located on both sides of the concave portion 52b in the X direction. The width of the lower protruding portion 4b in the X direction gradually decreases as it approaches the center C of the main body portion in the Y direction, similar to the opening width of the concave portion 52b.

[0056] Note that the lower protruding portions 4a and 4b do not necessarily have to be members connected to the bottom plate portion 24, and may be separate members from the bottom plate portion 24. Also, the lower protruding portions 4a and 4b do not necessarily have to be located at the same position as the bottom plate portion 24 in the vertical direction, and may be arranged above or below the bottom plate portion 24. For example, the lower protruding portion 4a may be arranged within the concave portion 52a above the bottom plate portion 24 and joined to the two outer side surfaces 221 that form the concave portion 52a. The lower protruding portion 4b may be arranged within the concave portion 52b above the bottom plate portion 24 and joined to the three outer side surfaces 221 that form the concave portion 52b. Alternatively, the lower protruding portions 4a and 4b may be arranged below the bottom plate portion 24 and joined to the main body portion 2 via a side wall-like connecting member or the like that extends downward from the lower end of the outer side surface 221.

[0057] As shown in FIGS. 1 and 2, and FIGS. 4 to 6, the outer peripheral portion of the top plate portion 23 of the main body portion 2 extends outwardly (i.e., in a direction away from the center C of the main body portion) from the outer peripheral surfaces of a plurality of main body elements 21 that constitute the honeycomb structure. Specifically, a part of the end portion of the top plate portion 23 extends outwardly from the two outer side surfaces 221 that constitute the concave portion 52a above the concave portion 52a of each concavo-convex structure 5a, and at least partially overlaps the concave portion 52a in plan view. Also, a part of the end portion of the top plate portion 23 extends outwardly from the three outer side surfaces 221 that constitute the concave portion 52b above the concave portion 52b of each concavo-convex structure 5b, and at least partially overlaps the concave portion 52b in plan view.

[0058] In the following description, the portion of the top plate portion 23 that overlaps the concave portion 52a in plan view is referred to as the "return portion 3a". Also, the portion of the top plate portion 23 that overlaps the concave portion 52b in plan view is referred to as the "return portion 3b".

[0059] As shown in FIG. 5, the wave reflecting portion 3a protrudes laterally from the upper end of the outer surface 221 of the main body portion 2 above the water surface 91 (i.e., in the air). The wave reflecting portion 3a is a substantially flat plate-shaped portion that extends substantially perpendicular to the Z direction. In the example shown in FIG. 4, the wave reflecting portion 3a overlaps substantially the entire concave portion 52a in plan view. The shape of the wave reflecting portion 3a in plan view is substantially the same as the shape of the concave portion 52a in plan view and is substantially triangular. The leading edge of the wave reflecting portion 3a (i.e., the edge that is farthest from the center C of the main body portion in the X direction) is located at substantially the same position as the opening 521a of the concave portion 52a in the X direction. In other words, the leading edge of the wave reflecting portion 3a is located at substantially the same position as the tips of the two convex portions 51a located on both sides of the concave portion 52a in the Y direction. The width of the wave reflecting portion 3a in the Y direction gradually decreases as it approaches the center C of the main body portion in the X direction, similar to the opening width of the concave portion 52a.

[0060] As shown in FIG. 6, the wave reflecting portion 3b protrudes laterally from the upper end of the outer surface 221 of the main body portion 2 above the water surface 91. The wave reflecting portion 3b is a substantially flat plate-shaped portion that extends substantially perpendicular to the Z direction. In the example shown in FIG. 4, the wave reflecting portion 3b overlaps substantially the entire concave portion 52b in plan view. The shape of the wave reflecting portion 3b in plan view is substantially the same as the shape of the concave portion 52b in plan view and is substantially trapezoidal. The leading edge of the wave reflecting portion 3b (i.e., the edge that is farthest from the center C of the main body portion in the Y direction) is located at substantially the same position as the opening 521b of the concave portion 52b in the Y direction. In other words, the leading edge of the wave reflecting portion 3b is located at substantially the same position as the front end surfaces of the two convex portions 51b located on both sides of the concave portion 52b in the X direction. The width of the wave reflecting portion 3b in the X direction gradually decreases as it approaches the center C of the main body portion in the Y direction, similar to the opening width of the concave portion 52b.

[0061] Note that the wave - reflecting portions 3a and 3b do not necessarily have to be members integrally connected to the top - plate portion 23 and may be separate members from the top - plate portion 23. Also, the wave - reflecting portions 3a and 3b do not necessarily have to be located at the same position as the top - plate portion 23 in the vertical direction and may be arranged above or below the top - plate portion 23. For example, as shown in FIG. 7, the wave - reflecting portion 3a may be arranged in the recess 52a below the top - plate portion 23 and joined to the two outer surfaces 221 forming the recess 52a. Further, as shown in FIG. 8, the wave - reflecting portion 3b may be arranged in the recess 52b below the top - plate portion 23 and joined to the three outer surfaces 221 forming the recess 52b. Alternatively, the wave - reflecting portions 3a and 3b may be arranged above the top - plate portion 23 and joined to the main body portion 2 via a side - wall - like connecting member or the like extending upward from the upper end of the outer surface 221.

[0062] In the floating structure 1, the waves that collide with the tip portions of the two convex portions 51a of the concavo - convex structure 5a are guided along the slopes (i.e., the outer surfaces 221) on the recess 52a side of each convex portion 51a to the deepest part of the recess 52a located between the two convex portions 51a (i.e., the end farthest from the opening 521a of the recess 52a). Also, the waves incident on the central portion of the recess 52a in the Y - direction (i.e., the waves that have passed through the central portion of the opening 521a of the recess 52a in the Y - direction) go straight to the deepest part of the recess 52a. As a result, the waves concentrate near the deepest part of the recess 52a, and the wave height increases in the vicinity of the deepest part of the recess 52a. The waves with an increased wave height collide from below with the wave - reflecting portion 3a provided at a position overlapping the recess 52a in plan view and are reflected by the wave - reflecting portion 3a and slapped down onto the water surface 91.

[0063] Below the wave reflecting portion 3a, a wave that rises toward the lower surface of the wave reflecting portion 3a while heading toward the inner part of the recess 52a collides with a water mass that is reflected by the wave reflecting portion 3a and descends with gravitational energy. As a result, the wave heading toward the inner part of the recess 52a is broken, the turbulent flow of the wave field in the vicinity of the recess 52a is promoted, and the wave dissipation around the uneven structure 5a is promoted. The promotion of the wave dissipation is achieved regardless of the wavelength of the wave incident on the uneven structure 5a. Therefore, the energy of the wave acting on the floating structure 1 is reduced regardless of the wavelength, and as a result, the sway (for example, pitch, roll, etc.) of the floating structure 1 is also reduced.

[0064] When the wave incident on the uneven structure 5a is a short-wavelength wave, if the phase of the wave that collides with the tip portions of the two convex portions 51a and is guided to the inner part of the recess 52a and the phase of the wave that is incident on the central portion of the recess 52a in the Y direction and directly heads toward the inner part are in opposite phases, these waves cancel each other out, and the wave height in the vicinity of the inner part of the recess 52a is reduced. On the other hand, if the phase of the wave that collides with the tip portions of the two convex portions 51a and is guided to the inner part of the recess 52a and the phase of the wave that is incident on the central portion of the recess 52a in the Y direction and directly heads toward the inner part are in the same phase, these waves overlap and the wave height in the vicinity of the inner part of the recess 52a increases. In any case, when the wave concentrated in the vicinity of the inner part of the recess 52a rises up to the wave reflecting portion 3a, it is reflected downward by the wave reflecting portion 3a, and the wave dissipation around the uneven structure 5a is promoted. As a result, as described above, the energy of the wave acting on the floating structure 1 is reduced, and the sway of the floating structure 1 is also reduced.

[0065] In the floating structure 1, the waves that collide with the tip surfaces of the two convex portions 51b of the concavo-convex structure 5b are guided along the slopes on the concave portion 52b side (i.e., the outer surface 221) of each convex portion 51b to the depths of the concave portions 52b located between the two convex portions 51b (i.e., the ends farthest from the openings 521b of the concave portions 52b). Also, the waves that enter the central portion of the concave portion 52b in the X direction (i.e., the waves that pass through the central portion of the opening 521b of the concave portion 52b in the X direction) directly head towards the depths of the concave portion 52b. As a result, the waves concentrate near the depths of the concave portions 52b, increasing the wave height in the vicinity of the depths of the concave portions 52b. The waves with increased wave height collide from below with the wave reflection portions 3b provided at positions overlapping the concave portions 52b in plan view, and are reflected by the wave reflection portions 3b and slapped down onto the water surface 91.

[0066] Below the wave reflection portions 3b, the waves that rise towards the lower surface of the wave reflection portions 3b while heading towards the depths of the concave portions 52b collide with the water masses that are reflected by the wave reflection portions 3b and descend with gravitational energy. As a result, the waves heading towards the depths of the concave portions 52b are disrupted, promoting the turbulent flow in the wave field near the concave portions 52b and promoting the wave dissipation around the concavo-convex structure 5b. This promotion of wave dissipation is achieved regardless of the length of the wavelength of the waves incident on the concavo-convex structure 5b. Therefore, the energy of the waves acting on the floating structure 1 is reduced regardless of the length of the wavelength, and as a result, the swaying of the floating structure 1 is also reduced.

[0067] In addition, when the wave incident on the uneven structure 5b is a short-wavelength wave, if the phase of the wave that collides with the tip surfaces of the two convex portions 51b and is guided to the inner part of the concave portion 52b and the phase of the wave that is incident on the central portion of the concave portion 52b in the X direction and directly goes to the inner part are in opposite phases, these waves cancel each other out, reducing the wave height near the inner part of the concave portion 52b. On the other hand, if the phase of the wave that collides with the tip surfaces of the two convex portions 51b and is guided to the inner part of the concave portion 52b and the phase of the wave that is incident on the central portion of the concave portion 52b in the X direction and directly goes to the inner part are in the same phase, these waves overlap and the wave height near the inner part of the concave portion 52b increases. In any case, when the wave concentrated near the inner part of the concave portion 52b rises to the wave reflection part 3b, it is reflected downward by the wave reflection part 3b, promoting the wave dissipation around the uneven structure 5b. As a result, as described above, the energy of the wave acting on the floating structure 1 is reduced, and the sway of the floating structure 1 is also reduced.

[0068] From the perspective of the wave reflection by the wave reflection parts 3a and 3b, the height from the draft of the floating structure 1 to the lower surface of the wave reflection parts 3a and 3b is preferably 20% - 50% of the maximum wave height in the installation water area of the floating structure 1.

[0069] As a conventional floating structure, there is known one in which a single convex portion protruding upward above the wave is provided on the side surface of the main body portion, and the wave colliding with the convex portion is dispersed left and right and guided to below the wave. In such a conventional floating structure, by dispersing the incident wave on the convex portion, the energy of the wave colliding with the convex portion can be reduced, but due to the waves dispersed on both sides of the convex portion, the wave height around the floating structure becomes larger below the convex portion. As a result, the energy of the wave acting on the floating structure from the surroundings is not much reduced, and there is a limit to reducing the sway of the floating structure. In contrast, in the floating structure 1 according to the present invention, as described above, by promoting the wave dissipation around the floating structure 1, the energy of the wave acting on the floating structure 1 can be reduced, and the sway of the floating structure 1 can also be reduced.

[0070] In the above-mentioned floating structure 1, in the plurality of sets of concavo-convex structures 5a, the shapes of the convex portions 51a may be different from each other, and the shapes of the concave portions 52a may be different from each other. Also, the shapes of the plurality of downward protruding portions 4a may be different from each other, and the shapes of the plurality of wave-returning portions 3a may be different from each other. The downward protruding portion 4a does not necessarily have to be provided in all the concavo-convex structures 5a. In one or more sets of concavo-convex structures 5a, it is sufficient if a downward protruding portion 4a that overlaps with the concave portion 52a in plan view is provided.

[0071] In the above-mentioned floating structure 1, in the plurality of sets of concavo-convex structures 5b, the shapes of the convex portions 51b may be different from each other, and the shapes of the concave portions 52b may be different from each other. Also, the shapes of the plurality of downward protruding portions 4b may be different from each other, and the shapes of the plurality of wave-returning portions 3b may be different from each other. The downward protruding portion 4b does not necessarily have to be provided in all the concavo-convex structures 5b. In one or more sets of concavo-convex structures 5b, it is sufficient if a downward protruding portion 4b that overlaps with the concave portion 52b in plan view is provided.

[0072] In the above-mentioned floating structure 1, the plurality of sets of concavo-convex structures 5a, 5b are provided over the entire circumference of the side surface of the main body portion 2 in plan view, but it is not limited thereto. It is sufficient if two or more sets of concavo-convex structures (that is, the concavo-convex structure 5a and / or the concavo-convex structure 5b) are provided on the side surface of the main body portion 2. For example, when the shape of the main body portion 2 in plan view is substantially rectangular, it is preferable that one or more sets of concavo-convex structures are provided on one side (for example, the short side) of the main body portion 2 in plan view, and one or more sets of concavo-convex structures are provided on the other side (for example, the long side) adjacent to the one side.

[0073] As described above, the floating structure 1 includes a main body 2 and a plurality of wave reflecting portions (i.e., wave reflecting portion 3a and / or wave reflecting portion 3b). The main body 2 floats on the water surface 91 in a state of penetrating the water surface 91. The plurality of wave reflecting portions protrude laterally from the main body 2 above the water surface 91. On the side surface of the main body 2, a plurality of sets of concavo-convex structures (i.e., concavo-convex structure 5a and / or concavo-convex structure 5b) that each penetrate the water surface 91 are provided. Each set of concavo-convex structures includes two convex portions (i.e., convex portion 51a and / or convex portion 51b) arranged side by side in the horizontal direction, and a concave portion (i.e., concave portion 52a and / or concave portion 52b) located in the space formed between the two convex portions by the two convex portions arranged side by side in the horizontal direction. The two convex portions each protrude in a direction away from the main body center C which is the center of the main body 2 in plan view. The width of the concave portion in plan view becomes smaller as it approaches the main body center C. Each of the plurality of wave reflecting portions overlaps with the concave portion in the plurality of sets of concavo-convex structures in plan view.

[0074] In the floating structure 1, as described above, waves are concentrated in the inner part of the concave portion by the two convex portions of the concavo-convex structure, and the concentrated waves are reflected downward by the wave reflecting portion, thereby promoting the wave dissipation around the floating structure 1. Therefore, the energy of the waves acting on the floating structure 1 can be reduced regardless of the wavelength of the incident waves. As a result, the sway of the floating structure 1 can be reduced regardless of the wavelength of the incident waves.

[0075] As described above, preferably, the shape of the main body 2 in plan view is rectangular. Also, the plurality of sets of concavo-convex structures preferably include one or more sets of concavo-convex structures (e.g., concavo-convex structure 5a) provided on one side (e.g., the short side) of the main body 2 in plan view, and one or more sets of concavo-convex structures (e.g., concavo-convex structure 5b) provided on the other side (e.g., the long side) adjacent to the one side of the main body 2 in plan view. In this way, by providing concavo-convex structures on two adjacent sides in plan view, even when the incident direction of the waves on the floating structure 1 changes to some extent, the wave dissipation around the floating structure 1 can be promoted.

[0076] As described above, it is preferable that the plurality of sets of concavo-convex structures are provided over the entire circumference of the side surface of the main body 2 in plan view. Thereby, regardless of the incident direction of waves on the floating structure 1, the wave dissipation around the floating structure 1 can be promoted.

[0077] As described above, in one or more sets of the plurality of sets of concavo-convex structures (that is, the concavo-convex structure 5a), it is preferable that the shape of the tips of the two convex portions (that is, the convex portions 51a) in plan view is angular. Thereby, the wave colliding with the tip of the convex portion 51a in the concavo-convex structure 5a can be suitably guided to the inner part of the concave portion 52a without being reflected in the direction away from the concave portion 52a adjacent to the convex portion 51a. As a result, the wave dissipation around the floating structure 1 can be further promoted.

[0078] As described above, in one or more sets of the plurality of sets of concavo-convex structures (that is, the concavo-convex structure 5a), it is preferable that the shape of the concave portion (that is, the concave portion 52a) in plan view is triangular. Thereby, the wave incident on the concave portion 52a is likely to concentrate in the inner part of the concave portion 52a, so that the wave can be suitably reflected downward by the wave reflecting portion 3a. As a result, the wave dissipation around the floating structure 1 can be further promoted. Also, the shape of the concavo-convex structure 5a can be simplified to facilitate the manufacture of the floating structure 1. Note that the shape of the concave portion 52a in plan view is the shape of the region surrounded by the opening 521a of the concave portion 52a (that is, the virtual plane connecting the tips of the two convex portions 51a located on both sides of the concave portion 52a) and the inner surface of the concave portion 52a in plan view.

[0079] As described above, in one or more sets of the uneven structures among the plurality of sets of uneven structures (i.e., the uneven structure 5b), it is preferable that the shape of the concave portion (i.e., the concave portion 52b) in plan view is a trapezoidal shape in which the opening 521b of the concave portion 52b is one bottom side and the end portion on the back side of the concave portion 52b is the other bottom side. Further, it is preferable that the length of the other bottom side is 50% or less of the length of the one bottom side. Thereby, the wave incident on the concave portion 52b is likely to concentrate in the inner part of the concave portion 52b, so that the wave can be suitably reflected downward by the wave reflecting portion 3b. As a result, the wave dissipation around the floating structure 1 can be further promoted. Also, the shape of the uneven structure 5b can be simplified to facilitate the manufacture of the floating structure 1. The shape of the concave portion 52b in plan view means the shape in plan view of the region surrounded by the opening 521b of the concave portion 52b (i.e., the virtual plane connecting the tip surfaces of the two convex portions 51b located on both sides of the concave portion 52b) and the inner surface of the concave portion 52b.

[0080] As described above, it is preferable that the main body portion 2 has a honeycomb structure in which a plurality of main body portion elements 21 having a hexagonal cylinder shape extending in the vertical direction are joined together by their outer surfaces 221. Thereby, while ensuring the strength of the main body portion 2, the main body portion 2 can be lightened. Also, the above-described plurality of sets of uneven structures (i.e., the uneven structure 5a and the uneven structure 5b) can be easily formed.

[0081] As described above, it is preferable that each of the plurality of wave reflecting portions (i.e., the wave reflecting portion 3a and / or the wave reflecting portion 3b) overlaps the entire concave portion (i.e., the concave portion 52a and / or the concave portion 52b) in the plurality of sets of uneven structures in plan view. Thereby, the wave incident on the concave portion can be suitably reflected downward by the wave reflecting portion. As a result, the wave dissipation around the floating structure 1 can be further promoted.

[0082] As described above, it is preferable that the floating structure 1 further includes a top plate portion 23 that constitutes the upper surface of the main body portion 2. Further, it is preferable that the plurality of wave reflecting portions (that is, the wave reflecting portion 3a and / or the wave reflecting portion 3b) are at the ends of the top plate portion 23. Thereby, the structure of the floating structure 1 can be simplified. As a result, the manufacture of the floating structure 1 can be facilitated.

[0083] As described above, it is preferable that the floating structure 1 further includes lower protruding portions (that is, the lower protruding portion 4a and / or the lower protruding portion 4b) that protrude laterally from the main body portion 2 below the water surface 91. Further, it is preferable that the lower protruding portion overlaps with the concave portion (that is, the concave portion 52a and / or the concave portion 52b) in one or more sets of uneven structures in plan view. In this way, since the additional mass during the swaying of the floating structure 1 increases due to the provision of the lower protruding portion, the swaying of the floating structure 1 can be reduced. Further, by positioning the lower protruding portion to overlap with the concave portion in plan view and below the wave reflecting portion, an increase in the size of the floating structure 1 in plan view can be suppressed.

[0084] In the floating structure 1, in order to prevent the bow of a ship or the like from entering the opening 521b of the concave portion 52b, as shown in FIGS. 9 and 10, an entry prevention portion 522 may be provided at the opening 521b. The entry prevention portion 522 is, for example, a fence constituted by a plurality of rod-shaped members 523 arranged at intervals in the X direction. Each rod-shaped member 523 is, for example, a quadrangular prism-shaped or cylindrical member that penetrates the water surface 91 and extends substantially parallel in the Z direction. The lower end and the upper end of each rod-shaped member 523 are joined to the lower protruding portion 4b and the wave reflecting portion 3b, for example. The waves entering and leaving the concave portion 52b pass between adjacent rod-shaped members 523 and between the rod-shaped member 523 and the inner surface of the concave portion 52b. The entry prevention portion 522 may be provided at the opening 521a of the concave portion 52a in addition to or instead of the opening 521b of the concave portion 52b. Further, the entry prevention portion 522 may be a net-like member formed of metal, resin, or the like.

[0085] In the above-described floating structure 1, various modifications are possible.

[0086] For example, the shape of the reflecting portion 3a does not necessarily have to be flat and may be variously modified. For example, the lower surface of the reflecting portion 3a may be an inclined surface that slopes upward as it goes from the inner part of the recess 52a toward the opening 521a. The inclined surface may be a substantially arc-shaped surface whose inclination with respect to the horizontal plane gradually becomes gentler as it goes from the inner part of the recess 52a toward the opening 521a. The same applies to the reflecting portion 3b.

[0087] The reflecting portion 3a does not necessarily have to overlap the entire recess 52a in plan view, and may overlap only a part of the recess 52a in plan view. For example, the reflecting portion 3a may overlap only the region extending from the inner part of the recess 52a to the intermediate position between the inner part and the opening 521a in plan view. The same applies to the reflecting portion 3b.

[0088] The leading edge of the reflecting portion 3a (that is, the edge that is farthest from the center C of the main body portion in the X direction) does not necessarily have to be located at the same position as the opening 521a of the recess 52a in the X direction. For example, the reflecting portion 3a may extend to the outside of the opening 521a (that is, the side away from the center C of the main body portion). The same applies to the reflecting portion 3b.

[0089] The lower protruding portion 4a does not necessarily have to overlap the entire recess 52a in plan view, and may overlap only a part of the recess 52a in plan view. For example, the lower protruding portion 4a may overlap only the region extending from the inner part of the recess 52a to the intermediate position between the inner part and the opening 521a in plan view. Further, a through hole that penetrates the lower protruding portion 4a in the vertical direction may be provided in the lower protruding portion 4a. The same applies to the lower protruding portion 4b.

[0090] The leading edge of the lower protrusion 4a (i.e., the edge that is farthest from the center C of the main body in the X direction) does not necessarily have to be located at the same position as the opening 521a of the recess 52a in the X direction. For example, the lower protrusion 4a may extend outside the opening 521a (i.e., on the side away from the center C of the main body). The same applies to the lower protrusion 4b. In the floating structure 1, the lower protrusions 4a and 4b may be omitted.

[0091] The shape of the recesses 52a and 52b in plan view, and the shape of the protrusions 51a and 51b in plan view are not limited to the above-described triangular or trapezoidal shapes, and may be variously changed. For example, the shape of the recesses 52a and 52b in plan view may be substantially semicircular.

[0092] In the floating structure 1, an uneven structure 5a may be provided on the long side in plan view of the substantially rectangular parallelepiped main body 2, and an uneven structure 5b may be provided on the short side in plan view.

[0093] In the floating structure 1, as described above, it is sufficient that two or more sets of uneven structures are provided on the side surface of the main body 2. For example, two or more sets of uneven structures may be provided only on one long side in plan view of the substantially rectangular parallelepiped main body 2, and uneven structures may not be provided on the other sides.

[0094] In the floating structure 1, the shape and structure of the main body 2 are not limited to the above examples, and may be variously changed. For example, the main body 2 does not necessarily have to have a honeycomb structure formed by joining a plurality of hexagonal cylindrical main body elements 21, and may be a structure in which the inside of a substantially rectangular parallelepiped box-shaped member is partitioned by a partition wall or the like. Also, the shape of the main body 2 does not necessarily have to be substantially rectangular parallelepiped, and may be, for example, substantially cylindrical.

[0095] The floating structure 1 does not necessarily have to be used as a floating bridge, and may be used for various purposes.

[0096] The configurations in the above-described embodiments and each modification may be appropriately combined as long as they do not conflict with each other.

Explanation of Reference Numerals

[0097] 1 Floating body structure 2 Main body part 3a, 3b Wave reflecting parts 4a, 4b Lower protruding parts 5a, 5b Concavo-convex structure 21 Main body part element 23 Top plate part 51a, 51b Protruding parts 52a, 52b Recessed parts 91 Water surface 221 Outer surface 521a, 521b Openings C Center of the main body part

Claims

1. A floating structure comprising: a main body floating on the water surface in a state of penetrating the water surface; a plurality of wave-returning portions protruding laterally from the main body above the water surface; and a plurality of sets of concavo-convex structures are provided on the side surface of the main body, each of which penetrates the water surface; each set of concavo-convex structures includes: two convex portions protruding in a direction away from the center of the main body, which is the center of the main body in plan view, and arranged side by side in the horizontal direction; a concave portion located in the space formed between the two convex portions arranged side by side in the horizontal direction, and having a width that decreases in plan view as it approaches the center of the main body; and each of the plurality of wave-returning portions is a floating structure that overlaps with the concave portion in the plurality of sets of concavo-convex structures in plan view.

2. The floating structure according to Claim 1, wherein the shape of the main body in plan view is rectangular, and the plurality of sets of concavo-convex structures include: one or more sets of concavo-convex structures provided on one side of the main body in plan view; and one or more sets of concavo-convex structures provided on the other side adjacent to the one side of the main body in plan view.

3. The floating structure according to Claim 1 or 2, wherein the plurality of sets of concavo-convex structures are provided over the entire circumference of the side surface of the main body in plan view.

4. The floating structure according to Claim 1 or 2, wherein in one or more sets of the plurality of sets of concavo-convex structures, the shape of the tip portions of the two convex portions in plan view is angular.

5. The floating structure according to Claim 1 or 2, wherein in one or more sets of the plurality of sets of concavo-convex structures, the shape of the concave portion in plan view is triangular.

6. The floating structure according to Claim 1 or 2, wherein in one or more sets of the plurality of sets of concavo-convex structures, the shape of the concave portion in plan view is trapezoidal, with the opening of the concave portion being one base and the end portion on the back side of the concave portion being the other base, and the length of the other base is 50% or less of the length of the one base.

7. The floating structure according to Claim 1 or 2, wherein the main body has a honeycomb structure in which a plurality of main body elements in the shape of hexagonal cylinders extending in the vertical direction are joined together on their outer surfaces.

8. The floating structure according to Claim 1 or 2, wherein Each of the plurality of wave-returning parts is a floating structure that overlaps with the entire concave part in the plurality of sets of concave-convex structures in plan view.

9. The floating structure according to claim 1 or 2, further comprising a top plate part that constitutes the upper surface of the main body part, wherein the plurality of wave-returning parts are floating structures that are the ends of the top plate part.

10. The floating structure according to claim 1 or 2, further comprising a lower protruding part that protrudes laterally from the main body part below the water surface, wherein the lower protruding part is a floating structure that overlaps with the concave part in one or more sets of the concave-convex structures in plan view.

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