Junction structure of floating structure

Abstract

To provide a floating structure capable of being efficiently constructed.SOLUTION: In a junction structure of a floating structure, an embedded part 40 embedded in a base body 20 is installed at the end of a floating body 30 extending toward the side of the base body 20. In a second part 92 located ahead of a first part 91, the embedded part 40 forms tensile resist means capable of resisting a tensile force generated in the floating body 30 by having a larger expansion part in the direction intersecting with the extending direction of the floating body 30 compared to the first part 91.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a joint structure in a floating structure. [Background technology]

[0002] In recent years, floating structures have been proposed as structures that utilize marine space (for example, Patent Document 1). Patent Document 1 discloses a floating structure that has a base (platform) that supports a superstructure and hollow legs (pontoons). In Patent Document 1, the superstructure is a wind power generation device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-018129 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional floating structures, both the base and the legs are made of concrete, or both the base and the legs are made of steel. The joints between the base and the legs are required to have a certain strength because they are susceptible to external forces such as wave force and mooring force. When both the base and the legs are made of steel, they need to be welded together, for example, at a port. In this case, constructing the floating structure may require significant time and effort due to the welding work, construction and dismantling of welding equipment, and non-destructive testing after welding. When both the base and the legs are made of concrete, it is possible to cast the base and the legs as a single unit. Concrete floating structures tend to be heavy. Therefore, concrete floating structures tend to be large in size in order to achieve high buoyancy. In this case, constructing the floating structure may require significant time and effort due to the work of pouring the concrete and transporting the floating structure to the sea. [Means for solving the problem]

[0005] A joint structure that solves the above problem is a joint structure for a floating structure, in which an embedded portion is provided at the end of a steel member that extends toward the side of a concrete member and is embedded in the concrete member, and in a second portion of the embedded portion that is located further toward the tip than the first portion, the embedded portion has an expansion portion that is larger in a direction intersecting the extension direction of the steel member than the first portion, thereby forming a tensile resistance means that can resist tensile forces generated in the steel member. [Effects of the Invention]

[0006] According to the present invention, a floating structure can be constructed efficiently. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of a floating structure. [Figure 2] FIG. 2 is a plan view of the floating structure. [Figure 3] FIG. 3 is a side view of the floating structure. [Figure 4] FIG. 4 is a cross-sectional view taken along line 2-2 in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing the joint structure of the floating structure. [Figure 6] FIG. 6 is a cross-sectional view showing a joint structure of a floating structure in a modified example. [Figure 7] FIG. 7 is a cross-sectional view showing a joint structure of a floating structure in a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of a joint structure in a floating structure will be described with reference to FIGS. [Outline of the floating structure] As shown in Fig. 1, a floating structure 10 is constructed on the sea. The floating structure 10 supports a superstructure 11. As an example, the superstructure 11 is a wind turbine generator 110. For example, the wind turbine generator 110 includes a tower 111, a nacelle 112 that houses a generator at the top of the tower 111, a rotor 113 connected to the generator, and blades 114 fixed to the rotor 113. The wind turbine generator 110 generates electricity using wind power at sea.

[0009] As shown in Fig. 2, the floating structure 10 has a base 20, which is an example of a concrete member. As an example, the base 20 has a hollow rectangular pillar shape. However, the base 20 may have a cylindrical shape. As shown in Fig. 3, the base 20 has a box shape having a lower wall 21, an upper wall 22, and a side wall 23.

[0010] The floating structure 10 has a plurality of floats 30, which are an example of steel members. The plurality of floats 30 are also called pontoons. Each float 30 has the same configuration, so only one of them will be described. Each float 30 is joined to the side wall 23 of the base 20. As an example, the float 30 is a hollow cylinder extending toward the side of the base 20. Each float 30 is airtight and generates buoyancy in the floating structure 10. Each float 30 may also be a hollow prism. In the following description, the direction toward the first end 31 of the float 30 is referred to as a first direction D1, and the direction toward the second end 32 is referred to as a second direction D2. In the following description, when the second direction D2 is viewed from the first end 31 side of the float 30, it will be simply referred to as "when viewed from the first direction D1," and when the first direction D1 is viewed from the side wall 23 side of the base 20, it will be simply referred to as "when viewed from the second direction D2."

[0011] As an example, the first end 31 of the floating body 30 is dome-shaped. 3, the first end 31 of the floating body 30 is connected to a mooring line 50. As an example, the mooring line 50 is a steel wire.

[0012] As shown in Fig. 1, the mooring lines 50 are connected to a weight 60. The weight 60 is fixed to the ground at the bottom of the water. As an example, the floating structure 10 is maintained in a submerged state in the sea by the buoyancy of the floating structure 10 and the tension of the mooring lines 50. However, the floating structure 10 may also be maintained in a semi-submerged state in the sea. By being connected to the weight 60 by the mooring lines 50, the floating structure 10 is able to maintain its position even when subjected to horizontal forces due to waves, wind, etc.

[0013] As shown in FIG. 4, the second end 32 of the floating body 30 is an open end that opens toward the side wall 23 of the base body 20. As shown in FIG. 5 , the float 30 has an annular flange 33 around the entire circumference of the circular second end 32. The second end 32 may be polygonal. When viewed from the second direction D2, the flange 33 protrudes both inward and outward in the diameter direction of the second end 32. The flange 33 has a plurality of anchors 332 extending in the second direction D2 from an opposing surface 331 facing the side wall 23 on the second direction D2 side. Each anchor 332 is a steel stud with an anchoring portion at its tip region. When viewed from the first direction D1, the plurality of anchors 332 are arranged in multiple rows along the circumferential direction of the flange 33. The plurality of anchors 332 includes multiple types with different lengths.

[0014] [Connection structure between base and floating body] The joining structure 12 between the base body 20 and the floating body 30 will be described with reference to FIG. The joining structure 12 includes a part of the second end 32 of the float 30, an embedded portion 40, and a part of the side wall 23 of the base 20. The second end 32 of the float 30 is joined to the embedded portion 40. The embedded portion 40 is embedded in the side wall 23 of the base 20. In other words, the float 30 is joined to the base 20 via the embedded portion 40 provided on the second end 32 side.

[0015] The embedded section 40 has an expansion frame 41 buried in the side wall 23, and a filling section 42 provided to fill the interior of the expansion frame 41 without any gaps. The filling section 42 is formed by filling the expansion frame 41 with a filler material. As an example, non-shrinkage mortar is used as the filler material. The anchors 332 of the floating body 30 are embedded in the filling section 42. The multiple anchors 332 are fixed to the non-shrinkage mortar. The expansion frame 41 containing the filling section 42 can be said to be fitted into the side wall 23.

[0016] The expansion frame 41 has an annular shape when viewed from the second direction D2 and is trough-shaped and open in the first direction D1. However, the shape of the expansion frame 41 may be a polygonal annular shape when viewed from the second direction D2. As an example, the expansion frame 41 has an annular shape when viewed from the second direction D2 and includes a side wall 411 that faces the opposing surface 331 of the flange 33 across the filling portion 42. The expansion frame 41 has an inner peripheral wall 412 that extends from the inner peripheral edge of the side wall 411 in the first direction D1, and an outer peripheral wall 413 that extends from the outer peripheral edge in the first direction D1. As an example, each of the walls 411 to 413 has a predetermined, uniform thickness.

[0017] The inner circumferential wall 412 has an inclined portion 414 between the connection portion with the side wall 411 and the opening end on the first direction D1 side. The inner circumferential wall 412 is inclined at the inclined portion 414 so that the diameter increases toward the first direction D1. The diameter of the inner circumferential wall 412 on the side wall 411 side of the inclined portion 414 is smaller than the diameter of the inner circumferential wall 412 on the opening side of the inclined portion 414.

[0018] The outer peripheral wall 413 has an inclined portion 415 between the connection portion with the side wall 411 and the opening end on the first direction D1 side. The outer peripheral wall 413 is inclined at the inclined portion 415 so that the diameter becomes smaller as it goes toward the first direction D1. The diameter of the outer peripheral wall 413 on the side wall 411 side of the inclined portion 415 is larger than the diameter of the outer peripheral wall 413 on the opening side of the inclined portion 415.

[0019] The distance in the diameter direction between the outer peripheral surface of the inner peripheral wall 412 and the inner peripheral surface of the outer peripheral wall 413 is greater on the second direction D2 side than on the first direction D1 side, based on each of the inclined portions 414, 415. The filling portion 42 is formed so as to contact each of the inclined portions 414, 415 inside the expansion frame 41. Each of the inclined portions 414, 415 and the portion of the filling portion 42 that contacts each of the inclined portions 414, 415 form a trapezoidal joint key, an example of a shear key.

[0020] The distance in the diameter direction between the inner peripheral surface of the inner peripheral wall 412 and the outer peripheral surface of the outer peripheral wall 413 is greater on the portion on the second direction D2 side than on the portion on the first direction D1 side, with each inclined portion 414, 415 as the reference. The expansion frame 41 is entirely embedded in the side wall 23 of the base 20. The side wall 23 is formed so as to contact each of the inclined portions 414, 415 outside the expansion frame 41. Each of the inclined portions 414, 415 and the portion of the side wall 23 that contacts each of the inclined portions 414, 415 form a trapezoidal joint key, an example of a shear key. In this way, in the floating structure 10, a shear key is formed by the embedded portion 40 and the base 20.

[0021] A portion of each of the peripheral walls 412, 413 that is closer to the first direction D1 than the inclined portions 414, 415 is an example of a first portion 91. A portion of each of the peripheral walls 412, 413 that is closer to the second direction D2 than the inclined portions 414, 415 is an example of a second portion 92 that is located closer to the tip end than the first portion 91. As described above, when viewed from the first direction D1, the width of the second portion 92 in the diameter direction is larger than the width of the first portion 91. In other words, the second portion 92 constitutes an example of an extension portion that is larger than the first portion 91 in a direction intersecting the extension direction of the steel member (for example, the diameter direction).

[0022] The expansion frame 41 includes an annular outer peripheral flange 416 that protrudes outward in the diameter direction around the entire circumference of the outer peripheral edge of the side wall 411. The outer peripheral flange 416 may be provided on the outer peripheral surface of the outer peripheral wall 413. The expansion frame 41 includes an annular inner peripheral flange 417 that protrudes inward in the diameter direction around the entire circumference of the inner peripheral edge of the side wall 411. The inner peripheral flange 417 may be provided on the inner peripheral surface of the inner peripheral wall 412.

[0023] The side wall 411 and each flange 416, 417 have a plurality of anchors 43 extending in the second direction D2 from a tip surface 418 on the second direction D2 side. Each anchor 43 is a steel stud with a fixing portion in the tip region.

[0024] When viewed from the first direction D1, the multiple anchors 43 are arranged in multiple rows along the circumferential direction of the side wall 411 and the flanges 416, 417. Some of the multiple anchors 43 are arranged in a row along the outer peripheral edge of the outer peripheral flange 416. Some of the multiple anchors 43 are arranged in a row along the inner peripheral edge of the inner peripheral flange 417.

[0025] The outer peripheral wall 413 has a plurality of anchors 44 extending from its outer peripheral surface in the diameter direction toward the outer side in the diameter direction. Each anchor 44 is a steel stud with an anchoring portion in its tip region. The plurality of anchors 44 are lined up along the outer peripheral surface of the outer peripheral wall 413. The inner peripheral wall 412 has a plurality of anchors 45 extending from its inner peripheral surface in the diameter direction toward the inner side in the diameter direction. Each anchor 45 is a steel stud with an anchoring portion in its tip region. The plurality of anchors 45 are lined up along the inner peripheral surface of the inner peripheral wall 412. Each of the anchors 43 to 45 is embedded in the side wall 23. Each of the anchors 43 to 45 is fixed to concrete.

[0026] The expansion frame 41 includes a plurality of ribs 46 extending in the first direction D1 from the surface of the outer peripheral flange 416 opposite the tip surface 418. The plurality of ribs 46 are made of steel and are aligned at predetermined intervals along the outer peripheral surface of the outer peripheral wall 413. The expansion frame 41 includes a plurality of ribs 47 extending in the first direction D1 from the surface of the inner peripheral flange 417 opposite the tip surface 418. The plurality of ribs 47 are made of steel and are aligned at predetermined intervals along the inner peripheral surface of the inner peripheral wall 412.

[0027] Reinforcing bars 24 are embedded in the base 20 as reinforcing materials. The arrangement of the reinforcing bars 24 in the side wall 23 of the base 20 will be described. Assuming that the embedded portion 40 falls off from the side wall 23 of the base 20 due to a tensile force in the first direction D1, there is a high possibility that a fracture surface 25 will be generated on the side wall 23, as shown by the dashed line in the figure. For example, when the floating body 30 is pulled out of the base 20 together with the embedded portion 40. Assuming that the expansion frame 41 is cut along a plane including the diameter direction, a first fracture surface 251 may be generated starting from the outer peripheral edge of the outer flange 416. A second fracture surface 252 may be generated starting from the inner peripheral edge of the inner flange 417. Assuming that the expansion frame 41 is cut along a plane including the diameter direction, each of the fracture surfaces 251, 252 can be formed at a position corresponding to one side of a trapezoid with the side wall 411 and each of the flanges 416, 417 as one of the parallel opposing sides. Each of the fracture surfaces 251, 252 is a so-called cone-shaped fracture surface.

[0028] The first reinforcing bars 241, which are at least a part of the reinforcing bars 24, are arranged along the extension direction of the float 30. The first reinforcing bars 241 are arranged so as to straddle at least one location on the fracture surface 25. As an example, the first reinforcing bars 241 are arranged so as to straddle at least multiple locations on the fracture surface 25. As an example, the first reinforcing bars 241 are arranged so as to straddle multiple locations on each of the fracture surfaces 251, 252. In other words, multiple portions of the first reinforcing bars 241 that extend along the extension direction of the float 30 are lined up along the circumferential direction on the outer diametrical side of the outer peripheral wall 413. Multiple portions of the first reinforcing bars 241 that extend along the extension direction of the float 30 are lined up along the circumferential direction on the inner diametrical side of the inner peripheral wall 412.

[0029] When viewed from the first direction D1, the second reinforcing bars 242, which are at least a part of the reinforcing bars 24, are arranged in a ring shape extending along the outer peripheral surface of the outer peripheral wall 413 in the diameter direction, on the first direction D1 side of the inclined portion 415. When viewed from the first direction D1, the diameter of the second reinforcing bars 242 is smaller than the outer diameter of the portion of the outer peripheral wall 413 on the second direction D2 side of the inclined portion 415.

[0030] When viewed from the first direction D1, the second reinforcing bars 242 are arranged in an annular shape extending along the inner circumferential surface of the inner circumferential wall 412 in the diameter direction, on the first direction D1 side of the inclined portion 414. When viewed from the first direction D1, the diameter of the second reinforcing bars 242 is larger than the outer diameter of the portion of the inner circumferential wall 412 on the second direction D2 side of the inclined portion 414.

[0031] The floating structure 10 includes a waterstop material 70 between the float 30 and the base 20. For example, the waterstop material 70 is made of a polymer material such as polyurethane or chloroprene rubber. As an example, the waterstop material 70 includes an outer periphery waterstop material 71 sandwiched between the opposing surface 331 of the flange 33 and the ends of the outer surface 231 of the side wall 23 and the inner periphery wall 412 on the first direction D1 side. As an example, the waterstop material 70 includes an inner periphery waterstop material 72 sandwiched between the opposing surface 331 of the flange 33 and the ends of the outer surface 231 of the side wall 23 and the outer periphery wall 413 on the first direction D1 side. Each of the waterstop materials 71, 72 has an annular shape when viewed from the first direction D1.

[0032] [How to construct a floating structure] The method for constructing the floating structure 10 will be described below together with its operation. The steps for creating the floating body 30 will now be described.

[0033] As an example, the float 30 may be fabricated in advance in a factory or the like. For example, a cylindrical body of the float 30 with a sealed first end 31 is formed by welding together multiple parts each made of steel plate of a predetermined thickness shaped into a specified shape. A flange 33 and multiple anchors 332 are welded to the open end of this body. The float 30 is then completed. The same number of floats 30 as those to be joined to the base 20 are fabricated. Each float 30 is transported to a work area set up at the pier. Because each float 30 is made of steel, its weight and size are reduced compared to a float made of concrete. Therefore, it is easy to transport the float 30 from the factory to the work area. Furthermore, because the float 30 can be fabricated in a factory with permanent welding equipment, it can be fabricated more efficiently than if welding equipment were prepared in a work area at the pier and the float 30 were fabricated there.

[0034] The steps for creating the enlargement frame 41 will now be described. As an example, the floating body 30 may be fabricated in the factory. As an example, the annular walls 411-413 are formed by welding together a plurality of parts each made of a steel plate of a predetermined thickness formed into a specified shape. The flanges 416, 417 and a plurality of anchors 43-45 are welded to specified portions of the walls 411-413. The expansion frame 41 is then completed. The expansion frame 41 is then transported to a work area at the pier.

[0035] The steps for producing the base body 20 will now be described. As an example, the base 20 may be created in the work area. In the work area, a concrete form is constructed to have a shape corresponding to the base 20. An expansion frame 41 is installed within the concrete form. An injection pipe is placed within the concrete form to form an injection hole 80 that penetrates the side wall 23 and the outer peripheral wall 413. The injection hole 80 is a hole for injecting non-shrinkage mortar into the expansion frame 41. Reinforcing bars 24 are arranged within the concrete form. Concrete is poured into the concrete form. At this time, the expansion frame 41 is used as part of the concrete form. Once the concrete has hardened, the concrete form is removed.

[0036] The step of joining the base body 20 and the floating body 30 will now be described. As an example, the base body 20 and the floating body 30 may be joined in the above-mentioned work area. Each water-stopping material 71, 72 is placed at a specified position on the side wall 23. The floating body 30 is supported so that the anchor 332 of the floating body 30 is housed in the expansion frame 41. Non-shrinkage mortar is poured through the injection hole 80 so that the inside of the expansion frame 41 is completely filled. The injection hole 80 is also filled with non-shrinkage mortar. Once the non-shrinkage mortar has completely hardened, the joining of the base body 20 and the floating body 30 is complete.

[0037] Since each floating body 30 is pre-assembled in a factory, most of the floating structure 10 is completed simply by joining it to the base body 20. This shortens the construction period in the work area of ​​the wharf. In addition, since the base body 20 and the floating body 30 are joined in the work area of ​​the wharf, the factory can be smaller in size than if they were joined inside the factory.

[0038] The assembly of the base body 20 and the floating body 30 is transported to a specified position on the sea by a ship. At sea, mooring lines 50 and weights 60 are connected to the floating body 30. Construction of the floating structure 10 is then completed. After that, the superstructure 11 is installed on the floating structure 10. The superstructure 11 may be transported to the sea in parts and constructed on the floating structure 10.

[0039] [Action of floating structures] A floating structure 10 installed on the sea is subjected to external forces such as wave forces and mooring forces. At this time, bending moments, shear forces, axial forces, etc. are applied to the joints between the base body 20 and the floating body 30. When a bending moment acts on the floating body 30, a tensile force is generated in the floating body 30 in the first direction D1. This tensile force is transmitted to the filling portion 42. The tensile force is then transmitted to each of the inclined portions 414, 415 of the expansion frame 41. The shear keys, which are the contact points between the filling portion 42 and each of the inclined portions 414, 415, resist the tensile force. In other words, the tensile force generated in the floating body 30 is transmitted to the expansion frame 41 via the filling portion 42. The tensile force transmitted to the embedded portion 40 is transmitted from each of the inclined portions 414, 415 to the side wall 23. The shear keys, which are the contact points between the side wall 23 and each of the inclined portions 414, 415, resist the tensile force. The shear key is an example of a tension resistance means capable of resisting tension forces acting on the floating body 30 .

[0040] The tensile force generated in the floating body 30 is transmitted from the flanges 416, 417 of the embedded portion 40 to the side wall 23. Because the flanges 416, 417 are buried in the side wall 23, the side wall 23 resists the tensile force generated in the embedded portion 40. At this time, because the first reinforcing bar 241 is arranged so as to straddle the expected fracture surface 25, the embedded portion 40 is prevented from falling off.

[0041] Furthermore, the second reinforcing bars 242 are arranged at positions overlapping the inclined portions 414, 415 when viewed from the first direction D1. Therefore, the second reinforcing bars 242 support the portions of the side wall 23 that contact the inclined portions 414, 415 from the first direction D1. This makes it possible to prevent damage to the portions of the side wall 23 that contact the inclined portions 414, 415. This prevents the embedded portion 40 from falling off.

[0042] [Effects of the embodiment] (1) The floating structure 10 employs a composite structure consisting of a concrete base 20 and a steel float 30. The floating structure 10 reduces the amount of welding work required in the wharf work area compared to a structure constructed entirely of steel. For example, by performing all welding work in a factory, welding work in the wharf work area can be eliminated. This shortens the construction period in the wharf work area, reduces welding costs, and makes it easier to maintain welding quality. The floating structure 10 is less heavy and larger than a structure constructed entirely of concrete. Furthermore, in the floating structure 10, when a tensile force is applied to the float 30, the extensions in the embedded sections 40 provided at the ends of the float 30 resist the tensile force. This prevents the embedded sections 40 from being pulled out. This improves the resistance to the tensile force applied to the float 30, and increases the joint strength between the float 30 and the base 20. Therefore, the floating structure 10 can be constructed efficiently.

[0043] (2) In the floating structure 10, when a tensile force is generated in the float 30, the tensile force is resisted by the shear key formed by the embedded portion 40 and the base 20. This improves the resistance to the tensile force generated in the float 30, and increases the joining strength between the float 30 and the base 20.

[0044] (3) In the floating structure 10, when a tensile force is generated in the float 30, the tensile force is resisted by the side wall 411 and the anchor 43 provided at the tip of the embedded portion 40. This improves the resistance to the tensile force generated in the float 30, and increases the bonding strength between the float 30 and the base 20.

[0045] (4) In the floating structure 10, the water-stopping material 70 can prevent water from entering the floating body 30. (5) In the floating structure 10, the first reinforcing bars 241 are arranged so as to straddle the fracture surface 25 that may occur when the float 30 is pulled out from the base 20 together with the embedded portion 40. This allows the first reinforcing bars 241 to bear the tensile force acting on the concrete when a tensile force is exerted on the float 30. This improves the resistance to the tensile force exerted on the float 30, and increases the bond strength between the float 30 and the base 20.

[0046] (6) In the floating structure 10, the entire embedded portion 40 is located inside the side wall 23 and does not penetrate the side wall 23. This prevents water from entering the base 20. (7) In the floating structure 10, the strength of the flanges 416, 417 can be increased by the ribs 46, 47. Therefore, the flanges 416, 417 resist tensile forces, and the joining strength between the floating body 30 and the base body 20 is increased.

[0047] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility. As shown in FIG. 6 , a trapezoidal shear key formed by the base 20 and the embedded portion 40 is used as the tension resistance means, but the tension resistance means is not limited to a trapezoidal shear key. The tension resistance means may be a concave-shaped shear key. The tension resistance means may include repeated concave shapes. A portion of the concave shape that protrudes outward in the radial direction of the inner circumferential wall 412 is an example of a first portion 91. A portion of the concave shape that is closer to the tip of the first portion 91 and protrudes inward in the radial direction of the inner circumferential wall 412 is an example of a second portion 92. A portion of the concave shape that protrudes inward in the radial direction of the outer circumferential wall 413 is an example of a first portion 91. A portion of the concave shape that is closer to the tip of the first portion 91 and protrudes outward in the radial direction of the outer circumferential wall 413 is an example of a second portion 92.

[0048] As shown in FIG. 7 , the shear key formed by the base 20 and the embedded portion 40 as the tensile resistance means may be a tapered shear key that widens in width from the end of the embedded portion 40 on the first direction D1 side to the end in the second direction D2 side. The end of the expansion frame 41 on the first direction D1 side is an example of a first portion 91. The portion of the expansion frame 41 closer to the second direction D2 side than the end on the first direction D1 side is an example of a second portion 92 located closer to the tip than the first portion 91. The tapered surface 419 constituting the shear key allows the tensile force to act as a pressing force on the friction surface. This generates frictional resistance and can resist the tensile force.

[0049] The thickness of the steel plate forming the flange 33 is set to a thickness that allows tensile force to be transmitted evenly to the anchors 332 arranged in multiple rows along the diameter direction. The thinner the flange 33 is, the more likely the tensile force will be concentrated on the anchors 332 provided near the center of the width of the flange 33 in the diameter direction. On the other hand, the thicker the flange 33 is, the more likely the tensile force will be concentrated on the anchors 332 provided near both edges of the width of the flange 33 in the diameter direction. The appropriate thickness of the flange 33 may be determined based on the results of experiments or simulations.

[0050] The steps of creating the floating body 30, creating the expansion frame 41, creating the base body 20, and joining the base body 20 and the floating body 30 are not limited to the order in the above-described embodiment. For example, they may be created in the order of the expansion frame 41, floating body 30, and base body 20, or in the order of the expansion frame 41, base body 20, and floating body 30, or may be created in parallel.

[0051] The floating body 30 and the expansion frame 41 may be fabricated in a work area at the pier. The base body 20 and the floating body 30 may be joined together in a factory. The steel member is not limited to the float 30 as in the above embodiment. For example, the steel member may be a hollow or solid support member extending to connect the float 30 and the base 20. The base 20 may be a steel member. In this case, the float 30 may be a concrete member.

[0052] The steel member may be a member that integrally comprises the floating body 30 and the buried portion 40. In this case, the buried portion 40 may be made entirely of steel. The embedded portion 40 does not have to be a continuous annular shape when viewed from the first direction D1. For example, the embedded portion 40 may be arranged intermittently. [Explanation of symbols]

[0053] 10...Floating structure, 11...Superstructure, 12...Connection structure, 20...Base, 21...Lower wall, 22...Upper wall, 23...Side wall, 24...Reinforcing bar, 25...Fracture surface, 30...Floating body, 31...First end, 32...Second end, 33...Flange, 40...Embedded portion, 41...Expansion frame, 42...Filling portion, 43...Anchor, 44...Anchor, 45...Anchor, 46...Rib, 47...Rib, 50...Mooring rope, 60...Plumbing weight, 70...Waterstop material, 71...Outer peripheral waterstop material, 72...Inner peripheral waterstop material, 80...Injection hole, 91... First part, 92...second part, 110...wind turbine generator, 111...tower, 112...nacelle, 113...rotor, 114...blade, 231...outer surface, 241...first reinforcing bar, 242...second reinforcing bar, 251...first failure surface, 252...second failure surface, 331...opposing surface, 332...anchor, 411...side wall, 412...inner wall, 413...outer wall, 414...inclined portion, 415...inclined portion, 416...outer flange, 417...inner flange, 418...tip surface, 419...tapered surface.

Claims

1. A joint structure in a floating structure, An embedded portion is provided at an end of the steel member extending toward the side of the concrete member and embedded in the concrete member, A joint structure characterized in that the embedded portion has an expansion portion in a second portion that is located further distal than the first portion, which is larger in a direction intersecting the extension direction of the steel member than the first portion, thereby forming a tensile resistance means that can resist the tensile force generated in the steel member.

2. 2. The joint structure according to claim 1, wherein the tension resistance means comprises a shear key formed by the embedded portion and the concrete member.

3. 2. The joint structure according to claim 1, wherein the embedded portion has a flange with an anchor at its tip, and the anchor is embedded in the concrete member.

4. The joint structure according to claim 1 , further comprising a water-stop material between the steel member and the concrete member.

5. The concrete member includes a reinforcing bar extending in the direction in which the steel member extends, The joint structure according to claim 1 , wherein the reinforcing bar is arranged so as to straddle a fracture surface that may occur when the steel member is pulled out of the concrete member together with the embedded portion.

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