JP2022033554A - Reinforcement device for cylindrical type precast concrete member and concrete floating structure in floating type wind power generation facility on ocean using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reinforcing device for a precast cylindrical body having advantages such as being able to be uniformly reinforced over the entire circumferential direction and being removable at least after installation. SOLUTION: The structure is such that tension cables 30, 30 ... Are stretched along an inscribed regular polygonal shape line inside a precast tubular body 15. Fixing metal fittings 31, 31 ... Are fixed at the positions of the vertices of the inscribed regular polygonal lines, and the tensioning cable 30 is bridged between the adjacent fixing metal fittings 31, 31 so that tension force can be introduced. Further, a plurality of reinforcing devices 2 in which tension cables 30 are stretched along inscribed regular polygonal lines are provided as a set in the axial core direction of the precast cylindrical body 15 at predetermined intervals. [Selection diagram] FIG. 6

Description

The present invention relates to a reinforcing device for a cylindrical precast concrete member and a concrete floating structure in a floating offshore wind power generation facility using the same.

Conventionally, power generation methods such as hydropower, thermal power, and nuclear power generation have been mainly adopted, but in recent years, wind power generation that uses natural wind to generate power has attracted attention from the viewpoint of effective utilization of the environment and natural energy. .. There are two types of this wind power generation facility, one is a land-based type and the other is a water-mounted type (mainly on the sea). .. On the other hand, Japan is surrounded on all sides by the sea, and has the advantages of being able to easily obtain wind suitable for power generation and having few restrictions on installation. Therefore, in recent years, many floating offshore wind turbines and floating structures for that purpose have been proposed.

The floating body structure is roughly classified into a pontoon type floating body in which the floating body is floated on the water surface, a semi-sub type in which the floating body is floated in a state of being submerged under the water surface, and a spar type in which the floating body is floated in an upright state like a fishing float.

Regarding the spar type floating structure, the following Patent Document 1 describes an offshore wind power generation facility including a floating body, a mooring line, a tower, a nacelle installed at the top of the tower, and a plurality of wind turbine blades. Is a lower concrete floating structure part in which concrete precast tubular bodies are stacked in multiple stages in the height direction, and each precast tubular body is tied together with PC steel to integrate them, and this lower concrete floating structure part. An offshore wind turbine (hereinafter referred to as a spar-type floating offshore wind turbine) having a spar-type floating structure composed of an upper steel floating structure unit connected to the upper side of the turbine has been proposed.

Further, in Patent Document 2 below, a lower floating body in which upper and lower lids and a tubular precast concrete block continuously installed between them are integrally joined with a PC steel material, and a PC on the lower floating body. It is composed of a precast concrete block with a smaller diameter than the precast concrete block and an upper floating body consisting of an upper lid, which are integrally joined with a steel material. Has proposed a floating structure for offshore wind turbines in which a plurality of watertight compartments are formed by partition walls.

In the case of an offshore wind power generation facility provided with a concrete floating structure portion for integrating a plurality of concrete precast tubular bodies in the height direction as in Patent Documents 1 and 2, the concrete floating structure portion is used. A large bending stress acts on the concrete floating structure during assembly and transportation, and when building up offshore wind power generation equipment. Here, since the concrete floating structure portion has a support structure in which both ends are almost free ends after installation, the structure is such that axial force mainly acts and large bending stress does not act. In particular, in the case of a structure in which a plurality of divided precast cylinders divided in the circumferential direction are joined as a precast cylinder, the strength against bending is weak, and there is a risk of deformation or breakage during assembly, transportation, or building up. rice field.

Therefore, in order to reinforce the precast tubular body, for example, a reinforcing support (round shape holding device) as disclosed in Patent Document 3 below may be provided inside the precast tubular body made of concrete, or the following patent. As disclosed in Document 4, the outer circumference of the precast tubular body is reinforced by winding an outer cable into which tension is introduced along the circumferential direction.

Japanese Patent No. 5274329 Japanese Unexamined Patent Publication No. 2009-18671 Japanese Unexamined Patent Publication No. 10-280894 Japanese Unexamined Patent Publication No. 2014-173586

However, in the case of the method using the reinforcing support work, when water pressure is received from the outside after operation, the reinforced part and the non-reinforced part receive the same water pressure, but the reinforced part is Since the deformation is constrained, there is a possibility that a distorted stress concentration may occur so that the perfect circle cannot be maintained. In addition, there is a problem that deformation of the precast cylinder cannot be prevented because the direction of action changes when it rotates around the axis when it is built up at sea (the direction of reinforcement is limited), and it is installed. There was a problem that it was difficult to remove the reinforcing support later.

On the other hand, in the case of the outer cable method, since the reinforcement is evenly performed over the entire circumference, distorted stress concentration does not occur, and the outer diameter of the precast tubular body is slightly reduced by the external water pressure after the operation. As a result, the tension is relaxed and no harmful stress is generated on the precast tubular body. However, since the outer cable is installed on the outer circumference of the precast cylinder, it will be located in the sea after installation, so it cannot be removed practically and the installation cost of the outer cable is high. was there.

Therefore, the main problem of the present invention is a reinforcing device for a cylindrical precast member having advantages such as being able to be reinforced evenly over the entire circumference and being removable at least after installation, and a floating offshore wind turbine using the same. The purpose is to provide a concrete floating structure in a power generation facility.

In order to solve the above problems, the present invention according to claim 1 is characterized in that a tension cable is stretched along a regular polygonal line inscribed in an inner space circle inside a cylindrical precast concrete member. A reinforcing device for a cylindrical precast concrete member is provided.

The invention according to claim 1 has a structure in which a tension cable is stretched along an inscribed regular polygonal line inside a cylindrical precast concrete member.

When tension force is introduced into each tension cable, tension force acts in two directions from each vertex of the regular polygon, and the component force of these tension forces is introduced into the precast concrete member as a presto force in the circumferential direction. Therefore, reinforcement is evenly performed over the entire circumference. Therefore, the introduction of the precast force increases the strength against bending, and it becomes possible to prevent the cylindrical precast concrete member from being deformed or damaged during assembly work, transportation work, building up, and the like.

Further, since the reinforcing device is provided inside the cylindrical precast concrete member, when applied to a concrete floating structure in a floating offshore wind power generation facility, it can be removed even after floating on the ocean, and can be removed again. It can also be used.

The first aspect of the present invention according to claim 1, wherein a fixing metal fitting is fixed at each apex position of the inscribed regular polygonal line, and a tensioning cable is laid between adjacent fixing metal fittings so that a tension force can be introduced. A reinforcing device for a cylindrical precast concrete member is provided.

The invention according to claim 2 shows a specific installation example of a tension cable. It is desirable to fix the fixing brackets at the positions of the vertices of the inscribed regular polygonal lines and to have a structure in which a tension cable is laid so that tension force can be introduced between the adjacent fixing brackets. The tension can be introduced by, for example, providing a turnbuckle mechanism at the fixing portion of the cable so that the cable can be expanded and contracted by rotating around the axis, and the tension can be introduced into the cable.

According to the third aspect of the present invention, the inscribed regular polygonal line is one of a regular triangle shape and a regular hexagon shape. The reinforcing device for a cylindrical precast concrete member according to any one of claims 1 and 2. Provided.

The invention according to claim 3 shows a suitable range of the inscribed regular polygonal line. Considering the number of fixing brackets to be installed and the time and effort required to stretch the cable, it is desirable that the inscribed regular polygonal line be one of a regular triangle shape and a regular hexagon shape in terms of balance.

According to the fourth aspect of the present invention, a plurality of reinforcing devices in which tension cables are stretched along the inscribed regular polygonal line are provided as a set in the axial core direction of the precast concrete member at predetermined intervals. 3. The reinforcing device for the cylindrical precast concrete member according to any one of 3 is provided.

In the invention according to claim 4, a plurality of reinforcing devices in which tension cables are stretched along the inscribed regular polygonal line are provided as a set in the axial core direction of the precast concrete member at predetermined intervals. .. The spacing can be varied depending on the degree of reinforcement with the tension cable.

According to the present invention according to claim 5, the fixing metal fitting is divided into two for each fixing portion of the tension cable in two directions adjacent to each other, and the cylindrical precast concrete member is divided at the same position in the circumferential direction. The reinforcing device for the cylindrical precast concrete member according to claim 2, wherein the divided precast concrete members are joined in the circumferential direction to be closed in a cylindrical shape is provided.

The invention according to claim 5 shows a modified example of the reinforcing device. When the size of the cylindrical precast concrete member is large and it is difficult to transport the vehicle, the cylindrical precast concrete member may be divided into a plurality of parts in the circumferential direction and transported. In such a case, the fixing bracket is divided into two for each fixing portion of the tension cable in two directions adjacent to each other, and the cylindrical precast concrete member is divided at the same position in the circumferential direction. By joining the precast concrete members in the circumferential direction, it is possible to form a structure that is closed in a cylindrical shape. Even in the state of the arc-shaped precast concrete member before closing in the circumferential direction, reinforcement is performed even in the state of the arc-shaped precast concrete member by the tension cable stretched just like a bowstring.

As the present invention according to claim 6, the floating body in a floating offshore wind power generation facility composed of a floating body, a mooring line, a tower, a nacelle installed at the top of the tower, and a wind turbine composed of a plurality of blades. The lower side is a concrete floating structure in which multiple concrete precast tubular bodies are stacked in the height direction, and the upper side is a steel floating structure made of steel members, and the lower side is a concrete precast tubular body. Provided is a concrete floating structure in a floating offshore wind turbine, characterized in that the body is provided with the reinforcing device for the cylindrical precast concrete member according to any one of claims 1 to 5.

The invention according to claim 6 shows a case where the reinforcing device for a cylindrical precast concrete member according to the present invention is applied to a concrete floating structure in a floating offshore wind power generation facility.

As described in detail above, according to the present invention, a reinforcing device for a cylindrical precast member having advantages such as being able to be reinforced evenly over the entire circumference and being removable at least after installation, and a floating type using the reinforcing device. It will be possible to provide concrete floating structures for offshore wind turbines.

It is a side view of the spar type floating offshore wind power generation facility 1. It is a vertical sectional view of a floating body 4. The precast cylindrical body 15 is shown, (A) is a vertical sectional view, (B) is a plan view (B-B line arrow view), and (C) is a bottom view (C-C arrow view). It is a binding procedure diagram (A) (B) between the precast tubular bodies 15. It is a vertical sectional view which shows the boundary part between the lower concrete floating structure part 4A and the upper steel floating structure part 4B. It is a cross-sectional view when the reinforcing device 2 which concerns on this invention is applied to the lower concrete floating structure part 4A. It is the vertical sectional view (the VII-VII line arrow view of FIG. 6). (A) is an enlarged view (part VIII of FIG. 6) of the fixing metal fitting 31 part, and (B) is a plan view thereof. The tension cable 30 is shown, (A) is a side view, and (B) is a plan view. It is explanatory drawing of the reinforcement mechanism by the reinforcement device 2. It is a water pressure action state diagram on the precast cylindrical body 15 when the floating body 4 is floated on the sea surface. It is a division mode diagram of the precast cylindrical body 15. It is a temporary phase diagram of the divided arc-shaped precast concrete member. It is a cross-sectional view of the precast cylindrical body 15 when the tension cable 30 is arranged in a regular square shape. It is a cross-sectional view of the precast cylindrical body 15 when the tension cable 30 is arranged into a regular hexagonal shape.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Spar type floating offshore wind power generation facility 1]
Before explaining the reinforcing device 2 according to the present invention, the spar type floating offshore wind power generation facility 1 to which the reinforcing device 2 can be applied will be described in detail with reference to FIGS. 1 to 5.

As shown in FIG. 1, the spar-type offshore wind power generation facility 1 includes a cylindrical floating body 4, a mooring line 5, a tower 6, a nacelle 8 installed at the top of the tower 6, and a plurality of blades 9. , 9 ... It is composed of a wind turbine 7 and a wind turbine 7.

As shown in FIG. 2, the floating body 4 is made by stacking a plurality of concrete precast tubular bodies 15, 15 ... In the height direction, and each precast tubular body 15, 15 ... Is tightly connected by a PC steel material 19 and integrated. It is composed of a lower concrete floating structure portion 4A that has been made into a concrete structure and an upper steel floating structure portion 4B that is connected to the upper side of the lower concrete floating structure portion 4A.

Ballast material such as water, gravel, fine aggregate or coarse aggregate, and metal grains can be put in or discharged from the hollow portion of the floating body 4, and the buoyancy (draft) can be adjusted. The ballast material can be charged / discharged by adopting the fluid transport method previously proposed by the applicant in Japanese Patent Application Laid-Open No. 2012-201217.

The lower concrete floating structure portion 4A is composed of concrete precast tubular bodies 15, 15 ... As shown in FIG. 3, the precast tubular body 15 is a circular tubular precast member having the same cross section in the axial direction, and each of them is manufactured by using the same formwork or by centrifugation. The manufactured hollow precast member is used.

In addition to the reinforcing bars 20, sheaths 21, 21 ... For inserting the PC steel rods 19 at appropriate intervals in the circumferential direction are embedded in the wall surface. A sheath diameter-expanded portion 21a is formed at the lower ends of the sheaths 21, 21 ... To allow a coupler for connecting the PC steel rods 19 to be inserted, and an anchor plate for fixing is fitted at the upper portion. A box punching portion 22 for installation is formed. Further, a plurality of hanging metal fittings 23 are provided on the upper surface.

As shown in FIG. 4A, the precast tubular bodies 15 are tightly connected by inserting PC steel rods 19, 19 ... Extending upward from the lower precast tubular body 15 into the sheaths 21, 21 .... However, when the precast cylindrical bodies 15 and 15 are stacked, the anchor plate 24 is fitted into the box punching portion 22, and tension is introduced into the PC steel rod 19 by the nut member 25 to integrate them. Further, the grout material is injected into the sheath 21 from the grout injection hole 27. The hole 24a formed in the anchor plate 24 is a grout injection confirmation hole, and filling of the grout material is completed when the grout material is discharged from the confirmation hole.

Next, as shown in FIG. 4B, if the coupler 26 is screwed into the protruding portion of the PC steel rod 19 and the PC steel rods 19, 19 ... On the upper stage side are connected, the upper stage is obtained. The PC steel rods 19, 19 ... Are stacked while being inserted into the sheaths 21, 21 ... Of the precast cylindrical body 15, and the PC steel rods 19 are stacked in the height direction by sequentially repeating the procedure for fixing the PC steel rods 19 according to the above procedure. At this time, an adhesive 28 such as an epoxy resin or a sealing material is applied to the joint surface between the lower precast tubular body 15 and the upper precast tubular body 15 to ensure water stoppage and join the mating surfaces. ..

The upper steel floating structure portion 4B is composed of a steel tubular body 17 relatively located on the lower stage side and a steel tubular body 18 relatively located on the upper stage side. The lower part of the steel tubular body 17 on the lower stage has the same outer diameter as the precast tubular body 15, and the precast tubular body 15 is bolted or welded (in the illustrated example, bolted). Be concatenated. The upper part of the steel tubular body 17 has a truncated cone shape with a gradually narrowing diameter.

The steel tubular body 18 on the upper stage side is a cylindrical body having an outer diameter dimension continuous with the upper outer diameter of the steel tubular body 17 on the lower stage side, and is formed on the steel tubular body 17 on the lower stage side. On the other hand, they are connected by bolts or welding (in the illustrated example, bolts are fastened). These steel tubular bodies 17, 18 are composed of steel rings 10, 10 ... Divided by a predetermined weight, and the steel rings 10, 10 ... Are integrated by being welded in the circumferential direction. There is.

On the other hand, the tower 6 is made of steel, concrete or PRC (prestressed reinforced concrete), but it is preferable to use one made of steel so that the total weight is small. The outer diameter of the tower 6 and the outer diameter of the upper steel tubular body 18 are substantially the same, and the outer shape is continuous in the vertical direction without steps or the like. In the illustrated example, a ladder 13 is provided on the upper portion of the upper steel tubular body 18, and a corridor scaffold 14 is provided in the circumferential direction at a substantially boundary portion between the tower 6 and the upper steel tubular body 18.

As shown in FIG. 1, the mooring point K of the mooring line 5 to the floating body 4 is set at a position below the sea surface and higher than the center of gravity G of the floating body 4. Therefore, it becomes possible to prevent the ship from coming into contact with the mooring line 5. Further, since a resistance moment centered on the center of gravity G of the floating body 4 is generated at the mooring point so as to prevent the floating body 4 from falling too much, the tilting posture state of the tower 6 can be appropriately maintained.

On the other hand, the nacelle 8 is a device equipped with a generator that converts the rotation of the wind turbine 7 into electricity, a controller that can automatically change the angle of the blade, and the like.

[Reinforcing device 2 for cylindrical precast concrete members]
Next, the reinforcing device 2 for the cylindrical precast concrete member according to the present invention will be described in detail with reference to FIGS. 6 to 15. Here, since the "cylindrical precast concrete member" is a member corresponding to the precast tubular body 15 of the floating body 4, the description will be described below by paraphrasing the "cylindrical precast concrete member" to the "precast tubular body 15". conduct.

In the reinforcing device 2 of the precast cylindrical body 15, tension cables 30, 30 ... Are stretched along the inscribed regular triangular line in the same cross section inside the precast tubular body 15. It is a structure. Each apex of the regular triangular line is in contact with the inner space circle (inner surface of the concrete thickness) of the precast cylindrical body 15, but it is not always necessary to touch the inner space circle, and before and after that ( It may be displaced in the radial direction). Specifically, it may be in contact with a virtual circle within approximately 100 mm inside the inner space circle, and may be in contact with the virtual circle within the thickness range of the precast cylindrical body 15 outside the inner space circle.

In order to stretch the tension cable 30, the fixing brackets 31, 31 ... Are fixed at the respective apex positions of the inscribed regular triangular wires, and the tensioning force can be introduced between the adjacent fixing brackets 31, 31. It is desirable to cross over.

As shown in FIGS. 8A and 8B in detail, the fixing bracket 31 is erected from the bottom plate 32 and the central portion of the upper surface of the bottom plate 32, and the fixing plate is oriented along the cross-sectional direction. It is a metal fitting composed of 33 and four anchor bolts 34 embedded in a precast tubular body 15 for bolting the bottom plate 32. When installing the bottom plate 32, an adjusting mortar is laid to make the installation surface flat. The fixing metal fitting 31 is arranged at each apex position of the inscribed regular polygonal line so that the fixing plate 33 faces the center of the precast tubular body 15.

On the other hand, as shown in detail in FIG. 9, the tension cable 30 connects the tension side fixing tool 35, the fixing side fixing tool 36, and the tension side fixing tool 35 and the fixing side fixing tool 36. It is composed of a cable 37 provided in. The tension side fixing tool 35 is a fixing tool connected by a screw rod 35C screwed into both the connecting fixing tool 35A and the sleeve 35B which are bolted to the fixing plate 33 of the fixing metal fitting 31 at the tip thereof. The expansion and contraction can be adjusted by rotating the screw rod 35C around the axis with a wrench or the like, and after the tension cable 30 is hung between the fixing brackets 31 and 31, a tension force is introduced into the cable 36. It is possible.

As the cable 36, for example, a rust-preventive PC steel stranded wire such as zinc-plated can be preferably used, but a PC steel wire, a deformed PC steel wire, a PC steel rod, or the like can also be used. Is.

As shown in FIG. 7, a set of reinforcing devices 2 in which tension cables 30, 30 ... Are stretched along the inscribed regular triangular line is set at a predetermined interval P in the axial core direction of the precast cylindrical body 15. Make sure to have more than one. In this embodiment, two sets of reinforcing devices 2 and 2 are provided for one ring of the precast tubular body 15. This arrangement interval depends on the degree of reinforcement, that is, the precast force introduced into the precast cylindrical body 15, and can be determined by design.

According to the reinforcing device 2 configured as described above, as shown in FIG. 10, when a tension force is introduced into each tension cable 30, 30 ..., the tension force acts in two directions from each apex of the equilateral triangle. However, the component force (Tcosθ) of these tension forces T is introduced into the precast tubular body 15 as a precast force in the circumferential direction, and the reinforcement is evenly performed over the entire circumferential direction. Therefore, the introduction of the precast force increases the strength against bending, and it becomes possible to prevent the precast tubular body 15 from being deformed or damaged during assembly work, transportation work, building up, and the like.

Further, when the floating body 4 is floated on the sea, the precast cylindrical body 15 receives water pressure from the entire outer circumference toward the center as shown in FIG. As a result, the tension force is relaxed by slightly reducing the outer diameter of the precast tubular body 15 due to elastic deformation, so that no harmful stress is generated in the precast tubular body 15. Further, since the reinforcing device 2 is provided inside the precast tubular body 15, it can be removed from the inside even after floating on the sea and can be reused.

By the way, in the above embodiment, one precast tubular body 15 continuous in the circumferential direction is targeted, but when the outer diameter of the precast tubular body 15 is large, it is divided into a plurality of pieces in the circumferential direction for transportation reasons. It is a split precast member, and after transporting these split precast members separately, they may be joined in the circumferential direction at a work yard or the like and closed in a circular shape. In such a case, as shown in FIG. 12, the fixing metal fittings 31 are divided into two half-split fixing metal fittings 31A and 31B for each fixing portion of the tension cables 30 and 30 in two directions adjacent to each other, and the fixing metal fittings 31A and 31B are used. The precast tubular body 15 can be divided at the same position in the circumferential direction. In this case, as shown in FIG. 13, even in the state of the arc-shaped precast members 15A to 15C before being closed in the circumferential direction, the arc-shaped precast members 15A to 15C are provided by the tension cable 30 stretched just like a bowstring. Reinforcement will be made even in the state of.

After being transported, the arc-shaped precast members 15A to 15C are closed in a circular shape by being joined in the circumferential direction in a work yard or the like, and a known joining structure is used as the joining structure. Is possible. For example, the "joint structure of precast concrete members" disclosed in Japanese Patent Application Laid-Open No. 2009-235850 is suitable. In the joint structure of the precast concrete member, a fixing embedded member joined to each reinforcing bar arranged in a plurality of stages in the vertical direction is embedded in the joint end surface of one of the precast concrete members, and the fixing embedded member is embedded. In addition to forming a pocket-shaped notch groove with the opening facing the outside, a notch groove is formed in the concrete along the vertical direction in the same shape as the notch groove, so that the notch groove is formed in the vertical direction. A continuous vertical groove is formed, and on the joint end surface of the other precast concrete member, each reinforcing bar arranged in a plurality of stages in the vertical direction is provided so as to project to the outside, and the protruding reinforcing bar has a pocket shape at the tip of the protruding reinforcing bar. The fixing member fitted in the notch groove is fixed, and the fixing member of the reinforcing bar provided so as to project from the joint end surface of the other precast concrete member is inserted along the vertical groove of the one precast concrete member. In a state where the precast concrete members are connected to each other and the fixing member of the other precast concrete member is positioned in the pocket-shaped notch groove portion of the embedding member for fixing the one precast concrete member, the grout material is formed in the gap portion. It is composed by filling. According to this joint structure, on-site welding work is not required, and by reducing the amount of grout material used, the work time can be shortened, the construction cost can be reduced, and the width of the joint can be reduced. This makes it possible to obtain a good appearance.

[Examples of other forms]
(1) In the above embodiment, the tension cable 30, 30 ... Is stretched along the inscribed regular triangular line inside the precast tubular body 15, but the tension cable 30 is the reinforcing device 2. It is possible to have a structure that is arranged along an arbitrary regular polygonal shape. However, in reality, it is desirable that the inscribed regular polygonal shape line be one of a regular triangle and a regular hexagon. FIG. 14 is an example in which the tension cable 30 is stretched along the inscribed regular square line, and FIG. 15 is an example in which the tension cable 30 is stretched along the inscribed regular hexagonal line. In the case of a regular heptagon or more, the number of fixing brackets 31 to be installed increases too much, and it takes a lot of time and effort to install the tension cable 30, which is not preferable in terms of construction.

(2) In the above embodiment, the case where the present invention is applied to a floating body of an offshore wind power generation facility has been described, but the present invention is applied to a chimney by precasting and a tower-shaped structure in general, in addition to the floating body. Applicable.

1 ... Spar type floating offshore wind turbine, 2 ... Reinforcing device, 4 ... Floating body, 4A ... Lower concrete floating structure, 4B ... Upper steel floating structure, 5 ... Mooring line, 6 ... Tower, 7 ... Wind turbine, 8 ... nacelle, 9 ... blade, 15 ... precast tubular body (circular precast concrete member), 17/18 ... steel tubular body, 19 ... PC steel rod, 30 ... tension cable, 31 ... fixing bracket, 35 ... Tension side fixing tool, 36 ... Fixed side fixing tool, 37 ... Cable

Claims (6)

A reinforcing device for a cylindrical precast concrete member, characterized in that a tension cable is stretched along an inscribed regular polygonal line inside the cylindrical precast concrete member. The reinforcing device for a cylindrical precast concrete member according to claim 1, wherein a fixing bracket is fixed at each apex position of the inscribed regular polygonal line, and a tension cable is laid between adjacent fixing brackets so that a tension force can be introduced. .. The reinforcing device for a cylindrical precast concrete member according to any one of claims 1 and 2, wherein the inscribed regular polygonal line is one of a regular triangle shape and a regular hexagon shape. The cylindrical precast according to any one of claims 1 to 3, wherein a plurality of reinforcing devices in which tension cables are stretched along the inscribed regular polygonal line are provided at predetermined intervals in the axial core direction of the precast concrete member as a set. Reinforcing device for concrete members. The fixing bracket is divided into two for each fixing portion of the tension cable in two directions adjacent to each other, and the cylindrical precast concrete member is divided at the same position in the circumferential direction. The reinforcing device for a cylindrical precast concrete member according to claim 2, wherein the concrete members are closed in a cylindrical shape by being joined in the circumferential direction. The floating body in a floating offshore wind turbine consisting of a floating body, a mooring line, a tower, a nacelle installed at the top of the tower, and a wind turbine consisting of a plurality of blades is a precast tubular body whose lower side is made of concrete. 1 to claim 1 to the concrete precast tubular body on the lower side, which has a concrete floating structure in which a plurality of stages are stacked in the height direction and a steel floating structure in which the upper side is made of a steel member. 5. A concrete floating structure in a floating offshore wind turbine, characterized in that the reinforcing device for the cylindrical precast concrete member according to any one of 5 is provided.

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