JP2024032525A - Manufacturing method for floating body type foundation - Google Patents

Abstract

To provide a manufacturing method for a floating body type foundation capable of realizing efficient manufacturing of a floating type foundation of a semi-submersible system made of concrete in a dock.SOLUTION: A manufacturing method for a floating body type foundation which is a semi-submersible system foundation 70 for supporting a tower 82 of an ocean windmill 80 includes: a manufacturing process of manufacturing at least a center column foundation 71, a side column foundation 73, and a pontoon 70C in respective manufacturing yards 10; a transportation positioning process of transporting and positioning at least the center column foundation 71 and the plurality of side column foundations 73 to a connection yard 20 and providing a gap G for a pontoon between the center column foundation and the side column foundation; a pontoon insertion process of inserting the pontoon 70C in the gap G for the pontoon; a pontoon connection process of connecting the pontoon 70C to the center column foundation and the side column foundation; a center tower connection process of connecting a center tower 72 to the center column foundation 71; and a side tower connection process of connecting a side tower 74 to the side column foundation 73.SELECTED DRAWING: Figure 4B

Description

The present invention relates to a method for manufacturing a floating foundation.

Demand for renewable energy is increasing with the aim of reducing greenhouse gas emissions. Examples of renewable energy include solar power generation, wind power generation, hydroelectric power generation, geothermal power generation, and biomass. Wind power generation facilities are installed in mountainous areas away from residential areas because noise and vibration from wind turbines can affect the living environment, and it is necessary to fully consider the impact on living spaces. There are many things.
However, it is difficult to secure land in mountainous areas to install large wind turbines, and it is also difficult to secure transportation routes to wind power generation facilities and install power transmission lines, etc. Technology development is underway to install offshore wind turbines on the ocean (including on water and lakes).
When constructing an offshore wind turbine on the sea, a floating foundation may be used as the foundation. ) types, etc. exist. Among these, semi-submersible foundations (semi-submersible floating foundations) consist of a center column that supports the wind turbine tower (post), and multiple (3 or 4 foundations) placed at intervals around the center column. It has a side column (base) and a pontoon that connects the center column and side column, and it is a foundation with a relatively good track record because it has excellent stability against waves and sea breezes.

Conventional floating foundations are generally made of steel, so one of the issues is the rising production cost, and as the scale of floating foundations increases, this problem becomes more pronounced. Become.
Therefore, although it is possible to reduce production costs by manufacturing semi-submersible concrete foundations at docks and towing them out to sea, currently, semi-submersible foundations made of concrete at docks can be installed. Since an efficient method for manufacturing floating foundations has not been established, a method for manufacturing floating foundations that can be manufactured efficiently is desired.

Here, in Patent Document 1, a plurality of tower members made by dividing the tower of an offshore wind turbine in the height direction are mounted on a pedestal with a jack built on a pedestal installed on the ground. A tower assembly method has been proposed.
On the other hand, Patent Document 2 proposes an installation method for an offshore wind turbine in which a plurality of tower members made by dividing the tower of an offshore wind turbine in the height direction are assembled and installed offshore. The caisson installation process involves installing the caisson, which serves as the foundation of the wind turbine, at the installation location of the offshore wind turbine; the assembly process involves assembling multiple tower members using the caisson; and the caisson is used to attach the blades to the nacelle attached to the top tower member. and a blade attachment step.

JP 2021-80852 Publication JP 2021-76043 Publication

Although Patent Documents 1 and 2 include descriptions of efficient tower assembly methods, as mentioned above, there is no description of technology for efficiently manufacturing semi-submersible concrete floating foundations at docks. .

An object of the present invention is to provide a method for manufacturing a floating foundation that can realize efficient manufacturing of a semi-submersible concrete floating foundation for a dock.

In order to achieve the above object, one aspect of the method for manufacturing a floating foundation according to the present invention is as follows:
A concrete center column, a plurality of concrete side columns arranged at intervals in three or four directions around the center column, and a plurality of concrete connecting the center column and each side column. The center column has a center column foundation and a center tower rising from the center column foundation, and the side column has a side column foundation and a side tower rising from the side column foundation. A method for manufacturing a floating foundation, which is a semi-submersible foundation for supporting a tower of an offshore wind turbine, comprising:
A manufacturing step of manufacturing at least the center column foundation, the side column foundation, and the pontoon in respective manufacturing yards;
At least transporting and positioning the center column foundation and the plurality of side column foundations to a connection yard, and providing a pontoon gap into which the pontoon is inserted between the center column foundation and the side column foundations. process and
a pontoon insertion step of inserting the pontoon into the pontoon gap;
a pontoon connecting step of connecting the pontoon to both the center column foundation and the side column foundation;
a center tower connecting step of connecting the center tower to the center column foundation;
The present invention is characterized by comprising a side tower connecting step of connecting the side tower to the side column foundation.

According to this aspect, after manufacturing a part or all of each of the center column, side columns, and pontoons constituting the semi-submersible type foundation in their respective manufacturing yards, at least the center column foundation and the plurality of side columns are manufactured. By transporting the column foundation to the connection yard and positioning it, and creating a pontoon gap between the two to insert the pontoon, the pontoon is inserted into the pontoon gap and connected to the center column foundation and side column foundation. , in particular the connection efficiency in the connection yard can be increased, which makes it possible to realize the efficient fabrication of floating foundations in docks.
In addition, after manufacturing the lower part of the floating foundation by connecting the center column foundation and multiple side column foundations positioned at the connection yard with pontoons, we will construct a center column foundation and a center tower for each of the center column foundation and multiple side column foundations. The connection method that connects the center tower and side towers allows the upper structure, such as the center tower and side towers, to be connected to a stable lower structure, resulting in smoother connections and improved safety during connection. .

Here, "made of concrete" means made of reinforced concrete (RC), and means that the center column, side columns, pontoons, and their constituent elements are made of reinforced concrete. In addition to the RC structure as the main structural type, an SRC (Steel Reinforced Concrete) structure that includes steel (S) is also included in "concrete" in this specification.

Furthermore, "manufacturing at least the center column foundation in a manufacturing yard" refers to manufacturing the center column foundation in the manufacturing yard, manufacturing the center column consisting of the center column foundation and center tower, and manufacturing the center column foundation in the manufacturing yard. It includes the form of manufacturing a part of the connection body between the foundation and the center tower.
In addition to being completely manufactured on a trestle, manufacturing on a trestle also involves mounting the center column foundation and center tower, which were manufactured in a place other than the trestle, on the trestle, and forming the center column on the trestle. In any case, when transporting to the connection yard, the center column foundation, center column, etc. to be transported must be mounted on the pedestal and placed on the transport means together with the pedestal. It will be transported by Note that the above explanation regarding the center column foundation is also applicable to ``manufacturing at least the side column foundation in a manufacturing yard'' and ``manufacturing at least the pontoon.''

At the connection yard, a floating foundation is fabricated by tensioning the center column foundation, pontoons, and side column foundations with tension materials such as prestressed concrete (PC) steel rods and PC steel wire. In other words, in each production yard, concrete center column foundations, side column foundations, etc. are manufactured as PCa (Precast Concrete) bodies, and in the connecting yards, each PCa body is tensioned with tendons to create PCaPC (Precast Concrete). A floating foundation made of prestressed concrete will be constructed. In addition, if the center column foundation and center tower are connected in the production yard and the center column is produced on a pedestal, the center column made of PCaPC will be produced in the production yard, and this means that the center column will be made of PCaPC at the production yard. This also applies to columns and pontoons.

Further, other aspects of the method for manufacturing a floating foundation according to the present invention include:
The manufacturing process includes at least one of the center tower connecting process and the side tower connecting process.

According to this aspect, the manufacturing process includes at least one of the center tower connecting process and the side tower connecting process, so that at least one of the center column and the side columns is manufactured in a unique manufacturing yard. Connection man-hours in the yard can be reduced.
Here, "includes at least one of the center tower connection process and the side tower connection process" includes only the center tower connection process; therefore, the center column is manufactured at the production yard, and the side columns are manufactured at the connection yard. Only the side column foundation and side tower are connected and manufactured, and the side tower connection process is included. Therefore, multiple side columns are manufactured in the manufacturing yard, and the center column is manufactured by connecting the center column foundation and the center column in the connection yard. This includes a form in which the towers are connected and manufactured, and a form in which both the center column connection process and the side tower connection process are manufactured, and therefore, the center column and a plurality of side columns are all manufactured in a manufacturing yard.

Further, in another aspect of the method for manufacturing a floating foundation according to the present invention,
The center tower is a laminate of a plurality of center tower elements,
The side tower is a laminate of a plurality of side tower elements,
The pontoon is a connection body of a plurality of pontoon elements,
When the center tower connecting step is included in the manufacturing step, at least a portion of the center tower is connected to the center column foundation,
When the side tower connecting step is included in the manufacturing step, at least a part of the side tower is connected to the side column foundation.

According to this aspect, when the center tower is a laminate of a plurality of center tower elements, the side tower is a laminate of a plurality of side tower elements, and the pontoon is a connection body of a plurality of pontoon elements, the production yard It is possible to manufacture PCa bodies with a variety of variations and to connect PCa bodies to each other at the connection yard.
Here, "If the center tower connection process is included in the manufacturing process, at least a part of the center tower is connected to the center column foundation" means that the center column foundation and part of the center tower are manufactured at the manufacturing yard. This means that it includes both the form where the center column is assembled and transported to the connection yard and the remaining center tower is connected at the connection yard, and the form where the center column consisting of the center column foundation and center tower is fabricated at the fabrication yard. do. Furthermore, the phrase "when the side tower connecting process is included in the manufacturing process" also means that the same form is included.

Further, in another aspect of the method for manufacturing a floating foundation according to the present invention,
The center tower is a laminate of a plurality of center tower elements,
The side tower is a laminate of a plurality of side tower elements,
the pontoon is a single pontoon element;
When the center tower connecting step is included in the manufacturing step, at least a portion of the center tower is connected to the center column foundation,
When the side tower connecting step is included in the manufacturing step, at least a part of the side tower is connected to the side column foundation.

According to this aspect, even when the pontoon is a single pontoon element, it is possible to manufacture PCa bodies with variations in the production yard and to connect the PCa bodies with each other in the connection yard.

Further, in another aspect of the method for manufacturing a floating foundation according to the present invention,
manufacturing the center column by tensioning the center column foundation and the center tower with a plurality of first tension members;
Tightening the side column foundation and the side tower with a plurality of second tension members to produce a plurality of side columns;
In the manufacturing step, the pontoon is manufactured by tensioning the plurality of pontoon elements with a plurality of third tension members in the manufacturing yard;
In the pontoon connecting step, the pontoon is connected to the center column and the side columns under tension using a plurality of fourth tension members in the connection yard.

According to this aspect, the center column is manufactured by tensioning each component of the center column with a first tension material, and the side column is manufactured by tensioning each component of the side column with a second tension material, After the pontoon is manufactured by tensioning each component of the pontoon with the third tension material, the pontoon is tensioned with the fourth tension material to connect the center column and side column to each other at the connection yard. , it is possible to manufacture floating foundations with high connection strength and excellent water-stopping properties. Here, it is preferable that wet joints are provided between each segment constituting the center tower, side towers, etc., and at the connection portions of the center column, pontoons, and side columns, and then tensioned with tension material.

Further, other aspects of the method for manufacturing a floating foundation according to the present invention include:
In the case where the four pontoons are arranged at 90 degree intervals around the center column, and the side columns are connected to each pontoon,
In the pontoon connecting step, the third tendon material and the fourth tendon material are the same tendon material, and the two pontoons facing each other around the center column foundation are connected to the third tendon material common to the center column foundation. It is characterized by being tensed by tension material.

According to this aspect, when four pontoons are arranged at 90 degree intervals around the center column and the side columns are connected, the third tension member and the fourth tension member are the same tension member, and the center column By tensioning the two pontoons facing each other around the foundation together with the center column foundation using a common third tension member, a more efficient connection in the connection yard can be realized.

Further, in another aspect of the method for manufacturing a floating foundation according to the present invention,
The pontoon gap has a length equal to the length of the inserted pontoon plus an error length due to manufacturing error and/or connection error.

According to this aspect, the pontoon gap has a length that is the sum of the length of the inserted pontoon and the error length due to manufacturing error and/or connection error, so that the positioned center column foundation It is now possible to reliably insert a pontoon into the pontoon gap between the center column foundation and the side column foundation, and this construction involves moving at least one of the center column foundation and side column foundation, which are positioned so that the pontoon cannot be inserted. It is possible to eliminate the hassle.

According to the method for manufacturing a floating foundation of the present invention, it is possible to efficiently manufacture a semi-submersible concrete floating foundation for a dock.

FIG. 1 is an overall perspective view of an example of a floating foundation manufacturing system according to an embodiment. FIG. 1 is a perspective view of an example of a floating foundation manufactured by a method for manufacturing a floating foundation according to an embodiment. FIG. 1 is a perspective view of an example of an offshore wind turbine manufactured by an offshore wind turbine manufacturing method according to an embodiment. It is a process chart of an example of the manufacturing method of the floating body type foundation concerning a 1st embodiment. Following FIG. 4A, it is a process diagram of an example of the method for manufacturing the floating foundation according to the first embodiment. It is a figure which shows both an example of the manufacturing method of the floating body type foundation based on 2nd Embodiment, and an example of the manufacturing method of the floating body type foundation based on 3rd Embodiment. It is a perspective view of an example of a multi-axis truck. FIG. 3 is a diagram illustrating the arrangement of multi-axle carts in the first transportation method of a floating foundation, in which (a) is a plan view of a plurality of multi-axle carts that transport side columns, and (b) is a plan view of a plurality of multi-axle carts that transport a pontoon. FIG. 3 is a plan view of a plurality of multi-axis carts that transport the center column; FIG. It is a figure explaining an example of the 1st conveyance method of conveying a floating foundation with a pedestal by a plurality of multi-axis vehicles. It is a figure showing the arrangement form of the multi-axis truck in the case of the second transportation method of the floating foundation, and (a), (b), (c) is a top view of the plurality of multi-axis trucks that convey the side column. (d), (e), and (f) are plan views of a plurality of multi-shaft carts that transport the pontoons, and (g) is a plan view of a plurality of multi-shaft carts that transport the center column. It is a figure explaining an example of the 2nd conveyance method of conveying a floating foundation with a gantry by a plurality of multi-axis vehicles. It is a process chart of an example of the launching method of the floating foundation concerning an embodiment. Continuing from FIG. 9, it is a process diagram of an example of a method for launching a floating foundation according to an embodiment. Continuing from FIG. 10, it is a process diagram of an example of a method for launching a floating foundation according to an embodiment. Continuing from FIG. 11 , it is a process diagram of an example of a method for launching a floating foundation according to an embodiment. Following FIG. 12, it is a process diagram of an example of a method for launching a floating foundation according to an embodiment, and a process diagram of an example of a method for recovering a pedestal on which a floating foundation according to an embodiment is mounted. . Continuing from FIG. 13, it is a process diagram of an example of a method for recovering a pedestal on which a floating foundation according to an embodiment is mounted. Continuing from FIG. 14, it is a process diagram of an example of a method for recovering the pedestal on which the floating foundation according to the embodiment is mounted. Continuing from FIG. 15, it is a process diagram of an example of a method for recovering the pedestal on which the floating foundation according to the embodiment is mounted. Continuing from FIG. 16, it is a process diagram of an example of a method for recovering the pedestal on which the floating foundation according to the embodiment is mounted. FIG. 2 is a diagram illustrating a method for manufacturing and towing an offshore wind turbine according to an embodiment.

Hereinafter, a method for manufacturing a floating foundation, a manufacturing system for a floating foundation, a method for manufacturing an offshore wind turbine, a method for launching a floating foundation, a method for recovering a pedestal on which a floating foundation is mounted, and a method for manufacturing an offshore wind turbine according to an embodiment are as follows. The production towing method will be explained with reference to the attached drawings. Note that in this specification and the drawings, substantially the same constituent elements may be given the same reference numerals to omit redundant explanation.

[Floating foundation manufacturing system and manufacturing method according to embodiment, and offshore wind turbine manufacturing method]
First, with reference to FIGS. 1 to 8, an example of a method for manufacturing a floating foundation, a system for manufacturing a floating foundation, and a method for manufacturing an offshore wind turbine according to an embodiment will be described.
Here, FIG. 1 is an overall perspective view of an example of a floating foundation manufacturing system according to an embodiment, and FIG. 2 is an example of a floating foundation manufactured by a floating foundation manufacturing method according to an embodiment. FIG. 3 is a perspective view of an example of an offshore wind turbine manufactured by the offshore wind turbine manufacturing method according to the embodiment. Moreover, FIG. 4A and FIG. 4B are process charts of an example of the method for manufacturing the floating foundation according to the first embodiment. Further, FIG. 5 is a diagram showing both an example of a method for manufacturing a floating foundation according to the second embodiment and an example of a method for manufacturing a floating foundation according to the third embodiment.

In addition, each figure shows the reinforcing bars that form each concrete (reinforced concrete) component that makes up the floating foundation, how each component is formed (connecting multiple elements), and how each component is connected. The illustration of tendons for connecting them is omitted.

The manufacturing system 60 shown in FIG. 1 is a system installed at the dock D for manufacturing the floating foundation 70. Although the floating foundation 70 to be manufactured in the illustrated example is a semi-submersible foundation, the floating foundation manufactured by the manufacturing system 60 may be other types of floating foundations such as spar type, purge type, TLP type, etc. There may be.

The manufacturing system 60 includes a plurality of manufacturing yards 10 for manufacturing multiple types of divided bodies constituting the semi-submersible foundation 70, a transport path 50 provided between each manufacturing yard 10, and a transport path 50 provided between each manufacturing yard. A transport means 30 that transports the divided bodies produced in step 10 via a transport path 50, and a connection yard 20 that connects the divided bodies transported by the transport means 30 to manufacture a floating foundation 70. has.

On the side of the quay P of the connection yard 20 in the dock D, there is a sea S where the fabricated floating foundation 70 is towed and installed. A barge 90 is moored for loading and towing 70 to a predetermined installation position.

As shown in FIG. 2, the semi-submersible foundation 70 includes a concrete center column 70A, and three foundations arranged at intervals of 120 degrees in three directions around the center column 70A in plan view. It has a side column 70B made of concrete, and three pontoons 70C made of concrete that connect the center column 70A at the center and each side column 70B. The three directions spaced apart by 120 degrees are the longitudinal directions of the pontoon 70C, and are therefore defined as the pontoon axis directions.

Further, the center column 70A includes a center column foundation 71 and a center tower 72 rising from the center column foundation 71, and the side column 70B includes a side column foundation 73 and a side tower 74 rising from the side column foundation 73.

The center tower 72 is a stacked body of a plurality of center tower elements 72a, the side tower 74 is a stacked body of a plurality of side tower elements 74a, and the pontoon 70C is a connected body of a plurality of pontoon elements 75a.

These are manufactured as divided bodies in various manners in a unique manufacturing yard 10, and each divided body is transported to the connection yard 20 and connected, whereby the floating foundation 70 is manufactured. Here, the semi-submersible type foundation 70 to be manufactured is equipped with three side columns 70B, and in addition, although not shown, four pontoons 70C are shown in plan view around a center column 70A. The pontoons 70C may be arranged at 90 degree intervals and the side columns 70B may be connected to each pontoon 70C.

As shown in FIG. 2, each divided body is placed on its own stand 40. As shown in FIG. Each frame 40 has a mounting plate 41, a plurality of legs 42 protruding below the mounting plate 41, and an entry space 43 below the mounting plate 41 into which the conveying means 30 enters. .

Here, "a mount unique to a divided body" means that in addition to the fact that the number of each divided body and each pedestal 40 corresponds 1:1, the number of mounts 40 is smaller than the number of divided bodies, In the case where each divided body is manufactured while providing a time lag in the manufacture of each divided body, one mount 40 is diverted from manufacturing to transporting the plurality of divided bodies.

The center column 70A, side columns 70B, and pontoons 70C are each mounted on their own mounts 40A, 40B, and 40D.

Returning to FIG. 1, each fabrication yard 10 is located within its own building 18. In the manufacturing yard 10, a gate type crane 15 for manufacturing the divided bodies is installed so as to be movable in the X1 direction along a plurality of rails 13.

A pedestal 40 is installed in the production yard 10, and the divided body is manufactured on the pedestal 40.

Here, there are various forms of the divided body. Explaining with reference to FIG. 2, the center column foundation 71 and side column foundations 73 are included in the divided body. Furthermore, the entire center tower 72 may be included in the divided body, each center tower element 72a may be included in the divided body, or a portion (in an unfinished state) of the center tower 72 may be included. This also applies to the side tower 74.

Regarding the pontoon 70C, the whole of it may be included in the divided body, or a part of it (in an unfinished state) may be included. Here, although the pontoon 70C in the illustrated example is a connected body of a plurality of pontoon elements 75a, the pontoon may be formed by a single pontoon element.

The divided bodies manufactured in the production yard 10 are manufactured on the pedestal 40 and then transported together with the pedestal 40 to the connection yard 20 by the conveyance means 30, and in the connection yard 20, other divided bodies are placed on the pedestal 40. Therefore, there are various forms of the divided body depending on how it is manufactured on the frame 40 in the manufacturing yard 10.

For example, if the entire center column 70A is a divided body, the entire center column 70A is manufactured as a divided body on the pedestal 40 in the manufacturing yard 10. On the other hand, when the center column foundation 71 and the center tower 72 are manufactured on a unique frame 40 in a unique manufacturing yard 10, the center column foundation 71 and the center tower 72 are each manufactured as separate bodies. Here, each center tower element 72a constituting the center tower 72 is manufactured individually, for example, inside the building 18 instead of on the pedestal 40, and then a plurality of center tower elements 72a are placed on the pedestal 40. In some cases, the center tower 72 is manufactured by being tensioned with a plurality of tension members, and even in this manufacturing method, the center tower 72 becomes a divided body.

In any case, the object mounted on the pedestal 40 while being transported to the connection yard 20 together with the pedestal 40 by the conveying means 30 is referred to as a "divided body" in this specification, and the object mounted on the pedestal 40 is In addition to being manufactured (manufactured from beginning to end), "divided objects" also include items manufactured elsewhere than on the mount and connected on the mount 40. .

In each production yard 10, a concrete divided body is manufactured as a PCa body, and in the connection yard 20, a floating foundation made of PCaPC is manufactured by tensioning each PCa body divided body with tension material. That will happen.

Returning to FIG. 1, in the illustrated example, the center column foundation 71, side column foundation 73, and pontoon 70C are manufactured on unique frames 40A, 40B, and 40D in respective manufacturing yards 10A, 10B, and 10D. Regarding the pontoon 70C, after a plurality of pontoon elements 75a are manufactured at a location other than the pedestal 40D in the manufacturing yard 10D, the pontoon elements 75a are tensioned with a plurality of tension members on the pedestal 40D. be done.

Further, the center tower element 72a and the side tower element 74a are manufactured in a common manufacturing yard 10C. The plurality of manufactured center tower elements 72a are connected to each other via tendons on a common pedestal 40, and similarly, the plurality of side tower elements 74a are also connected to each other via tendons on a common pedestal 40. are connected to the connection yard 20 together with the pedestal 40. As already described, the center tower 72 and side towers 74 are manufactured as unfinished divided units on the frame 40, and after being transported to the connection yard 20, they are assembled into the center column foundation 71 and side column foundations. 73 may be sequentially stacked.

In FIG. 1, the side column foundation 73 placed on the pedestal 40B is being conveyed in the X2 direction via the conveyance path 50 to the connection yard 20 by the conveying means 30, and the side column foundation 73 is being conveyed on the pedestal 40D by the conveying means 30. It also shows a state in which the pontoon 70C is being transported in the X2 direction to the connection yard 20 via the transport path 50.

In the connection yard 20, the semi-submersible foundation 70 is manufactured by connecting the divided bodies to each other via tendons on a plurality of frames 40 while appropriately using heavy machinery 55 and the like. Then, as shown in FIG. 3, an offshore wind turbine 80 is manufactured by connecting a tower 82 having a wind turbine 84 to a center column 70A that constitutes a semi-submersible foundation 70. Here, in the illustrated example, the tower 82 is connected to the center column 70A, but a single tower or a wind turbine tower may be connected to the side column 70B.

Here, the method of connecting the tower 82 to the semi-submersible foundation 70 is the method of connecting the tower 82 while lifting it with heavy equipment 55 in the connection yard 20 as shown in FIG. There is a method of connecting the tower 82 to the installed semi-submersible type foundation 70 using a barge equipped with a lifting machine in the ocean, or a method of connecting the tower 82 to the semi-submersible type foundation 70 using a barge equipped with a lifting machine in the ocean, or a method of connecting the tower 82 to the semi-submersible type foundation 70 using a barge 90 moored at the quay P. After the foundation 70 is transported and loaded, there is a method of connecting the tower 82 from the quay P using heavy equipment. Furthermore, as will be explained below with reference to FIG. 18, it is possible to use heavy machinery from the quay P with the semi-submersible foundation 70 floating on the water on the side of the quay P without using a barge. There is also a method of connecting the tower 82.

Next, an example of a method for manufacturing a floating foundation according to the first embodiment will be described with reference to FIGS. 4A, 4B, and 2. Here, FIG. 4A, FIG. 4B, and FIG. 2 are process charts of an example of the method for manufacturing the floating foundation according to the first embodiment.

In the illustrated manufacturing method, a center column foundation 71 and three side column foundations 73 are each manufactured as divided bodies on a frame 40 in a unique manufacturing yard 10 (manufacturing process, divided body manufacturing process).

Next, each divided body is transported with its own pedestal 40 to the connection yard 20 by the conveyance means 30, and in the connection yard 20, the center column foundation 71 and three side column foundations 73 are positioned together with the pedestals 40 on which they are placed. Then, a pontoon gap G for inserting the pontoon 70C is provided between the center column foundation 71 and each side column foundation 73 (transport positioning step). Here, the process of transporting the divided bodies together with the gantry 40 from each manufacturing yard 10 can also be referred to as a divided body conveying process.

That is, in the transportation and positioning step, the center column foundation 71 and each side column foundation 73 are positioned in a posture that makes it unnecessary to move them when connecting other divided bodies later on.

In addition, the center column foundation 71, the side column foundation 73, and each pontoon 70C are each equipped with an upper floor slab 76, a lower floor slab 77, and left and right side walls 78, and a hollow 79 forming a ballast chamber is provided inside. ing. A plurality of mutually corresponding sheath pipes (not shown) are provided at corresponding positions on the upper floor slab 76, lower floor slab 77, and side wall 78 of the center column foundation 71, side column foundation 73, and each pontoon 70C, A tension material (not shown) is inserted into each sheath pipe and tensioned, thereby connecting the center column foundation 71, side column foundation 73, and each pontoon 70C.

Next, as shown in FIG. 4B, the pontoon 70C, which has been transported from the manufacturing yard 10 together with the mount 40D, is inserted into each pontoon gap G in the Y1 direction (pontoon insertion step).

Here, the width t1 of the pontoon gap G shown in FIGS. 4A and 4B is set to the sum of the longitudinal length t2 of the pontoon 70C and the error length due to manufacturing error and/or connection error. has been done. This makes it possible to reliably insert the pontoon 70C into the pontoon gap G between the positioned center column foundation 71 and side column foundation 73, and prevents the pontoon 70C from being inserted and positioned. The construction work required to move at least one of the center column foundation 71 and the side column foundation 73 can be eliminated.

Next, a wet joint WJ filled with mortar etc. is constructed between the center column foundation 71 and side column foundation 73 and the pontoon 70C, and by tensioning these with tension material, the center column foundation 71 and side column foundation 73 and the pontoon 70C (pontoon connection process). Here, it is desirable from the viewpoint of waterproofing that wet joints WJ are also constructed between mutually adjacent pontoon elements 75a, between center tower elements 72a, and between side tower elements 74a.

Next, the center tower 72 is lifted and connected to the center column foundation 71 using heavy machinery 55 etc. (center tower connection step), and the heavy machinery 55 etc. is similarly connected to each side column foundation 73. The semi-submersible type foundation 70 shown in FIG. 2 is manufactured by connecting the side towers 74 while lifting them using the method (side tower connecting process). Here, the conveyance positioning process, the pontoon insertion process, the pontoon connection process, the center tower connection process, and the side tower connection process can also be collectively referred to as the connection process.

Here, although illustration of each tendon is omitted, the center column foundation 71 and the center tower 72 are tensioned by a plurality of first tendons to produce the center column 70A, and the side column foundation 73 and the side tower 74 are Each side column 70B is manufactured by tensioning with a plurality of second tension members. Moreover, the pontoon 70C is manufactured by tensioning a plurality of pontoon elements 75a with a plurality of third tension members in a unique manufacturing yard 10C. In the pontoon connection step, the pontoon 70C is connected to the center column 70A and the side columns 70B in the connection yard 20 under tension using a plurality of fourth tension members. In addition, a PC steel rod, a PC steel wire, etc. are applied to the 1st tension material thru|or the 4th tension material.

In addition, in the production of a semi-submersible type foundation (not shown) in which four pontoons 70C are arranged at 90 degree intervals around a center column 70A and a side column 70B is connected to each pontoon 70C, during the pontoon connection process, In this case, the third tension material and the fourth tension material are the same tension material, and the two pontoons 70C facing each other around the center column foundation 71 are tensioned by the common third tension material together with the center column foundation 71. preferable. According to this tensioning method, the two pontoons 70C facing each other around the center column foundation 71 are tensioned together with the center column foundation 71 by the common third tensioning material, thereby achieving a more efficient connection in the connection yard 20. realizable.

According to the method for manufacturing a floating foundation according to the first embodiment shown in the drawings, the transportation and positioning process eliminates the need to move the center column foundation 71 and each side column foundation 73 when connecting other divided bodies thereafter. Because of this, it is possible to realize efficient connections between divided bodies.

Furthermore, as shown in FIG. 4B, after the lower structure of the semi-submersible foundation 70 is manufactured in advance, the upper structures such as the center tower 72 and side towers 74 are connected to maintain a stable posture. The upper structure can be connected to the lower structure efficiently and with high construction safety.

Next, an example of a method for manufacturing a floating foundation according to the second embodiment and the third embodiment will be described with reference to FIGS. 5 and 2. Note that FIG. 4A will be referred to in the description of the manufacturing method according to the third embodiment.

The manufacturing method according to the second embodiment is to manufacture the center column 70A on the pedestal 40A and the side columns 70B on the pedestal 40B in a unique manufacturing yard 10, and then attach these divided bodies to the pedestal 40. In this method, the pontoons 70C are transported to the connection yard 20 and positioned, and the pontoons 70C are inserted into each pontoon gap G to connect them.

According to this manufacturing method, the number of man-hours required for connection in the connection yard 20 is reduced as much as possible, so that the connection efficiency between the divided bodies in the connection yard 20 is significantly increased.

Further, in the manufacturing method according to the third embodiment, similarly to the method shown in FIG. , as shown in FIG. 5, the center column 70A and each side column 70B are manufactured in advance by connecting the center tower 72 and side tower 74 to each foundation, and finally, for each pontoon gap G, This is a method of connecting by inserting a pontoon 70C.

In addition, although not shown, in the connection yard 20, the side column foundation 73 and side column 70B are connected to the pontoon 70C in advance, and the three connecting bodies are moved and connected to the center column foundation 71 and the center column 70A. There are also methods. Furthermore, the center column foundation 71 and part of the center tower 72 are manufactured as divided bodies, and similarly, the side column foundation 73 and part of the side tower 74 are manufactured as divided bodies, and are transported to the connection yard 20. In this case, the pontoon 70C is connected to these, and the remaining center tower element 72a of the center tower 72 and the remaining side tower element 74a of the side tower 74 are also connected to these.

The offshore wind turbine manufacturing method according to the embodiment is a semi-submersible wind turbine manufactured by the floating foundation manufacturing method according to the first to third embodiments or the floating foundation manufacturing method according to the other embodiments described above. As already explained, the type foundation 70 is connected to the tower 82 while being lifted by the heavy machinery 55 in the connection yard 20. Another method is to connect the tower 82 at sea using a barge equipped with a lifting machine after the manufactured semi-submersible foundation 70 is towed to the sea and installed at sea. . Furthermore, there is a method of transporting the semi-submersible foundation 70 to a barge 90 moored to the quay P and loading it thereon, and then connecting the tower 82 from the quay P using heavy equipment. In addition, as described below with reference to FIG. 18, the semi-submersible foundation 70 is floated on the water on the side of the quay P without using a barge, and heavy machinery is used to get it from the quay P. There is also a method of connecting the tower 82.

Next, with reference to FIGS. 6 to 8, an example of a conveyance means and an example of a method of conveying the manufactured floating foundation in the connection step in the floating foundation manufacturing method according to the embodiment will be described.
Here, FIG. 6 is a perspective view of an example of a multi-shaft truck. Further, FIG. 7A is a diagram showing the arrangement of multi-axis carts during the first transportation method of the floating foundation, and (a) is a plan view of a plurality of multi-axis carts that transport the side columns, (b) is a plan view of a plurality of multi-axis carts that transport the pontoon, and (c) is a plan view of a plurality of multi-axle carts that transport the center column. Moreover, FIG. 8A is a diagram showing the arrangement form of multi-axle carts in the case of the second transportation method of the floating foundation, and (a), (b), and (c) are diagrams showing a plurality of multi-axle carts for transporting side columns. FIG. 3 is a plan view of a shaft truck, (d), (e), and (f) are plan views of a plurality of multi-shaft trucks that transport pontoons, and (g) is a plan view of a plurality of multi-shaft trucks that transport a center column. FIG. Further, FIGS. 7B and 8B are diagrams respectively illustrating an example of a first transport method and a second transport method in which the floating foundation is transported together with the pedestal using a plurality of multi-axis carts.

The illustrated transport means 30 is a multi-shaft truck, which is an example of a self-propelled truck, and is equipped with a lifting mechanism that lifts the pedestal 40 and lifts it off the ground. In the multi-axle truck 30, a plurality of axles 33 are provided on a long car body 31 in the car body axis direction (L direction), and each axle 33 has a plurality of left and right wheels 35 spaced apart from each other in the car body axis direction. All the wheels 35 are mounted rotatably in the Y3 direction with respect to the corresponding axle 33, and the loading platform 32 on the vehicle body 31 is mounted so as to be freely raised and lowered by a lifting mechanism (not shown). The whole is made up of these things.

When the multi-axis truck 30 enters the entry space 43 of each pedestal 40 shown in FIG. 2 etc. with the loading platform 32 lowered as in the illustrated example, and transports the pedestal 40 together with the divided body, it is moved by the lifting mechanism. By raising the loading platform 32, the gantry 40 can be cut off.

Here, although not shown in the drawings, the conveying means may be provided with wheels driven by an actuator on the pedestal 40, and the driven wheels may be the conveying means. Further, the pedestal 40 may be equipped with wheels, and the conveyance means may be a tow type truck or a push type truck. Furthermore, the transport means may be a mobile lifting machine such as a crane.

The first transportation method of the floating foundation 70 shown in FIG. The multi-axis carts 30 are arranged parallel to or perpendicular to the direction, and the semi-submersible foundations 70 are manufactured by connecting the divided bodies. Here, the vehicle body axis direction of each multi-axis bogie 30 may not be strictly oriented in these directions, but may also be oriented in a direction shifted by several degrees.

Next, when loading out the semi-submersible type foundation 70 together with the plurality of frames 40 using the plurality of multi-axis carts 30 and transporting it to the barge 90 moored to the quay P, all of the By controlling the wheels 35 in the same direction or substantially the same direction, all the multi-axis carts 30 can be moved in the Y5 direction, which is the transport direction toward the barge 90. Here, controlling the wheels 35 in substantially the same direction means that there is an angular error of, for example, about ±10 degrees with respect to the reference wheel angle along the Y5 direction, which is the loadout direction.

According to this transportation method, when manufacturing the semi-submersible type foundation 70 by connecting the divided bodies on the plurality of frames 40 in the connection yard 20, or when manufacturing the semi-submersible type foundation 70 on the plurality of frames 40, 70 is manufactured (both are connection processes), by controlling all the wheels 35 of all the multi-axis bogies 30 in the same direction or approximately the same direction, the vehicle body axis direction (L direction) of each multi-axis bogie 30 is controlled. ) can be smoothly moved in a desired loadout direction without having to specify a fixed direction, and the semi-submersible foundation 70 including the pedestal 40 can be stably and smoothly transported and loaded onto the barge 90. becomes possible. In addition, there is no need to change the shape of the loading platform 32 of the multi-axis truck 30 in plan view depending on the placement position. It can be used without any need.

On the other hand, in the second transportation method of the floating foundation 70 shown in FIG. The semi-submersible type foundation 70 is manufactured by positioning each multi-axis truck 30 while facing the direction, and connecting each divided body.

Next, when loading out the semi-submersible type foundation 70 together with the plurality of frames 40 using the plurality of multi-axis carts 30 and transporting it to the barge 90 moored to the quay P, each multi-axis cart 30 is By moving straight ahead, all the multi-axis carts 30 can be moved in the Y5 direction, which is the transport direction toward the barge 90.

According to this transportation method, when manufacturing the semi-submersible type foundation 70 by connecting the divided bodies on a plurality of frames 40 in the connection yard 20, or when manufacturing a semi-submersible type foundation 70 on a plurality of frames 40, 70 is manufactured (both in the connection process), by moving straight ahead without controlling the angle of each wheel 35 in the same direction, etc., it is possible to smoothly move it in the desired loadout direction, and the frame 40 can be stably and smoothly transported and loaded onto the barge 90. In addition, since the body axis direction of all the multi-axis carts 30 is set as the transport direction toward the barge 90, each multi-axis cart 30 has a loading platform 32 of various planar shapes depending on its arrangement position, as shown in the figure. It may be necessary to prepare.

Next, an example of a method for launching a floating foundation according to an embodiment and an example of a method for recovering a pedestal on which a floating foundation is mounted will be described with reference to FIGS. 9 to 17.
Here, FIGS. 9 to 13 are process charts of an example of a method for launching a floating foundation according to an embodiment. Moreover, FIG. 13 thru|or FIG. 17 are process drawings of an example of the recovery method of the frame on which the floating foundation based on embodiment is mounted.

The method for launching the floating foundation according to the embodiment is as shown in FIG. A semi-submersible type foundation 70 is manufactured by manufacturing a plurality of concrete divided bodies on respective pedestals 40 and connecting the plurality of divided bodies on the plurality of pedestals 40.

Next, as shown in FIG. 10, the semi-submersible type foundation 70 is transported to the barge 90 in the Y7 direction by the plurality of multi-axis carts 30 together with the plurality of frames 40, and loaded thereon. Each mount 40 that has been transported onto, for example, the deck of the barge 90 is fixed to the deck (the above is the transport process).

Following this transportation process, the tower 82 may be connected to the semi-submersible foundation 70 from the quay P using heavy machinery to manufacture the offshore wind turbine 80, but here, the tower 82 is installed offshore. This will be explained below.

After fixing each frame 40 to the barge 90, as shown in FIG. 11, after moving (evacuating) all the multi-axis carts 30 to the connection yard 20 in the Y8 direction, as shown in FIG. The barge 90 loaded with the semi-submersible foundation 70 along with the plurality of frames 40 is moved (towed) in the Y9 direction to an offshore wind turbine installation position on the ocean.

Next, as shown in FIG. 13, the barge 90 is submerged in the Y10 direction, and the semi-submersible foundation 70 is launched into the water. Here, the method of diving the barge 90 is performed by pouring water into a ballast chamber (not shown) provided in the barge 90. In addition, as another method of diving, if the barge 90 has support legs equipped with an elevating mechanism (not shown), the barge 90 can be submerged by lowering the support legs (the above is the launching step).

According to the illustrated method for launching a floating foundation, it is possible to efficiently transport the semi-submersible foundation 70 to the barge 90, and after transporting it to the barge 90, it is semi-submerged to a predetermined position on the ocean. By towing the bull type foundation 70 and launching it into the water, stable and smooth launching of the semi-submersible type foundation 70 can be realized.

On the other hand, as shown in FIG. 13, the method for recovering the trestle on which the floating foundation according to the embodiment is mounted is to attach the semi-submersible type foundation to the barge 90 together with a plurality of trestles 40 at the installation position of the semi-submersible type foundation 70. After the barge 90 with the foundation 70 loaded is submerged in the Y10 direction and the semi-submersible foundation 70 is floated (floated) on the water, as shown in FIG. The barge 90 is moved in the Y11 direction to a distant position.

Here, if the barge 90 is equipped with a ballast chamber (not shown), the method of diving the barge 90 is by pouring water into the ballast chamber, and the surfacing of the barge 90 is performed by draining ballast water from the ballast chamber. This can be done by In addition, if the barge 90 has support legs equipped with an elevating mechanism (not shown), diving of the barge 90 is performed by lowering the elevating mechanism, and surfacing of the barge 90 is performed by the elevating mechanism. This can be done by increasing the

Next, as shown in FIG. 15, (part of) the barge 90 is floated above the water in the Y12 direction, and as shown in FIG. (pulling back process).

After the pulled back barge 90 is moored to the quay P, the plurality of multi-axis bogies 30 waiting in the connection yard 20 are moved from the quay P to the barge 90 in the Y14 direction.

The plurality of mounts 40 fixed to the deck of the barge 90 are unfixed, the plurality of multi-axis carts 30 are entered into the entry spaces 43 of the corresponding mounts 40, the loading platform 32 is raised, the mounts 40 are lifted, and the mounts 40 are lifted to the ground. After cutting, as shown in FIG. 17, by moving each multi-axis cart 30 from the barge 90 to the quay P in the Y15 direction, the plurality of frames 40 are recovered from the barge 90 to the quay P. process).

According to the illustrated method for recovering a trestle on which a floating foundation is mounted, a plurality of concrete divided bodies are manufactured, and the divided bodies are connected to each other to manufacture a semi-submersible type foundation 70. When recovering the semi-submersible foundation 70, the barge 90 floating on the water is pulled back to the quay P, and then a plurality of multi-axis bogies 30 are moved from the quay P to the barge 90, and a plurality of pedestals 40 are moved to the barge 90. By recovering the pedestal 40 from the barge 90 to the quay P using a plurality of multi-axis carts 30, it becomes possible to recover the pedestal 40 efficiently and reliably.

Next, with reference to FIG. 18, an example of a method for manufacturing and towing an offshore wind turbine according to an embodiment will be described. Here, FIG. 18 is a diagram mainly illustrating a method for manufacturing an offshore wind turbine among methods for manufacturing and towing an offshore wind turbine.

The production of an offshore wind turbine in the illustrated example offshore wind turbine production towing method includes, as already explained, the method of connecting the tower 82 (see FIG. 3) to the semi-submersible type foundation 70 at the connection yard 20, the method of connecting the tower 82 (see FIG. 3), Unlike the method of connecting the tower 82 from the quay P to the semi-submersible foundation 70 mounted on the barge 90 of , is a method of connecting the tower 82 from the quay P.

In FIG. 18, the dashed line indicates the seabed B and the quay P before water is poured into the ballast chamber 79A of the semi-submersible foundation 70, and the water depth t5 and the swamp t6 of the semi-submersible foundation 70. On the other hand, the solid line shows the seabed B, quay P, water depth t7, and stagnant water t8 of the semi-submersible foundation 70 after water is poured into the ballast chamber 79A, and the water depths t5 and t7 before and after water injection are substantially There is no difference.

By injecting water into the ballast chamber 79A of the semi-submersible foundation 70 that is suspended from the quay P by a mobile lifting machine 56 (heavy equipment) such as a crane and moored to the quay P, the semi-submersible foundation is constructed. Adjustments are made to lower the level of the semi-submersible type foundation 70 than the level before water injection while making the water depth t8 of the quay P 70 smaller than the water depth t7 of the quay P. By this level adjustment, the lifting height of the tower 82 by the heavy equipment 56 can be made as low as possible, and the connectivity of the tower to the floating foundation can be improved (preparation step).

Next, the offshore wind turbine 80 (see FIG. 3) is manufactured by lifting and connecting the tower 82 using the heavy equipment 56 to the semi-submersible foundation 70 which is floating on the water.

Here, by adjusting the level of the semi-submergible foundation 70 to be lowered, the semi-submergible foundation 70 can also be brought to the bottom of the seabed B on the side of the quay P.

According to this method, it is possible to stabilize the semi-submersible foundation 70 in an immovable position when connecting the tower 82, thereby improving the progress when connecting the tower 82 to the semi-submersible foundation 70. can be done.

In addition to the method of connecting the tower 82 to the semi-submersible type foundation 70, in addition to the method of using the mobile lifting machine 56, the tower 82 can be erected by an erecting device (not shown) located on the quay P. A method of connecting to the foundation 70 may also be used. Alternatively, the tower 82 may be connected to the semi-submersible foundation 70 using a self-elevating work barge (SEP boat) on the water (the above is an offshore wind turbine manufacturing process).

Next, after the offshore wind turbine 80 is manufactured on the side of the quay P, the ballast water is drained from the ballast chamber 79A of the semi-submersible type foundation 70 and the ballast water is returned to the ballast water for towing, and then the offshore wind turbine is built. It is towed to a predetermined location on the ocean (towing process).

In this towing process, by injecting ballast water into the ballast chamber 79A to increase the amount of water as needed, it becomes possible to tow the semi-submersible foundation 70 in a stable posture.

According to the manufacturing and towing method of the offshore wind turbine shown in the example, water is poured into the ballast chamber 79A of the semi-submersible type foundation 70 to make the water depth of the semi-submersible type foundation 70 smaller than the water depth of the quay P. After making adjustments to lower the level of the foundation 70, the tower 82 is connected to the semi-submersible foundation 70 floating above water to manufacture the offshore wind turbine 80. The connectivity of the tower 82 can be improved. Then, after draining the ballast water from the ballast chamber 79A and returning the water to the towing water, the offshore wind turbine 80 is towed to a predetermined position on the ocean, thereby safely bringing the offshore wind turbine 80 to the predetermined position on the ocean. It will be possible to tow it.

It should be noted that other embodiments may be adopted in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited to the configurations shown here. In this regard, changes can be made without departing from the spirit of the present invention, and can be appropriately determined depending on the application form.

10, 10A, 10B, 10C, 10D: Fabrication yard 13: Rail 15: Portal crane 18: Building 20: Connection yard 30: Transport means (multi-axis trolley)
31: Vehicle body 32: Loading platform 33: Axle 35: Wheels 40, 40A, 40B, 40C, 40D: Frame 41: Mounting plate 42: Legs 43: Approach space 50: Transport path 55: Heavy equipment (crane)
56: Mobile lifting equipment (crane, heavy equipment)
60: Manufacturing system (floating foundation manufacturing system)
70: Floating foundation (semi-submersible foundation)
70A: Center column (split body)
70B: Side column (split body)
70C: Pontoon (split body)
71: Center column foundation (split body)
72: Center tower (divided body)
72a: Center tower element (divided body)
73: Side column foundation (split body)
74: Side tower (split body)
74a: Side tower element (split body)
75a: Pontoon element (split body)
76: Upper floor slab 77: Lower floor slab 78: Side wall 79: Hollow 79A: Ballast room 80: Offshore windmill 82: Tower 84: Windmill 90: Barge D: Dock P: Quay S: Offshore (sea, water)
G: Gap for pontoon WJ: Wet joint B: Seabed

Claims (7)

A concrete center column, a plurality of concrete side columns arranged at intervals in three or four directions around the center column, and a plurality of concrete connecting the center column and each side column. The center column has a center column foundation and a center tower rising from the center column foundation, and the side column has a side column foundation and a side tower rising from the side column foundation. A method for manufacturing a floating foundation, which is a semi-submersible foundation for supporting a tower of an offshore wind turbine, comprising:
A manufacturing step of manufacturing at least the center column foundation, the side column foundation, and the pontoon in respective manufacturing yards;
At least transporting and positioning the center column foundation and the plurality of side column foundations to a connection yard, and providing a pontoon gap into which the pontoon is inserted between the center column foundation and the side column foundations. process and
a pontoon insertion step of inserting the pontoon into the pontoon gap;
a pontoon connecting step of connecting the pontoon to both the center column foundation and the side column foundation;
a center tower connecting step of connecting the center tower to the center column foundation;
A method for manufacturing a floating foundation, comprising the step of connecting the side tower to the side column foundation. 2. The method for manufacturing a floating foundation according to claim 1, wherein the manufacturing step includes at least one of the center tower connecting step and the side tower connecting step. The center tower is a laminate of a plurality of center tower elements,
The side tower is a laminate of a plurality of side tower elements,
The pontoon is a connection body of a plurality of pontoon elements,
When the center tower connecting step is included in the manufacturing step, at least a portion of the center tower is connected to the center column foundation,
3. The method for manufacturing a floating foundation according to claim 2, wherein when the side tower connecting step is included in the manufacturing step, at least a portion of the side tower is connected to the side column foundation. The center tower is a laminate of a plurality of center tower elements,
The side tower is a laminate of a plurality of side tower elements,
the pontoon is a single pontoon element;
When the center tower connecting step is included in the manufacturing step, at least a portion of the center tower is connected to the center column foundation,
3. The method for manufacturing a floating foundation according to claim 2, wherein when the side tower connecting step is included in the manufacturing step, at least a portion of the side tower is connected to the side column foundation. manufacturing the center column by tensioning the center column foundation and the center tower with a plurality of first tension members;
Tightening the side column foundation and the side tower with a plurality of second tension members to produce a plurality of side columns;
In the manufacturing step, the pontoon is manufactured by tensioning the plurality of pontoon elements with a plurality of third tension members in the manufacturing yard;
4. The floating body according to claim 3, wherein in the pontoon connecting step, the pontoon is connected to the center column and the side columns under tension by a plurality of fourth tension members in the connection yard. How to make a type foundation. In a case where the four pontoons are arranged at 90 degree intervals around the center column, and the side column is connected to each pontoon,
In the pontoon connecting step, the third tendon material and the fourth tendon material are the same tendon material, and the two pontoons facing each other around the center column foundation are connected to the third tendon material common to the center column foundation. 6. The method of manufacturing a floating foundation according to claim 5, wherein the floating foundation is tensioned by tensioning material. The floating body according to claim 1, wherein the pontoon gap has a length that is the sum of the length of the pontoon to be inserted and an error length due to manufacturing error and/or connection error. How to make a type foundation.

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