JP7827388B2 - Floating foundation manufacturing method and manufacturing system, and offshore wind turbine manufacturing method - Google Patents

Description

The present invention relates to a method and system for manufacturing a floating foundation, and a method for manufacturing an offshore wind turbine.

Demand for renewable energy is increasing with the aim of reducing greenhouse gas emissions. Renewable energy sources include, for example, solar power generation, wind power generation, hydroelectric power generation, geothermal power generation, and biomass power generation. Wind power generation facilities are often installed in mountainous areas away from residential areas, as the noise and vibrations from wind turbines can have an impact on the living environment and the impact on living spaces must be fully considered.
However, it is difficult to secure land in mountainous areas for installing large wind turbines, and it is also difficult to secure transportation routes to wind power generation facilities and install power transmission lines, etc., so technological development is underway to install offshore wind turbines that make up wind power generation facilities on the sea (including on water or lakes).
When constructing an offshore wind turbine on the sea, a floating foundation may be used as its foundation, and these floating foundations include semi-submersible, spar, purge, and TLP (Tension Leg Platform) types. Of these, the semi-submersible foundation (semi-submersible floating foundation) has a center column that supports the wind turbine tower (support), multiple side columns (three or four) spaced around the center column, and pontoons that connect the center column and side columns, and is a foundation with a relatively good track record due to its excellent stability against waves and sea breezes.

Conventional floating foundations are generally made of steel, which has led to rising manufacturing costs, and this problem becomes even more pronounced as the size of the floating foundations increases.
Therefore, while it is possible to reduce production costs by fabricating a concrete floating foundation in a dock and then towing it out to sea for installation, there is currently no established efficient method for fabricating concrete floating foundations in a dock, and therefore a floating foundation fabrication method and system that can achieve efficient fabrication is desired.

Patent Document 1 proposes a tower assembly method in which multiple tower components created by dividing the tower of an offshore wind turbine vertically are assembled on a jack-equipped platform constructed on a base that is installed on the ground.
Meanwhile, Patent Document 2 proposes an installation method for offshore wind turbines in which the tower of the offshore wind turbine is divided vertically into multiple tower components that are assembled and installed offshore.This installation method includes a caisson installation process in which a caisson, which forms the base of the offshore wind turbine, is installed at the installation position of the offshore wind turbine, an assembly process in which multiple tower components are assembled in the caisson, and a blade installation process in which blades are attached to a nacelle attached to the topmost tower component in the caisson.

Japanese Patent Application Laid-Open No. 2021-80852 Japanese Patent Application Laid-Open No. 2021-76043

Patent Documents 1 and 2 describe efficient tower assembly methods, but, as mentioned above, do not describe technology for efficiently fabricating floating concrete foundations in a dock.

The present invention aims to provide a method and system for manufacturing floating foundations, as well as a method for manufacturing offshore wind turbines, that enable efficient manufacturing of concrete floating foundations in a dock.

In order to achieve the above object, one aspect of the method for manufacturing a floating foundation according to the present invention includes:
A method for fabricating a floating foundation that supports a tower of an offshore wind turbine, comprising the steps of:
a segment fabrication process in which a plurality of concrete segments that form the floating foundation are fabricated on frames in their own fabrication yards;
and a connecting step in which the plurality of divided bodies are transported together with the frame by a transport means to a connection yard, and the divided bodies are connected on the frame at the connection yard to fabricate the floating foundation.

According to this aspect, the multiple concrete segments that form the floating foundation are fabricated on frames in their own fabrication yards, and then the multiple segments are transported together with their frames by a transport means to a connection yard, where each segment is connected on its frame to fabricate the floating foundation, thereby enabling efficient fabrication of concrete floating foundations in a dock.
Here, concrete segments refer to center columns, side columns, and pontoons made of reinforced concrete (RC), and more specifically, the components of the center column, side columns, and pontoons. Note that in this specification, "concrete" also includes SRC (Steel Reinforced Concrete) structures, which are primarily made of RC but also contain steel (S).
By fabricating these segments on their own platforms, transportability is improved when transporting the fabricated segments together with the platforms to the connection yard by transport means. Furthermore, at the connection yard, the segments are connected together while each is mounted on its own platform, which also improves connectivity at the connection yard. The combination of good transportability from each fabrication yard to the connection yard and good connectivity at the connection yard leads to efficient fabrication of floating foundations.
In the connecting yard, the floating foundation is fabricated by tensioning each of the segments with tendons such as PC (Prestressed Concrete) steel bars or PC steel wires. That is, in each fabrication yard, concrete segments are fabricated as PCa (Precast Concrete) bodies on a frame, and in the connecting yard, each PCa body (segment) mounted on the frame is tensioned with tendons to fabricate a PCaPC (Precast Prestressed Concrete) floating foundation.

In another aspect of the method for manufacturing a floating foundation according to the present invention,
The transport means is a self-propelled carriage equipped with a lifting mechanism that lifts the platform and lifts it off the ground.
According to this aspect, the transport means is a self-propelled carriage equipped with a lifting mechanism that lifts the platform and lifts it off the ground, which further improves the transportability of the divided body including the platform.

In another aspect of the method for manufacturing a floating foundation according to the present invention,
The frame is provided with wheels driven by an actuator, and the wheels serve as the transport means.
According to this aspect, the stand is equipped with wheels, which are a transport means driven by an actuator, thereby eliminating the need for a transport means separate from the stand, and improving the transportability of the divided body including the stand.

In another aspect of the method for manufacturing a floating foundation according to the present invention,
The frame is equipped with wheels, and the transport means is a towed cart or a push cart.
According to this aspect, the base is provided with wheels and the transport means is a tow-type cart or a push-type cart, so that the transportability of the divided body including the base is further improved.

In another aspect of the method for manufacturing a floating foundation according to the present invention,
The transport means is a mobile lifting machine.
According to this aspect, since the transport means is a mobile lifting machine such as a crane, the divided body including the frame can be transported by a general transport means.

In another aspect of the method for manufacturing a floating foundation according to the present invention,
The floating foundation is a semi-submersible foundation, and the semi-submersible foundation has a concrete center column, a plurality of concrete side columns, and a plurality of concrete pontoons connecting the center column and the side columns, the center column has a center column foundation and a center tower rising from the center column foundation, and the side columns have side column foundations and side towers rising from the side column foundations,
a first form in which the center column foundation, the side column foundation, and the pontoon are each the divided body;
a second mode in which the center column, the side columns, and the pontoons are each the divided bodies;
The connecting body between the center column foundation and the side column foundation and the pontoon is one of the above-mentioned third forms, which is a divided body.

According to this aspect, the floating foundation is a semi-submersible foundation equipped with a center column, side columns, and pontoons, all made of concrete. When the center column has a center column foundation and a center tower, and the side columns have side column foundations and side towers, the segments are various types of segments included in the first to third types, which enables a variety of segments to be fabricated in each fabrication yard and a variety of segments to be connected to each other in the connection yard. It is preferable to select a type that enables more efficient fabrication of the floating foundation from the combinations of segments of the first to third types, depending on the size of each segment, etc.

In another aspect of the method for manufacturing a floating foundation according to the present invention,
The center tower is a stack of multiple center tower elements,
the side tower is a stack of multiple side tower elements;
The pontoon is a connection of a plurality of pontoon elements,
In the first embodiment, at least a portion of the center tower is formed and connected to the center column foundation in the connection yard, and at least a portion of the side tower is formed and connected to the side column foundation.

According to this aspect, when the center tower is a stack of multiple center tower elements, the side tower is a stack of multiple side tower elements, and the pontoon is a connection of multiple pontoon elements, it is possible to manufacture a variety of divided bodies in the production yard and connect the divided bodies to each other in the connection yard.
Here, "in the first form, at least a portion of the center tower is formed and connected to the center column foundation in the connection yard" means that the first form includes a form in which the center column foundation and center tower are fabricated on separate frames in the fabrication yard and then connected to each other in the connection yard, and a form in which the center column foundation and even a portion of the center tower are fabricated on frames in the fabrication yard and then transported to the connection yard, and then the remaining center tower is connected in the connection yard.
In addition, fabrication on a pedestal includes not only fabrication entirely on the pedestal, but also mounting multiple intermediate bodies (intermediates of segments) fabricated elsewhere than on the pedestal, and connecting the multiple intermediate bodies on the pedestal to form segments (segments are fabricated). In either case, when transporting to the connection yard, both the segments and the pedestal will be transported by transport means with the segments mounted on the pedestal.
Incidentally, the above explanation regarding the center column foundation and center tower also applies to the statement that "in the first form, at least a portion of the side tower is formed and connected to the side column foundation in the connection yard."
In contrast, in the second embodiment, the center column, side columns, and pontoons are completed at each manufacturing yard, and then connected together at the connection yard.
In the third form, the connectors for the side column foundations and pontoons are fabricated on a frame in the fabrication yard, and in the connection yard, multiple connectors are connected to the center column foundation to form a stable structure, after which the center tower is connected to the center column foundation and the side towers are connected to each side column foundation.

In another aspect of the method for manufacturing a floating foundation according to the present invention,
The center tower is a stack of multiple center tower elements,
the side tower is a stack of multiple side tower elements;
the pontoon is a single pontoon element;
In the first embodiment, at least a portion of the center tower is formed and connected to the center column foundation in the connection yard, and at least a portion of the side tower is formed and connected to the side column foundation.

According to this aspect, even when the pontoon is a single pontoon element, it is possible to manufacture a variety of segments in the manufacturing yard and connect the segments together in the connection yard.

Furthermore, one aspect of the method for manufacturing an offshore wind turbine according to the present invention is to
The method is characterized in that the tower is connected to the floating foundation manufactured by the floating foundation manufacturing method in the connection yard, thereby manufacturing the offshore wind turbine formed by the floating foundation and the tower.

According to this aspect, by connecting a tower to a floating foundation manufactured on a frame using the floating foundation manufacturing method of the present invention to manufacture an offshore wind turbine, it is possible to efficiently manufacture not only the floating foundation but also the entire offshore wind turbine including the tower.
Here, "tower" includes a wind turbine that is rotatably attached to a tower. For example, a long tower can be connected to a floating foundation while being lifted by a mobile lifting machine such as a crane, or can be connected to a floating foundation while being erected by an erection device. In addition, if the tower is a stack of multiple sections (tower sections), the tower can be formed by stacking the tower sections on the floating foundation in order, and the floating foundation and tower can be connected at the same time as the tower is formed.
The tower may be connected to the center tower of the floating foundation, or to a side tower.

Furthermore, one aspect of the floating foundation manufacturing system according to the present invention is to
A manufacturing system for a floating foundation that supports a tower of an offshore wind turbine, comprising:
a plurality of fabrication yards including platforms for fabricating a plurality of concrete sections that form the floating foundation;
a transport means for transporting the plurality of divided bodies together with the base;
and a connection yard where the plurality of divided bodies transported by the transport means are connected on the platform to fabricate the floating foundation.

According to this aspect, the multiple concrete segments that make up the floating foundation are fabricated on frames in their own fabrication yards, and then the multiple segments are transported together with their frames to a connection yard by transport means. At the connection yard, the segments are connected on their frames to fabricate the floating foundation, thereby enabling efficient fabrication of concrete floating foundations in a dock.

The floating foundation manufacturing method and manufacturing system, and offshore wind turbine manufacturing method of the present invention enable efficient manufacturing of concrete floating foundations in docks, which in turn leads to efficient manufacturing of offshore wind turbines in docks.

FIG. 1 is an overall perspective view of an example of a floating foundation manufacturing system according to an embodiment. 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 a method for manufacturing an offshore wind turbine according to an embodiment. FIG. FIG. 2 is a process diagram of an example of a manufacturing method for the floating foundation according to the first embodiment. 4A , which is a process diagram of an example of a method for manufacturing a floating foundation according to the first embodiment. FIG. 10A and 10B are diagrams showing 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. FIG. 1 is a perspective view of an example of a multi-axle truck. 1A and 1B are diagrams showing the arrangement of multi-axle carriages during the first transportation method for a floating foundation, in which (a) is a plan view of multiple multi-axle carriages transporting side columns, (b) is a plan view of multiple multi-axle carriages transporting pontoons, and (c) is a plan view of multiple multi-axle carriages transporting a center column. FIG. 10 is a diagram illustrating an example of a first transportation method in which a floating foundation is transported together with a frame by a plurality of multi-axle carriages. 10A, 10B, and 10C are plan views of multiple multi-axle carriages transporting side columns; FIG. 10D, 10E, and 10F are plan views of multiple multi-axle carriages transporting pontoons; and FIG. 10G is a plan view of multiple multi-axle carriages transporting a center column. FIG. 10 is a diagram illustrating an example of a second transportation method in which a floating foundation is transported together with a frame by a plurality of multi-axle carriages. FIG. 1 is a process diagram of an example of a launching method for a floating foundation according to an embodiment. 9 , which is a flow chart of an example of a launching method for a floating foundation according to an embodiment. 10 , which is a flow chart of an example of a launching method for a floating foundation according to an embodiment. 11 , and is a process diagram of an example of a launching method for a floating foundation according to an embodiment. Following Figure 12, this is a process diagram of an example of a method for launching a floating foundation according to an embodiment, and also a process diagram of an example of a method for recovering a platform on which the floating foundation according to an embodiment is mounted. 13 , which is a process diagram of an example of a method for recovering a platform on which a floating foundation according to an embodiment is mounted. 14 , which is a process diagram of an example of a method for recovering a platform on which a floating foundation according to an embodiment is mounted. 15 , which is a process diagram of an example of a method for recovering a platform on which a floating foundation according to an embodiment is mounted. 16 , which is a process diagram of an example of a method for recovering a platform on which a floating foundation according to an embodiment is mounted. FIG. 1 is a diagram illustrating a method for manufacturing and towing an offshore wind turbine according to an embodiment.

The following describes, with reference to the accompanying drawings, a floating foundation manufacturing method, a floating foundation manufacturing system, an offshore wind turbine manufacturing method, a floating foundation launching method, a method for recovering a platform on which a floating foundation is mounted, and an offshore wind turbine manufacturing and towing method according to embodiments. Note that in this specification and drawings, substantially identical components may be designated by the same reference numerals to avoid redundant description.

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

In addition, in each drawing, the steel bars that form each of the concrete (reinforced concrete) components that make up the floating foundation, as well as the tension members that form each component (connect multiple elements together) and connect each component together, are omitted.

The fabrication system 60 shown in Figure 1 is installed in a dock D and is a system for fabricating a floating foundation 70. In the illustrated example, the floating foundation 70 to be fabricated is a semi-submersible foundation, but the floating foundation fabricated by the fabrication system 60 may also be other types of floating foundations, such as spar, purge, or TLP types.

The production system 60 comprises multiple production yards 10 for producing the various types of segments that make up the semi-submersible foundation 70, transport paths 50 provided between each production yard 10, a transport means 30 that transports the segments produced at each production yard 10 via the transport paths 50, and a connection yard 20 that connects the segments transported by the transport means 30 to produce the floating foundation 70.

In dock D, to the side of the quay P of the connecting yard 20, there is an offshore area S where the manufactured floating foundation 70 is towed and installed, and a barge 90 is moored to the quay P to load the manufactured floating foundation 70 and tow it to the designated installation location for installation.

As shown in Figure 2, the semi-submersible foundation 70 has a concrete center column 70A, three concrete side columns 70B arranged at 120-degree intervals in a plan view in three directions around the center column 70A, and three concrete pontoons 70C connecting the central center column 70A to each side column 70B. The three 120-degree intervals are the longitudinal directions of the pontoons 70C, and are therefore referred to as the pontoon axial directions.

The center column 70A also includes a center column foundation 71 and a center tower 72 rising from the center column foundation 71, while 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 stack of multiple center tower elements 72a, the side tower 74 is a stack of multiple side tower elements 74a, and the pontoon 70C is a connection of multiple pontoon elements 75a.

These are fabricated as separate sections in various configurations at a specific fabrication yard 10, and then transported to a connection yard 20 where each section is connected to fabricate the floating foundation 70. Here, the semi-submersible foundation 70 to be fabricated is equipped with three side columns 70B, but other configurations (not shown) may also be used, in which four pontoons 70C are arranged at 90-degree intervals in a plan view around a center column 70A, with a side column 70B connected to each pontoon 70C.

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

Here, "a stand specific to each segment" means that there is a 1:1 correspondence between each segment and each stand 40. In addition, if the number of stands 40 is small compared to the number of segments and each segment is manufactured with a time lag, one stand 40 will be diverted from manufacturing multiple segments to transporting them.

The center column 70A, side column 70B, and pontoon 70C are mounted on their own platforms 40A, 40B, and 40D, respectively.

Returning to Figure 1, each production yard 10 is located inside its own building 18. In the production yard 10, a gantry crane 15 for producing the sections is installed so that it can move freely in the X1 direction along multiple rails 13.

A stand 40 is installed in the production yard 10, and the sections are produced on the stand 40.

The segments can take various forms. Referring to Figure 2, the center column foundation 71 and side column foundation 73 are included in the segments. The entire center tower 72 may be included in the segment, or each center tower element 72a may be included in the segment, or a portion of the center tower 72 (in an unfinished state) may be included. This also applies to the side tower 74.

The pontoon 70C may be included in its entirety in a divided body, or may include only a portion of it (in an unfinished state). Here, the pontoon 70C in the illustrated example is a connected body of multiple pontoon elements 75a, but the pontoon may also be formed from a single pontoon element.

The segments produced in the production yard 10 are fabricated on the platform 40, then transported together with the platform 40 by the transport means 30 to the connection yard 20, where they are connected to other segments on the platform 40. As a result, the shapes of the segments vary depending on the extent to which they are fabricated on the platform 40 in the production yard 10.

For example, if the entire center column 70A is a separate unit, the entire center column 70A is fabricated as a separate unit on a frame 40 in a fabrication yard 10. On the other hand, if the center column foundation 71 and center tower 72 are fabricated on a specific frame 40 in a specific fabrication yard 10, the center column foundation 71 and center tower 72 are each fabricated as separate units. Here, each center tower element 72a that makes up the center tower 72 may be fabricated individually, for example, inside a building 18, rather than on a frame 40. Then, multiple center tower elements 72a are placed on the frame 40 and tensioned with multiple tendons to fabricate the center tower 72. Even with this fabrication method, the center tower 72 is fabricated as a separate unit.

In any case, the object mounted on the platform 40 and transported to the connection yard 20 together with the platform 40 by the transport means 30 is referred to in this specification as a "divided body." In addition to objects that are 100% manufactured (manufactured from start to finish) on the platform 40, "divided bodies" also include objects that are manufactured elsewhere and then connected together on the platform 40.

At each production yard 10, concrete segments are fabricated into PCa bodies, and at the connection yard 20, each PCa body segment is tensioned with tendons to produce a PCaPC floating foundation.

Returning to Figure 1, in the illustrated example, the center column foundation 71, side column foundation 73, and pontoon 70C are fabricated on specific frames 40A, 40B, and 40D in specific fabrication yards 10A, 10B, and 10D, respectively. Pontoon 70C is fabricated by fabricating multiple pontoon elements 75a at a location other than frame 40D in fabrication yard 10D, and then tensioning the multiple pontoon elements 75a with multiple tendons on frame 40D.

The center tower element 72a and the side tower element 74a are fabricated in a common fabrication yard 10C. The fabricated center tower elements 72a are connected to each other via tendons on a common frame 40, and similarly, the side tower elements 74a are connected to each other via tendons on the common frame 40 and transported together with the frame 40 to the connection yard 20. As already described, the center tower 72 and the side tower 74 may be fabricated in an unfinished state as separate units on the frame 40, transported to the connection yard 20, and then stacked sequentially on the center column foundation 71 and the side column foundation 73.

Figure 1 also shows the state in which the side column foundation 73 placed on the platform 40B is being transported in the X2 direction via the transport path 50 to the connecting yard 20 by the transport means 30, and the state in which the pontoon 70C placed on the platform 40D is being transported in the X2 direction via the transport path 50 to the connecting yard 20.

In the connection yard 20, heavy machinery 55 and the like are used as needed to connect the segments together via tendons on multiple frames 40, thereby fabricating the semi-submersible foundation 70. Then, as shown in Figure 3, a tower 82 equipped with a wind turbine 84 is connected to the center column 70A that constitutes the semi-submersible foundation 70, thereby fabricating the offshore wind turbine 80. While the illustrated example shows a configuration in which the tower 82 is connected to the center column 70A, a single wind turbine tower may also be connected to the side column 70B.

Methods for connecting the tower 82 to the semi-submersible foundation 70 include connecting the tower 82 while lifting it using heavy machinery 55 at the connection yard 20 as shown in Figure 1, connecting the tower 82 to a semi-submersible foundation 70 installed offshore (offshore) using a barge equipped with a lifting machine at sea, or transporting the semi-submersible foundation 70 to a barge 90 moored to a quay P, loading it, and then connecting the tower 82 from the quay P using heavy machinery. Furthermore, as will be explained below with reference to Figure 18, there is also a method in which the tower 82 is connected from the quay P using heavy machinery while the semi-submersible foundation 70 is floating on the water next to the quay P, without using a barge.

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

In the illustrated example, the manufacturing method involves manufacturing the center column foundation 71 and three side column foundations 73 as separate units on a platform 40 in a specific manufacturing yard 10 (manufacturing process, separate unit manufacturing process).

Next, each segment is transported by the transport means 30 along with its own frame 40 to the connection yard 20. At the connection yard 20, the center column foundation 71 and three side column foundations 73 are positioned along with the frames 40 on which they are placed, and pontoon gaps G are provided between the center column foundation 71 and each side column foundation 73 to allow the pontoons 70C to be inserted (transport and positioning process). Here, the process of transporting the segments together with the frames 40 from each production yard 10 can also be referred to as the segment transport process.

In other words, during the transport and positioning process, the center column base 71 and each side column base 73 are positioned in a position that eliminates the need to move them when connecting the other segments thereafter.

The center column foundation 71, side column foundation 73, and each pontoon 70C all have an upper deck 76, a lower deck 77, and left and right side walls 78, with a hollow 79 formed inside that forms a ballast chamber. A plurality of corresponding sheath pipes (not shown) are provided in corresponding positions on the upper deck 76, lower deck 77, and side walls 78 of the center column foundation 71, side column foundation 73, and each pontoon 70C, and tensioning members (not shown) are inserted through each sheath pipe to connect the center column foundation 71, side column foundation 73, and each pontoon 70C.

Next, as shown in Figure 4B, the pontoons 70C, which have been transported from the production yard 10 together with the frames 40D, are inserted into each pontoon gap G in the Y1 direction (pontoon insertion process).

Here, the width t1 of the pontoon gap G shown in Figures 4A and 4B is set to the longitudinal length t2 of the pontoon 70C plus an error length due to manufacturing error and/or connection error. 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, eliminating the construction labor required to move at least one of the center column foundation 71 and side column foundation 73 when the pontoon 70C cannot be inserted.

Next, wet joints WJ filled with mortar or the like are constructed between the center column foundation 71 and the side column foundation 73 and the pontoon 70C, and these are tensioned with tensioning materials to connect the center column foundation 71 and the side column foundation 73 to the pontoon 70C (pontoon connection process). From a watertight standpoint, it is desirable to also construct wet joints WJ between adjacent pontoon elements 75a, center tower elements 72a, and side tower elements 74a.

Next, the center tower 72 is lifted and connected to the center column foundation 71 using heavy machinery 55 or the like (center tower connection process), and the side towers 74 are lifted and connected to each side column foundation 73 using heavy machinery 55 or the like (side tower connection process), thereby producing the semi-submersible foundation 70 shown in Figure 2. Here, the transportation and positioning process, pontoon insertion process, pontoon connection process, center tower connection process, and side tower connection process can be collectively referred to as the connection process.

Although the individual tendons are not shown here, the center column foundation 71 and center tower 72 are tensioned by multiple first tendons to produce the center column 70A, and the side column foundation 73 and side tower 74 are tensioned by multiple second tendons to produce each side column 70B. The pontoon 70C is produced in a specific production yard 10C by tensioning multiple pontoon elements 75a with multiple third tendons. Then, in the pontoon connection process, the pontoon 70C is connected to the center column 70A and side column 70B in the connection yard 20 by tensioning them with multiple fourth tendons. Note that the first through fourth tendons are made of PC steel rods, PC steel wires, or the like.

Furthermore, in the fabrication of a semi-submersible 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, it is preferable to use the same third tendon for the third and fourth tendons during the pontoon connection process, and tension the two pontoons 70C facing each other around the center column foundation 71 together with the center column foundation 71 using the same third tendon. This tensioning method allows for a more efficient connection in the connection yard 20 by tensioning the two pontoons 70C facing each other around the center column foundation 71 together with the center column foundation 71 using the same third tendon.

In the manufacturing method for a floating foundation according to the first embodiment shown in the figures, the transport and positioning process eliminates the need to move the center column foundation 71 and each side column foundation 73 when connecting other segments, thereby enabling efficient connection between segments.

Furthermore, as shown in Figure 4B, by first fabricating the lower structure of the semi-submersible foundation 70 and then connecting the upper structure, such as the center tower 72 and side towers 74, the upper structure can be connected to the lower structure in a stable position efficiently and with high construction safety.

Next, an example of a manufacturing method for a floating foundation according to the second and third embodiments will be described with reference to Figures 5 and 2. Note that Figure 4A will be referenced when explaining the manufacturing method according to the third embodiment.

The manufacturing method according to the second embodiment involves manufacturing the center column 70A on the mounting base 40A and the side column 70B on the mounting base 40B at a specific manufacturing yard 10, after which these sections are transported together with the mounting base 40 to the connection yard 20 for positioning, and the pontoons 70C are inserted into each pontoon gap G and connected.

This manufacturing method minimizes the number of connection steps required at the connection yard 20, significantly increasing the efficiency of connecting the segments at the connection yard 20.

The manufacturing method according to the third embodiment is similar to the method shown in Figure 4A, in which the center column foundation 71 and three side column foundations 73 are positioned in the connection yard 20 along with the platforms 40 on which they are placed, and then, as shown in Figure 5, the center tower 72 and side towers 74 are connected to each foundation, thereby manufacturing the center column 70A and each side column 70B in advance, and finally, pontoons 70C are inserted into each pontoon gap G and connected.

Another method, not shown in the figures, is to first connect the side column foundation 73 and side column 70B to the pontoon 70C in the connection yard 20, and then move the three connectors to connect to the center column foundation 71 and center column 70A. Alternatively, if the center column foundation 71 and part of the center tower 72 are manufactured as separate units, and similarly the side column foundation 73 and part of the side tower 74 are manufactured as separate units and transported to the connection yard 20, the pontoon 70C will be 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 will be connected.

The offshore wind turbine manufacturing method according to this embodiment involves connecting a semi-submersible foundation 70 manufactured by the floating foundation manufacturing methods according to the first to third embodiments or the other embodiments described above, while lifting the tower 82 using heavy machinery 55 at the connection yard 20, as already explained. Alternatively, the manufactured semi-submersible foundation 70 may be towed out to sea (offshore) and installed there, and then the tower 82 may be connected at sea using a barge equipped with a lifting machine. Another method involves transporting the semi-submersible foundation 70 to a barge 90 moored to a quay P, loading it onto the barge, and then connecting the tower 82 from the quay P using heavy machinery. Alternatively, as will be explained below with reference to Figure 18, there is also a method in which the semi-submersible foundation 70 is floated on the water next to the quay P, without using a barge, and then the tower 82 is connected from the quay P using heavy machinery.

Next, an example of a transport means and an example of a method for transporting a manufactured floating foundation in the connection step of the manufacturing method of a floating foundation according to the embodiment will be described with reference to FIGS. 6 to 8.
Here, Fig. 6 is a perspective view of an example of a multi-axle bogie. Fig. 7A is a diagram showing the arrangement of multi-axle bogies during a first transportation method for a floating foundation, where (a) is a plan view of multiple multi-axle bogies transporting side columns, (b) is a plan view of multiple multi-axle bogies transporting pontoons, and (c) is a plan view of multiple multi-axle bogies transporting a center column. Fig. 8A is a diagram showing the arrangement of multi-axle bogies during a second transportation method for a floating foundation, where (a), (b), and (c) are plan views of multiple multi-axle bogies transporting side columns, (d), (e), and (f) are plan views of multiple multi-axle bogies transporting pontoons, and (g) is a plan view of multiple multi-axle bogies transporting a center column. Furthermore, Figs. 7B and 8B are diagrams illustrating an example of a first transportation method and a second transportation method, respectively, for transporting a floating foundation together with a platform using multiple multi-axle bogies.

The transport means 30 shown in the figure is a multi-axle bogie, an example of a self-propelled bogie, equipped with a lifting mechanism that lifts the platform 40 and clears the ground. The multi-axle bogie 30 has multiple axles 33 attached to a long car body 31 in the axial direction (L direction), and each axle 33 has multiple pairs of left and right wheels 35 spaced apart in the axial direction of the car body. All wheels 35 are attached to their corresponding axles 33 so that they can rotate freely in the Y3 direction, and a loading platform 32 above the car body 31 is attached so that it can be raised and lowered by a lifting mechanism (not shown), thereby forming the entire structure.

The multi-axle trolley 30 enters the entry space 43 of each platform 40 shown in Figure 2, etc., with the platform 32 lowered as shown in the illustrated example. When transporting the platform 40 together with the segments, the platform 32 can be raised by the lifting mechanism to allow the platform 40 to be lifted off the ground.

Although not shown in the figures, the transport means may be such that the platform 40 is equipped with wheels driven by an actuator, and these driven wheels serve as the transport means. Alternatively, the platform 40 may be equipped with wheels, and the transport means may be a towed cart or a push cart. Furthermore, the transport means may be a mobile lifting machine such as a crane.

The first transportation method for the floating foundation 70 shown in Figure 7 involves arranging each multi-axle bogie 30 in the connection process at the connection yard 20 so that the body axis direction (L direction) of each multi-axle bogie 30 is parallel to or perpendicular to at least one of the three pontoon axis directions, and connecting each segment to produce the semi-submersible foundation 70. Here, the body axis direction of each multi-axle bogie 30 does not have to be strictly aligned with these directions, but may also be aligned in a direction that is slightly offset by a few degrees.

Next, when the semi-submersible foundation 70 is loaded out along with the multiple platforms 40 using multiple multi-axle trolleys 30 and transported to the barge 90 moored at the quay P, all of the wheels 35 of all of the multi-axle trolleys can be controlled in the same or approximately the same direction, allowing all of the multi-axle trolleys 30 to move in the Y5 direction, which is the transport direction toward the barge 90. Here, controlling the wheels 35 in approximately the same direction means that there is an angle error of, for example, approximately ±10 degrees with respect to the reference wheel angle along the Y5 direction, which is the load-out direction.

With this transportation method, when the semi-submersible foundation 70 is fabricated by connecting the segments on multiple cradles 40 in the connection yard 20, or when the semi-submersible foundation 70 has been fabricated on multiple cradles 40 (both connection processes), all of the wheels 35 of all of the multi-axle bogies 30 are controlled to move in the same or approximately the same direction. This allows the vehicle axial direction (L direction) of each multi-axle bogie 30 to be smoothly moved in the desired load-out direction without having to be set in a specific direction, making it possible to stably and smoothly transport the semi-submersible foundation 70, including the cradles 40, and load it onto the barge 90. Furthermore, there is no need to change the planar shape of the loading platform 32 of the multi-axle bogie 30 depending on the placement position. In other words, multi-axle bogies 30 equipped with loading platforms 32 of the same planar shape can be used without being restricted by placement position.

On the other hand, the second transportation method for the floating foundation 70 shown in Figure 8 involves positioning each multi-axle carriage 30 with its body axis direction (L direction) facing in the Y5 direction, which is the transport direction toward the barge 90, during the connection process in the connection yard 20, and then connecting each section to produce the semi-submersible foundation 70.

Next, when the semi-submersible foundation 70 is loaded onto the multiple multi-axle trolleys 30 along with the multiple platforms 40 and transported to the barge 90 moored at the quay P, each multi-axle trolley 30 can be moved in a straight line to move all of the multi-axle trolleys 30 in the Y5 direction, which is the transport direction toward the barge 90.

With this transportation method, when the semi-submersible foundation 70 is fabricated by connecting the segments on multiple cradles 40 in the connection yard 20, or when the semi-submersible foundation 70 has been fabricated on multiple cradles 40 (both connection processes), the wheels 35 can be moved in a straight line without controlling the angle of each wheel 35 to be in the same direction, allowing for smooth movement in the desired load-out direction. This makes it possible to stably and smoothly transport the semi-submersible foundation 70, including the cradles 40, and load it onto the barge 90. Furthermore, since the axial direction of the vehicle body of all multi-axle bogies 30 is the transport direction toward the barge 90, as shown in the figure, each multi-axle bogie 30 may be required to have a loading platform 32 with a variety of shapes in plan view depending on its location.

Next, an example of a method for launching a floating foundation according to an embodiment and an example of a method for recovering a platform on which the floating foundation is mounted will be described with reference to FIGS. 9 to 17.
9 to 13 are process diagrams showing an example of a method for launching a floating foundation according to an embodiment, and FIGS. 13 to 17 are process diagrams showing an example of a method for recovering a platform on which a floating foundation according to an embodiment is mounted.

As shown in Figure 9, the method for launching a floating foundation according to this embodiment involves mooring a barge 90 on the water S to the side of the quay P of the connecting yard 20 of dock D, and then, as already explained, fabricating multiple concrete segments, each on its own platform 40, and connecting the multiple segments on the platforms 40 to fabricate a semi-submersible foundation 70.

Next, as shown in Figure 10, the semi-submersible foundation 70, along with the multiple platforms 40, is transported in the Y7 direction by multiple multi-axle carts 30 to the barge 90 and loaded onto it. Each platform 40 transported onto, for example, the deck of the barge 90 is fixed to the deck (this completes the transport process).

Following this transportation process, the tower 82 can be connected to the semi-submersible foundation 70 from the quay P using heavy machinery to complete the construction of the offshore wind turbine 80, but the following description will assume that the tower 82 will be installed offshore.

After each mounting frame 40 is secured to the barge 90, all multi-axle carriages 30 are moved (evacuated) in the Y8 direction to the connecting yard 20 as shown in Figure 11. Then, as shown in Figure 12, the barge 90 carrying the semi-submersible foundations 70 along with multiple mounting frames 40 is moved (towed) in the Y9 direction to the offshore offshore wind turbine installation position.

Next, as shown in Figure 13, the barge 90 is submerged in the Y10 direction, and the semi-submersible foundation 70 is launched into the water. Here, the barge 90 is submerged by pouring water into a ballast chamber (not shown) equipped on the barge 90. Alternatively, if the barge 90 has support legs equipped with a lifting mechanism (not shown), the support legs can be lowered to submerge the barge (this completes the launching process).

The floating foundation launching method shown in the illustration allows for efficient transport of the semi-submersible foundation 70 to the barge 90. After transport to the barge 90, the semi-submersible foundation 70 is towed to a predetermined position offshore and launched into the water, ensuring stable and smooth launching of the semi-submersible foundation 70.

On the other hand, in the method for recovering the platform on which the floating foundation is mounted according to the embodiment, as shown in Figure 13, the semi-submersible foundation 70 is mounted on a barge 90 together with multiple platforms 40 at the installation position of the semi-submersible foundation 70, and the barge 90 is submerged in the Y10 direction with the semi-submersible foundation 70 floating (surface floating) above the water, and then the barge 90 is moved in the Y11 direction to a position away from the semi-submersible foundation 70, as shown in Figure 14.

Here, if the barge 90 is equipped with a ballast room (not shown), the barge 90 can be submerged by injecting water into the ballast room, and the barge 90 can be surfaced by discharging ballast water from the ballast room. Also, if the barge 90 has support legs equipped with a lifting mechanism (not shown), the barge 90 can be submerged by lowering the lifting mechanism, and the barge 90 can be surfaced by raising the lifting mechanism.

Next, as shown in Figure 15, (part of) the barge 90 is raised onto the water in the direction Y12, and as shown in Figure 16, the barge 90 carrying multiple platforms 40 is towed back to the quay P in the direction Y13 (towing process).

After the pulled-back barge 90 is moored to the quay P, multiple multi-axle carriages 30 waiting in the connecting yard 20 are moved in the direction Y14 from the quay P to the barge 90.

The multiple platforms 40 fixed to the deck of the barge 90 are released, the multiple multi-axle trolleys 30 are allowed to enter the access spaces 43 of the corresponding platforms 40, the loading platform 32 is raised to lift the platforms 40 and remove them from the ground, and then, as shown in Figure 17, each multi-axle trolley 30 is moved in the Y15 direction from the barge 90 to the quay P, thereby recovering the multiple platforms 40 from the barge 90 to the quay P (this completes the recovery process).

In the illustrated example, the method for recovering a platform on which a floating foundation is mounted involves fabricating multiple concrete segments that are then connected to form a semi-submersible foundation 70. When recovering multiple platforms 40, the barge 90 that has raised the semi-submersible foundation 70 to the surface is towed back to the quay P, after which multiple multi-axle trolleys 30 are moved from the quay P to the barge 90, and the multiple platforms 40 are recovered from the barge 90 to the quay P using the multiple multi-axle trolleys 30, enabling efficient and reliable recovery of the platforms 40.

Next, an example of a method for manufacturing and towing an offshore wind turbine according to an embodiment will be described with reference to Figure 18. Here, Figure 18 is a diagram that primarily explains the method for manufacturing an offshore wind turbine, among the methods for manufacturing and towing an offshore wind turbine.

As already explained, the offshore wind turbine construction method shown in the figure differs from methods of connecting the tower 82 (see Figure 3) to the semi-submersible foundation 70 at the connection yard 20, or methods of connecting the tower 82 from a quay P to a semi-submersible foundation 70 mounted on a barge 90 on the water, in that the semi-submersible foundation 70 is floated above the water next to the quay P, and the tower 82 is connected to the quay P.

In Figure 18, the dashed dotted lines indicate the seabed B and quay wall P, as well as the water depth t5 and draft t6 of the semi-submersible foundation 70 before water is poured into the ballast chamber 79A of the semi-submersible foundation 70. In contrast, the solid lines indicate the seabed B and quay wall P, as well as the water depth t7 and draft t8 of the semi-submersible foundation 70 after water has been poured into the ballast chamber 79A, and the water depths t5 and t7 before and after water pouring are essentially unchanged.

The semi-submersible foundation 70 is lowered onto the water by a mobile lifting machine 56 (heavy machinery) such as a crane from the quay P, and water is poured into the ballast chamber 79A of the semi-submersible foundation 70 moored to the quay P. This adjusts the draft t8 of the semi-submersible foundation 70 to be smaller than the water depth t7 of the quay P, while also lowering the level of the semi-submersible foundation 70 below the level before water was poured in. This level adjustment makes it possible to lower the lifting height of the tower 82 by the heavy machinery 56 as low as possible, ensuring good connectivity of the tower to the floating foundation (preparation process).

Next, the tower 82 is lifted and connected to the semi-submersible foundation 70, which has been raised above the water, using heavy machinery 56, thereby completing the offshore wind turbine 80 (see Figure 3).

Here, by adjusting the level of the semi-submersible foundation 70 to lower it, the semi-submersible foundation 70 can be placed on the seabed B beside the quay P.

This method allows the semi-submersible foundation 70 to be stabilized in an immovable position when connecting the tower 82, thereby improving the yield when connecting the tower 82 to the semi-submersible foundation 70.

In addition to using a mobile lifting machine 56, the method of connecting the tower 82 to the semi-submersible foundation 70 may involve using an erection device (not shown) located on the quay P to erect the tower 82 and connect it to the semi-submersible foundation 70. Alternatively, the tower 82 may be connected to the semi-submersible foundation 70 using a self-elevating work platform (SEP) located on the water (the above is the offshore wind turbine manufacturing process).

Next, after the offshore wind turbine 80 is assembled next to the quay P, ballast water is drained from the ballast chamber 79A of the semi-submersible foundation 70, the draft is returned to the draft for towing, and the offshore wind turbine is then towed to a designated position offshore (towing process).

During this towing process, ballast water can be injected into the ballast chamber 79A as needed to increase the draft, allowing the semi-submersible foundation 70 to be towed in a stable position.

In the illustrated method for constructing and towing an offshore wind turbine, water is poured into the ballast chamber 79A of the semi-submersible foundation 70 to make the draft of the semi-submersible foundation 70 smaller than the water depth of the quay P, and the level of the semi-submersible foundation 70 is adjusted to be lowered. The offshore wind turbine 80 is then constructed by connecting the tower 82 to the semi-submersible foundation 70 while it is floating above the water, thereby ensuring good connectivity of the tower 82 to the semi-submersible foundation 70. After that, ballast water is drained from the ballast chamber 79A to return the draft to the draft for towing, and the offshore wind turbine 80 can be towed safely to the designated location offshore.

Note that other embodiments may be possible in which other components are combined with the configurations described in the above embodiments, and the present invention is in no way 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 determined appropriately depending on the application form.

10, 10A, 10B, 10C, 10D: Production yard 13: Rail 15: Gantry crane 18: Building 20: Connection yard 30: Transport means (multi-axle cart)
31: Vehicle body 32: Loading platform 33: Axle 35: Wheels 40, 40A, 40B, 40C, 40D: Platform 41: Mounting plate 42: Legs 43: Access space 50: Transport path 55: Heavy equipment (crane)
56: Mobile lifting equipment (cranes, heavy machinery)
60: Manufacturing system (floating foundation manufacturing system)
70: Floating foundation (semi-submersible foundation)
70A: Center column (divided body)
70B: Side column (divided body)
70C: Pontoon (divided body)
71: Center column foundation (divided body)
72: Center tower (divided body)
72a: Center tower element (divided body)
73: Side column foundation (divided body)
74: Side tower (divided body)
74a: Side tower element (divided body)
75a: Pontoon element (divided body)
76: Upper deck 77: Lower deck 78: Side wall 79: Hollow 79A: Ballast room 80: Offshore wind turbine 82: Tower 84: Wind turbine 90: Barge D: Dock P: Quay S: Offshore (on the sea, on the water)
G: Pontoon gap WJ: Wet joint B: Seabed

Claims (9)

A method for fabricating a floating foundation that supports a tower of an offshore wind turbine, comprising the steps of:
a segment fabrication process in which a plurality of concrete segments that form the floating foundation are fabricated on frames in their own fabrication yards;
a connecting step of transporting the plurality of segments together with the frame by a transport means to a connection yard, and connecting the segments on the frame at the connection yard to fabricate the floating foundation ;
The floating foundation is a semi-submersible foundation, and the semi-submersible foundation has a concrete center column, a plurality of concrete side columns, and a plurality of concrete pontoons connecting the center column and the side columns, the center column has a center column foundation and a center tower rising from the center column foundation, and the side columns have side column foundations and side towers rising from the side column foundations,
a first form in which the center column foundation, the side column foundation, and the pontoon are each the divided body;
a second mode in which the center column, the side columns, and the pontoons are each the divided bodies;
a third form in which the connecting bodies between the center column foundation, the side column foundation and the pontoon are each the divided bodies; The floating foundation fabrication method described in claim 1, characterized in that the transport means is a self-propelled carriage equipped with a lifting mechanism that lifts the platform and removes it from the ground. The floating foundation manufacturing method described in claim 1, characterized in that the platform is equipped with wheels driven by actuators, and the wheels serve as the transport means. The method for manufacturing a floating foundation described in claim 1, characterized in that the platform is equipped with wheels and the transportation means is a towed cart or a push-out cart. The floating foundation manufacturing method described in claim 1, characterized in that the transport means is a mobile lifting machine. The center tower is a stack of multiple center tower elements,
the side tower is a stack of multiple side tower elements;
The pontoon is a connection of a plurality of pontoon elements,
2. The method for fabricating a floating foundation according to claim 1, wherein in the first embodiment, at least a portion of the center tower is formed and connected to the center column foundation in the connection yard, and at least a portion of the side tower is formed and connected to the side column foundation in the connection yard . The center tower is a stack of multiple center tower elements,
the side tower is a stack of multiple side tower elements;
the pontoon is a single pontoon element;
2. The method for fabricating a floating foundation according to claim 1, wherein in the first embodiment, at least a portion of the center tower is formed and connected to the center column foundation in the connection yard, and at least a portion of the side tower is formed and connected to the side column foundation in the connection yard . 8. A method for manufacturing an offshore wind turbine, comprising: connecting the tower in the connection yard to the floating foundation manufactured by the method for manufacturing a floating foundation according to any one of claims 1 to 7 , thereby manufacturing the offshore wind turbine formed by the floating foundation and the tower. A manufacturing system for a floating foundation that supports a tower of an offshore wind turbine, comprising:
a plurality of fabrication yards including platforms for fabricating a plurality of concrete sections that form the floating foundation;
a transport means for transporting the plurality of divided bodies together with the base;
a connection yard for connecting the plurality of segments transported by the transport means on the platform to fabricate the floating foundation ,
The floating foundation is a semi-submersible foundation, and the semi-submersible foundation has a concrete center column, a plurality of concrete side columns, and a plurality of concrete pontoons connecting the center column and the side columns, the center column has a center column foundation and a center tower rising from the center column foundation, and the side columns have side column foundations and side towers rising from the side column foundations,
a first form in which the center column foundation, the side column foundation, and the pontoon are each the divided body;
a second mode in which the center column, the side columns, and the pontoons are each the divided bodies;
a third form in which the connecting bodies of the center column foundation, the side column foundation and the pontoon are each the divided bodies ;