EP4647331A1

EP4647331A1 - Lifting auxiliary device, lifting system, disassembling method, and installation method

Info

Publication number: EP4647331A1
Application number: EP23927561.3A
Authority: EP
Inventors: Tomoaki Inoue; Masayuki Kanemasu; Akihito Suzuki; Kentaro Shindo; Makoto Nishigaki
Original assignee: Mitsubishi Heavy Industries Ltd
Current assignee: Mitsubishi Heavy Industries Ltd
Priority date: 2023-03-14
Filing date: 2023-09-28
Publication date: 2025-11-12
Also published as: WO2024189945A1; JP2024130045A; EP4647331A4

Abstract

A lifting auxiliary device according to the present disclosure comprises: a fixing part to be fixed to an elongated structure extending in the vertical direction; a suspension part that is connected to the fixing part and can be suspended by a lifting device; and a weight that is connected to the fixing part and is able to move relative to the fixing part in the vertical direction. The suspension part is able to move relative to the fixing part in the vertical direction. The lift auxiliary device further comprises a buoyancy device that is connected to the fixing part, is able to move relative to the fixing part in the vertical direction, and generates buoyancy with respect to the structure.

Description

Technical Field

The present disclosure relates to a lifting auxiliary device, a lifting system, a disassembling method, and an installation method.
Priority is claimed on Japanese Patent Application No. 2023-039535, filed March 14, 2023 , the content of which is incorporated herein by reference.

Background Art

When installing or disassembling a structure, work is performed while supporting the structure by lifting the entire structure or a part of the structure with a device such as a crane.
For example, as described in PTL 1 below, in a case of maintaining an offshore structure, a self-elevating platform (SEP) vessel or a large crane vessel is used.

Citation List

Patent Literature

[PTL 1] European Unexamined Patent Application Publication No. 2146006

Summary of Invention

Technical Problem

However, SEP vessels and large cranes have high construction and operational costs. Therefore, the use of cost-effective devices such as a crane is desired. However, low-cost lifting devices such as a crane have lower lifting capacity, which may reduce stability during work depending on the structure.
The present disclosure has been made to solve the above-described problem, and an object of the present disclosure is to provide a lifting auxiliary device, a lifting system, a disassembling method, and an installation method capable of improving stability.

Solution to Problem

In order to solve the above-described problem, according to the present disclosure, there is provided a lifting auxiliary device including: a fixing part that is fixed to an elongated structure extending in an up-down direction; a suspension part that is connected to the fixing part and that is capable of being suspended by a lifting device; and a weight that is connected to the fixing part and that is movable in the up-down direction relative to the fixing part.
According to the present disclosure, there is provided a lifting system including: the above-described lifting auxiliary device; and the lifting device.
According to the present disclosure, there is provided a disassembling method for the structure using the above-described lifting auxiliary device, the method including: a weight movement step of moving the weight downward; a suspension step of suspending the suspension part with the lifting device after the weight movement step; a posture change step of changing a posture of the structure by tilting the structure with the lifting device after the suspension step; and a disassembly step of disassembling the structure after the posture change step.
According to the present disclosure, there is provided an installation method for the structure using the above-described lifting auxiliary device, the method including: a weight movement step of moving the weight to a leg part side of the structure in an extension direction of the structure; a suspension step of suspending the suspension part with the lifting device after the weight movement step; a posture change step of changing a posture of the structure with the lifting device to extend in the up-down direction after the suspension step; and an installation step of installing the structure while maintaining the posture extending in the up-down direction after the posture change step.

Advantageous Effects of Invention

With the lifting auxiliary device, the lifting system, the disassembling method, and the installation method of the present disclosure, it is possible to improve stability. Brief Description of Drawings

Fig. 1 is an overall configuration diagram of a lifting system according to a first embodiment of the present disclosure.
Fig. 2 is a top view of a mounting portion according to the first embodiment of the present disclosure.
Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2.
Fig. 4 is a flowchart showing a procedure of a disassembling method according to the first embodiment of the present disclosure.
Fig. 5 is a view illustrating the disassembling method according to the first embodiment of the present disclosure.
Fig. 6 is a view illustrating the disassembling method according to the first embodiment of the present disclosure.
Fig. 7 is a flowchart showing a procedure of an installation method according to the first embodiment of the present disclosure.
Fig. 8 is a top view of a mounting portion according to a first modification example of the first embodiment of the present disclosure.
Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 8.
Fig. 10 is a top view of a mounting portion according to a second modification example of the first embodiment of the present disclosure.
Fig. 11 is a cross-sectional view taken along line XI-XI in Fig. 10.
Fig. 12 is an overall configuration diagram of a lifting system according to a second embodiment of the present disclosure.
Fig. 13 is a flowchart showing a procedure of a disassembling method according to the second embodiment of the present disclosure.
Fig. 14 is a flowchart showing a procedure of an installation method according to the second embodiment of the present disclosure.
Fig. 15 is an overall configuration diagram of a lifting system according to a third embodiment of the present disclosure.
Fig. 16 is a top view of an elevating platform according to the third embodiment of the present disclosure.
Fig. 17 is a flowchart showing a procedure of a disassembling method according to the third embodiment of the present disclosure.
Fig. 18 is a flowchart showing a procedure of a heavy load movement step in the disassembling method according to the third embodiment of the present disclosure.
Fig. 19 is a flowchart showing a procedure of an installation method according to the third embodiment of the present disclosure.
Fig. 20 is a flowchart showing a procedure of a heavy load movement step in the installation method according to the third embodiment of the present disclosure.
Fig. 21 is a view showing a lifting system according to a fourth embodiment of the present disclosure.
Fig. 22 is a view showing the lifting system according to the fourth embodiment of the present disclosure.
Fig. 23 is a top view of an elevating platform according to the fourth embodiment of the present disclosure.
Fig. 24 is a flowchart showing a procedure of a heavy load movement step according to the fourth embodiment of the present disclosure.
Fig. 25 is a view illustrating the disassembling method according to the fourth embodiment of the present disclosure.
Fig. 26 is a flowchart showing a procedure of an installation method according to the fourth embodiment of the present disclosure.
Fig. 27 is a view showing a lifting system according to a modification example of the fourth embodiment of the present disclosure.
Fig. 28 is a top view of a lifting device and a lifting auxiliary device according to the modification example of the fourth embodiment of the present disclosure.
Fig. 29 is a side view of the lifting device and the lifting auxiliary device according to the modification example of the fourth embodiment of the present disclosure.
Fig. 30 is a view illustrating a disassembling method according to the modification example of the fourth embodiment of the present disclosure.
Fig. 31 is a view illustrating the disassembling method according to the modification example of the fourth embodiment of the present disclosure.
Fig. 32 is a view illustrating the disassembling method according to the modification example of the fourth embodiment of the present disclosure.
Fig. 33 is an overall configuration diagram of a lifting system according to another modification example of the present disclosure.

Description of Embodiments

(Configuration of Lifting System)

Hereinafter, a lifting auxiliary device 3, a lifting system 100, a disassembling method, and an installation method according to a first embodiment of the present disclosure will be described with reference to Figs. 1 to 7.
As shown in Fig. 1, the lifting system 100 lifts a large elongated structure 10 extending in an up-down direction D1. The lifting system 100 is used when the structure 10 is disassembled and installed. The structure 10 is, for example, a waterborne structure 10a. In the present embodiment, an example will be described in which the structure 10 is, for example, an offshore structure 10b erected on the seabed. Examples of the offshore structure 10b include, for example, a wind turbine and the like. The structure 10 is not limited to the example of the present embodiment.

(Structure)

In the illustrated example, the structure 10 includes a tower 11 and a heavy load 12. The tower 11 includes a tower body 13 and a leg part 14. The leg part 14 is a cylindrical member that extends upward from the seabed. A lower portion of the leg part 14 is embedded in the seabed. The tower body 13 is attached to an upper end portion of the leg part 14 and is formed in a cylindrical shape that extends upward from the leg part 14. Fig. 1 shows an inside of a connection portion between the tower body 13 and the leg part 14. A lower end portion of the tower body 13 is fixed to the leg part 14 with the upper end portion of the leg part 14 inserted therein. The tower body 13 is formed in a tapered shape that tapers while extending upward. A shape of the tower body 13 is not limited to such a tapered shape. For example, a thickness of the tower body 13 may be uniform regardless of a position in the up-down direction D1. In addition, the tower body 13 is formed, for example, by connecting a plurality of tower elements (not shown) arranged in the up-down direction D1. The heavy load 12 is attached to an upper end of the tower body 13. In a case where the structure 10 is, for example, a wind turbine, examples of the heavy load 12 include a nacelle in which a shaft of the wind turbine is incorporated and the like.
The structure 10 to which the lifting auxiliary device 3 is applied may be a structure other than a wind turbine. Therefore, the heavy load 12 is not limited to the nacelle of the wind turbine. For example, in a case where the structure 10 is a tower with an observation deck provided at the upper end, the observation deck corresponds to the heavy load 12.
In the following description, an axis O of the tower 11 will be simply referred to as an "axis O". In a state in which the tower 11 is installed, the axis O extends along the up-down direction D1. Hereinafter, a radial direction with respect to the axis O may be simply referred to as a "radial direction", and a circumferential direction with respect to the axis O may be simply referred to as a "circumferential direction".

(Lifting System)

The lifting system 100 of the present embodiment includes a floating structure 1, a lifting device 2, and the lifting auxiliary device 3.

(Floating Structure)

The floating structure 1 of the present embodiment is a barge 1a that moves on a water surface. The floating structure 1 is capable of loading the structure 10. The lifting device 2 is placed on the floating structure 1. The floating structure 1 supports the lifting device 2 from below.
The barge 1a of the present embodiment is, for example, a multi-purpose barge capable of performing a wide range of tasks, such as extracting fuel oil or hazardous substances from marine vessels and removing vessels.
The floating structure 1 is not limited to the barge 1a. The floating structure 1 may be a small work vessel or a work vessel including a spud pile or a dynamic positioning system. Additionally, the floating structure 1 may use an SEP vessel, a crane vessel, or the like.

(Lifting Device)

The lifting device 2 lifts the structure 10 via the lifting auxiliary device 3, which will be described below. Hereinafter, an example will be described in which the lifting device 2 is a crane 20.
The crane 20 of the present embodiment is a crawler crane.
The crane 20 includes a vehicle part 21, a move 22, a wire rope 23, and a lifting gear 24. The vehicle part 21 runs on the floating structure 1. The move 22 extends upward from the vehicle part 21. The wire rope 23 is attached to the move 22 and extends downward from a tip of the move 22. The lifting gear 24 is attached to a tip of the wire rope 23. The lifting gear 24 suspends the lifting auxiliary device 3. The lifting gear 24 is, for example, a hook. The lifting gear 24 is not limited to a hook as long as the lifting gear can support the lifting auxiliary device 3 and the structure 10. The lifting gear 24 may be, for example, a shackle, a ring, an eye bolt, or the like.
The crane 20 may be a wheel crane or may be a crane that does not include the vehicle part 21.

(Lifting Auxiliary Device)

The lifting auxiliary device 3 includes a fixing part 4, a base 5, a suspension part 6, and a weight 7. A size of the lifting auxiliary device 3 is variable. In the present embodiment, by replacing devices and components constituting the lifting auxiliary device 3, the size of the lifting auxiliary device 3 can be changed according to a size of the structure 10.

(Fixing Part)

The fixing part 4 is fixed to the structure 10. The fixing part 4 of the present embodiment includes a guide portion 4a and a mounting portion 30.
The guide portion 4a is a rail extending in the up-down direction D1. The guide portion 4a guides the suspension part 6 and the weight 7 in the up-down direction D1. In the present embodiment, the guide portion 4a is replaceable according to the size of the structure 10.
The guide portion 4a is not limited to the rail as shown in the drawing. The fixing part 4 and the weight 7 may independently exist without such a rail.

(Mounting Portion)

The mounting portion 30 is provided at both end portions of the guide portion 4a in the up-down direction D1. The mounting portion 30 supports the guide portion 4a and is attached to the structure 10. The mounting portions 30 are attached to the structure 10 by clamping the structure 10 with a clamp mechanism using, for example, hydraulic pressure or the like. Specifically, the mounting portion 30 has the following configuration.
As shown in Figs. 2 and 3, the mounting portion 30 includes an outer shell frame 31, a reinforcing arm 32, and a fixing mechanism 40.
The outer shell frame 31 has a tubular shape that extends in the up-down direction D1 and that covers the tower 11 from an outer peripheral side. The outer shell frame 31 is formed in a rectangular frame shape as viewed in the up-down direction D1.
The reinforcing arm 32 is provided on an inner side of the outer shell frame 31, at each of four corners of the outer shell frame 31, as viewed in the up-down direction D1. Each of the reinforcing arms 32 extends in a straight line to connect a pair of adjacent bulkheads 33 of the outer shell frame 31. The reinforcing arm 32 supports the outer shell frame 31 from the inner side.
The fixing mechanism 40 is provided inside the outer shell frame 31. The fixing mechanism 40 includes an inner plate 41, a rotational movement mechanism 50, a claw 42, and a pressing mechanism 43.
A plurality of inner plates 41 are provided to surround the tower 11 from a radial outer side. In the present modification example, four inner plates 41 are arranged at equal intervals in the circumferential direction. Each of the inner plates 41 is formed in a curved shape to fit along an outer peripheral surface of the tower 11 as viewed in the up-down direction D1. The rotational movement mechanism 50 is provided on an outer peripheral side of the inner plate 41.
The rotational movement mechanism 50 is provided on an inner peripheral surface of the outer shell frame 31. Two rotational movement mechanisms 50 are provided for each of the inner plates 41 to be spaced apart from each other in the circumferential direction. The rotational movement mechanism 50 includes a first support member 51, a support shaft 52, and a second support member 53.
The first support member 51 extends from the inner peripheral surface of the outer shell frame 31 toward the inner plate 41. A pair of first support members 51 are provided to face each other in the circumferential direction. The support shaft 52 is provided between the pair of facing first support members 51. The support shaft 52 is formed in a columnar shape extending in a direction in which the pair of first support members 51 face each other. The support shaft 52 connects the pair of first support members 51. In addition, the second support member 53 is disposed between the pair of first support members 51 in addition to the support shaft 52. The second support member 53 is attached to the outer peripheral surface of the inner plate 41. The second support member 53 is formed in a V-like shape that protrudes from the inner plate 41 toward the outer shell frame 31, as viewed from the side in the circumferential direction. An insertion hole 54 is formed in a bent portion 53a of the second support member 53. The support shaft 52 is inserted through the insertion hole 54. The second support member 53 is rotationally movable about the support shaft 52.
The second support member 53 is fixed to the inner plate 41. Therefore, the inner plate 41 can rotationally move about the support shaft 52 integrally with the second support member 53. Here, as viewed from the side in the circumferential direction, a point on a central axis of the support shaft 52 is referred to as a "pivot point 52a", and an inner peripheral surface of the inner plate 41 facing a tower 11 side is referred to as a "mounting surface 44". The mounting surface 44 forms an involute curve with the pivot point 52a as the center of the base circle, as viewed from the side in the circumferential direction.
A plurality of claws 42 protruding to the tower 11 side are provided on the mounting surface 44. The plurality of claws 42 are arranged in the circumferential direction of the tower 11 and in a direction of the axis O. Additionally, the plurality of claws 42 are provided along the outer peripheral surface of the tower 11, as viewed in the up-down direction D1. Each of the claws 42 is formed in a triangular shape that tapers while extending from the mounting surface 44 toward the tower 11 side, as viewed from the side. Further, each of the claws 42 extends obliquely upward from the mounting surface 44. By the plurality of claws 42 biting into the outer peripheral surface of the tower 11, the lifting auxiliary device 3 is fixed to the tower 11.
In addition, the pressing mechanism 43 is provided between the outer shell frame 31 and the inner plate 41. Two pressing mechanisms 43 are provided for each inner plate 41 to face each other in the circumferential direction. The pressing mechanism 43 extends from the outer shell frame 31 toward the inner plate 41 and is obliquely disposed such that the position gradually moves upward while extending inward. The pressing mechanism 43 connects the outer shell frame 31 and the inner plate 41 in the radial direction. The pressing mechanism 43 presses the inner plate 41 toward the tower 11. Consequently, since the claws 42 strongly bite into the tower 11, the lifting auxiliary device 3 is strongly fixed to the tower 11. Examples of the pressing mechanism 43 include a hydraulic mechanism 45 and the like.
The mounting portion 30 is not limited to the above-described form. For example, a mechanism by which the mounting portions 30 clamp the structure 10 is not limited to a clamp mechanism.
Additionally, for example, the outer shell frame 31 may be formed in a circular frame shape or a triangular frame shape as viewed in the up-down direction D1. The number and disposition of the reinforcing arms 32 for reinforcing the outer shell frame 31 can also be changed as appropriate. The reinforcing arm 32 need not be provided.
Further, the number of the rotational movement mechanisms 50 can be changed as appropriate.
In addition, a case where the fixing mechanism 40 fixes the lifting auxiliary device 3 to the tower 11 by causing the claws 42 to bite into the outer peripheral surface of the tower 11 has been described, but the present disclosure is not limited thereto. The fixing mechanism 40 may fix the lifting auxiliary device 3 by using a clamping pressure or a pressure using the tapered shape of the tower 11, in addition to the claws 42.
Further, the pressing mechanism 43 is not limited to the hydraulic mechanism 45. The pressing mechanism 43 may be electric pressing mechanism, or may be driven by pneumatic pressure or water pressure.
The base 5 is attached to the guide portion 4a that constitutes the fixing part 4. Two bases 5 are provided in an up-down arrangement. The base 5 is movable in the up-down direction D1 along the guide portion 4a. The base 5 can be fixed to the guide portion 4a at any height. Each of the bases 5 is formed in a frame shape to surround the tower 11 from the radial outer side. Of the two bases 5, the upper base 5 is provided with the suspension part 6, and the lower base 5 is provided with the weight 7.

(Suspension Part)

The suspension part 6 is connected to the fixing part 4. The suspension part 6 can be suspended by the lifting device 2. The suspension part 6 is movable in the up-down direction D1 with respect to the fixing part 4. In the present embodiment, the suspension part 6 is connected to the fixing part 4 via the upper base 5. The suspension part 6 is attached to an upper surface of the base 5. The suspension part 6 engages with the lifting gear 24 of the crane 20. The suspension part 6 moves in the up-down direction D1 as the base 5 moves in the up-down direction D1 along the guide portion 4a.

(Weight)

The weight 7 is movable in the up-down direction D1 with respect to the fixing part 4. In the present embodiment, the weight 7 is connected to the fixing part 4 via the lower base 5. The weight 7 is attached to a lower surface of the base 5. The weight 7 moves in the up-down direction D1 as the base 5 moves in the up-down direction D1 along the guide portion 4a. In the illustrated example, a pair of weights 7 are provided such that the tower 11 is interposed therebetween on both radial sides. In the present embodiment, the weight 7 is a counterweight 7a that is solid throughout the inside. The weight 7 need not be solid inside. The weight 7 may be formed as hollow, and the inside of the weight 7 may be filled with seawater.

(Procedure of Disassembling Method)

Subsequently, a disassembling method for the structure 10 using the lifting auxiliary device 3 mentioned above will be described.
As shown in Fig. 4, the disassembling method according to the embodiment of the present disclosure includes a fixing step S1, a weight movement step S2, a suspension part movement step S3, a suspension step S4, a cutting step S5, a posture change step S6, and a disassembly step S7.

(Fixing Step)

First, the fixing step S1 is performed. In the fixing step S1, the fixing part 4 is fixed to the structure 10 by the mounting portion 30. In the present embodiment, the plurality of claws 42 provided on the mounting portion 30 bite into the outer peripheral surface of the tower 11. Further, the claws 42 are pressed against the tower 11 by the pressing mechanism 43. In this manner, the fixing part 4 is firmly fixed to the tower 11. As a result, the installation of the lifting auxiliary device 3 is completed.
In this step, the lifting auxiliary device 3 is attached to the structure 10. Consequently, as shown in Fig. 1, a center of gravity M of the structure 10 moves, for example, from an initial position P11 to a lower second position P12. The center of gravity M of the structure 10 herein means the overall center of gravity M, including not only the structure 10 but also other devices (in the case of the present embodiment, the lifting auxiliary device 3) that are lifted together with the structure 10.
After the fixing step S1, the weight movement step S2 is performed.

(Weight Movement Step)

In the weight movement step S2, the weight 7 is moved downward. For example, by moving the lower base 5 along the guide portion 4a, the weight 7 moves from an initial position P21 to a lower second position P22. Consequently, the center of gravity M of the structure 10 moves, for example, from the second position P12 to a third position P13. In the illustrated example, the weight 7 is located above the seawater surface at the second position P22, but the weight 7 may be submerged in seawater. However, it is more efficient for the weight 7 to be located below the seawater surface. Additionally, the weight 7 may be divided.
After the weight movement step S2, the suspension part movement step S3 is performed.

(Suspension Part Movement Step)

In the suspension part movement step S3, the suspension part 6 is moved to a position higher than the center of gravity M of the structure 10. For example, by moving the upper base 5 along the guide portion 4a, the suspension part 6 moves from an initial position P31 to a second position P32. Consequently, the suspension part 6 is located above the center of gravity M of the structure 10.
After the suspension part movement step S3, the suspension step S4 is performed.

(Suspension Step)

In the suspension step S4, the lifting device 2 suspends the suspension part 6. For example, as shown in Fig. 1, the crane 20 suspends the suspension part 6 using the lifting gear 24.
After the suspension step S4, the cutting step S5 is performed.

(Cutting Step)

As shown in Fig. 5, in the cutting step S5, the structure 10 is cut. Examples of the cutting method include a wire saw, a disk cutter, and thermal cutting such as using a laser or a burner. For cutting the structure 10, in addition to the thermal cutting, for example, mechanical cutting, blasting, or the like may be used.
In the present embodiment, the seabed is first excavated, and the leg part 14 of the structure 10 is cut at a cutting position 15 below the seabed surface.
After the cutting step S5, the posture change step S6 is performed.

(Posture Change Step)

In the posture change step S6, the posture of the structure 10 is changed by tilting the structure 10 with the lifting device 2. Specifically, first, the crane 20 lifts the structure 10 by hoisting the suspension part 6. The crane 20 gradually tilts the structure 10 in a horizontal direction while lifting the structure 10. Finally, as shown in Fig. 6, the posture of the structure 10 is changed to a posture along a horizontal plane. After that, the crane 20 loads the structure 10 onto the barge 1a.
In the illustrated example, the posture of the structure 10 is changed by pulling the upper part of the structure 10, but the present disclosure is not limited thereto. For example, the posture of the structure 10 may be changed by pushing or pulling the lower part of the structure 10 such that the structure 10 is easily tilted.
After the posture change step S6, the disassembly step S7 is performed.

(Disassembly Step)

In the disassembly step S7, the structure 10 is disassembled. In this step, for example, first, the structure 10 is disassembled into the heavy load 12 and the tower 11. After that, the heavy load 12 and the tower 11 are each disassembled. In a case where the tower body 13 is formed by connecting a plurality of tower elements as in the present embodiment, the tower 11 can be disassembled by disconnecting the plurality of tower elements.
The disassembling of the structure 10 is completed through the above procedure.
The lifting auxiliary device 3 can also be used for installation of the structure 10.
As shown in Fig. 7, an installation method for the structure 10 includes the fixing step S1, the weight movement step S2, the suspension part movement step S3, the suspension step S4, the posture change step S6, and an installation step S11. In the installation method for the structure 10, first, the lifting auxiliary device 3 is fixed to the structure 10 that is, for example, laid down to extend in the horizontal direction in the fixing step S1. In the subsequent weight movement step S2, the weight 7 is moved to a leg part 14 side of the structure 10. In the subsequent suspension part movement step S3, the suspension part 6 is moved to a side opposite to the leg part 14 with respect to the center of gravity of the structure 10. In the subsequent suspension step S4, the suspension part 6 is suspended by the lifting auxiliary device 3. In the subsequent posture change step S6, the posture of the structure is changed by the lifting device 2 to extend in the up-down direction D1. In the subsequent installation step S11, the structure 10 is installed while maintaining the posture extending in the up-down direction D1. In the example of the present embodiment, in the installation step S11, the leg part 14 of the structure 10 is fixed to the ground such as the seabed. The installation of the structure 10 is completed through the above procedure.

(Actions and Effects)

According to the present embodiment, the following actions and effects can be obtained.
In the present embodiment, the lifting auxiliary device 3 includes: the fixing part 4 that is fixed to the elongated structure 10 extending in the up-down direction D1; the suspension part 6 that is connected to the fixing part 4 and that is capable of being suspended by the lifting device 2; and the weight 7 that is connected to the fixing part 4 and that is movable in the up-down direction D1 relative to the fixing part 4.
According to the present embodiment, by moving the weight 7 downward, the center of gravity M of the structure 10 having a high center of gravity M can be moved downward. After that, the structure 10 can be lifted by suspending the suspension part 6 using the lifting device 2. As a result, the lifting and posture change of the structure 10 can be stably performed.
Therefore, during the disassembling of the structure 10, the work of significantly tilting the structure 10 having a high center of gravity M from an upright state in the up-down direction D1 to a lying posture in the horizontal direction can be stably performed. On the contrary, during the installation of the structure 10, the work of significantly raising the structure 10 having a high center of gravity M from a lying state in the horizontal direction to an upright state in the up-down direction D1 can be stably performed. As a result, according to the present embodiment, it is possible to improve stability.
As described above, according to the present embodiment, since the structure 10 can be stably lifted, it is possible to lift the relatively small lifting device 2 (such as the crane 20 of the present embodiment) and the large structure 10 having a high center of gravity M. As a result, in the disassembling and installing work of the large structure 10, for example, it is possible to eliminate a step of dividing the structure 10 to be lifted, thereby shortening the construction period and reducing costs.
In addition, as in the present embodiment, in a case where the structure 10 to be lifted is the offshore structure 10b, by integrating the structure 10 above the seawater surface and the structure 10 under the seawater for lifting, the overall center of gravity M of the offshore structure 10b, as viewed from the barge on the seawater surface, can be lowered. Consequently, it is possible to disassemble and install the offshore structure 10b by using the relatively small barge 1a, instead of a large SEP vessel or a crane vessel. As a result, charter fees for vessels can be reduced, thereby enabling the disassembling of the offshore structure 10b at a lower cost.
In the present embodiment, the suspension part 6 is movable in the up-down direction D1 relative to the fixing part 4.
Consequently, the suspension part 6 can be positioned at a position higher than the center of gravity M of the structure 10. In this manner, the relative position between the position of the center of gravity M of the structure 10 and the position of the hoist point can be freely set. Therefore, the stability of the structure 10 during the lifting is further improved. Accordingly, the work related to the disassembling and installation of the structure 10 can be more stably performed.
In the present embodiment, the fixing part 4 includes the guide portion 4a that extends in the up-down direction D1 and that guides the suspension part 6 and the weight 7 in the up-down direction D1, and the mounting portion 30 that supports the guide portion 4a and that is attached to the structure 10.
According to the present embodiment, after the fixing part 4 is disposed at any height with respect to the structure 10, the mounting portion 30 is attached to the structure 10. In this manner, the fixing part 4 can be fixed to the structure 10. As a result, since the fixing part 4 can be installed at any height, convenience can be improved, and the fixing part 4 can be fixed at an appropriate position to further improve stability.
In the present embodiment, the mounting surface 44 forms an involute curve with the pivot point 52a as the center of the base circle, as viewed from the side in the circumferential direction.
Consequently, even when the mounting portion 30 moves in the horizontal direction of the structure 10, the contact position between the mounting surface 44 and the structure 10 is maintained at a constant distance from the pivot point 52a. Therefore, the mounting accuracy of the mounting portion 30 can be improved. That is, the installation accuracy of the lifting auxiliary device 3 can be improved.
In the present embodiment, by replacing devices and components constituting the lifting auxiliary device 3, the size of the lifting auxiliary device 3 can be changed according to the size of the structure 10. For example, the guide portion 4a is replaceable according to the size of the structure 10. As a result, the guide portion 4a having an appropriate length can be selected with respect to a length of the structure 10.
In the present embodiment, the lifting system 100 includes the floating structure 1 that moves on the water surface, that supports the lifting device 2 from below, and that is capable of loading the structure 10.
According to the present embodiment, by moving the floating structure 1, the lifting device 2 can be disposed at an appropriate position with respect to the structure 10.
The disassembling method of the present embodiment is the disassembling method for the structure 10 using the lifting auxiliary device 3, the method including: the weight movement step S2 of moving the weight 7 downward; the suspension step S4 of suspending the suspension part 6 with the lifting device 2 after the weight movement step S2; the posture change step S6 of changing the posture of the structure 10 by tilting the structure 10 with the lifting device 2 after the suspension step S4; and the disassembly step S7 of disassembling the structure 10 after the posture change step S6.
According to the present embodiment, by moving the weight 7 downward, the center of gravity M of the structure 10 can be moved downward. Consequently, the center of gravity M of the structure 10 can be moved below the suspension part 6, and then the suspension part 6 can be suspended by the lifting device 2, thereby lifting the structure 10. Therefore, during the disassembling of the structure 10, the lifting and posture change of the structure 10 can be stably performed. In this manner, according to the present embodiment, it is possible to improve stability during the disassembling of the structure 10.
The disassembling method of the present embodiment further includes the suspension part movement step S3 of moving the suspension part 6 to a position higher than the center of gravity M of the structure 10 before the suspension step S4.
According to the present embodiment, after the suspension part 6 is moved to a position higher than the center of gravity M of the structure 10, the suspension part 6 can be suspended by the lifting device 2, thereby lifting the structure 10. Therefore, the lifting of the structure 10 can be stably performed. In this manner, according to the present embodiment, it is possible to further improve stability during the disassembling of the structure 10.
The disassembling method of the present embodiment further includes the fixing step S1 of fixing the fixing part 4 to the structure 10 with the mounting portion 30 before the weight movement step S2.
According to the present embodiment, after the fixing part 4 is disposed at any height with respect to the structure 10, the mounting portion 30 is attached to the structure 10. In this manner, the fixing part 4 can be fixed to the structure 10. As a result, since the fixing part 4 can be installed at any height, convenience can be improved, and the fixing part 4 can be fixed at an appropriate position to further improve stability.
The installation method of the present embodiment includes: the weight movement step S2 of moving the weight 7 to the leg part 14 side of the structure 10 in the extension direction of the structure 10; the suspension step S4 of suspending the suspension part 6 with the lifting device 2 after the weight movement step S2; the posture change step S6 of changing the posture of the structure 10 with the lifting device to extend in the up-down direction D1 after the suspension step S4; and the installation step S11 of installing the structure 10 while maintaining the posture extending in the up-down direction D1 after the posture change step S6.
According to the present embodiment, by moving the weight 7 to the leg part 14 side, the center of gravity M of the structure 10 can be moved to the leg part 14 side. Consequently, the center of gravity M of the structure 10 can be moved to the leg part 14 side with respect to the suspension part 6, and then the suspension part 6 can be suspended by the lifting device 2, thereby lifting the structure 10. Therefore, during the installation of the structure 10, the lifting and posture change of the structure 10 can be stably performed.
In the present embodiment, an example has been described in which the floating structure 1 is a multi-purpose barge and the crane 20 is loaded onto the deck so as to be able to run, but the present disclosure is not limited thereto. The floating structure 1 may be a relatively small crane vessel or a small work vessel. Alternatively, the floating structure 1 may be an SEP vessel or a crane vessel. Additionally, it is preferable that the floating structure 1 is a work vessel including a spud pile or a dynamic positioning system to prevent the structure 10 from being drifted by the influence of waves.
In addition, in the present embodiment, a case where the structure 10 is lifted by a single crane 20 has been described, but the present disclosure is not limited thereto. For example, a plurality of cranes 20 may be loaded onto the floating structure 1, and the plurality of cranes 20 may lift the structure 10. In this case, a crane 20 having a relatively low lifting capacity can be applied, thereby increasing the options for construction methods. Further, since posture control and the like are easier than in a case where the lifting is performed by a single crane 20, the work efficiency related to the disassembling and the installation of the structure 10 can be improved.
Moreover, a plurality of floating structures 1 on which the crane 20 is placed may be used.
Additionally, in the present embodiment, a case where the guide portion 4a is replaceable has been described, but the present disclosure is not limited thereto. The guide portion 4a may have an extendable and contractible structure using a linear guide or the like. In this case, a length of the guide portion 4a can be changed according to the size of the structure 10 without replacing the guide portion 4a.
In addition, in the disassembling method of the present embodiment, a case where the suspension part movement step S3 is performed after the weight movement step S2 has been described, but the present disclosure is not limited thereto.
The order of the weight movement step S2 and the suspension part movement step S3 can be changed as appropriate. For example, the suspension part movement step S3 may be performed before the weight movement step S2, the weight movement step S2 and the suspension part movement step S3 may be performed at the same time, or the weight movement step S2 may be performed again after the suspension part movement step S3.
Further, in the cutting step S5 of the present embodiment, the seabed is first excavated, and the leg part 14 of the structure 10 is cut at the cutting position below the seabed surface, but the present disclosure is not limited thereto. In the cutting step S5, the structure 10 may be cut above the seabed surface, and then the remaining structure may be cut underwater, or extracted and removed from the seabed.
Additionally, in the present embodiment, an example has been described in which the weight 7 is provided in advance in the lifting auxiliary device 3, but the present disclosure is not limited thereto. For example, the weight 7 may be installed on the lifting auxiliary device 3 as an additional attachment in the weight movement step S2.

Subsequently, a first modification example of the first embodiment will be described with reference to Figs. 8 and 9.
As shown in Figs. 8 and 9, a fixing mechanism 40a of the present modification example includes the inner plate 41, the rotational movement mechanism 50, a fixing piece 46, and the pressing mechanism 43.
In the present modification example, the inner plate 41 is formed in a straight line as viewed from above. In addition, the inner plate 41 extends in the direction of the axis O along the outer peripheral surface of the tower 11 as viewed from the side in the circumferential direction.
One rotational movement mechanism 50 is provided for each inner plate 41. The rotational movement mechanism 50 includes the first support member 51, the support shaft 52, and the second support member 53. The second support member 53 extends from a lower end of the inner plate 41 toward the outer peripheral side. The second support member 53 is obliquely formed in a straight line such that the position gradually moves downward while extending toward the outer peripheral side as viewed from the side in the circumferential direction. The second support member 53 is rotationally movable about the support shaft 52.
The fixing piece 46 is provided on the mounting surface 44 of each of the inner plates 41. The fixing piece 46 is formed in a pillar shape extending radially inward from the inner plate 41 toward the tower 11. The fixing piece 46 penetrates the tower 11. The fixing piece 46 is formed of, for example, a metallic material.
In the present modification example, first, in the fixing step S1, a hole 46a penetrating the structure 10 in the radial direction is formed in the structure 10 to be lifted. The hole 46a is formed for each fixing piece 46. The fixing pieces 46 are inserted through the holes 46a. In this state, each of the fixing pieces 46 is joined to the structure 10 by, for example, welding. As a result, the fixing part 4 is firmly fixed to the structure 10.

Subsequently, a second modification example of the first embodiment will be described with reference to Figs. 10 and 11.
A fixing mechanism 40b of the present modification example includes a feeding device 47 and a fixing shaft 48.
Four feeding devices 47 are provided at equal intervals in the circumferential direction to surround the tower 11 from the outer peripheral side. The feeding device 47 is placed on an upper surface of the outer shell frame 31.
The fixing shaft 48 is provided to connect a pair of feeding devices 47 facing each other in the radial direction. The fixing shaft 48 is provided for each pair of the feeding devices 47. That is, a total of two fixing shafts 48 are provided. The fixing shaft 48 is fed by the feeding device 47 and penetrates the tower 11 in the radial direction (in the horizontal direction in the illustrated example). Consequently, the lifting auxiliary device 203 is fixed to the tower 11. In the illustrated example, two fixing shafts 48 are disposed to be orthogonal to each other as viewed in the up-down direction D1. Additionally, the two fixing shafts 48 are disposed to be staggered in the up-down direction D1.
In the present modification example, in the fixing step S1, after a hole 48a penetrating the structure 10 in the radial direction is formed in the structure 10 to be lifted, the fixing shaft 48 is passed through the hole 48a by the feeding device 47. A total of four holes 48a are formed in the structure 10. Two holes 48a of the four holes 48a are formed to face each other in the radial direction. The remaining two holes 48a are also formed to face each other in the radial direction and in a direction orthogonal to the facing direction of the other two holes 48a. Each of the fixing shafts 48 is inserted through a pair of facing two holes 48a. As a result, the fixing part 4 is firmly fixed to the structure 10.

Hereinafter, a lifting auxiliary device 203, a lifting system 200, a disassembling method, and an installation method according to a second embodiment of the present disclosure will be described with reference to Figs. 12 to 14. Among the configurations of the second embodiment, the configurations common to those of the above-described embodiment will be assigned identical names, reference numerals, and the like, and the descriptions will be omitted as appropriate.
As shown in Fig. 12, in the present embodiment, the lifting auxiliary device 203 further includes a buoyancy device 16, in addition to the counterweight 7a of the above-described embodiment. The buoyancy device 16 is connected to the fixing part 4 and is movable in the up-down direction D1 with respect to the fixing part 4. The buoyancy device 16 of the present embodiment is a ballast tank 16a capable of supplying and discharging water (ballast water) to and from the inside.

(Ballast Tank)

The ballast tank 16a is provided on the lower surface of the lower base 5. The ballast tank 16a faces the counterweight 7a in the horizontal direction with the tower 11 interposed therebetween. By moving the base 5 in the up-down direction D1 along the guide portion 4a, the ballast tank 16a moves in the up-down direction D1 together with the counterweight 7a.
The ballast tank 16a is a housing with an adjustable internal water volume. When the water volume in the ballast tank 16a is adjusted, the ballast tank 16a is submerged in seawater. When adjusting the water volume inside the ballast tank 16a, for example, discharging water using a pump (not shown) installed in the ballast tank 16a, and sending compressed air from a device on the seawater surface to discharge water are considered. The ballast tank 16a has sufficient strength to withstand the fluctuating water pressure without deformation.

(Procedure of Disassembling Method)

Subsequently, the disassembling method for the structure 10 using the lifting auxiliary device 203 mentioned above will be described.
In the present embodiment, the disassembling of the structure 10 is performed in the same procedure as in the first embodiment. However, as shown in Fig. 13, the disassembling method according to the embodiment of the present disclosure further includes a buoyancy adjustment step S8.

(Buoyancy Adjustment Step)

The buoyancy adjustment step S8 is performed before the suspension step S4. In the present embodiment, the buoyancy adjustment step S8 is performed after the fixing step S1 and before the weight movement step S2. In the buoyancy adjustment step S8, buoyancy of the buoyancy device 16 is adjusted. In the present embodiment, at the time of the buoyancy adjustment step S8, the ballast tank 16a is submerged in the seawater. The buoyancy of the buoyancy device 16 is adjusted by adjusting the water volume inside the ballast tank 16a.
After the buoyancy adjustment step S8, the weight movement step S2, the suspension part movement step S3, the suspension step S4, the cutting step S5, the posture change step S6, and the disassembly step S7 are performed in this order in the same manner as in first embodiment.
The disassembling of the structure 10 is completed through the above procedure. The lifting auxiliary device 203 can also be used for the installation of the structure 10, in the same manner as in the case of the first embodiment.
As shown in Fig. 14, the installation method for the structure 10 of the present embodiment includes the fixing step S1, the weight movement step S2, the suspension part movement step S3, the suspension step S4, the posture change step S6, the buoyancy adjustment step S8, and the installation step S11. For example, the installation method for the structure 10 proceeds in the order of the fixing step S1, the weight movement step S2, the suspension part movement step S3, the suspension step S4, the posture change step S6, the buoyancy adjustment step S8, and the installation step S11. The buoyancy adjustment step S8 may be performed during the posture change step S6. That is, in the posture change step S6, when the posture of the structure 10 is changed and the ballast tank 16a is submerged in the water, the buoyancy adjustment step S8 may be performed to adjust the water volume inside the ballast tank 16a.
The installation of the structure 10 is completed through the above procedure.

(Actions and Effects)

According to the present embodiment, the following actions and effects can be obtained.
In the present embodiment, the lifting auxiliary device further includes the buoyancy device 16 that is connected to the fixing part 4, that is movable in the up-down direction D1 with respect to the fixing part 4, and that generates the buoyancy with respect to the structure 10.
Consequently, by adjusting the position of the buoyancy device 16 in the up-down direction D1, the buoyancy device 16 is disposed underwater, thereby allowing the buoyancy device 16 to generate buoyancy. This makes it possible to reduce the load on the lifting device 2 when the lifting device 2 lifts the structure 10. Therefore, it is possible to use equipment having a relatively low lifting capacity as the lifting device 2 and a relatively small vessel as the floating structure 1. As a result, charter fees for vessels can be reduced, thereby reducing costs associated with the disassembling and the installation of the structure 10.
In addition, in a case where the buoyancy generated by the buoyancy device 16 is sufficiently greater than the total gravitational force acting on the structure 10 and the lifting auxiliary device 203 combined, the lifting auxiliary device 203 alone can float the structure 10 and change the posture. In this case, it is also possible to tow and move the structure 10 using a relatively small vessel.
The disassembling method of the present embodiment further includes the buoyancy adjustment step S8 of adjusting the buoyancy of the buoyancy device 16 before the suspension step S4.
Consequently, by adjusting the buoyancy of the buoyancy device 16, the posture of the structure 10 can be adjusted. Accordingly, the lifting of the structure 10 can be more stably performed.
In the present embodiment, a case where the lifting auxiliary device 203 includes the ballast tank 16a in addition to the counterweight 7a has been described, but the present disclosure is not limited thereto. Instead of all of the counterweights 7a, the ballast tanks 16a may be provided. In this case, the ballast tank 16a functions as the weight 7 that changes the position of the center of gravity M of the structure 10.
Additionally, the buoyancy device 16 of the present embodiment is the ballast tank 16a including the housing with sufficient strength, but the present disclosure is not limited thereto. The buoyancy device 16 may be an airtight flotation bag. In this case, compressed air can be sent into the flotation bag to obtain buoyancy.
In addition, in the present embodiment, a case where the buoyancy adjustment step S8 is performed before the weight movement step S2 in the disassembling method has been described, but the present disclosure is not limited thereto. The timing of the buoyancy adjustment step S8 can be changed as appropriate. For example, the buoyancy adjustment step S8 may be performed after the weight movement step S2.

Hereinafter, a lifting system 300, a disassembling method, and an installation method according to a third embodiment of the present disclosure will be described with reference to Figs. 15 to 20. Among the configurations of the third embodiment, the configurations common to those of the above-described embodiments will be assigned identical names, reference numerals, and the like, and the descriptions will be omitted as appropriate.
As shown in Fig. 15, in the present embodiment, the lifting system 300 further includes an elevating device 8 in addition to the lifting device 2 and the lifting auxiliary device 203.

(Elevating Device)

In the present embodiment, the elevating device 8 is provided integrally with the lifting auxiliary device 203. The elevating device 8 includes a jack system 60 and an elevating device body 61.
The jack system 60 is a member provided on the fixing part 4. The jack system 60 is provided on the upper base 5 and is vertically extendable and contractible with respect to the base 5. The jack system 60 can raise and lower the elevating device body 61 in the up-down direction D1 by vertically extending and contracting with respect to the base 5.
The elevating device body 61 includes an elevating platform 62, a rotational movement portion 63, and a clamp portion 64.
The elevating platform 62 is movable in the up-down direction D1 relative to the fixing part 4. In the present embodiment, the elevating platform 62 can be moved in the up-down direction D1 by the extension and contraction of the jack system 60. The elevating platform 62 is fixed at its height after being moved by the jack system 60. The mechanism for raising and lowering the elevating platform 62 in the up-down direction D1 is not limited to the jack system 60. As such a mechanism, for example, a rail extending in the up-down direction may be used.
Additionally, as shown in Fig. 16, the elevating platform 62 is a frame-shaped member that surrounds the tower 11 from the outer peripheral side. In Fig. 16, the general shapes of the elevating device body 61, the mounting portion 30, and the base 5 are simplified and schematically shown, and the fixing mechanism 40, the guide portion 4a, and the like are omitted. The elevating platform 62 is formed in a rectangular frame shape as viewed from above. The clamp portion 64 is connected to the elevating platform 62 via the rotational movement portion 63.
The rotational movement portion 63 is provided at one of four outer edges of the elevating platform 62. In the illustrated example, the rotational movement portion 63 is a hinge-like portion extending along the outer edge of the elevating platform 62. The rotational movement portion 63 rotationally moves the clamp portion 64, which will be described below, about itself with respect to the elevating platform 62.
The clamp portion 64 can change the posture with respect to the elevating platform 62 by being attached to the elevating platform 62 and can clamp the heavy load 12. In the present embodiment, the posture of the clamp portion 64 is changed by the rotational movement about the rotational movement portion 63 with respect to the elevating platform 62. The clamp portion 64 is, for example, two arms facing each other in the horizontal direction. The two clamp portions 64 are rotationally moved about the rotational movement portion 63 by the rotational movement portion 63. The two clamp portions 64 can clamp the heavy load 12.
In the present embodiment, the elevating platform 62 mentioned above moves in the up-down direction D1. Therefore, the mounting portion 30 and the base 5 are formed in U-like shapes that are open toward a rotational movement portion 63 side as viewed from the up-down direction D1, in order to prevent obstructing the movement of the elevating platform 62 in the up-down direction D1.

(Procedure of Disassembling Method)

Subsequently, the disassembling method for the structure 10 using the lifting system 300 mentioned above will be described.
In the present embodiment, the disassembling of the structure 10 is performed in the same procedure as in the second embodiment. However, as shown in Fig. 17, the disassembling method according to the embodiment of the present disclosure further includes a heavy load movement step S9.
In the present embodiment, as in the previous embodiments, the fixing step S1 is first performed. By the lifting auxiliary device 203 being attached to the structure 10 in the fixing step S1, the elevating device 8 integrated with the lifting auxiliary device 203 is also attached to the structure 10.
In the present embodiment, the heavy load movement step S9 is performed after the fixing step S1.
The heavy load movement step S9 is a step of moving the heavy load 12 downward. As shown in Fig. 18, the heavy load movement step S9 includes a clamp step S91, a heavy load posture change step S92, a lowering step S93, and a heavy load disassembly step S94.
In the heavy load movement step S9, first, the clamp step S91 is performed. In the clamp step S91, as shown in Fig. 15, the elevating device 8 clamps the heavy load 12 located at an initial position P41 on the tower 11 with the clamp portions 64.
After the clamp step S91, the heavy load posture change step S92 is performed.
In the heavy load posture change step S92, the elevating device 8 changes the posture of the heavy load 12 with the clamp portions 64. For example, as shown in Fig. 15, by rotating the clamp portions 64 around the rotational movement portion 63 by approximately 90 degrees with the heavy load 12 being clamped, the heavy load 12 moves from the initial position P41 to a second position P42 shifted in the horizontal direction from the top of the tower 11.
After the heavy load posture change step S92, the lowering step S93 is performed.
In the lowering step S93, the elevating device 8 lowers the heavy load 12. For example, as shown in Fig. 15, the elevating device body 61 is lowered by the extension and contraction of the jack system 60, so that the heavy load 12 moves from the second position P42 to a third position P43 closer to the barge 1a below.
After the lowering step S93, the heavy load disassembly step S94 is performed.
In the heavy load disassembly step S94, for example, the heavy load 12 is disassembled on the barge 1a.
The heavy load movement step S9 is completed through the above procedure. After the heavy load movement step S9, the buoyancy adjustment step S8, the weight movement step S2, the suspension part movement step S3, the suspension step S4, the cutting step S5, the posture change step S6, and the disassembly step S7 are performed in this order in the same manner as in the second embodiment.
The disassembling of the structure 10 is completed through the above procedure. The lifting system 300 can also be used for the installation of the structure 10, in the same manner as in the case of the first embodiment.
As shown in Fig. 19, the installation method for the structure 10 of the present embodiment includes the fixing step S1, the weight movement step S2, the suspension part movement step S3, the suspension step S4, the posture change step S6, the buoyancy adjustment step S8, the installation step S11, and the heavy load movement step S9. For example, the installation method for the structure 10 proceeds in the order of the fixing step S1, the weight movement step S2, the suspension part movement step S3, the suspension step S4, the posture change step S6, the buoyancy adjustment step S8, the installation step S11, and the heavy load movement step S9.
In the heavy load movement step S9, the heavy load 12 is raised. As shown in Fig. 20, the heavy load movement step S9 includes the clamp step S91, a raising step S95, the heavy load posture change step S92, and a heavy load installation step S96. First, the clamp step S91 is performed. In the subsequent raising step S95, the heavy load 12 is raised. After that, the heavy load posture change step S92 is performed. In the subsequent heavy load installation step S96, the heavy load 12 is assembled to the upper end portion of the structure 10.
The installation of the structure 10 is completed through the above procedure.

(Actions and Effects)

According to the present embodiment, the following actions and effects can be obtained.
In the present embodiment, the lifting system 300 further includes the elevating device 8 including the elevating platform 62 that is movable in the up-down direction D1 relative to the fixing part 4, and the clamp portion 64 that is attached to the elevating platform 62 and capable of changing the posture with respect to the elevating platform 62, and that is capable of clamping the structure 10.
According to the present embodiment, the elevating device 8 can move the heavy load 12 downward in advance, thereby lowering the center of gravity M of the structure 10. As a result, the structure 10 can be lifted in a more stable state.
The disassembling method of the present embodiment further includes the heavy load movement step S9 of moving the heavy load 12 downward before the suspension step S4, and the heavy load movement step S9 includes the clamp step S91 of clamping the heavy load 12 with the clamp portion 64, using the elevating device 8, the heavy load posture change step S92 of changing the posture of the heavy load 12 with the clamp portion 64 after the clamp step S91, using the elevating device 8, and the lowering step S93 of lowering the heavy load 12 after the heavy load posture change step S92, using the elevating device 8.
According to the present embodiment, when the structure 10 is disassembled, the elevating device 8 can move the heavy load 12 downward in advance before the posture of the structure 10 is changed, thereby lowering the center of gravity M of the structure 10. Therefore, the disassembling of the structure 10 can be performed in a stable state.
In the disassembling method of the present embodiment, a case where the heavy load 12 is loaded onto the barge 1a and the heavy load 12 is disassembled at the end of the heavy load movement step S9 has been described, but the present disclosure is not limited thereto. For example, the heavy load 12 moved downward in the lowering step S93 of the heavy load movement step S9 may be fixed to the structure 10 and may be used as the weight 7. In this case, the center of gravity M can be lowered by integrating the structure 10 and the tower 11 below the suspension part 6.

Hereinafter, a lifting system 400, a disassembling method, and an installation method according to a fourth embodiment of the present disclosure will be described with reference to Figs. 21 to 26. Among the configurations of the fourth embodiment, the configurations common to those of the above-described embodiments will be assigned identical names, reference numerals, and the like, and the descriptions will be omitted as appropriate.
As shown in Figs. 21 and 22, in the present embodiment, the lifting system 400 includes an elevating device 408 in addition to the lifting device 2 and the lifting auxiliary device 203. In the present embodiment, although details will be described below, the heavy load 12 is moved by the elevating device 408, and then the lifting auxiliary device 203 is installed on the structure 10.

(Elevating Device)

As shown in Figs. 21 to 23, the elevating device 408 includes a pulley 65, an elevating wire 66, and a winch 70 in addition to the elevating device body 61.
The pulley 65 is attached to an upper part of the structure 10, more specifically, the upper end of the tower 11. The elevating wire 66 extends downward from the pulley 65 and is attached to the elevating platform 62 of the elevating device body 61. In addition, a portion of the elevating wire 66 on a side opposite to the elevating platform 62 is wound around the winch 70.
In the present embodiment, the winch 70 is provided at the upper part of the structure 10, for example, the upper end of the tower 11 where the heavy load 12 is disposed. The winch 70 can wind up or feed out the elevating wire 66. The winch 70 winds up and feeds out the elevating wire 66, thereby changing the length of the elevating wire 66 drawn from the pulley 65. As a result, the elevating platform 62 suspended by the elevating wire 66 can be raised and lowered.
Additionally, the elevating device body 61 further includes a support mechanism 17. A plurality of support mechanisms 17 are provided on the outer peripheral side of the tower 11 to be arranged at equal intervals in the circumferential direction. The support mechanism 17 includes a jack 67, a holding mechanism 68, and a support wheel 69.
The jack 67 is provided on an inner peripheral side of the elevating platform 62. Two jacks 67 are provided to face each other in the circumferential direction. Each of the jacks 67 extends from an inner peripheral surface of the elevating platform 62 toward the tower 11. The jack 67 is extendable and contractible in the radial direction of the tower 11. The holding mechanism 68 is provided at a radial inner end portion of the jack 67.
The holding mechanism 68 is provided on the inner peripheral side with respect to the jack 67. The holding mechanism 68 includes a first holding member 68a, a second holding member 68b, and a rotary shaft 68c. The first holding member 68a connects radial inner ends of a pair of corresponding jacks 67. Four second holding members 68b are provided on an inner peripheral surface of the first holding member 68a to be arranged in the circumferential direction. Each pair of the second holding members 68b at both ends in the circumferential direction is provided with the rotary shaft 68c. The rotary shaft 68c connects two second holding members 68b. The rotary shaft 68c is inserted through the support wheel 69.
The support wheel 69 can rotate around the rotary shaft 68c. An outer peripheral surface of the support wheel 69 is pressed against the outer peripheral surface of the tower 11 by the jack 67 on the outer peripheral side. By rotating the support wheel 69 around the rotary shaft 68c, the support wheel 69 can move in the up-down direction D1 along the outer peripheral surface of the tower 11.

(Procedure of Disassembling Method)

Subsequently, the disassembling method for the structure 10 using the lifting system 400 mentioned above will be described.
In the present embodiment, the disassembling of the structure 10 is performed in the same procedure as in the third embodiment. However, as shown in Fig. 24, the disassembling method of the present embodiment further includes an elevating device installation step S10.
The elevating device installation step S10 is performed at the beginning of the disassembly procedure. In the elevating device installation step S10, the elevating device 408 is attached to the structure 10. Specifically, as shown in Fig. 21, the pulley 65 and the winch 70 are attached to the upper end of the tower 11, and the elevating device body 61 is suspended by the elevating wire 66.
After the elevating device installation step S10, the weight movement step S9 is performed.
The heavy load movement step S9 of the present embodiment proceeds in the same procedure as in the third embodiment.
In the present embodiment, in the lowering step S93 of the heavy load movement step S9, as shown in Fig. 21, the winch 70 feeds out the elevating wire 66, thereby lowering the elevating platform 62. As a result, the heavy load 12 clamped by the clamp portions 64 is lowered.
After that, the fixing step S1 is performed, and the lifting auxiliary device 203 is attached to the structure 10. After the fixing step S1, the buoyancy adjustment step S8, the weight movement step S2, the suspension part movement step S3, the suspension step S4, the cutting step S5, the posture change step S6, and the disassembly step S7 are performed in this order in the same manner as in the third embodiment.
In the present embodiment, in the posture change step S6, as shown in Fig. 25, the structure 10 is suspended by the crane 20 to extend in the horizontal direction and is placed on the barge 1a.
After the posture change step S6, the disassembly step S7 is performed.
In the disassembly step S7, the disassembling is performed on the barge 1a in the same manner as in the embodiments mentioned above.
The disassembling method of the present embodiment is completed through the above procedure.
The lifting system 400 can also be used for the installation of the structure 10, in the same manner as in the case of the first embodiment.
As shown in Fig. 26, the installation method for the structure 10 of the present embodiment includes the fixing step S1, the weight movement step S2, the suspension part movement step S3, the suspension step S4, the posture change step S6, the buoyancy adjustment step S8, the installation step S11, the elevating device installation step S10, and the heavy load movement step S9. For example, the installation method for the structure 10 proceeds in the order of the fixing step S1, the weight movement step S2, the suspension part movement step S3, the suspension step S4, the posture change step S6, the buoyancy adjustment step S8, the installation step S11, the elevating device installation step S10, and the heavy load movement step S9. The installation of the structure 10 is completed through the above procedure.

(Actions and Effects)

According to the present embodiment, the following actions and effects can be obtained.
In the present embodiment, the elevating device 408 is provided separately from the lifting auxiliary device 203.
As a result, the elevating device 408 and the lifting auxiliary device 203 can be separately attached to the structure 10, thereby making the installation of the elevating device 408 and the lifting auxiliary device 203 easier.
In the present embodiment, the elevating device 408 further includes the pulley 65, the elevating wire 66 that extends downward from the pulley 65 to suspend the elevating platform 62, and the winch 70 that winds up or feeds out the elevating wire 66.
As a result, the elevating device 408 can be configured simply, thereby eliminating the need for a large-scale device to raise and lower the elevating platform 62.
In the present embodiment, a case where the pulley 65 is provided in addition to the winch 70 has been described, but the present disclosure is not limited thereto. As in the present embodiment, in a case where the winch 70 is provided at the upper part of the structure 10, for example, the upper end of the tower 11 where the heavy load 12 is disposed, the pulley 65 need not be provided.
In the present embodiment, the winch 70 is provided at the upper part of the structure 10, for example, the upper end of the tower 11 where the heavy load 12 is disposed, but the present disclosure is not limited thereto. The winch 70 may be installed at a position of a water surface height on the structure 10 or on the barge 1a. In a case where the winch 70 is installed at a low position near the water surface, the pulley 65 on the upper part of the structure 10 is essential.
In addition, in the illustrated example, the path of the elevating wire 66 exists outside the structure 10, but the path of the elevating wire 66 may exist inside the structure 10.

Next, a modification example of the fourth embodiment will be described with reference to Figs. 27 to 32.
As shown in Figs. 27 to 29, a lifting system 400a of the present modification example includes a lifting device 402, a lifting auxiliary device 403, and the elevating device 408.
The lifting device 402 is a derrick 420 smaller than the crane 20. In the present modification example, by using the derrick 420, the disassembling and the installation of the structure 10 can be performed without using the crane 20. The floating structure 1 of the present embodiment is a dedicated barge 1b that can use the derrick 420. The barge 1b includes a recessed portion 1c provided at one end in a longitudinal direction (for example, at an end portion on a stern side), which is open on one side in the longitudinal direction to allow the structure 10 to enter. The recessed portion 1c penetrates the barge 1b in the up-down direction D1. In the recessed portion 1c, cushioning materials 1d are provided such that the structure 10, which has entered the recessed portion 1c, is interposed therebetween on both horizontal sides (both radial sides), in order to reduce the impact when the structure 10 comes into contact with the barge 1b.

(Derrick)

The derrick 420 includes a derrick body 421, a support bar 422, a connecting portion 423, and a wire rope 424.
A pair of derrick bodies 421 are disposed on the deck of the barge 1b to face each other in the horizontal direction. When the derrick 420 is used, the pair of derrick bodies 421 are disposed inside the recessed portion 1c with the tower 11 interposed therebetween. The derrick body 421 is formed by combining, for example, a plurality of steel frames. The support bar 422 is provided at an upper end of the derrick body 421. Two wire ropes 424 are provided on the support bar 422 via the connecting portions 423. A tip of each of the wire ropes 424 is connected to the suspension part 6 of the lifting auxiliary device 403.
In the present modification example, the lifting auxiliary device 403 is disposed at a lower part of the tower 11. The lifting auxiliary device 403 is interposed between the derrick bodies 421. In the illustrated example, the suspension part 6 of the lifting auxiliary device 403 is provided at each vertex of a virtual rectangle as viewed in the up-down direction D1, that is, a total of four suspension parts 6, is provided. Each of the suspension parts 6 is suspended by the wire rope 424.
Additionally, on the same side as an opening direction of the recessed portion 1c of the lifting auxiliary device 403, a door structure that can be opened and closed is provided. Specifically, a part of the recessed portion 1c of the base 5 on a side in an opening direction is a door portion 5a that can be opened and closed to the same side as the opening direction of the recessed portion 1c, and a part of the outer shell frame 31 is a door portion 31a. In Fig. 28, the general shapes of the mounting portion 30 and the base 5 are simplified and schematically shown, and the guide portion 4a and the like are omitted.
By bringing each of the door portions 5a and 31a into an open state as shown by a virtual line in Fig. 28, the lifting auxiliary device 403 is easily movable in the horizontal direction. When the lifting auxiliary device 403 is attached to the structure 10, each of the door portions 5a and 31a is brought into a closed state as shown by a solid line in Fig. 28.

(Procedure of Disassembling Method)

Subsequently, the disassembling method for the structure 10 using the lifting system 400a mentioned above will be described.
In the present modification example, the disassembling of the structure 10 is performed in the same procedure as in the fourth embodiment as shown in Fig. 24. However, the posture of the structure 10 is changed using the derrick 420 instead of the crane 20, which is different from the fourth embodiment mentioned above.
In the present modification example, first, the elevating device installation step S10 is performed, and then the heavy load movement step S9 is performed.
In the heavy load movement step S9, as shown in Fig. 30, the derrick 420 is separated from the tower 11.
After the heavy load movement step S9, the lifting auxiliary device 403 is attached to the derrick 420, and the derrick 420 and the lifting auxiliary device 403 are moved such that the tower 11 is interposed between the pair of derrick bodies 421.
After that, the fixing step S1, the buoyancy adjustment step S8, the weight movement step S2, the suspension part movement step S3, the suspension step S4, and the cutting step S5 are performed in this order in the same procedure as in the fourth embodiment.
After the cutting step S5, the posture change step S6 is performed. In the posture change step S6, for example, a posture change wire 425 or the like is attached to the upper end of the structure 10 suspended by the derrick 420 as shown in Fig. 31. By winding up the posture change wire 425 with the posture change winch 426 installed on the barge 1b, the upper end of the structure 10 is pulled in the horizontal direction. Consequently, the structure 10 gradually tilts to rotate around the derrick 420. Finally, as shown in Fig. 32, the posture of the structure 10 is changed to a posture extending in the horizontal direction, and the structure 10 is loaded onto the barge 1b. In the subsequent disassembly step S7, the structure 10 is disassembled on the barge 1b.
The disassembling method for the present modification example is completed through the above procedure.
The lifting system 400a can also be used for the installation of the structure 10. The installation method for the structure 10 of the present modification example proceeds in the same procedure (see Fig. 26) as in the fourth embodiment mentioned above. However, as in the disassembling method, the installation method of the present modification example is different from the fourth embodiment mentioned above in that the posture of the structure 10 is changed using the derrick 420 instead of the crane 20.

(Actions and Effects)

According to the present modification example, the following actions and effects can be obtained.
In the present modification example, the structure 10 can be lifted using the derrick 420, the posture change winch 426, and the posture change wire 425 without using the crane 20. Therefore, the structure 10 can be disassembled using the simpler lifting device 402, thereby reducing costs associated with the disassembling while improving work efficiency.
In addition, in the present modification example, the derrick 420 is used to suspend the lower position of the offshore structure 10b, which is close to the seawater surface.
As a result, relative displacement between the barge 1b and the structure 10 caused by wave motion can be absorbed.

(Other Embodiments)

The embodiments of the present disclosure have been described in detail hereinabove with reference to the drawings, but specific configurations are not limited to the embodiments, and design changes and the like within a scope that does not deviate from the gist of the present disclosure are also included.
In the above-described embodiments, a case where the structure 10 is, for example, the offshore structure 10b and is, more specifically, the wind turbine provided offshore has been described, but the present disclosure is not limited thereto. The structure 10 may be a structure built in a lake or a pond, rather than the ocean. The structure 10 may be a land-based structure and is not necessarily limited to a wind turbine. The structure 10 may be, for example, an offshore steel tower (for example, a steel tower functioning as a pier shown in Fig. 33), a chimney, an offshore environmental observation tower, a marine resource investigation base, a lighthouse, an antenna base station, or a pier. In the example of Fig. 33, although the case of the first embodiment is shown, the structure 10 is also applicable to a structure 10 other than the offshore wind turbine in other embodiments.
In the above-described embodiments, the tower body 13 is formed, for example, by connecting a plurality of tower elements arranged in the up-down direction D1, but the present disclosure is not limited thereto. The tower body 13 may be, for example, a single tubular body made of concrete. In this case, in the disassembly step S7, the tower body 13 is disassembled by crushing the tower body 13.

The lifting auxiliary devices 3, 203, and 403, the lifting systems 100, 200, 300, and 400, and the disassembling methods described in the embodiments are understood as follows, for example.

(1) The lifting auxiliary device 3, 203, 403 according to a first aspect includes: the fixing part 4 that is fixed to the elongated structure 10 extending in the up-down direction D1; the suspension part 6 that is connected to the fixing part 4 and that is capable of being suspended by the lifting device 2, 402; and the weight 7 that is connected to the fixing part 4 and that is movable in the up-down direction D1 relative to the fixing part 4.

According to the present aspect, by moving the weight 7 downward, the center of gravity M of the structure 10 having a high center of gravity M can be moved downward. After that, the structure 10 can be lifted by suspending the suspension part 6 using the lifting device 2, 402. Consequently, the lifting and posture change of the structure 10 can be stably performed.
Examples of the structure 10 include, for example, a wind turbine, a chimney, and the like.
Examples of the lifting device 2, 402 include, for example, the crane 20, the derrick 420, and the like.
(2) The lifting auxiliary device 3, 203, 403 of a second aspect is the lifting auxiliary device 3, 203, 403 of (1), in which the suspension part 6 may be movable in the up-down direction D1 relative to the fixing part 4.
Consequently, the suspension part 6 can be positioned at a position higher than the center of gravity M of the structure 10. In this manner, the relative position between the position of the center of gravity M of the structure 10 and the position of the hoist point can be freely set. Therefore, the stability of the structure 10 during the lifting is further improved.
(3) The lifting auxiliary device 203, 403 of a third aspect is the lifting auxiliary device 203, 403 of (1) or (2), in which the buoyancy device 16 that is connected to the fixing part 4, that is movable in the up-down direction D1 relative to the fixing part 4, and that generates buoyancy with respect to the structure 10 may be further provided.
Examples of the buoyancy device 16 include the ballast tank 16a, a flotation bag, and the like.
For example, in a case where the structure 10 is the waterborne structure 10a, by adjusting the position of the buoyancy device in the up-down direction D1, the buoyancy device 16 is disposed underwater, thereby allowing the buoyancy device 16 to generate buoyancy. This makes it possible to reduce the load on the lifting device 2, 402 when the lifting device 2, 402 lifts the structure 10.
(4) The lifting auxiliary device 3, 203, 403 of a fourth aspect is the lifting auxiliary device 3, 203, 403 of any one of (1) to (3), in which the fixing part 4 may include the guide portion 4a that extends in the up-down direction D1 and that guides the suspension part 6 and the weight 7 in the up-down direction D1, and the mounting portion 30 that supports the guide portion 4a and that is attached to the structure 10.
According to the present aspect, after the fixing part 4 is disposed at any height with respect to the structure 10, the mounting portion 30 is attached to the structure 10. As a result, the fixing part 4 can be installed at any height.

(5) The lifting system 100, 200, 300, 400, 400a of a fifth aspect includes the lifting auxiliary device 3, 203, 403 according to any one of (1) to (4), and the lifting device 2, 402.
(6) The lifting system 300, 400, 400a of a sixth aspect is the lifting system 300, 400, 400a of (5), in which the structure 10 may include the heavy load 12 at the upper part, and the elevating device 8, 408 including the elevating platform 62 that is movable in the up-down direction D1 relative to the fixing part 4, and the clamp portion 64 that is attached to the elevating platform 62 and capable of changing the posture with respect to the elevating platform 62, and that is capable of clamping the heavy load 12 may be further provided.

According to the present aspect, the elevating device 8, 408 can move the heavy load 12 downward in advance, thereby lowering the center of gravity M of the structure 10.
In a case where the structure 10 is, for example, a wind turbine, examples of the heavy load 12 include a nacelle in which a shaft of the wind turbine is incorporated and the like.
(7) The lifting system 100, 200, 300, 400, 400a of a seventh aspect is the lifting system 100, 200, 300, 400, 400a of (5) or (6), in which the structure 10 may be the waterborne structure 10a, and the floating structure 1 that moves on the water surface, that supports the lifting device 2, 402 from below, and that is capable of loading the structure 10 may be further provided.
According to the present aspect, in a case where the structure 10 is the waterborne structure 10a, by moving the floating structure 1, the lifting device 2, 402 can be disposed at an appropriate position with respect to the structure 10.
Examples of the floating structure 1 include, for example, the barge 1a, 1b and the like.
(8) The disassembling method of an eighth aspect is the disassembling method for the structure 10 using the above-described lifting auxiliary device 3, 203, 403 of (1), the method including: the weight movement step S2 of moving the weight 7 downward; the suspension step S4 of suspending the suspension part 6 with the lifting device 2, 402 after the weight movement step S2; the posture change step S6 of changing the posture of the structure 10 by tilting the structure 10 with the lifting device 2, 402 after the suspension step S4; and the disassembly step S7 of disassembling the structure 10 after the posture change step S6.
According to the present aspect, by moving the weight 7 downward, the center of gravity M of the structure 10 can be moved downward. Consequently, the center of gravity M of the structure 10 can be moved below the suspension part 6, and then the suspension part 6 can be suspended by the lifting device 2, 402, thereby lifting the structure 10. As a result, during the disassembling of the structure 10, the lifting and posture change of the structure 10 can be stably performed.
(9) The disassembling method of a ninth aspect is the disassembling method of (8), in which the suspension part 6 may be movable in the up-down direction D1 relative to the fixing part 4, and the suspension part movement step S3 of moving the suspension part 6 to a position higher than the center of gravity M of the structure 10 before the suspension step S4 may be further provided.
According to the present aspect, after the suspension part 6 is moved to a position higher than the center of gravity M of the structure 10, the suspension part 6 can be suspended by the lifting device 2, 402, thereby lifting the structure 10. Accordingly, the lifting of the structure 10 can be more stably performed.
(10) The disassembling method of a tenth aspect is the disassembling method of (8) or (9), in which the lifting auxiliary device 203, 403 may further include the buoyancy device 16 that is connected to the fixing part 4, that is movable in the up-down direction D1 relative to the fixing part 4, and that generates buoyancy with respect to the structure 10, and the buoyancy adjustment step S8 of adjusting buoyancy of the buoyancy device before the suspension step S4 may be further provided.
For example, when the structure 10 is the waterborne structure 10a, by adjusting the buoyancy of the buoyancy device 16, the posture of the structure 10 can be adjusted.
(11) The disassembling method of an eleventh aspect is the disassembling method of any one of (8) to (10), in which the fixing part 4 may include the guide portion 4a that extends in the up-down direction D1 and that guides the suspension part 6 and the weight 7 in the up-down direction D1, and the mounting portion 30 that supports the guide portion 4a and that is attached to the structure 10, and the fixing step S1 of fixing the fixing part 4 to the structure 10 with the mounting portion 30 before the weight movement step S2 may be further provided.
According to the present aspect, after the fixing part 4 is disposed at any height with respect to the structure 10, the mounting portion 30 is attached to the structure 10. As a result, the fixing part 4 can be installed at any height.
(12) The disassembling method of a twelfth aspect is the disassembling method of any one of (8) to (11), in which the structure 10 may include the heavy load 12 at the upper part, the elevating device 8, 408 including the elevating platform 62 that is movable in the up-down direction D1 relative to the fixing part 4, and the clamp portion 64 that is attached to the elevating platform 62 and capable of changing the posture with respect to the elevating platform 62, and that is capable of clamping the heavy load 12 may be further used, the heavy load movement step S9 of moving the heavy load 12 downward before the suspension step S4 may be further provided, and the heavy load movement step S9 may include the clamp step S91 of clamping the heavy load 12 with the clamp portion 64, using the elevating device 8, 408, the heavy load posture change step S92 of changing the posture of the heavy load 12 with the clamp portion 64 after the clamp step S91, using the elevating device 8, 408, and the lowering step S93 of lowering the heavy load 12 after the heavy load posture change step S92, using the elevating device 8, 408.
According to the present aspect, when the structure 10 is disassembled, the elevating device 8, 408 can move the heavy load 12 downward in advance before the posture of the structure 10 is changed, thereby lowering the center of gravity M of the structure 10.
(13) The installation method of a thirteenth aspect is the installation method for the structure 10 using the lifting auxiliary device 3, 203, 403 of (1), the method including: the weight movement step S2 of moving the weight 7 to the leg part 14 side of the structure 10 in the extension direction of the structure 10; the suspension step S4 of suspending the suspension part 6 with the lifting device 2, 402 after the weight movement step S2; the posture change step S6 of changing the posture of the structure 10 with the lifting device to extend in the up-down direction D1 after the suspension step S4; and the installation step S11 of installing the structure 10 while maintaining the posture extending in the up-down direction D1 after the posture change step S6.
According to the present aspect, by moving the weight 7 to the leg part 14 side, the center of gravity M of the structure 10 can be moved to the leg part 14 side. Consequently, the center of gravity M of the structure 10 can be moved to the leg part 14 side with respect to the suspension part 6, and then the suspension part 6 can be suspended by the lifting device 2, 402, thereby lifting the structure 10. As a result, during the installation of the structure 10, the lifting and posture change of the structure 10 can be stably performed.

Industrial Applicability

With the lifting auxiliary device, the lifting system, the disassembling method, and the installation method of the present disclosure, it is possible to improve stability.

Reference Signs List

1: floating structure
1a: barge
1b: barge
1c: recessed portion
1d: cushioning material
2: lifting device
3: lifting auxiliary device
4: fixing part
4a: guide portion
5: base
5a: door portion
6: suspension part
7: weight
7a: counterweight
8: elevating device
10: structure
10a: waterborne structure
10b: offshore structure
11: tower
12: heavy load
13: tower body
14: leg part
15: cutting position
16: buoyancy device
16a: ballast tank
17: support mechanism
20: crane
21: vehicle part
22: move
23: wire rope
24: lifting gear
30: mounting portion
31: outer shell frame
31a: door portion
32: reinforcing arm
33: bulkhead
40: fixing mechanism
40a: fixing mechanism
40b: fixing mechanism
41: inner plate
42: claw
43: pressing mechanism
44: mounting surface
45: hydraulic mechanism
46: fixing piece
46a: hole
47: feeding device
48: fixing shaft
48a: hole
50: rotational movement mechanism
51: first support member
52: support shaft
52a: pivot point
53: second support member
53a: bent portion
54: insertion hole
60: jack system
61: elevating device body
62: elevating platform
63: rotational movement portion
64: clamp portion
65: pulley
66: elevating wire
67: jack
68: holding mechanism
68a: first holding member
68b: second holding member
68c: rotary shaft
69: support wheel
70: winch
100: lifting system
200: lifting system
203: lifting auxiliary device
300: lifting system
400: lifting system
400a: lifting system
402: lifting device
403: lifting auxiliary device
408: elevating device
420: derrick
421: derrick body
422: support bar
423: connecting portion
424: wire rope
425: posture change wire
426: posture change winch
D1: up-down direction
M: center of gravity
O: axis
P11: initial position
P12: second position
P13: third position
P21: initial position
P22: second position
P31: initial position
P32: second position
P41: initial position
P42: second position
P43: third position
S1: fixing step
S2: weight movement step
S3: suspension part movement step
S4: suspension step
S5: cutting step
S6: posture change step
S7: disassembly step
S8: buoyancy adjustment step
S9: heavy load movement step
S10: elevating device installation step
S11: installation step
S91: clamp step
S92: heavy load posture change step
S93: lowering step
S94: heavy load disassembly step
S95: raising step
S96: heavy load installation step

Claims

A lifting auxiliary device comprising:
a fixing part that is fixed to an elongated structure extending in an up-down direction;

a suspension part that is connected to the fixing part and that is capable of being suspended by a lifting device; and

a weight that is connected to the fixing part and that is movable in the up-down direction relative to the fixing part.
The lifting auxiliary device according to Claim 1,
wherein the suspension part is movable in the up-down direction relative to the fixing part.
The lifting auxiliary device according to Claim 1 or 2, further comprising:
a buoyancy device that is connected to the fixing part, that is movable in the up-down direction relative to the fixing part, and that generates buoyancy with respect to the structure.
The lifting auxiliary device according to Claim 1 or 2,
wherein the fixing part includes
a guide portion that extends in the up-down direction and that guides the suspension part and the weight in the up-down direction, and

a mounting portion that supports the guide portion and that is attached to the structure.
A lifting system comprising:
the lifting auxiliary device according to Claim 1; and

the lifting device.
The lifting system according to Claim 5,
wherein the structure includes a heavy load at an upper part, and

the lifting system further comprises an elevating device including an elevating platform that is movable in the up-down direction relative to the fixing part, and a clamp portion that is attached to the elevating platform and capable of changing a posture with respect to the elevating platform, and that is capable of clamping the heavy load.
The lifting system according to Claim 5 or 6, further comprising:
a floating structure that moves on a water surface, that supports the lifting device from below, and that is capable of loading the structure.
A disassembling method for the structure using the lifting auxiliary device according to Claim 1, the method comprising:
a weight movement step of moving the weight downward;

a suspension step of suspending the suspension part with the lifting device after the weight movement step;

a posture change step of changing a posture of the structure by tilting the structure with the lifting device after the suspension step; and

a disassembly step of disassembling the structure after the posture change step.
The disassembling method according to Claim 8,
wherein the suspension part is movable in the up-down direction relative to the fixing part, and

the disassembling method further comprises a suspension part movement step of moving the suspension part to a position higher than a center of gravity of the structure before the suspension step.
The disassembling method according to Claim 8 or 9,
wherein the lifting auxiliary device further includes a buoyancy device that is connected to the fixing part, that is movable in the up-down direction relative to the fixing part, and that generates buoyancy with respect to the structure, and

the disassembling method further comprises a buoyancy adjustment step of adjusting buoyancy of the buoyancy device before the suspension step.
The disassembling method according to Claim 8 or 9,
wherein the fixing part includes
a guide portion that extends in the up-down direction and that guides the suspension part and the weight in the up-down direction, and

a mounting portion that supports the guide portion and that is attached to the structure, and

the disassembling method further comprises a fixing step of fixing the fixing part to the structure with the mounting portion before the weight movement step.
The disassembling method according to Claim 8 or 9,
wherein the structure includes a heavy load at an upper part,

an elevating device including an elevating platform that is movable in the up-down direction relative to the fixing part, and a clamp portion that is attached to the elevating platform and capable of changing a posture with respect to the elevating platform, and that is capable of clamping the heavy load is further used,

the disassembling method further comprises a heavy load movement step of moving the heavy load downward before the suspension step, and

the heavy load movement step includes
a clamp step of clamping the heavy load with the clamp portion, using the elevating device,

a heavy load posture change step of changing a posture of the heavy load with the clamp portion after the clamp step, using the elevating device, and

a lowering step of lowering the heavy load after the heavy load posture change step, using the elevating device.
An installation method for the structure using the lifting auxiliary device according to Claim 1, the method comprising:
a weight movement step of moving the weight to a leg part side of the structure in an extension direction of the structure;

a suspension step of suspending the suspension part with the lifting device after the weight movement step;

a posture change step of changing a posture of the structure with the lifting device to extend in the up-down direction after the suspension step; and

an installation step of installing the structure while maintaining the posture extending in the up-down direction after the posture change step.