Jacket structure system, gangway spanning method, and transition piece system

Abstract

To improve work efficiency.SOLUTION: A jacket structure system includes a first jacket structure capable of supporting an offshore wind turbine, a second jacket structure capable of supporting an offshore wind turbine, and a gangway spanning the first jacket structure and the second jacket structure. The first jacket structure has a first external work floor. The second jacket structure has a second external work floor. The gangway spans between the first external work floor and the second external work floor so that a worker can move between the first external work floor and the second external work floor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a jacket structure system, a gangway installation method, and a transition piece system. [Background technology]

[0002] Patent Document 1 discloses a jig for assembling a support device having a jacket-type foundation structure used in offshore wind power generation facilities. Patent Document 2 discloses a transition piece provided in a jacket structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-46721 [Patent Document 2] Patent No. 7253657 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a jacket structure system, a gangway installation method, and a transition piece system that are useful for improving work efficiency. [Means for solving the problem]

[0005] [1] A jacket structure system comprising: a first jacket structure capable of supporting an offshore wind turbine; a second jacket structure capable of supporting an offshore wind turbine; and a gangway spanning the first jacket structure and the second jacket structure, wherein the first jacket structure has a first external work floor and the second jacket structure has a second external work floor, and the gangway spans between the first external work floor and the second external work floor so that workers can move between the first external work floor and the second external work floor.

[0006] [2] The jacket structure system described in [1] above, wherein the first external work floor includes a first fence that is removable or openable, the second external work floor includes a second fence that is removable or openable, one end of the gangway is connected to a first space created when the first fence is removed or opened from the first external work floor, and the other end of the gangway is connected to a second space created when the second fence is removed or opened from the second external work floor.

[0007] [3] A jacket structure system as described in [2] above, wherein the first fence and the second fence face each other in a plan view.

[0008] [4] A jacket structure system as described in [2] or [3] above, wherein the one end is fixed to a part of the first jacket structure corresponding to the first space by a first connecting member, and the other end is fixed to a part of the second jacket structure corresponding to the second space by a second connecting member.

[0009] [5] A jacket structure system described in any one of [1] to [4] above, wherein the first jacket structure further has a first center pipe, the second jacket structure further has a second center pipe, and the gangway is arranged on one side of a plane including a tube axis of the first center pipe and a tube axis of the second center pipe.

[0010] [6] A jacket structure system described in any one of [1] to [4] above, wherein the first jacket structure further has a first center pipe, the second jacket structure further has a second center pipe, one end of the gangway is arranged on one side of a plane including a tube axis of the first center pipe and a tube axis of the second center pipe, and the other end of the gangway is arranged on the other side of the plane.

[0011] [7] A jacket structure system as described in [5] above, wherein the length between the first center pipe and the end of the first external work floor on one side is longer than the length between the first center pipe and the end of the first external work floor on the other side of the plane, and the length between the second center pipe and the end of the second external work floor on one side is longer than the length between the second center pipe and the end of the second external work floor on the other side.

[0012] [8] A jacket structure system described in any one of [1] to [4] above, wherein the first jacket structure further has a first center pipe, the second jacket structure further has a second center pipe, the first external work floor has a hole or notch through which the first center pipe is inserted, and the second external work floor has a hole or notch through which the second center pipe is inserted.

[0013] [9] A jacket structure system described in any one of [1] to [8] above, wherein the first external work floor is permanently installed in the first jacket structure, and the second external work floor is permanently installed in the second jacket structure.

[0014]

[10] A jacket structure system comprising: a first jacket structure capable of supporting an offshore wind turbine; a second jacket structure capable of supporting an offshore wind turbine; a first gangway, a second gangway, and a work tower, wherein the first jacket structure has a first external work floor, the second jacket structure has a second external work floor, the first gangway is spanned between the first external work floor and the work tower so as to enable workers to move between the first external work floor and the work tower, and the second gangway is spanned between the second external work floor and the work tower so as to enable workers to move between the second external work floor and the work tower.

[0015]

[11] A wind farm or sea area comprising a plurality of jacket structures each capable of supporting an offshore wind turbine, a first gangway, and a second gangway, the plurality of jacket structures including two or more jacket structures belonging to a first group and two or more jacket structures belonging to a second group, each of the two or more jacket structures belonging to the first group having a first external working floor, each of the two or more jacket structures belonging to the second group having a second external working floor, and a height of the first external working floor from the ground between the two or more jacket structures belonging to the first group. A jacket structure system in which a first height is common, and a second height, which is the height of the second external work floor from the ground, is common between two or more jacket structures belonging to the second group, and the first height and the second height are different, and the first gangway is spanned between the first external work floors of each of the two or more jacket structures belonging to the first group so that workers can move between the first external work floors, and the second gangway is spanned between the second external work floors of each of the two or more jacket structures belonging to the second group so that workers can move between the second external work floors.

[0016]

[12] A gangway installation method for a jacket structure system comprising a first jacket structure capable of supporting an offshore wind turbine, a second jacket structure capable of supporting an offshore wind turbine, and a gangway, the gangway installation method including: a first assembly step of placing a first external work floor above a first lower jacket structure and assembling the first jacket structure; a second assembly step of placing a second external work floor above a second lower jacket structure and assembling the second jacket structure; and an installation step of installing the gangway between the first external work floor and the second external work floor so that a worker can move between the first external work floor and the second external work floor in accordance with the first assembly step and the second assembly step.

[0017]

[13] The gangway installation method described in

[12] above, wherein the first assembly step includes a first pipe insertion step of inserting a first center pipe of the first jacket structure into a hole or notch provided in the first external work floor, and the second assembly step includes a second pipe insertion step of inserting a second center pipe of the second jacket structure into a hole or notch provided in the second external work floor.

[0018]

[14] The gangway installation method described in

[12] or

[13] above, further comprising a first transition piece placement process of placing a first transition piece on the first lower jacket structure and a second transition piece placement process of placing a second transition piece on the second lower jacket structure, wherein the first assembly step is performed after the first transition piece placement process and the second assembly step is performed after the second transition piece placement process.

[0019]

[15] A transition piece system comprising: a first transition piece capable of supporting an offshore wind turbine and provided on a first offshore structure; a second transition piece capable of supporting an offshore wind turbine and provided on a second offshore structure; a first external work floor provided on the first transition piece; a second external work floor provided on the second transition piece; and a gangway spanning between the first external work floor and the second external work floor so that workers can move between the first external work floor and the second external work floor.

[0020]

[16] The transition piece system described in

[15] above, wherein the first external work floor includes a first fence that is removable or openable, the second external work floor includes a second fence that is removable or openable, one end of the gangway is connected to a first space created when the first fence is removed or opened from the first external work floor, and the other end of the gangway is connected to a second space created when the second fence is removed or opened from the second external work floor.

[0021]

[17] A transition piece system as described in

[16] above, wherein the first fence and the second fence face each other in a plan view.

[0022]

[18] A transition piece system as described in

[16] or

[17] above, wherein the one end is fixed to a part of the first transition piece or the first external work floor corresponding to the first space by a first connecting member, and the other end is fixed to a part of the second transition piece or the second external work floor corresponding to the second space by a second connecting member.

[0023]

[19] A transition piece system comprising: a first transition piece capable of supporting an offshore wind turbine and provided on a first offshore structure, the first transition piece having a first external work floor installed thereon; a second transition piece capable of supporting an offshore wind turbine and provided on a second offshore structure, the second transition piece having a second external work floor installed thereon; and a gangway spanning the first transition piece and the second transition piece so that workers can move between the first transition piece on which the first external work floor is installed and the second transition piece on which the second external work floor is installed.

[0024]

[20] A transition piece system comprising: a first transition piece capable of supporting an offshore wind turbine and provided on a first offshore structure, the first transition piece having a first external work floor installed thereon; a second transition piece capable of supporting an offshore wind turbine and provided on a second offshore structure, the second transition piece having a second external work floor installed thereon; and a gangway spanning between the first transition piece and the second external work floor so that workers can move between the first transition piece on which the first external work floor is installed and the second external work floor. Effect of the Invention

[0025] According to the present disclosure, a jacket structure system, a gangway installation method, and a transition piece system are provided that are useful for improving work efficiency. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic diagram showing an example of a jacket structure system. [Diagram 2] FIG. 2 is a perspective view that illustrates an example of the jacket structure. [Diagram 3] Fig. 3(a) is a plan view and Fig. 3(b) are a side view and a schematic view of an example of an external work platform. [Figure 4] FIG. 4 is a plan view showing a schematic example of a state in which the gangway is suspended. [Diagram 5] FIG. 5 is a flow chart showing an example of a series of work steps for laying out a gangway. [Figure 6] 6(a) and 6(b) are schematic diagrams illustrating the working steps. [Figure 7] 7(a) and 7(b) are schematic diagrams illustrating the working steps. [Figure 8] FIG. 8 is a plan view showing a schematic example of a state in which the gangway is suspended. [Figure 9] FIG. 9 is a plan view showing a schematic example of a state in which the gangway is suspended. [Figure 10] FIG. 10 is a schematic diagram showing an example of a jacket structure system. [Figure 11] FIG. 11 is a schematic diagram showing an example of a jacket structure system. [Figure 12] FIG. 12 is a plan view showing a schematic example of a state in which the gangway is suspended. [Figure 13] FIG. 13 is a schematic diagram showing an example of a transition piece system. [Figure 14] FIG. 14 is a perspective view that diagrammatically illustrates an example of an offshore structure. [Figure 15] 15(a) and 15(b) are schematic diagrams showing an example of a transition piece system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, an embodiment will be described with reference to the drawings. In the description, the same elements or elements having the same functions are denoted by the same reference numerals, and duplicated description will be omitted.

[0028] [Jacket structure system] FIG. 1 shows a schematic diagram of a jacket structure system according to an embodiment. FIG. 2 shows a schematic diagram of an example of a jacket structure included in the jacket structure system. The jacket structure system 1 shown in FIG. 1 is a system composed of two or more jacket structures. The jacket structure system 1 is disposed, for example, in a work area on the ground called a yard. The jacket structure system 1 includes two or more jacket structures 10, a work tower 4, a gangway 5, and a gangway 6.

[0029] (Jacket structure) Each of the two or more jacket structures 10 is a jacket-type structure capable of supporting an offshore wind turbine 200 (see also FIG. 2). The jacket structure 10 has a jacket-type foundation structure. Each of the two or more jacket structures 10 is a structure that supports the offshore wind turbine 200 in an offshore wind power generation facility, or an intermediate product of that structure. The jacket structure system 1 may include two jacket structures 10 as the two or more jacket structures 10. Hereinafter, one of the two jacket structures 10 will be referred to as "jacket structure 10A" and the other will be referred to as "jacket structure 10B".

[0030] The jacket structure 10A and the jacket structure 10B are configured similarly to each other. The height of the upper end of the jacket structure 10A from the ground G (ground) may be approximately the same as the height of the upper end of the jacket structure 10B from the ground G (ground). The jacket structure 10A and the jacket structure 10B are disposed apart from each other. Each of the jacket structure 10A and the jacket structure 10B has, for example, a lower jacket structure 20, a transition piece 30, and an external work floor 40.

[0031] The lower jacket structure 20 is a structure that supports the transition piece 30 and the external working floor 40. Since the offshore wind turbine 200 is connected to the transition piece 30, the lower jacket structure 20 is a jacket-type structure that can support the offshore wind turbine 200. The lower jacket structure 20 has at least three legs 22. In Figs. 1 and 2, the lower jacket structure 20 having four legs 22 is illustrated, but some of the legs 22 are hidden by other members. Each of the four legs 22 is a support for supporting the offshore wind turbine 200, which is the member to be supported. Each leg 22 may be a steel pipe. The four legs 22 are erected on the ground G. The four legs 22 are arranged at equal intervals in the circumferential direction around the pipe axis Ax described later, and each of the four legs 22 is inclined so as to approach the pipe axis Ax as it goes upward.

[0032] A transition piece 30 is connected to the upper end of each of the four legs 22. In the jacket structure 10 located on the ground G, an installation member may be connected to the lower end of the legs 22, and each leg 22 may be erected on the ground G via the installation member. When the jacket structure 10 is installed on the seabed, a connecting member may be connected to the lower end of each of the four legs 22, and a pile may be connected via the connecting member.

[0033] The lower jacket structure 20 has one or more stages of braces 24. The one or more stages of braces 24 are members for reinforcing the lower jacket structure 20 (or the jacket structure 10). The one or more stages of braces 24 connect adjacent legs 22 in the circumferential direction around the pipe axis Ax. The braces 24 are, for example, X-shaped diagonal braces. The braces 24 may be steel pipes or steel columns. The lower jacket structure 20 may have two or more stages of braces 24 arranged in the vertical direction. Note that in FIG. 1 and other figures, the vertical direction is represented by "direction Z", and a case in which the lower jacket structure 20 has two stages of braces 24 is illustrated.

[0034] The transition piece 30 is a member on which the offshore wind turbine 200 is mounted when the jacket structure 10 is installed on the seabed. The transition piece 30 is connected to the upper end of the lower jacket structure 20. The transition piece 30 has a center pipe 32 and at least three connection parts 34.

[0035] In a plan view, the center pipe 32 is located at the center of the transition piece 30. When the jacket structure 10 is installed on the seabed, for example, the lower end of the tower portion of the offshore wind turbine 200 is connected to the center pipe 32. At least a portion of the center pipe 32 may be formed in a cylindrical shape. The transition piece 30 is provided in the lower jacket structure 20 so that the pipe axis Ax of the center pipe 32 is aligned in the up-down direction. The pipe axis Ax is an imaginary line (axis) that passes through the center of the center pipe 32 when the center pipe 32 is cut horizontally.

[0036] The transition piece 30 has the same number of connection parts 34 as the number of legs 22. The transition piece 30 has, for example, four connection parts 34. The four connection parts 34 may be arranged at equal intervals in the circumferential direction about the pipe axis Ax. The upper ends of the corresponding legs 22 are connected to each of the four connection parts 34. The connection parts 34 may be pipes having approximately the same inner diameter as the legs 22. The center pipe 32 and each of the four connection parts 34 may be connected by upper and lower flanges arranged vertically, as shown in, for example, Patent Document 2.

[0037] The external work floor 40 is a work floor (deck) for workers to perform various works at the upper end of the jacket structure 10. The external work floor 40 is, for example, permanently installed in the jacket structure 10. Unlike a temporary installation, the external work floor 40 is permanently installed, meaning that after the external work floor 40 is installed, the external work floor 40 is not removed until the jacket structure 10 is dismantled or the like. That is, the external work floor 40 is permanently installed in the jacket structure 10. In this case, even after the jacket structure 10 is installed on the seabed, the external work floor 40 remains on the jacket structure 10. In one example, after the offshore wind turbine 200 is installed on the sea via the jacket structure 10, the external work floor 40 is used for maintenance of the power generation equipment including the offshore wind turbine 200.

[0038] As shown in Fig. 2, the jacket structure 10 may include a work crane 56 and a boat landing section 58. The work crane 56 is provided on the external work floor 40. The work crane 56 is, for example, permanently installed on the external work floor 40. In one example, after the offshore wind turbine 200 is installed on the sea via the jacket structure 10, the work crane 56 hoists the cargo carried from the ship up to the external work floor 40. After the offshore wind turbine 200 is installed on the sea via the jacket structure 10, the boat landing section 58 forms a passage for workers who have traveled on the ship to move to the external work floor 40.

[0039] FIG. 3(a) is a plan view showing an example of the external work floor 40, and FIG. 3(b) is a side view showing an example of the external work floor 40. The external work floor 40 has a floor portion 42 and a fence 44. The floor portion 42 is a portion forming a floor on which workers can work. The upper surface of the floor portion 42 may be horizontal. The floor portion 42 may be made of FRP (Fiber Reinforced Plastics) or steel, and may be formed in a mesh shape with small holes that allow workers to walk on the upper surface. The above-mentioned work crane 56 is installed on the floor portion 42.

[0040] The fence 44 is provided on the peripheral portion of the upper surface of the floor portion 42 (e.g., the entire peripheral portion) and is a member for preventing a worker from falling from the floor portion 42. The peripheral portion means the peripheral portion of the upper surface of the floor portion 42 and the area nearby. The fence 44 has a fixed fence 44a and a movable fence 44b. The fixed fence 44a is a fence fixed to the peripheral portion of the upper surface of the floor portion 42, and the relative position of the fixed fence 44a with respect to the floor portion 42 does not change. The fixed fence 44a is provided on most of the peripheral portion, for example.

[0041] The movable fence 44b is a removable fence or a fence that can be opened and closed. By removing or opening the movable fence 44b, workers can move between the floor portion 42 and the outside of the floor portion 42 without crossing the fence 44. After the offshore wind turbine 200 is installed offshore via the jacket structure 10, the movable fence 44b may be maintained in a state where it is attached to the floor portion 42 or in a closed state. The movable fence 44b has a width that allows workers to pass through the space left by the fence 44 when it is removed, etc.

[0042] The external work floor 40 may be provided with a hole 46 into which the center pipe 32 of the transition piece 30 is inserted. The hole 46 passes through the floor portion 42 of the external work floor 40 in the up-down direction. Instead of the hole 46, the external work floor 40 may be provided with a notch into which the center pipe 32 is inserted.

[0043] With the center pipe 32 inserted into the hole 46 or the like of the external work floor 40, the external work floor 40 is connected to the transition piece 30. The external work floor 40 may include a member that is interposed between the floor portion 42 and the upper surface of the portion of the transition piece 30 around the center pipe 32 and supports the floor portion 42. With the center pipe 32 inserted into the hole 46 or the like of the external work floor 40, a part of the center pipe 32 protrudes above the floor portion 42 (see FIG. 1 or FIG. 2).

[0044] The work tower 4 shown in Fig. 1 is a tower that workers can ascend and descend. The work tower 4 is installed on the ground G at a position away from the jacket structure 10A and the jacket structure 10B. The work tower 4 is formed so that its entirety extends in the vertical direction, and the height of the upper end of the work tower 4 from the ground G may be higher than the height of the external work floors 40 of the jacket structure 10A and the jacket structure 10B from the ground G.

[0045] The gangway 5 is a member forming a passage for workers to move above the ground G. The gangway 5 may be formed so that the entire gangway 5 extends in one direction. The gangway 5 is spanned between the work tower 4 and one jacket structure 10 (for example, the jacket structure 10B). The gangway 5 is spanned between the work tower 4 and the external work floor 40 of the jacket structure 10B, for example, so that a worker can move between the work tower 4 and the external work floor 40 of the jacket structure 10B. Being able to move between one structure and another structure means that it is possible to move from one structure to the other structure and also possible to move from the other structure to the one structure.

[0046] One end of the gangway 5 may be connected to the work tower 4, and the other end of the gangway 5 may be connected to the external work floor 40 of the jacket structure 10B. One end of the gangway 5 may be fixed to any location of the work tower 4 via a connecting member. The other end of the gangway 5 may be fixed to any location of the external work floor 40 of the jacket structure 10B or any location around the external work floor 40 in the jacket structure 10B via a connecting member.

[0047] The gangway 6, like the gangway 5, is a member that forms a passage for workers to move above the ground G. The gangway 6 may be formed so that the entirety of the gangway 6 extends in one direction. The gangway 6 is spanned between the jacket structure 10A (first jacket structure) and the jacket structure 10B (second jacket structure). The gangway 6 is spanned between the external work floor 40 of the jacket structure 10A and the external work floor 40 of the jacket structure 10B so that workers can move between the external work floor 40 (first external work floor) of the jacket structure 10A and the external work floor 40 (second external work floor) of the jacket structure 10B.

[0048] The span between the external work floor 40 of the jacket structure 10A and the external work floor 40 of the jacket structure 10B is not limited to span between one external work floor 40 and the other external work floor 40. The span between a pair of external work floors 40 includes span between a location near one external work floor 40 and a location near the other external work floor 40, and span between one external work floor 40 and a location near the other external work floor 40. The location near where the gangway 6 is spanned is, for example, the upper flange of the transition piece 30. The location near where the gangway 6 is spanned may be a space in the upper flange of the transition piece 30 where the external work floor 40 is installed.

[0049] 4 is a plan view showing a schematic example of a state in which the gangway 6 is spanned between one external work floor 40 and the other external work floor 40. Here, the direction in which an imaginary line connecting the tube axis Ax of the center pipe 32 (first center pipe) of the jacket structure 10A and the tube axis Ax of the center pipe 32 (second center pipe) of the jacket structure 10B at the shortest distance extends is defined as "direction D1". The direction D1 is a horizontal direction. In addition, a horizontal direction perpendicular to the direction D1 and the up-down direction is defined as "direction D2". The jacket structure 10A and the jacket structure 10B are aligned along the direction D1.

[0050] In FIG. 4, the movable fences 44b of the fences 44 in the jacket structure 10A and the jacket structure 10B are removed or open. The external work floors 40 of the jacket structure 10A and the jacket structure 10B are installed so that the movable fences 44b before being removed or in a closed state face each other in a plan view. For example, in a plan view, the movable fence 44b (first fence) of the jacket structure 10A and the movable fence 44b (second fence) of the jacket structure 10B face each other in the direction D1. When the movable fences 44b face each other in the direction D1, at least a part of one movable fence 44b overlaps with at least a part of the other movable fence 44b in the direction D2.

[0051] One end 6a of the gangway 6 is connected to a space SA (first space) that is generated when the movable fence 44b is removed or opened from the external work floor 40 (floor portion 42) of the jacket structure 10A. The space SA is a part of the upper surface of the floor portion 42 of the jacket structure 10A, and is a space that surrounds the location of the movable fence 44b before it is removed or when it is closed.

[0052] The one end 6a may be fixed to a part of the jacket structure 10A that corresponds to the space SA by a connecting member 52 (first connecting member). The part that corresponds to the space SA includes at least the space SA itself and a portion of the jacket structure 10A that is located near the space SA. The connecting member 52 may be any member that can fix the one end 6a to the jacket structure 10A, and may include, for example, a connecting rope. The connecting member 52 may include a bulking member that is disposed below the one end 6a and is interposed between the connecting member 52 and the jacket structure 10A, and a connecting rope or the like included in the connecting member 52 may fix the one end 6a together with the bulking member.

[0053] The other end 6b of the gangway 6 is connected to a space SB (second space) that is generated when the movable fence 44b is removed or opened from the external work floor 40 (floor portion 42) of the jacket structure 10B. The space SB is a part of the upper surface of the floor portion 42 of the jacket structure 10B, and is a space that surrounds the location of the movable fence 44b before it is removed or when it is closed.

[0054] The other end 6b may be fixed to a part of the jacket structure 10B that corresponds to the space SB by a connecting member 52 (second connecting member). The part that corresponds to the space SB includes at least the space SB itself and a portion of the jacket structure 10B that is located in the vicinity of the space SB. The connecting member 52 for fixing the other end 6b to the jacket structure 10B may be the same type of member as the connecting member 52 for fixing the one end 6a to the jacket structure 10A.

[0055] The gangway 6 may be disposed on one side of a plane IP including the tube axis Ax of the center pipe 32 of the jacket structure 10A and the tube axis Ax of the center pipe 32 of the jacket structure 10B. The plane IP is a virtual plane extending in the direction Z, which is the vertical direction, and the direction D1. Here, one of the two regions partitioned by the plane IP as a boundary is defined as "region R1", and the other is defined as "region R2". The boundary (boundary surface) between the region R1 and the region R2 is the plane IP. The region R1 is on one side of the plane IP, and the region R2 is on the other side of the plane IP. When the gangway 6 is disposed on one side of the plane IP, the entire gangway 6 is located in the region R1, and no part of the gangway 6 is located in the region R2.

[0056] In a plan view, the shape of the external work floor 40 of each of the jacket structures 10A and 10B may be asymmetric with respect to a plane IP (a straight line connecting the pipe axes Ax). The lengths LA1, LA2, LB1, and LB2 of the external work floor 40 when provided on the transition piece 30 are defined as follows. Length LA1: the length between the center pipe 32 of the jacket structure 10A and the end portion on the one side of the external working floor 40 of the jacket structure 10A Length LA2: the length between the center pipe 32 of the jacket structure 10A and the end portion on the other side of the external working floor 40 of the jacket structure 10A Length LB1: the length between the center pipe 32 of the jacket structure 10B and the end portion on the one side of the external working floor 40 of the jacket structure 10B Length LB2: the length between the center pipe 32 of the jacket structure 10B and the end portion on the other side of the external working floor 40 of the jacket structure 10B

[0057] In each of the jacket structures 10A and 10B, the end portion on the one side of the external work floor 40 is located in region R1 of the external work floor 40, and is the end portion that is the furthest from the center pipe 32 (pipe axis Ax) in distance in direction D2. In each of the jacket structures 10A and 10B, the end portion on the other side of the plane IP of the external work floor 40 is located in region R2 of the external work floor 40, and is the end portion that is the furthest from the center pipe 32 (pipe axis Ax) in distance in direction D2. The length between the center pipe 32 and the end portion on the one side or the other side of the external work floor 40 is defined as the shortest distance between them in direction D2.

[0058] When focusing on the external work floor 40 of the jacket structure 10A, the length LA1 may be longer than the length LA2. When focusing on the external work floor 40 of the jacket structure 10B, the length LB1 may be longer than the length LB2. For each of the jacket structure 10A and the jacket structure 10B, the area of ​​the portion of the external work floor 40 located in region R1 may be larger than the area of ​​the portion of the external work floor 40 located in region R2 in a plan view.

[0059] [Gangway transfer method] Next, as an example of a gangway handover method, a series of work steps executed in the jacket structure system 1 will be described. This series of work steps includes at least a first assembly step, a second assembly step, and a handover step.

[0060] The first assembly step is a step of assembling the jacket structure 10A by placing the external work floor 40 above the lower jacket structure 20 (first lower jacket structure). The first assembly step may include a first pipe insertion step of inserting the center pipe 32 of the jacket structure 10A into a hole 46 or a notch provided in the external work floor 40. The above series of work steps may further include a first transition piece arrangement step of placing the transition piece 30 in the lower jacket structure 20 constituting the jacket structure 10A. The first assembly step may be performed after the first transition piece arrangement step. In this case, the first pipe insertion step is performed in a state in which the transition piece 30 is arranged in the lower jacket structure 20.

[0061] The second assembly step is a step of assembling the jacket structure 10B by placing the external work floor 40 above the lower jacket structure 20 (second lower jacket structure). The second assembly step may include a second pipe insertion step of inserting the center pipe 32 of the jacket structure 10B into a hole 46 or a notch provided in the external work floor 40. The above series of work steps may further include a second transition piece arrangement step of placing the transition piece 30 in the lower jacket structure 20 constituting the jacket structure 10B. The second assembly step may be performed after the second transition piece arrangement step. In this case, the second pipe insertion step is performed in a state in which the transition piece 30 is arranged in the lower jacket structure 20.

[0062] The connecting step is a step of connecting the gangway 6 between the external work floor 40 of the jacket structure 10A and the external work floor 40 of the jacket structure 10B in accordance with the first assembly step and the second assembly step. In the connecting step, for example, the gangway 6 is connected between the external work floor 40 of the jacket structure 10A and the external work floor 40 of the jacket structure 10B. The above series of work steps may further include a step of connecting the gangway 5 between the work tower 4 and either one of the assembled jacket structure 10A and the assembled jacket structure 10B.

[0063] Fig. 5 is a flow chart showing a specific example of a series of work steps executed in the jacket structure system 1. The series of work steps shown in Fig. 5 is started in a state where the work tower 4 has been installed in advance in the yard.

[0064] First, step S11 is performed. In step S11, for example, a worker assembles the lower jacket structure 20 that constitutes the jacket structure 10A. FIG. 6(a) illustrates the lower jacket structure 20 in an assembled state. In one example, a worker assembles the lower jacket structure 20 using the assembly jig described in the above-mentioned Patent Document 1. After step S11 is performed, the upper end of the brace 24 located at the uppermost level and the leg 22 may not be joined together.

[0065] Next, step S12 is performed. In step S12, for example, a worker places the transition piece 30 on the upper end of the lower jacket structure 20 assembled in step S11. FIG. 6(b) illustrates a state in which the transition piece 30 is placed. In one example, a worker hoists the transition piece 30 with a crane or the like, and places the transition piece 30 such that the upper ends of the legs 22 of the lower jacket structure 20 are inserted into the corresponding connection portions 34 of the transition piece 30.

[0066] Next, step S13 is executed. In step S13, for example, a worker places the external work floor 40 on the transition piece 30 placed in step S12. Fig. 7(a) illustrates a state in which the external work floor 40 is placed. In one example, a worker hoists the external work floor 40 with a crane or the like, and places the external work floor 40 so that the center pipe 32 of the transition piece 30 is inserted into the hole 46 of the external work floor 40.

[0067] Steps S21, S22, and S23 are executed in sequence in parallel with or at different timings from the series of steps S11 to S13. Steps S21 to S23 are executed in the same manner as steps S11 to S13, respectively, except that the work targets are the lower jacket structure 20, the transition piece 30, and the external work floor 40 that constitute the jacket structure 10B.

[0068] The jacket structure 10A is assembled by executing a series of steps S11 to S13, and the jacket structure 10B is assembled by executing a series of steps S21 to S23. At the time when both steps S13 and S23 are executed, the movable fences 44b of the fences 44 in each of the jacket structures 10A and 10B may be in a detached state (a state before being attached) or in an open state. In addition, the space SA and the space SB may be disposed on one side of the plane IP including the pipe axis Ax of the center pipe 32 of each of the jacket structures 10A and 10B.

[0069] After both steps S13 and S23 are performed, step S34 is performed. In step S34, for example, a worker hoists the gangway 5 between the work tower 4 and the jacket structure 10B. In one example, the worker uses a crane or the like to hoist the gangway 5, and places one end of the gangway 5 on the work tower 4 and the other end of the gangway 5 on the external work floor 40 of the jacket structure 10B. Then, the worker may fix one end of the gangway 5 to the work tower 4 with a connecting member and fix the other end of the gangway 5 to the jacket structure 10B with a connecting member. This allows the worker to move between the work tower 4 and the external work floor 40 of the jacket structure 10B.

[0070] Next, step S35 is executed. In step S35, for example, a worker hoists the gangway 6 between the jacket structure 10A and the jacket structure 10B. In one example, the worker hoists the gangway 6 using a crane or the like, and places one end 6a of the gangway 6 in the above-mentioned space SA on the external work floor 40 of the jacket structure 10A, and places the other end 6b of the gangway 6 in the above-mentioned space SB on the external work floor 40 of the jacket structure 10B. Then, the worker may fix one end 6a of the gangway 6 to a location corresponding to the space SA of the jacket structure 10A with a connecting member 52, and fix the other end 6b of the gangway 6 to a location corresponding to the space SB of the jacket structure 10B with a connecting member 52.

[0071] By bridging the gangway 6 between the jacket structure 10A and the jacket structure 10B, workers can move between the external work floor 40 of the jacket structure 10A and the external work floor 40 of the jacket structure 10B. In the jacket structure system 1, workers can access the external work floors 40 of both the jacket structure 10A and the jacket structure 10B by climbing up the work tower 4. In addition, after working on one of the external work floors 40 of the jacket structure 10A and the jacket structure 10B, the workers can move to the other external work floor 40 via the gangway 6 without descending to the ground G.

[0072] Next, step S16 is performed. In step S16, for example, a worker installs a scaffolding 60 on the transition piece 30 in the jacket structure 10A as shown in FIG. 7(b). The scaffolding 60 is a temporary facility for performing joining work (e.g., welding work) between the transition piece 30 and each leg 22 of the lower jacket structure 20, and is fixed to the transition piece 30. The scaffolding 60 may be composed of steel pipes and steel plates, etc., and may include stairs for workers to ascend and descend. The scaffolding 60 may be installed (temporarily) so that a worker can move to a position where joining work between the upper end of the brace 24 located at the uppermost level and the leg 22 can be performed.

[0073] Next, step S17 is executed. In step S17, for example, a worker performs permanent installation of the external work floor 40 in the jacket structure 10A. In one example, a worker performs welding work between the external work floor 40 and the transition piece 30 at the external work floor 40 of the jacket structure 10A or the transition piece 30. Instead of welding work, the worker may fix the external work floor 40 to the transition piece 30 using a fixing (permanent installation) member. By executing step S17, the external work floor 40 is permanently installed in the jacket structure 10. In step S17, in addition to the permanent installation of the external work floor 40, the worker may perform welding work between the upper end of each leg 22 and the transition piece 30, and welding work between the upper end of the uppermost brace 24 and the leg 22.

[0074] Steps S26 and S27 are executed in parallel with or at different timings from steps S16 and S17. Steps S26 and S27 are executed in the same manner as steps S16 and S17, respectively, except that the work targets are the lower jacket structure 20, the transition piece 30, and the external work floor 40 that constitute the jacket structure 10B.

[0075] [Variations] The series of work steps illustrated in Fig. 5 is an example and can be changed as appropriate. In the series of work steps illustrated in Fig. 5, one step and other steps may be performed in parallel, may be performed in a different order, or other steps may be additionally performed.

[0076] In the above example, the transition piece 30 is placed on the lower jacket structure 20, and then the external work floor 40 is placed on the transition piece 30. However, the transition piece 30 and the external work floor 40 may be assembled to each other on the ground G. Then, a worker may place the external work floor 40 to which the transition piece 30 is assembled, on the lower jacket structure 20. As described above, placing the external work floor 40 above the lower jacket structure 20 in the first assembly step and the second assembly step also includes a case where the external work floor 40 is placed together with the transition piece 30 on the lower jacket structure 20 in a state where it is assembled to the transition piece 30.

[0077] Depending on the arrangement of the two jacket structures 10, the entire gangway 6 may not be arranged in the region R1 located on one side of the plane IP. As shown in FIG. 8, one end 6a of the gangway 6 may be arranged on one side (region R1) of the plane IP, and the other end 6b of the gangway 6 may be arranged on the other side (region R2) of the plane IP. In the example shown in FIG. 8, the gangway 6 is arranged to intersect with the plane IP while overlapping with any part of the plane IP. In the direction D2, the position of the movable fence 44b (space SA) in the jacket structure 10A and the position of the movable fence 44b (space SB) in the jacket structure 10B may be different from each other.

[0078] In the jacket structure 10A, the length between the center pipe 32 and the end of the one side of the external work floor 40 is longer than the length between the center pipe 32 and the end of the other side of the external work floor 40. On the other hand, in the jacket structure 10B, the length between the center pipe 32 and the end of the one side of the external work floor 40 is shorter than the length between the center pipe 32 and the end of the other side of the external work floor 40.

[0079] As described above, one end 6a of the gangway 6 may be connected to the vicinity of the external work floor 40 instead of a part of the external work floor 40 of the jacket structure 10A, and the other end 6b of the gangway 6 may be connected to the vicinity of the external work floor 40 instead of a part of the external work floor 40 of the jacket structure 10B. Fig. 9 illustrates a case where each of both ends of the gangway 6 is disposed in the vicinity of the corresponding external work floor 40.

[0080] As shown in FIG. 9, one end 6a of the gangway 6 may be connected to the top of a portion of the transition piece 30 of the jacket structure 10A excluding the center pipe 32 (for example, the upper flange of the transition piece 30). The other end 6b of the gangway 6 may be connected to the top of a portion of the transition piece 30 of the jacket structure 10B excluding the center pipe 32 (for example, the upper flange of the transition piece 30). Each of the two ends of the gangway 6 is disposed close to the corresponding external work floor 40 so that, for example, a worker can move between the gangway 6 and the external work floor 40 without using other members. Note that, unlike the example shown in FIG. 9, one of the two ends of the gangway 6 may be connected to the external work floor 40, and the other of the two ends of the gangway 6 may be connected to the vicinity of the external work floor 40.

[0081] Another example of the jacket structure system is shown in Fig. 10. The jacket structure system 81 shown in Fig. 10 differs from the jacket structure system 1 shown in Fig. 1 in that the jacket structure system 81 includes gangways 5A and 5B instead of the gangways 5 and 6.

[0082] The gangway 5A (first gangway) is spanned between the external work floor 40 (first external work floor) of the jacket structure 10A and the work tower 4 so that a worker can move between the external work floor 40 and the work tower 4. One end of the gangway 5A may be connected to the external work floor 40 of the jacket structure 10A, or may be connected to a location of the jacket structure 10A near the external work floor 40. The other end of the gangway 5A is connected to the work tower 4. When one end of the gangway 5A is connected to a location near the external work floor 40 of the jacket structure 10A (for example, the upper flange of the transition piece 30), one end of the gangway 5A may be connected as in the example shown in FIG. 9. The above-mentioned nearby location where the gangway 5A is spanned may be a space of the upper flange of the transition piece 30 where the external work floor 40 is installed.

[0083] The gangway 5B (second gangway) is spanned between the external work floor 40 (second external work floor) of the jacket structure 10B and the work tower 4 so that workers can move between the external work floor 40 and the work tower 4. One end of the gangway 5B may be connected to the external work floor 40 of the jacket structure 10B, or may be connected to a location of the jacket structure 10B near the external work floor 40. The other end of the gangway 5B is connected to the work tower 4. When one end of the gangway 5B is connected to a location near the external work floor 40 of the jacket structure 10B (for example, the upper flange of the transition piece 30), one end of the gangway 5B may be connected as in the example shown in FIG. 9. The nearby location where the gangway 5B is spanned may be a space of the upper flange of the transition piece 30 where the external work floor 40 is installed.

[0084] As shown in Fig. 10, in the jacket structure system 81, the height of the external work floor 40 of the jacket structure 10A from the ground G may be different from the height of the external work floor 40 of the jacket structure 10B from the ground G. Unlike the example shown in Fig. 10, in the jacket structure system 81, the height of the external work floor 40 of the jacket structure 10A from the ground G may be the same as the height of the external work floor 40 of the jacket structure 10B from the ground G.

[0085] In the jacket structure system 81, by bridging the gangway 5A and the gangway 5B, workers can access the external work floors 40 of the jacket structures 10A and 10B, respectively, using one work tower 4. In addition, after working on one of the external work floors 40 of the jacket structures 10A and 10B, the workers can move to the other external work floor 40 via the work tower 4, the gangway 5A, and the gangway 5B without descending to the ground G.

[0086] In the above example, the gangway 6 is formed to extend in one direction, but the gangway 6 may be provided with stairs that allow workers to ascend and descend. The gangway 6 provided with such stairs is suitable for cases where the height from the ground G differs between the jacket structure 10A and the jacket structure 10B (for example, cases where the height from the ground G differs between the external work floors 40). The gangways 5, 5A, and 5B may also be provided with stairs that allow workers to ascend and descend.

[0087] FIG. 11 shows another example of the jacket structure system. The jacket structure system 91 shown in FIG. 11 includes two or more jacket structures 10A and two or more jacket structures 10B. The two or more jacket structures 10A and the two or more jacket structures 10B are provided in the same wind farm or sea area. For example, the two or more jacket structures 10A and the two or more jacket structures 10B are used as foundation parts of a plurality of offshore wind turbines 200 included in one offshore wind power generation facility installed in the same wind farm or the same sea area. FIG. 11 shows the jacket structure 10A and the jacket structure 10B in a state where they are arranged in a yard before being transported to a wind farm or the like. In FIG. 11, the figure is drawn in two stages, upper and lower, due to space on the paper, but the right end of the upper stage is connected to the left end of the lower stage.

[0088] The height of the external work floor 40 from the ground G (hereinafter referred to as "height H1") is common between two or more jacket structures 10A. The height of the external work floor 40 from the ground G (hereinafter referred to as "height H2") is common between two or more jacket structures 10B. When grouped according to the height of the external work floor 40 from the ground G, the jacket structure system 1 includes two or more jacket structures 10A belonging to group Gp1 (first group) and two or more jacket structures 10B belonging to group Gp2 (second group). The height H1 (first height) and the height H2 (second height) are different. The height H2 may be higher than the height H1. The height of the external work floor 40 from the ground G may be defined by the height position in the vertical direction of the upper surface of the floor portion 42 of the external work floor 40.

[0089] Fig. 12 is a schematic plan view of a jacket structure system 91 arranged in a predetermined area GA in a yard. In Fig. 12, the lower jacket structure 20 of each jacket structure is omitted. The jacket structure system 91 includes one or more gangways 6A and one or more gangways 6B. Each of the gangway 6A and the gangway 6B has the same function and role as the gangway 6, and the method of installation on the jacket structure is also the same as that of the gangway 6.

[0090] One or more gangways 6A are spanned between the external work floors 40 of two or more jacket structures 10A so that workers can move between the external work floors 40 (first external work floors) of the jacket structures 10A. When focusing on one of the one or more gangways 6A, the gangway 6A may be spanned between the external work floor 40 of one jacket structure 10A and the external work floor 40 of another jacket structure 10A. Alternatively, the gangway 6A may be spanned between a nearby location of the external work floor 40 of one jacket structure 10A (for example, the upper flange of the transition piece 30) and a nearby location of the external work floor 40 of another jacket structure 10A (for example, the upper flange of the transition piece 30) as in the example shown in FIG. 9. Alternatively, one end of the gangway 6A may be connected to the external work floor 40 of one jacket structure 10A, and the other end of the gangway 6A may be connected to a location in the vicinity of the external work floor 40 of another jacket structure 10A. When at least one of both ends of the gangway 6A is connected to a location in the vicinity of the external work floor 40, the location in the vicinity where the gangway 6A is spanned may be a space in the upper flange of the transition piece 30 where the external work floor 40 is installed. The connection location of at least one end may be different between one gangway 6A and another gangway 6A.

[0091] One or more gangways 6B are spanned between the external work floors 40 of two or more jacket structures 10B so that workers can move between the external work floors 40 (second external work floors) of the jacket structures 10B. When focusing on one of the one or more gangways 6B, the gangway 6B may be spanned between the external work floor 40 of one jacket structure 10B and the external work floor 40 of another jacket structure 10B. Alternatively, both ends of the gangway 6B may be spanned between a nearby location of the external work floor 40 of one jacket structure 10B (for example, the upper flange of the transition piece 30) and a nearby location of the external work floor 40 of the other jacket structure 10B (for example, the upper flange of the transition piece 30) as in the example shown in FIG. 9. One end of the gangway 6B may be connected to the external work floor 40 of one jacket structure 10B, and the other end of the gangway 6B may be connected to a location in the vicinity of the external work floor 40 of another jacket structure 10B. When at least one of both ends of the gangway 6B is connected to a location in the vicinity of the external work floor 40, the location in the vicinity where the gangway 6B is spanned may be a space in the upper flange of the transition piece 30 where the external work floor 40 is installed. The connection location of at least one end may be different between one gangway 6B and another gangway 6B.

[0092] In the jacket structure system 91, when attention is focused on each jacket structure 10A (each jacket structure 10A), a gangway 6A is spanned between that jacket structure 10A and at least one other jacket structure 10A. In the jacket structure system 91, when attention is focused on each jacket structure 10B, a gangway 6B is spanned between that jacket structure 10B and at least one other jacket structure 10B. As described above, when attention is focused on each jacket structure, a gangway is spanned between the external work floors 40 of two or more jacket structures, but this does not necessarily mean that a gangway is spanned between that jacket structure and all other jacket structures.

[0093] 11 and 12, the jacket structure system 91 has a jacket structure 10A1, a jacket structure 10A2, and a jacket structure 10A3 as two or more jacket structures 10A. The jacket structure system 91 has a jacket structure 10B1 and a jacket structure 10B2 as two or more jacket structures 10B. The jacket structure system 91 has two gangways 6A and a gangway 6B.

[0094] As shown in Fig. 12, one gangway 6A is spanned between the external work floor 40 of the jacket structure 10A1 and the jacket structure 10A2, and the other gangway 6A is spanned between the jacket structure 10A2 and the jacket structure 10A3. A gangway does not have to be spanned between the jacket structure 10A1 and the jacket structure 10A3. The gangway 6B is spanned between the external work floor 40 of the jacket structure 10B1 and the external work floor 40 of the jacket structure 10B2.

[0095] Fig. 13 shows a transition piece system according to one embodiment. Fig. 14 shows a schematic diagram of an example of an offshore structure in which a transition piece provided in the transition piece system is provided. The transition piece system 100 shown in Fig. 13 is a system configured with two or more transition pieces. The transition piece system 100 includes, for example, a transition piece 130A and a transition piece 130B as the two or more transition pieces. In addition to the transition piece 130A and the transition piece 130B, the transition piece system 100 includes two external work floors 40, a work rafter 4, a gangway 5, and a gangway 6.

[0096] Each of the transition piece 130A and the transition piece 130B is capable of supporting the offshore wind turbine 200. Like the transition piece 30, each of the transition piece 130A and the transition piece 130B has a center pipe 32 to which a part of the offshore wind turbine 200 is connected. The transition piece 130A is provided on the offshore structure 110 (first offshore structure), and the transition piece 130B is provided on the offshore structure 110 (second offshore structure). The offshore structure 110 is, for example, a monopile-type foundation structure (see also FIG. 14 ).

[0097] An external work floor 40 (first external work floor) is provided in the transition piece 130A (first transition piece), and an external work floor 40 (second external work floor) is provided in the transition piece 130B (second transition piece). In other words, the external work floor 40 is installed in the transition piece 130A, and the external work floor 40 is installed in the transition piece 130B. As in the jacket structures 10A and 10B shown in FIG. 2, a work crane 56 is provided on the external work floor 40, and a boat landing section 58 is provided on the marine structure 110. The gangway 5 is spanned between the work rafter 4 and the external work floor 40 provided in either the transition piece 130A or the transition piece 130B (for example, the transition piece 130B).

[0098] The gangway 6 is spanned between the external work floor 40 provided in the transition piece 130A and the external work floor 40 provided in the transition piece 130B so that workers can move between the external work floor 40 provided in the transition piece 130A and the external work floor 40 provided in the transition piece 130B. Details of the spanning method of the gangway 5 and the gangway 6 are similar to the various spanning methods in the jacket structure system 1, except that the external work floor 40 is provided in the transition piece 130A or the transition piece 130B instead of the transition piece 30. In the transition piece system 100, a pair of external work floors 40 (a pair of movable fences 44b) and the gangway 6 may also be arranged as in the example shown in FIG. 4, FIG. 8, or FIG. 9.

[0099] In the transition piece system 100, the gangway 6 may be installed between the transition piece 130A and the transition piece 130B so that workers can move between the transition piece 130A on which the external work floor 40 is installed and the transition piece 130B on which the external work floor 40 is installed. FIG. 15(a) illustrates an example of the gangway 6 installed such that one end of the gangway 6 is connected to the transition piece 130A and the other end of the gangway 6 is connected to the transition piece 130B. Both ends of the gangway 6 may be connected to the upper flange of the transition piece 130A or the transition piece 130B (for example, the space of the upper flange on which the external work floor 40 is installed). In this transition piece system 100, the gangway 6 may be installed before the external work floor 40 is installed on both or one of the transition pieces 130A and 130B. In this case, the external work floor 40 may be installed with the gangway 6 suspended, or the external work floor 40 may be installed after the gangway 6 is removed. Note that the gangway 6 may be suspended after the external work floor 40 is installed on the transition piece 130A and the transition piece 130B.

[0100] In the transition piece system 100, the gangway 6 may be bridged between the transition piece 130A and the external work floor 40B after installation (second external work floor) so that workers can move between the transition piece 130A on which the external work floor 40 is to be installed and the external work floor 40 already installed on the transition piece 130B (hereinafter referred to as the "external work floor 40B after installation"). As shown in FIG. 15(b), one end of the gangway 6 may be connected to the transition piece 130A (e.g., the upper flange of the transition piece 130A), and the other end of the gangway 6 may be connected to the external work floor 40B after installation. Alternatively, one end of the gangway 6 may be connected to the transition piece 130A, and the other end of the gangway 6 may be connected to a location near the external work floor 40B after installation (e.g., the upper flange of the transition piece 130B).

[0101] The one end of the gangway 6 may be connected to a space in the upper flange of the transition piece 130A where the external work floor 40 is to be installed. The other end of the gangway 6 may be connected to a space in the upper flange of the transition piece 130B where the external work floor 40 is to be installed. In this transition piece system 100, the gangway 6 may be installed before the external work floor 40 is installed on the transition piece 130A. In this case, the external work floor 40 may be installed on the transition piece 130A with the gangway 6 installed, or the external work floor 40 may be installed on the transition piece 130A after the gangway 6 is removed. The gangway 6 may be installed after the external work floor 40 is installed on the transition piece 130A.

[0102] 1 and the like, a transition piece system may be configured by the transition piece 30 and external work floor 40 of the jacket structure 10A, the transition piece 30 and external work floor 40 of the jacket structure 10B, and the gangway 6. The lower jacket structure 20 of the jacket structure 10A functions as an offshore structure (first offshore structure), and the lower jacket structure 20 of the jacket structure 10B functions as an offshore structure (second offshore structure).

[0103] In the jacket structure system 1 shown in FIG. 1 and the like, a transition piece system may be configured by the transition piece 30 of the jacket structure 10A, the transition piece 30 of the jacket structure 10B, and the gangway 6. In this case, the gangway 6 may be spanned between the transition piece 30 of the jacket structure 10A and the transition piece 30 of the jacket structure 10B so that workers can move between the transition piece 30 of the jacket structure 10A and the transition piece 30 of the jacket structure 10B. Alternatively, the gangway 6 may be spanned between the transition piece 30 of the jacket structure 10A and the external work floor 40 installed in the jacket structure 10B so that workers can move between the transition piece 30 of the jacket structure 10A and the external work floor 40 already installed in the transition piece 30 of the jacket structure 10B.

[0104] Of the various examples described above, at least a portion of the matters described in other examples may be combined in one example.

[0105] [Summary of this disclosure] The jacket structure system (1) described above includes a first jacket structure (10A) capable of supporting an offshore wind turbine (200), a second jacket structure (10B) capable of supporting an offshore wind turbine (200), and a gangway (6) that is spanned between the first jacket structure (10A) and the second jacket structure (10B). The first jacket structure (10A) has a first external work floor (40). The second jacket structure (10A) has a second external work floor. The gangway (6) is spanned between the first external work floor (40) and the second external work floor (40) so that workers can move between the first external work floor (40) and the second external work floor (40).

[0106] In this jacket structure system (1), workers can move from the first external work floor (40) to the second external work floor (40) and from the second external work floor (40) to the first external work floor (40) using the gangway (6). Therefore, if it is possible to move to one external work floor using one lifting means (for example, a work tower), it is possible to move to the other external work floor without using another lifting means to lift. Therefore, the jacket structure system (1) is useful for improving work efficiency.

[0107] The first external work floor (40) may include a first fence (44b) that is removable or openable. The second external work floor (40) may include a second fence (44b) that is removable or openable. One end (6a) of the gangway (6) may be connected to a first space (SA) that is created when the first fence (44b) is removed or opened from the first external work floor (40). The other end (6b) of the gangway (6) may be connected to a second space (SB) that is created when the second fence (44b) is removed or opened from the second external work floor (40). For the safety of workers, it is necessary to provide a fence on the external work floor (40). In the above configuration, a space for bridging the gangway (6) can be easily formed by the removable or openable fence, and since there is no fence in the space, the gangway (6) can be stably installed. Therefore, the gangway (6) can be easily and more reliably installed across the first external work floor (40) and the second external work floor (40).

[0108] In a plan view, the first fence (44b) and the second fence (44b) may face each other. In this case, the distance between the spaces created by the first fence (44b) and the second fence (44b), which are removable or openable, tends to be shorter. Therefore, the gangway (6) can be easily spanned by the first external work floor (40) and the second external work floor (40).

[0109] The one end (6a) may be fixed to a part of the first jacket structure (10A) that corresponds to the first space (SA) by a first connecting member (52). The other end (6b) may be fixed to a part of the second jacket structure (10B) that corresponds to the second space (SB) by a second connecting member (52). In this case, the gangway (8) can be more reliably connected to each of the first external work floor (40) and the second external work floor (40).

[0110] The first jacket structure (10A) may further include a first center pipe (32). The second jacket structure (10B) may further include a second center pipe (32). The gangway (6) may be disposed on one side of a plane (IP) including the pipe axis (Ax) of the first center pipe (32) and the pipe axis (Ax) of the second center pipe (32). In this case, it is easy to install the gangway (6) between the external work floors (40) having an asymmetric shape in a plan view.

[0111] The first jacket structure (10A) may further include a first center pipe (32). The second jacket structure (10B) may further include a second center pipe (32). One end (6a) of the gangway (6) may be disposed on one side of a plane (IP) including the pipe axis (Ax) of the first center pipe (32) and the pipe axis (Ax) of the second center pipe (32). The other end of the gangway (6) may be disposed on the other side of the plane (IP). In this case, the gangway (6) can be installed even if the orientations of the external work floors (40) having asymmetric shapes in a plan view are different from each other.

[0112] The length (LA1) between the first center pipe (32) and the end of the first external work floor (40) on one side may be longer than the length (LA2) between the first center pipe (32) and the end of the first external work floor (40) on the other side of the plane (IP). The length (LB1) between the second center pipe (32) and the end of the second external work floor (40) on one side may be longer than the length (LB2) between the second center pipe (32) and the end of the second external work floor (40) on the other side. In this configuration, the area of ​​each of the pair of external work floors (40) tends to be large on the one side. Therefore, when a work crane (56) is installed on the external work floor (40), it is easy to bridge the gangway (6) in the area of ​​the external work floor (40) on the side where the work crane (56) is installed.

[0113] The first jacket structure (10A) may further include a first center pipe (32). The second jacket structure (10B) may further include a second center pipe (32). The first external work floor (40) may be provided with a hole (46) or a notch into which the first center pipe (32) is inserted. The second external work floor (40) may be provided with a hole (46) or a notch into which the second center pipe (32) is inserted. In this case, it is easy to install the external work floor (40) in the jacket structures (10A, 10B).

[0114] The first external work floor (40) may be permanently installed in the first jacket structure (10A). The second external work floor (40) may be permanently installed in the second jacket structure (10B). In this case, the external work floor can be more reliably provided in the jacket structures (10A, 10B). In addition, even after the jacket structures (10A, 10B) are installed in the sea, workers can use the external work floor (40) to perform work.

[0115] The jacket structure system (81) described above includes a first jacket structure (10A) capable of supporting an offshore wind turbine (200), a second jacket structure (10B) capable of supporting an offshore wind turbine (200), a first gangway (5A), a second gangway (5B), and a work tower (4). The first jacket structure (10A) has a first external work floor (40). The second jacket structure (10B) has a second external work floor (40). The first gangway (5A) is spanned between the first external work floor (40) and the work tower (4) so ​​that a worker can move between the first external work floor (40) and the work tower (4). The second gangway (5B) is disposed between the second external work floor (40) and the work tower (4) so ​​that workers can move between the second external work floor (40) and the work tower (4).

[0116] In this jacket structure system (81), workers can move from the first external work floor (40) to the second external work floor (40) and from the second external work floor (40) to the first external work floor (40) by using the gangways (5A, 5B) and the work tower (4). Therefore, by using the work tower (4), which is one lifting and lowering means, it is possible to move to both the first external work floor (40) and the second external work floor (40) without using another lifting and lowering means to lift and lower. Therefore, the jacket structure system (81) is useful for improving work efficiency.

[0117] The jacket structure system (91) described above includes a plurality of jacket structures (10A, 10B) that are provided in the same wind farm or sea area and can each support an offshore wind turbine (200), a first gangway (6A), and a second gangway (6B). The plurality of jacket structures (10A, 10B) include two or more jacket structures (10A) that belong to a first group (Gp1) and two or more jacket structures (10B) that belong to a second group (Gp2). Each of the two or more jacket structures (10A) that belong to the first group (Gp1) has a first external work floor (40). Each of the two or more jacket structures (10B) that belong to the second group (Gp2) has a second external work floor (40). The first height (H1), which is the height of the first external work floor (40) from the ground (G), is common between the two or more jacket structures (10A) that belong to the first group (Gp1). The second height (H2), which is the height of the second external work floor (40) from the ground (G), is common between the two or more jacket structures (10B) belonging to the second group (Gp2). The first height (H1) and the second height (H2) are different. The first gangway (6A) is bridged between the first external work floors (40) of the two or more jacket structures (10A) belonging to the first group (Gp1) so that workers can move between the first external work floors (40). The second gangway (6B) is bridged between the second external work floors (40) of the two or more jacket structures (10B) belonging to the second group (Gp2) so that workers can move between the second external work floors (40).

[0118] In this jacket structure system (91), in each of the first group (Gp1) and the second group (Gp2), workers can move from one external work floor (40) to another external work floor (40) using the gangways (6A, 6B). Therefore, if it is possible to move to one external work floor using one lifting means (for example, a work tower), it is possible to move to another external work floor without using another lifting means to lift. Therefore, the jacket structure system (91) is useful for improving work efficiency. In addition, since one group is formed by jacket structures having the same height from the ground (G) of the external work floor (40), the gangways (6A, 6B) can be arranged horizontally, and workers can move from one external work floor (40) to another external work floor (40) more safely.

[0119] The gangway installation method described above is a gangway installation method for a jacket structure system (1) including a first jacket structure (10A) capable of supporting an offshore wind turbine (200), a second jacket structure (10B) capable of supporting the offshore wind turbine (200), and a gangway (6). This gangway installation method includes a first assembly step of assembling the first jacket structure (10A) by placing a first external work floor (40) above the first lower jacket structure (20), a second assembly step of assembling the second jacket structure (10B) by placing a second external work floor (40) above the second lower jacket structure (20), and a installation step of installing the gangway (6) between the first external work floor (40) and the second external work floor (40) so that a worker can move between the first external work floor (40) and the second external work floor (40) in accordance with the first assembly step and the second assembly step. This gangway installation method is useful for improving work efficiency, similar to the above-mentioned jacket structure system (1).

[0120] The first assembly step may include a first pipe insertion step of inserting a first center pipe (32) of the first jacket structure (10A) into a hole (46) or a notch provided in the first external work floor (40). The second assembly step may include a second pipe insertion step of inserting a second center pipe (32) of the second jacket structure (10B) into a hole (46) or a notch provided in the second external work floor (40). In this case, the external work floor (40) can be disposed in the jacket structures (10A, 10B) without interfering with the center pipe (32).

[0121] The gangway installation method may further include a first transition piece arranging step of arranging a first transition piece (30) on the first lower jacket structure (20), and a second transition piece arranging step of arranging a second transition piece (30) on the second lower jacket structure (20). The first assembly step may be performed after the first transition piece arranging step. The second assembly step may be performed after the second transition piece arranging step. In this case, the transition piece (30) and the external work floor (40) are separately arranged above the lower jacket structure (20). Therefore, the external work floor (40) can be more reliably arranged above the transition piece (30).

[0122] The transition piece system (100) described above comprises a first transition piece (130A) capable of supporting an offshore wind turbine (200) and provided on the first marine structure (110), a second transition piece (130B) capable of supporting the offshore wind turbine (200) and provided on the second marine structure (110), a first external work floor (40) provided on the first transition piece (130A), a second external work floor (40) provided on the second transition piece (130B), and a gangway (6) spanned between the first external work floor (40) and the second external work floor (40) so that workers can move between the first external work floor (40) and the second external work floor (40).

[0123] In this transition piece system (100), workers can move from the first external work floor (40) to the second external work floor (40) and from the second external work floor (40) to the first external work floor (40) using the gangway (6). Therefore, if it is possible to move to one external work floor using one lifting means (e.g., a work tower), it is possible to move to the other external work floor without using another lifting means to lift. Therefore, the transition piece system (100) is useful for improving work efficiency.

[0124] The first external work floor (40) may include a first fence (44b) that is removable or openable. The second external work floor (40) may include a second fence (44b) that is removable or openable. One end (6a) of the gangway (6) may be connected to a first space (SA) that is generated when the first fence (44b) is removed or opened from the first external work floor (40). The other end (6b) of the gangway (6) may be connected to a second space (SB) that is generated when the second fence (44b) is removed or opened from the second external work floor (40). In this case, similar to the above-mentioned jacket structure system (1), the gangway (6) can be easily and more reliably spanned across the first external work floor (40) and the second external work floor (40).

[0125] In a plan view, the first fence (44b) and the second fence (44b) may face each other. In this case, as in the above-described jacket structure system (1), the gangway (6) can be easily spanned by the first external work floor (40) and the second external work floor (40).

[0126] The one end (6a) may be fixed to a part of the first transition piece (30) or the first external work floor (40) that corresponds to the first space (SA) by a first connecting member (52). The other end (6b) may be fixed to a part of the second transition piece (30) or the second external work floor (40) that corresponds to the second space (SB) by a second connecting member (52). In this case, the gangway (6) can be more reliably connected to each of the first external work floor (40) and the second external work floor (40).

[0127] The transition piece system (100) described above comprises a first transition piece (130A) capable of supporting an offshore wind turbine (200) and provided on a first marine structure (110), the first transition piece (130A) on which a first external work floor (40) is installed; a second transition piece (130B) capable of supporting an offshore wind turbine (200) and provided on a second marine structure (110), the second transition piece (130B) on which the second external work floor (40) is installed; and a gangway (6) connected between the first transition piece (130A) and the second transition piece (130B) so that workers can move between the first transition piece (130A) on which the first external work floor (40) is installed and the second transition piece (130B) on which the second external work floor (40) is installed.

[0128] In this transition piece system (100), workers can move from the first transition piece (130A) to the second transition piece (130B) and from the second transition piece (130B) to the first transition piece (130A) using the gangway (6). Therefore, if workers can move to one transition piece using one lifting means (e.g., a work tower), they can move to the other transition piece without using another lifting means to lift. Therefore, the transition piece system (100) is useful for improving work efficiency.

[0129] The transition piece system (100) described above comprises a first transition piece (130A) capable of supporting an offshore wind turbine (200) and provided on a first marine structure (110), the first transition piece (130A) on which a first external work floor (40) is installed; a second transition piece (130B) capable of supporting an offshore wind turbine (200) and provided on a second marine structure (110), the second transition piece (130B) on which a second external work floor (40, 40B) is installed; and a gangway (6) bridged between the first transition piece (130A) and the second external work floor (40, 40B) so that workers can move between the first transition piece (130B) on which the first external work floor (40) is installed and the second external work floor (40, 40B).

[0130] In this transition piece system (100), workers can move from the first transition piece (130A) to the second external work floor (40, 40B) and from the second external work floor (40, 40B) to the first transition piece (130A) by using the gangway (6). Therefore, if it is possible to move to one of the first transition piece (130A) and the second external work floor (40, 40B) by using one lifting and lowering means (e.g., a work tower), it is possible to move to the other of the first transition piece (130A) and the second external work floor (40, 40B) without using another lifting and lowering means to lift and lower. Therefore, the transition piece system (100) is useful for improving the efficiency of work. [Explanation of symbols]

[0131] 1,81,91...jacket structure system, 5,5A,5B,6,6A,6B...gangway, 6a...one end, 6b...other end, 10,10A,10B...jacket structure, G...ground, H1,H2...height, 20...lower jacket structure, 30...transition piece, 32...center pipe, Ax...pipe axis, IP...plane, 40...external work floor, 44b...movable fence, SA,SB...space, 100...transition piece system, 110...offshore structure, 130A,130B...transition piece, 200...offshore wind turbine.

Claims

1. A first jacket structure capable of supporting an offshore wind turbine; A second jacket structure capable of supporting an offshore wind turbine; A gangway that spans the first jacket structure and the second jacket structure; Equipped with The first jacket structure has a first external working floor, The second jacket structure has a second external working floor, The gangway is spanned between the first external work floor and the second external work floor so that a worker can move between the first external work floor and the second external work floor. Jacket structure system.

2. The first external work floor includes a removable or openable first fence, The second external work floor includes a removable or openable second fence, One end of the gangway is connected to a first space created when the first fence is removed or opened from the first external work floor, The other end of the gangway is connected to a second space created when the second fence is removed or opened from the second external work floor. The jacket structure system of claim 1 .

3. In a plan view, the first fence and the second fence face each other. The jacket structure system of claim 2 .

4. The one end is fixed to a part of the first jacket structure corresponding to the first space by a first connecting member, The other end is fixed to a part of the second jacket structure corresponding to the second space by a second connecting member. The jacket structure system of claim 2 .

5. The first jacket structure further includes a first center pipe, The second jacket structure further includes a second center pipe, the gangway is disposed on one side of a plane including a tube axis of the first center pipe and a tube axis of the second center pipe. A jacket structure system according to any one of claims 1 to 4.

6. The first jacket structure further includes a first center pipe, The second jacket structure further includes a second center pipe, one end of the gangway is disposed on one side of a plane including a pipe axis of the first center pipe and a pipe axis of the second center pipe, the other end of the gangway is disposed on the other side of the plane; A jacket structure system according to any one of claims 1 to 4.

7. The length of the first center pipe and the end portion on one side of the first external work floor is a length longer than a length between the first center pipe and an end of the first external work floor on the other side of the plane, a length between the second center pipe and the end portion on one side of the second external work floor is longer than a length between the second center pipe and the end portion on the other side of the second external work floor; The jacket structure system of claim 5.

8. The first jacket structure further includes a first center pipe, The second jacket structure further includes a second center pipe, the first external work floor is provided with a hole or a notch into which the first center pipe is inserted, The second external work floor is provided with a hole or a notch into which the second center pipe is inserted. A jacket structure system according to any one of claims 1 to 4.

9. The first external work floor is permanently installed in the first jacket structure, The second external work floor is permanently installed in the second jacket structure. A jacket structure system according to any one of claims 1 to 4.

10. A first jacket structure capable of supporting an offshore wind turbine; A second jacket structure capable of supporting an offshore wind turbine; The first gangway; A second gangway; A work tower and Equipped with The first jacket structure has a first external working floor, The second jacket structure has a second external working floor, The first gangway is spanned between the first external work platform and the work tower so that a worker can move between the first external work platform and the work tower, The second gangway is spanned between the second external work floor and the work tower so that workers can move between the second external work floor and the work tower. Jacket structure system.

11. A plurality of jacket structures provided in the same wind farm or sea area and capable of supporting each of the offshore wind turbines; The first gangway; A second gangway; Equipped with The plurality of jacket structures include two or more jacket structures belonging to a first group and two or more jacket structures belonging to a second group, Each of the two or more jacket structures belonging to the first group has a first external working floor, Each of the two or more jacket structures belonging to the second group has a second external working floor, The first height, which is the height of the first external working floor from the ground, is common between the two or more jacket structures belonging to the first group, The second height, which is the height of the second external working floor from the ground, is common between the two or more jacket structures belonging to the second group, The first height and the second height are different, the first gangway is spanned between the first external work floors of each of the two or more jacket structures belonging to the first group so that workers can move between the first external work floors; The second gangway is spanned between the second external work floors of each of the two or more jacket structures belonging to the second group so that workers can move between the second external work floors. Jacket structure system.

12. A first jacket structure capable of supporting an offshore wind turbine; A second jacket structure capable of supporting an offshore wind turbine; Gangway and A gangway installation method for a jacket structure system comprising: a first assembly step of disposing a first external work floor above a first lower jacket structure and assembling the first jacket structure; a second assembly step of disposing a second external work floor above a second lower jacket structure and assembling the second jacket structure; a connecting step of connecting the gangway between the first external work floor and the second external work floor so that a worker can move between the first external work floor and the second external work floor in accordance with the first assembly step and the second assembly step; A gangway transfer method including:

13. the first assembling step includes a first pipe inserting step of inserting a first center pipe of the first jacket structure into a hole or a notch provided in the first external work floor, the second assembling step includes a second pipe inserting step of inserting a second center pipe of the second jacket structure into a hole or a notch provided in the second external work floor, A gangway transfer method according to claim 12.

14. a first transition piece placement step of placing a first transition piece on the first lower jacket structure; a second transition piece disposing step of disposing a second transition piece on the second lower jacket structure; Further comprising: the first assembly step is performed after the first transition piece placement step; The second assembly step is performed after the second transition piece placement step. A gangway transfer method according to claim 12.

15. A first transition piece capable of supporting an offshore wind turbine and provided on the first offshore structure; a second transition piece capable of supporting the offshore wind turbine and provided on the second offshore structure; a first external work floor provided on the first transition piece; A second external work floor provided on the second transition piece; a gangway spanning between the first external work floor and the second external work floor so that a worker can move between the first external work floor and the second external work floor; A transition piece system comprising:

16. The first external work floor includes a removable or openable first fence, The second external work floor includes a removable or openable second fence, One end of the gangway is connected to a first space created when the first fence is removed or opened from the first external work floor, The other end of the gangway is connected to a second space created when the second fence is removed or opened from the second external work floor. The transition piece system of claim 15.

17. In a plan view, the first fence and the second fence face each other. The transition piece system of claim 16.

18. The one end is fixed to a part of the first transition piece or the first external working floor corresponding to the first space by a first connecting member; The other end is fixed to a part of the second transition piece or the second external working floor corresponding to the second space by a second connecting member. A transition piece system according to claim 16 or 17.

19. a first transition piece capable of supporting an offshore wind turbine and provided on a first marine structure, the first transition piece having a first external working floor installed thereon; a second transition piece capable of supporting the offshore wind turbine and provided on the second marine structure, the second transition piece having a second external working floor installed thereon; a gangway that is spanned between the first transition piece and the second transition piece so that workers can move between the first transition piece on which the first external work floor is installed and the second transition piece on which the second external work floor is installed; and A transition piece system comprising:

20. a first transition piece capable of supporting an offshore wind turbine and provided on a first marine structure, the first transition piece having a first external working floor installed thereon; a second transition piece capable of supporting the offshore wind turbine and provided on the second marine structure, the second transition piece having a second external working floor installed thereon; a gangway that is spanned between the first transition piece and the second external work floor so that workers can move between the first transition piece on which the first external work floor is installed and the second external work floor; A transition piece system comprising:

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