Landing structure and repair method for landing

Abstract

To provide a ship arrival part structure and a ship arrival part repair method capable of reducing work below a water level in the repairing of a ship arrival part.SOLUTION: A structure of a ship arrival part 51 provided in a transition piece 3 of a leg 41 of an ocean wind power generator 1 comprises a fender 57 that is fixed to the outer peripheral surface 3a of the transition piece 3 and that extends from above a sea water level to below the sea water level. The fender 57 has a lower constituent 69 fixed to the outer peripheral surface 3a to constitute a lower part of the fender 57, and an upper constituent 67 fitted to the lower constituent 69 below the sea water level by means of a burying structure and joined to the outer peripheral surface 3a above the sea water level to constitute an upper part of the fender 57.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a dock structure and a dock repair method for an offshore structure. [Background technology]

[0002] When workers access an offshore structure, they dock a ship alongside a landing area located near the waterline at the base of the offshore structure, and then climb onto a ladder installed at the landing area. The workers then climb the ladder to a platform above and can enter the offshore structure through a doorway installed on the platform. The landing area is equipped with a fender to prevent direct collision between the ship and the base of the offshore structure (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6663988 Summary of the Invention [Problem to be solved by the invention]

[0004] When a ship hits such a fender hard, it can cause dents or scratches, requiring repairs. However, because the fender is installed around the outer periphery of the legs of the offshore structure, repair work on the water is complicated. The fender extends from above the waterline to below, and work below the waterline requires diving by divers or other personnel, which is particularly demanding.

[0005] An object of the present invention is to provide a dock structure and a dock repair method that can reduce the amount of work required underwater when repairing a dock. [Means for solving the problem]

[0006] The landing structure of the present invention is a landing structure provided on the leg of an offshore structure, and comprises a fender joined to the outer peripheral surface of the leg and extending from above sea level to below sea level, the fender having a lower component part fixed to the outer peripheral surface and constituting the lower part of the fender, and an upper component part attached to the lower component part below sea level by a fitting structure and joined to the outer peripheral surface above sea level and constituting the upper part of the fender.

[0007] In the landing structure of the present invention, the lower end of the upper constituent part may be inserted from above into the inside of the cylindrical upper end of the lower constituent part so as to be insertable and detachable.

[0008] The landing structure of the present invention is a method for repairing any of the above-mentioned landing structure, which involves cutting the existing upper component from the outer periphery above sea level, detaching and removing the upper component from the lower component, fitting and attaching the lower end of the new replacement upper component to the lower component, and joining the upper component to the outer periphery above sea level. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a dock structure and a dock repair method that can reduce the amount of work required underwater when repairing a dock. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a front view of a wind power generator to which the dock structure and dock repair method of the present embodiment are applied. [Figure 2] FIG. 2 is an enlarged perspective view showing the vicinity of the platform of the wind power generator. [Figure 3] FIG. 2 is an enlarged perspective view showing the vicinity of the dock of the wind power generator. [Figure 4] FIG. 2 is an enlarged cross-sectional view showing the vicinity of a connection portion between an upper component and a lower component. [Figure 5] 10(a) and 10(b) are diagrams sequentially showing a method for repairing a landing section. [Figure 6] 5(a) and 5(b) are diagrams sequentially showing the method for repairing the anchorage section. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of a dock structure and a dock repair method according to the present invention will be described in detail with reference to the drawings. In the following description, identical or corresponding elements will be designated by the same reference numerals in the drawings, and duplicate explanations will be omitted as appropriate. Furthermore, the drawings may be simplified or exaggerated for ease of understanding, and the dimensional proportions and the like are not limited to those shown in the drawings.

[0012] FIG. 1 is a front view showing a wind turbine generator 1 as an example of an offshore structure to which the dock structure and dock repair method of this embodiment can be applied. As shown in the figure, the wind turbine generator 1 is installed, for example, on the seabed B and generates offshore wind power. However, the wind turbine generator 1 is not limited to being installed in the ocean, and may be installed, for example, in a lake or river. The wind turbine generator 1 includes legs 41 that extend vertically above the seawater surface from the seabed B, and a generator body 42 attached to the upper ends of the legs 41.

[0013] The generator main body 42 includes a nacelle 5 and blades 6 attached to the nacelle 5. The nacelle 5 houses a generator, a speed increaser, and the like, and for example, a rotor shaft protrudes from the speed increaser to the outside of the nacelle 5. The blades 6 are fixed to the rotor shaft of the nacelle 5. The wind power generator 1 includes, for example, three blades 6. When the blades 6 rotate in response to the wind, this rotation is increased to a certain rotation speed by an amplifier inside the nacelle 5, and this rotational motion is converted into electricity by a generator inside the nacelle 5. For example, the nacelle 5 is equipped with a wind vane and anemometer, and efficient power generation is achieved by controlling the direction of the rotor and the angle of the blades 6 in accordance with the wind speed and direction.

[0014] The leg 41 comprises a foundation 2, which is a monopile driven into the seabed B, a transition piece 3 connected above the foundation 2, and a tower 4 connected further above the transition piece 3. The main bodies of the foundation 2, transition piece 3, and tower 4 each have a roughly circular cross section and are arranged coaxially in the vertical direction. Note that instead of a monopile foundation, the foundation 2 may be a tripile-type offshore wind turbine foundation or a jacket-type offshore wind turbine foundation, and the type of foundation is not particularly limited.

[0015] The upper end of the foundation 2 is located below sea level and has a tapered shape. The lower end of the transition piece 3 has a conical inner surface that corresponds to the tapered shape of the upper end of the foundation 2, and the transition piece 3 is installed on the foundation 2 so that this lower end covers the upper end of the foundation 2. During construction, the verticality of the transition piece 3 on the foundation 2 is adjusted, and then grout is filled between the lower end of the transition piece 3 and the upper end of the foundation 2. The foundation 2 and the transition piece 3 are joined (grout joined) via this grout, ensuring the verticality of the transition piece 3 and, ultimately, the verticality of the wind turbine 1. The tower 4 is a vertical column made of, for example, concrete or steel, and is bolted to the upper end of the transition piece 3.

[0016] FIG. 2 is an enlarged perspective view showing the vicinity of the bolted joint between the transition piece 3 and the tower 4. As shown in FIG. 2, a multi-tiered internal platform 9 is provided inside the transition piece 3 for operating and maintaining the wind turbine generator 1. Workers can move between the internal platforms 9 using a ladder or the like. Furthermore, an external platform 10 that extends horizontally outward from the outer circumferential surface 3a is provided at the upper end of the transition piece 3. Furthermore, an entrance / exit 11 for accessing and exiting the interior of the tower 4 is provided at the lower end of the tower 4, which is bolted to the transition piece 3. Workers who operate and maintain the wind turbine generator 1 move up the ladder to the external platform 10 from a ship moored at the landing 51 ( FIG. 1 ) near seawater level. The worker then opens the door of the entrance / exit 11 to enter the tower 4 and can further access the internal platform 9 via an internal ladder or the like. The external platform 10 is used not only as an access route for workers as described above, but also for purposes such as carrying in, carrying out, and temporarily storing materials, and a davit crane (not shown) is installed on the external platform 10, for example.

[0017] As shown in FIG. 3 , a landing 51 is provided on the outer peripheral surface 3a of the transition piece 3 near sea level W to allow workers to access the wind turbine generator 1 by boat. Here, "sea level W" refers to mean sea level. In the following, the terms "above sea level" and "below sea level" refer to the area above sea level W and the area below sea level W, respectively. The landing 51 is provided across sea level W, stretching from above to below sea level. The landing 51 has a fender 53 extending vertically and a ladder 55 attached to the fender 53. The fender 53 has two fenders 57 extending parallel to the vertical direction. The main portion of the fender 57 is made of a circular steel pipe. The ladder 55 extends vertically between the fenders 57.

[0018] The fenders 57, 57 and the ladder 55 both extend from above sea level to below sea level. The fender 53 is intended to prevent the above-mentioned vessel from directly colliding with the outer peripheral surface 3a of the transition piece 3. The fenders 57, 57 of the fender 53 have cylindrical portions that extend vertically at a position floating outward from the outer peripheral surface 3a, and have the function of cushioning contact when a vessel comes into contact. The ladder 55 is not directly connected to the outer peripheral surface 3a, but is supported at both ends in the width direction by the two fenders 57, 57. The ladder 55 is positioned closer to the outer peripheral surface 3a than the fenders 57, 57 to prevent the vessel from colliding.

[0019] Further above the dock 51, another ladder 56 is provided, which is attached directly to the outer peripheral surface 3a. This ladder 56 extends further upward from the dock 51, and its upper end reaches the external platform 10 (FIG. 2). The upper end of the ladder 55 on the dock 51 is connected to the lower end of this ladder 56. When a worker accesses the wind turbine generator 1, a ship is moored at the dock 51, and the worker transfers from the ship to the ladder 55. The worker then climbs the ladders 55 and 56 to reach the upper external platform 10, and can enter the interior of the transition piece 3 through the entrance 11 (FIG. 2), as described above. A rest platform (not shown) may be provided midway along the ladder 56, as appropriate.

[0020] Because the two fenders 57, 57 have nearly the same structure, the following description will focus on one fender 57 and omit redundant explanations. The fender 57 is joined to the outer peripheral surface 3a of the transition piece 3 at three locations: a position near the upper end, a position near the lower end, and a position midway between the upper and lower ends. Specifically, an upper mounting seat 60, an intermediate mounting seat 62, and a lower mounting seat 64 for mounting the fender 57 are provided on the outer peripheral surface 3a at approximately equal intervals and aligned vertically at different heights. Of these, the upper mounting seat 60 and the intermediate mounting seat 62 are located above sea level, and the lower mounting seat 64 is located below sea level.

[0021] In contrast, the fender 57 has a fender main body 59 made of a vertical circular steel pipe, and three connecting steel pipes 61, 63, and 65 extending horizontally from the side of the fender main body 59 toward the outer circumferential surface 3a. The connecting steel pipes 61, 63, and 65 are located at height positions corresponding to the above-mentioned mounting seats 60, 62, and 64, respectively. The connecting steel pipes 61, 63, and 65 are welded to the mounting seats 60, 62, and 64, respectively, thereby fixing the fender 57 to the outer circumferential surface 3a. The connecting steel pipes 61 and 63 of the fender 57 are located above sea level, and the connecting steel pipe 65 is located below sea level.

[0022] Additionally, four ladder support portions 58 for supporting a ladder 55 are provided on the side surface of the fender main body 59 on the outer peripheral surface 3a side. The four ladder support portions 58 are positioned approximately equally spaced apart so that they are lined up vertically at different heights. Each ladder support portion 58 is L-shaped in a plan view, and connects the side surface of the fender main body 59 to the side surface of the vertical support of the ladder 55 via this ladder support portion 58 at each height of the ladder 55. The number of ladder support portions 58 is not limited to four and may be changed as appropriate.

[0023] The fender 57 is composed of two parts, an upper part and an lower part. Specifically, the fender 57 has an upper part component 67 that forms the upper part of the fender 57, and a lower part component 69 that forms the lower part of the fender 57. The upper part component 67 includes the upper part of the fender main body 59, the connecting steel pipes 61 and 63, and all of the ladder support parts 58. The lower part component 69 includes the lower part of the fender main body 59 and the connecting steel pipe 65. The boundary between the upper part component 67 and the lower part component 69 is a connection part 71 between the upper and lower parts of the fender main body 59, which is located below sea level. The lower part component 69 is located below sea level and is joined by welding to a mounting seat 64 on the outer circumferential surface 3a below sea level. The upper component 67 is located across the seawater level W, extending from above to below the seawater level, and is connected to the lower component 69 at a connection portion 71 below the seawater level, and is joined by welding to the mounting seats 60, 62 above the seawater level.

[0024] FIG. 4 is a cross-sectional view showing the vicinity of connecting portion 71. Hereinafter, of fender main body 59, the portion that belongs to upper constituent portion 67 will be referred to as "fender main body upper portion 59A," and the portion that belongs to lower constituent portion 69 will be referred to as "fender main body lower portion 59B." As shown in the figure, a fitting recess 71b formed by opening the upper end face of a cylinder is formed at the upper end of fender main body lower portion 59B. Note that a partition plate 71d that forms the bottom wall of fitting recess 71b is provided in the hollow portion of fender main body lower portion 59B, and seawater is prevented from entering this hollow portion.

[0025] Correspondingly, a fitting protrusion 71a, which has a smaller diameter than the upper portion, is formed at the lower end of the fender main body upper portion 59A so as to protrude downward. The fitting recess 71b and the fitting protrusion 71a are fitted together with a buffer member 71c sandwiched between them. The buffer member 71c is a cylindrical rubber member that is sandwiched between the cylindrical inner surface of the fitting recess 71b and the cylindrical outer surface of the fitting protrusion 71a. The fender main body portion 59 is formed so that the outer peripheral surfaces of the fender main body upper portion 59A and the fender main body lower portion 59B are flush with each other. In this way, the upper constituent portion 67 of the fender 57 is attached to the lower constituent portion 69 using a fitting structure (socket structure). Furthermore, no other attachment structure (e.g., bolting, welding, etc.) is used in addition to this fitting structure. Therefore, by vertically moving the upper constituent part 67 relative to the lower constituent part 69 against the frictional resistance of the connecting part 71, the fitting convex part 71a can be inserted into or removed from the fitting concave part 71b in the vertical direction.

[0026] Here, if a ship collides strongly against the fender section 53, dents or scratches may occur in the fender 57, making it necessary to repair the landing section 51. A method for repairing the landing section 51 will be described below. It is believed that the portion of the fender section 53 that a ship collides with is mainly the portion above sea level. In other words, it is believed that dents and scratches on the fender 57 mainly occur in the upper fender body 59A. This repair method involves replacing the replacement unit 73, which includes the upper fender body 59A, with a new unit. The replacement unit 73 includes the two upper fender body parts 59A, the ladder 55, and the four connecting steel pipes 61, 63, 61, 63, and can be separated from the lower structural section 69 at the connecting section 71.

[0027] As shown in FIG. 5(a), for each of the two fenders 57 of the fender section 53, the connecting steel pipes 61, 63 are cut (e.g., thermally cut) from the mounting seats 60, 62 at a total of four locations. Furthermore, the ladders 55, 56 are disconnected. The replacement unit 73 is then lifted almost vertically using a crane or the like. As shown in FIG. 5(b), the mating protrusions 71a at the two connection sections 71 are removed from the mating recesses 71b, allowing the existing replacement unit 73 to be removed as a whole. At this time, the two buffer members 71c (FIG. 4) are also removed as appropriate. Even if the replacement unit 73 is lifted off-vertically, this does not pose a problem because the buffer members 71c are deformed as the mating protrusions 71a are removed from the mating recesses 71b at a slightly upward angle. Therefore, for example, to avoid interference between the ladders 55 and 56, the replacement unit 73 may be intentionally lifted at a slightly upward angle. After the replacement unit 73 is removed, the two lower constituent parts 69, the two mounting seats 60, and the two mounting seats 62 are left on the outer circumferential surface 3a.

[0028] Next, a new replacement unit 73 is prepared, and as shown in FIG. 6(a), the two mating protrusions 71a of the new replacement unit 73 are inserted into the mating recesses 71b of the two lower structural parts 69, respectively, and the replacement unit 73 is erected using a crane or other device. At this time, a new buffer member 71c is sandwiched between the mating recesses 71b and the mating protrusions 71a. In this way, the mating protrusions 71a are fitted into the mating recesses 71b, connecting the upper fender body 59A and the lower fender body 59B. Then, as shown in FIG. 6(b), the four connecting steel pipes 61, 63, 61, 63 of the replacement unit 73 are welded to the mounting seats 60, 62, 60, 62, respectively, and the ladder 55 is connected to the ladder 56. This completes the repair of the new boat landing 51 (FIG. 3).

[0029] Next, the effects of the landing 51 and its repair method will be described. In the landing 51, the lower component 69 and the upper component 67 of the fender 57 are connected by a fitting structure. With this configuration, when repairing the landing 51, the connecting steel pipes 61, 63 above the waterline can be cut to remove the upper component 67, leaving the lower component 69, and the replacement unit 73 can be removed. The replacement unit 73 can then be installed by fitting the upper component 67 to the remaining lower component 69 using the connecting part 71. After that, the connecting steel pipes 61, 63, 61, 63 can be welded together above the waterline. With this repair method, the fitting protrusion 71a simply needs to be fitted into the fitting recess 71b below the waterline; no work such as cutting or welding of steel pipes is required.

[0030] Furthermore, at the connection part 71 below sea level, the mating protrusion 71a is inserted, removed, and fitted into the mating recess 71b in a direction approximately vertical to eliminate the need for complex operations to move the replacement unit 73 when removing and installing the connection part 71. This also makes it possible to omit the need for diving work to guide the removal and installation near the connection part 71. As described above, this repair method reduces the amount of work required underwater when repairing the landing part 51. As mentioned above, it is believed that the part of the fender part 53 that is most likely to be hit by a ship is the part above sea level, and therefore, in many cases, there is no need to replace the lower structural part 69.

[0031] Furthermore, because buffer member 71c is sandwiched between mating recess 71b and mating protrusion 71a, when a boat collides with fender main body upper portion 59A, the horizontal force of the collision is transmitted to fender main body lower portion 59B via buffer member 71c, thereby cushioning the collision of the boat.

[0032] The present invention can be implemented in various forms, including the above-described embodiment, with various modifications and improvements based on the knowledge of those skilled in the art. It is also possible to create modified versions by utilizing the technical details described in the above-described embodiment. The configurations of the various embodiments may be combined as appropriate. For example, while the above embodiment describes an example in which the dock structure and dock repair method of the present invention are applied to an offshore wind turbine 1, the present invention can also be applied to other offshore structures. [Explanation of symbols]

[0033] 1...wind turbine generator (offshore structure), 3...transition piece, 3a...outer surface, 41...leg, 51...landing portion, 57...fender, 67...upper component, 69...lower component, 71b...engaging recess, 71a...engaging protrusion, W...sea surface.

Claims

1. A landing structure provided on a leg of an offshore structure, a fender fixed to an outer peripheral surface of the leg and extending from above sea level to below sea level, The fender is a lower component that is joined to the outer peripheral surface and that constitutes a lower portion of the fender; an upper constituent part that is attached to the lower constituent part by a fitting structure below the seawater level and is joined to the outer circumferential surface above the seawater level and forms an upper part of the fender, one of the upper constituent part and the lower constituent part has a fitting recess that opens to the other side, and the other has a fitting protrusion that protrudes to the one side and is inserted into the fitting recess, When the fitting convex portion and the fitting concave portion are fitted together, an outer circumferential surface of the upper constituent portion and an outer circumferential surface of the lower constituent portion are flush and continuous with each other, A boat landing structure in which a buffer member is sandwiched between the outer surface of the mating protrusion and the inner surface of the mating recess.

2. 2. The boat landing structure according to claim 1, wherein the lower end of the upper constituent part is removably inserted into the inside of the cylindrical upper end of the lower constituent part from above.

3. A method for repairing a landing structure according to claim 1 or 2, comprising: above the seawater surface, the existing upper constituent part is separated from the outer circumferential surface, and the upper constituent part is detached from the lower constituent part and removed; A method for repairing a landing portion, comprising fitting and attaching a lower end portion of a new replacement upper constituent part to the lower constituent part, and joining the upper constituent part to the outer peripheral surface above the seawater surface.

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