JP7386959B1 - Offshore wind turbine jacket structure and offshore wind turbine jacket structure welding method - Google Patents

Abstract

An object of the present invention is to provide a jacket structure for an offshore wind turbine and a welding method for the jacket structure for an offshore wind turbine, which can ensure sufficient fatigue strength at a connection part. SOLUTION: A first diagonal brace 40 that is a cylindrical member, a second diagonal brace 50 that is a cylindrical member and intersects with the first diagonal brace 40, and an offshore wind turbine 300 are installed; A jacket structure 100 for an offshore wind turbine includes a base 20 supported by a first diagonal brace 40 and a second diagonal brace 50, in which the intersection of the first diagonal brace 40 and the second diagonal brace 50 is welded on both sides. It is characterized by [Selection diagram] Figure 1

Description

The present invention relates to a jacket structure for an offshore wind turbine and a welding method for the jacket structure for an offshore wind turbine.

In order to place structures such as wind turbines used for wind power generation offshore, a jacket structure made of steel pipes is sometimes used.
Patent Document 1 discloses a structure for alleviating stress concentration at a joint between steel pipes, in which a joint is formed by overlapping steel pipes with different diameters, and grout is poured into the joint.
Patent Document 2 discloses a structure in which a wall is formed by arranging sheet piles in a row of piles and filled with backing material, in order to reduce the amount of steel in a seawall structure that is an offshore structure.

JP 2015-55045 Publication Japanese Patent Application Publication No. 2004-308328

In conventional jacket structures, when welding a steel pipe at a point, it was common to weld only from the outside of the steel pipe (one-sided welding).
However, when a wind turbine is placed offshore (an offshore wind turbine), the offshore wind turbine is placed under a severe fatigue environment. For this reason, with the above-mentioned one-sided welding, it has been impossible to provide the welded portion with sufficient fatigue strength.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a jacket structure for an offshore wind turbine and a welding method for the jacket structure for an offshore wind turbine, which can ensure sufficient fatigue strength at the connection part. With the goal.

<1> The jacket structure for an offshore wind turbine according to aspect 1 of the present invention includes a first diagonal brace that is a cylindrical member, and a second diagonal brace that is a cylindrical member and intersects with the first diagonal brace. and a stand on which an offshore wind turbine is installed and supported by the first diagonal brace and the second diagonal brace, the jacket structure for an offshore wind turbine comprising: the first diagonal brace and the second diagonal brace. The intersection with the brace is characterized by being welded on both sides.

According to this invention, the intersection of the first diagonal brace and the second diagonal brace is double-sided welded. Thereby, sufficient fatigue strength can be ensured at the connection portion between the first diagonal brace and the second diagonal brace.

<2> In the offshore wind turbine jacket structure according to Aspect 2 of the present invention, in the offshore wind turbine jacket structure according to Aspect 1, the outer diameter of the first diagonal brace is larger than the outer diameter of the second diagonal brace. It is characterized by being large.

According to this invention, the outer diameter of the first diagonal brace is larger than the outer diameter of the second diagonal brace. Thereby, it is possible to facilitate double-sided welding of the intersection between the first diagonal brace and the second diagonal brace.

<3> In the offshore wind turbine jacket structure according to aspect 3 of the present invention, in the offshore wind turbine jacket structure according to aspect 1 or aspect 2, the base is connected to the first diagonal brace and the above through a plurality of legs. a first leg can portion that is supported by a second diagonal brace and is a portion of one of the plurality of legs, the plate of the first leg can portion including an intersection between the one leg and an end of the first diagonal brace; The thickness of the second leg can portion, which is the one portion, is thinner than the plate thickness of the second leg can portion, which includes the intersection of the one portion and the end of the second diagonal brace.

According to this invention, the plate thickness of the first leg can portion including the intersection between one of the plurality of legs and the end of the first diagonal brace is equal to the thickness of the first leg can portion including the intersection between one of the plurality of legs and the end of the second diagonal brace. It is thinner than the plate thickness of the second leg can part including the intersection with . Thereby, the thickness of the first leg can portion can be suppressed. Therefore, the material cost of the legs can be reduced.

<4> The jacket structure for an offshore wind turbine according to aspect 4 of the present invention is the jacket structure for an offshore wind turbine according to any one of aspects 1 to 3, in which the base is connected to the a first leg can part that is supported by the first diagonal brace and the second diagonal brace and is one part of the plurality of legs, the first leg can part including the intersection of the one leg and the end of the first diagonal brace; The strength of the steel material of the first leg can part is lower than the strength of the steel material of the second leg can part, which is the one part, and includes the intersection of the one part and the end of the second diagonal brace. It is characterized by

According to this invention, the strength of the steel material of the first leg can portion including the intersection point between one of the plurality of legs and the end of the first diagonal brace is equal to The strength is weaker than the steel material of the second leg can part including the intersection with the part. Thereby, an inexpensive material can be used for the first leg can portion. Therefore, the material cost of the legs can be reduced.

<5> The offshore wind turbine jacket structure according to aspect 5 of the present invention is the offshore wind turbine jacket structure according to aspect 3 or aspect 4, wherein the steel material of the first leg can portion is SM490Y or SM520, and the steel material of the first leg can portion is SM490Y or SM520. The steel material of the 2-leg can part is SA440.

According to this invention, the steel material of the first leg can part is SM490Y or SM520, and the steel material of the second leg can part is SA440. Thereby, the strength of the steel material in the first leg can portion can be made weaker than the strength of the steel material in the second leg can portion. Therefore, the material cost of the legs can be reduced.

<6> The jacket structure for an offshore wind turbine according to aspect 6 of the present invention is the jacket structure for an offshore wind turbine according to any one of aspects 3 to 5, wherein the length of the first leg can portion is The length along one longitudinal direction is the length of the second leg can portion and is longer than the length along the longitudinal direction.

According to this invention, the length of the first leg can portion along one longitudinal direction is longer than the length of the second leg can portion along the longitudinal direction. With this, for example, when the outer diameter of the first diagonal brace is larger than the outer diameter of the second diagonal brace, it is possible to suppress the length of the second leg can part while making the length of the first leg can part sufficient. can. Therefore, the material cost of the legs can be reduced.

<7> A jacket structure for an offshore wind turbine according to aspect 7 of the present invention is the jacket structure for an offshore wind turbine according to any one of aspects 1 to 6, further comprising a third diagonal brace, and the base is , a first leg can portion that is supported by the first diagonal brace, the second diagonal brace, and the third diagonal brace via a plurality of legs, and is one portion of the plurality of legs, The third diagonal brace is connected to the first leg can portion including the intersection of the first diagonal brace and the end of the first diagonal brace, and the outer diameter of the third diagonal brace is smaller than the outer diameter of the second diagonal brace. , is characterized by being large.

According to this invention, the third diagonal brace is connected to the first leg can portion including the intersection of one of the plurality of legs and the end of the first diagonal brace, and the outer diameter of the third diagonal brace is It is larger than the outer diameter of the second diagonal brace. With this, for example, when the outer diameter of the first diagonal brace and the outer diameter of the third diagonal brace are made the same, the cross sections of the first diagonal brace and the third diagonal brace connected to the first leg can portion are unified. be able to. Therefore, it is possible to easily manage parts when manufacturing the jacket structure. Moreover, structural calculation of the jacket structure can be facilitated.

<8> A jacket structure for an offshore wind turbine according to aspect 8 of the present invention is the jacket structure for an offshore wind turbine according to any one of aspects 1 to 7, further comprising a fourth diagonal brace, and the base is , a second leg can portion that is supported by the first diagonal brace, the second diagonal brace, and the fourth diagonal brace via a plurality of legs, and is one portion of the plurality of legs; The fourth diagonal brace is connected to the second leg can portion including the intersection of the first diagonal brace and the end of the second diagonal brace, and the outer diameter of the fourth diagonal brace is smaller than the outer diameter of the first diagonal brace. It is characterized by its small size.

According to this invention, the fourth diagonal brace is connected to the second leg can portion including the intersection of one of the plurality of legs and the end of the second diagonal brace, and the outer diameter of the fourth diagonal brace is It is smaller than the outer diameter of the first diagonal brace. With this, for example, when the outer diameter of the second diagonal brace and the outer diameter of the fourth diagonal brace are made the same, the cross sections of the second diagonal brace and the fourth diagonal brace connected to the second leg can portion are unified. be able to. Therefore, it is possible to easily manage parts when manufacturing the jacket structure. Moreover, structural calculation of the jacket structure can be facilitated.

<9> The jacket structure for an offshore wind turbine according to aspect 9 of the present invention is the jacket structure for an offshore wind turbine according to any one of aspects 1 to 8, wherein the cylindrical portion of the second diagonal brace is , a cylindrical part within a predetermined range including the intersection of the first diagonal brace and the second diagonal brace is defined as a second neighboring part, and the cylindrical part of the second diagonal brace is smaller than the second neighboring part. A cylindrical part far from the intersection point is a second remote part, an outer diameter of the second neighboring part is greater than or equal to an outer diameter of the second remote part, and an inner diameter of the second neighboring part is greater than or equal to the outer diameter of the second neighboring part. It is characterized by having an inner diameter of less than or equal to the inner diameter of.

According to the invention, the outer diameter of the second proximate portion is greater than or equal to the outer diameter of the second distal portion, and the inner diameter of the second proximate portion is less than or equal to the inner diameter of the second distal portion. Therefore, the thickness of the second proximate portion is at least the same as or greater than the second remote portion. Thereby, the strength of the intersection in the second diagonal brace can be ensured. Further, when the plate thickness of the second neighboring portion is increased, the second neighboring portion can be more easily double-sided welded at the intersection with the first neighboring portion. This makes it possible to improve fatigue strength.
In addition, by making the plate thickness of the second remote part smaller than that of the second neighboring part, while ensuring sufficient strength against bending moments etc. in the second neighboring part, the weight of the entire second diagonal brace is increased more than necessary. can be prevented from happening.

<10> The jacket structure for an offshore wind turbine according to Aspect 10 of the present invention is the jacket structure for an offshore wind turbine according to Aspect 9, wherein between the inner surface of the second proximate portion and the inner surface of the second remote portion. It is characterized by further comprising a tapered portion provided at the.

According to the invention, a tapered portion is provided between the inner surface of the second proximal portion and the inner surface of the second remote portion. Thereby, the second neighboring part and the second remote part can be connected by continuously changing the distance between the second neighboring part and the second remote part. Therefore, it is possible to suppress stress concentration occurring at the connection portion between the second nearby portion and the second remote portion.

<11> In the jacket structure for an offshore wind turbine according to Aspect 11 of the present invention, in the jacket structure for an offshore wind turbine according to Aspect 10, the tapered portion and the second remote portion are formed from the inside of the second diagonal brace. It is characterized by being welded on one side.

According to the invention, the tapered portion and the second remote portion are welded on one side from the inside of the second diagonal brace. Here, if the inner diameter of the second proximate portion is less than or equal to the inner diameter of the second remote portion, stress concentration is likely to occur on the inner surface of the second diagonal brace at the boundary between the tapered portion and the second remote portion. Weld defects are particularly likely to occur at the root portion of the weld. By welding one side from the inside of the second diagonal brace, the root portion can be placed outside the second diagonal brace. Therefore, at the boundary between the tapered portion and the second remote portion, it is possible to move the welding root portion away from a location where stress concentration is likely to occur. Therefore, the decrease in fatigue life at the boundary can be suppressed.

<12> The jacket structure for an offshore wind turbine according to aspect 12 of the present invention is the jacket structure for an offshore wind turbine according to any one of aspects 1 to 8, wherein the cylindrical portion of the second diagonal brace is , a cylindrical part within a predetermined range including the intersection of the first diagonal brace and the second diagonal brace is defined as a second neighboring part, and the cylindrical part of the second diagonal brace is smaller than the second neighboring part. A cylindrical portion far from the intersection is defined as a second remote portion, the outer diameter of the second remote portion is greater than or equal to the outer diameter of the second neighboring portion, and the inner diameter of the second remote portion is greater than or equal to the outer diameter of the second neighboring portion. It is characterized by having an inner diameter of less than or equal to the inner diameter of.

According to this invention, the outer diameter of the second remote portion is greater than or equal to the outer diameter of the second proximate portion, and the inner diameter of the second distal portion is less than or equal to the inner diameter of the second proximate portion. Therefore, the plate thickness of the second remote portion is at least the same as or greater than the second neighboring portion. Thereby, sufficient strength against bending moments and the like can be ensured in the second remote portion.

<13> In the offshore wind turbine jacket structure according to Aspect 13 of the present invention, in the offshore wind turbine jacket structure according to Aspect 12, between the outer surface of the second proximate portion and the outer surface of the second remote portion. It is characterized by further comprising a tapered portion provided at the.

According to the invention, a tapered portion is provided between the outer surface of the second proximal portion and the outer surface of the second remote portion. Thereby, the second neighboring part and the second remote part can be connected by continuously changing the distance between the second neighboring part and the second remote part. Therefore, it is possible to suppress stress concentration occurring at the connection portion between the second nearby portion and the second remote portion.

<14> In the jacket structure for an offshore wind turbine according to Aspect 14 of the present invention, in the offshore wind turbine jacket structure according to Aspect 13, the tapered portion and the second neighboring portion are formed from the outside of the second diagonal brace. It is characterized by being welded on one side.

According to this invention, the tapered portion and the second neighboring portion are welded on one side from the outside of the second diagonal brace. Here, if the outer diameter of the second remote portion is greater than or equal to the outer diameter of the second proximate portion, stress concentration is likely to occur on the outer surface of the second diagonal brace at the boundary between the tapered portion and the second proximate portion. Weld defects are particularly likely to occur at the root portion of the weld. By performing single-sided welding from the outside of the second diagonal brace, the root portion can be placed inside the second diagonal brace. Therefore, at the boundary between the tapered portion and the second neighboring portion, it is possible to move the welding root portion away from a location where stress concentration is likely to occur. Therefore, the decrease in fatigue life at the boundary can be suppressed.

<15> The offshore wind turbine jacket structure according to aspect 15 of the present invention is the offshore wind turbine jacket structure according to any one of aspects 1 to 14, wherein the outer diameter of the first diagonal brace is 1. The diagonal brace is characterized by having the same diameter over its entire length.

According to this invention, the outer diameter of the first diagonal brace is the same over the entire length of the first diagonal brace. Thereby, for example, it is possible to easily provide a stainless steel plate for rust prevention on the outer peripheral surface of the first diagonal brace.

<16> A jacket structure for an offshore wind turbine according to aspect 16 of the present invention includes a plurality of cylindrical legs and a cylindrical member, a first diagonal brace connected to the legs, and a cylindrical member. a second diagonal brace that is connected to the leg and intersects with the first diagonal brace, supported by the leg, the first diagonal brace, and the second diagonal brace; A jacket structure for an offshore wind turbine, comprising: a stand on which the first diagonal brace is installed; an outer diameter of the first diagonal brace is larger than an outer diameter of the second diagonal brace; a double-sided weld provided at an intersection with the brace and an intersection between the second diagonal brace and one of the legs; and a cylindrical portion of the second diagonal brace, wherein the second diagonal brace a brace vicinity portion that is a cylindrical portion within a predetermined range including the intersection with the first diagonal brace; and a cylindrical portion of the second diagonal brace from the intersection of the second diagonal brace and the first diagonal brace. and a cylindrical portion of the second diagonal brace, which is a cylindrical portion of the second diagonal brace, within a predetermined range including the intersection of the second diagonal brace and the one. a cylindrical portion of the second diagonal brace that is a cylindrical portion of the second diagonal brace, and a remote portion of the leg that is a cylindrical portion that is farther from the intersection of the second diagonal brace and the first diagonal brace than the adjacent leg portion; and a one-sided welded portion provided between and.

According to this invention, the double-sided welded portion is provided at the intersection of the first diagonal brace and the second diagonal brace and the intersection of the second diagonal brace and one of the legs. In other words, the intersection between the first diagonal brace and the second diagonal brace and the intersection between the second diagonal brace and one of the legs are welded on both sides. Thereby, sufficient fatigue strength can be ensured at the intersection between the first diagonal brace and the second diagonal brace and the intersection between the second diagonal brace and one of the legs.

A single-sided weld is provided between the proximal brace portion and the distal brace portion and between the proximal leg portion and the distal leg portion. That is, the portions near the brace and the remote portions of the brace and between the near portions of the legs and the remote portions of the legs are welded on one side. Thereby, for example, by double-sided welding each welding part in the jacket structure, it is possible to avoid leaving the operator behind inside the jacket structure.

<17> A method for welding a jacket structure for an offshore wind turbine according to aspect 17 of the present invention includes a plurality of cylindrical legs, a cylindrical member, a first diagonal brace connected to the legs, and a cylindrical member. a second diagonal brace connected to the leg and intersecting with the first diagonal brace, supported by the leg, the first diagonal brace, and the second diagonal brace, and A method for welding a jacket structure for an offshore wind turbine, comprising: a stand on which an offshore wind turbine is installed; the outer diameter of the first diagonal brace is larger than the outer diameter of the second diagonal brace; a double-sided welding step of welding both sides of the intersection of the brace and the second diagonal brace and the intersection of the second diagonal brace and one of the legs; and after the double-sided welding step, the cylinder of the second diagonal brace is a brace-near portion that is a cylindrical portion within a predetermined range including the intersection of the second diagonal brace and the first diagonal brace, and a cylindrical portion of the second diagonal brace, A cylindrical portion of the second diagonal brace is welded on one side between the two diagonal braces and a brace remote portion, which is a cylindrical portion farther from the intersection of the first diagonal brace than a portion near the brace. , a leg vicinity portion that is a cylindrical portion within a predetermined range including an intersection of the second diagonal brace and the one, and a cylindrical portion of the second diagonal brace, the second diagonal brace and the one and a leg remote part, which is a cylindrical part that is farther from the intersection point than the leg vicinity part, and a one-sided welding step of welding the leg remote part on one side.

According to this invention, a double-sided welding step of welding both sides of the intersection of the first diagonal brace and the second diagonal brace and the intersection of the second diagonal brace and one of the legs; and a single-sided welding step between the leg portion and the brace remote portion, and a single-sided welding step between the leg proximal portion and the leg remote portion.

Here, when the first diagonal brace is an integral cylindrical member, double-sided welding of both ends of the first diagonal brace to the leg means that the worker will be left inside the first diagonal brace after welding work. That is impossible. On the other hand, by performing the single-sided welding process after the double-sided welding process, it is possible to avoid the operator from being left behind inside, and to connect the intersection between the first diagonal brace and the second diagonal brace and the position between the second diagonal brace and the leg. It is possible to weld both sides of the intersection with one. Therefore, it is possible to ensure the welding strength at each intersection point where both sides are welded.

According to the present invention, it is possible to provide a jacket structure for an offshore wind turbine and a welding method for the jacket structure for an offshore wind turbine, which can ensure sufficient fatigue strength at the connection portion.

FIG. 1 is a front view of a jacket structure for an offshore wind turbine according to the present embodiment. FIG. 2 is an enlarged sectional view of section II shown in FIG. 1. FIG. It is an enlarged view of a K-shaped groove. This is the positional relationship between the first diagonal brace and the second diagonal brace, or the third diagonal brace and the fourth diagonal brace when viewed from the axial direction of the leg. FIG. 2 is an enlarged sectional view of the V section shown in FIG. 1. FIG. FIG. 2 is an enlarged sectional view of the VI section shown in FIG. 1. FIG. This is the positional relationship between the second proximal portion and the second remote portion when viewed from the axial direction of the second diagonal brace. This is the positional relationship between the near portion of the second leg and the remote portion of the second leg when viewed from the axial direction of the second diagonal brace. It is an enlarged view of a rectangular groove. FIG. 3 is a cross-sectional view of the intersection of the first diagonal brace and the second diagonal brace when viewed from the axial direction of the first diagonal brace. FIG. 2 is an enlarged sectional view of the V section shown in FIG. 1 in the second embodiment. FIG. 2 is an enlarged sectional view of the VI section shown in FIG. 1 in the second embodiment. FIG. 2 is an enlarged sectional view of a modified example of the V portion shown in FIG. 1;

(First embodiment)
EMBODIMENT OF THE INVENTION Hereinafter, with reference to drawings, the jacket structure 100 for offshore wind turbines and the welding method of the jacket structure 100 for offshore wind turbines which concern on one Embodiment of this invention are demonstrated.
The offshore wind turbine jacket structure 100 is installed on the ocean via piles L driven into the ground such as the seabed. As shown in FIG. 1, an offshore wind turbine jacket structure 100 is used to support an offshore wind turbine 300.

(About offshore wind turbine jacket structure 100)
As shown in FIG. 1, the offshore wind turbine jacket structure 100 includes a leg 10, a stand 20, a skirt sleeve 30, a first diagonal brace 40, a second diagonal brace 50, a third diagonal brace 60, A fourth diagonal brace 70.

A plurality of legs 10 are provided in the jacket structure 100 for an offshore wind turbine. In this embodiment, the number of legs 10 is four. As shown in FIG. 1, the leg 10 extends, for example, in the vertical direction. For example, the tube axis of the leg 10 is inclined with respect to the vertical direction. The upper end of the leg 10 is connected to a stand 20. The lower end of the leg 10 is connected to the stake L via a skirt sleeve 30. For example, a steel pipe is preferably used for the leg 10. A first diagonal brace 40 , a second diagonal brace 50 , a third diagonal brace 60 , and a fourth diagonal brace 70 are connected to the leg 10 .

In this embodiment, a double-sided weld BW is provided at the intersection of the second diagonal brace 50 and one of the plurality of legs 10, as shown in FIG. That is, the second diagonal brace 50 and one of the plurality of legs 10 are welded on both sides. This ensures sufficient fatigue strength at the connection between the second diagonal brace 50 and the leg 10. At this time, the double-sided welded portion BW is provided with both-side grooves or K-shaped grooves K, for example, as shown in FIG.
As shown in FIG. 1, the leg 10 includes a first leg can portion 11, a second leg can portion 12, and a straight pipe portion 13.

The first leg can portion 11 is one portion of the plurality of legs 10. The first leg can portion 11 includes the intersection of one of the plurality of legs 10 and the end of the first diagonal brace 40 . That is, the first diagonal brace 40 is connected to the first leg can portion 11. Further, a third diagonal brace 60 is connected to the first leg can portion 11 (details will be described later). In this embodiment, the length of the first leg can portion 11 along one longitudinal direction of the leg 10 is, for example, 1.5 to 2.5 times the outer diameter of the first diagonal brace 40. be.

The second leg can portion 12 is one portion of the plurality of legs 10. The second leg can portion 12 includes the intersection of one of the plurality of legs 10 and an end of the second diagonal brace 50. That is, the second diagonal brace 50 is connected to the second leg can portion 12. Further, a fourth diagonal brace 70 is connected to the second leg can portion 12 (details will be described later). In this embodiment, the length of the second leg can portion 12 along one longitudinal direction of the leg 10 is, for example, 1.5 to 2.5 times the outer diameter of the second diagonal brace 50. be.
The straight pipe portion 13 is a portion of the leg 10 other than the first leg can portion 11 and the second leg can portion 12. The straight pipe portion 13 is located, for example, between the first leg can portion 11 and the second leg can portion 12.

In this embodiment, the first leg can part 11 and the second leg can part 12 in one of the legs 10 have the following relationship.
For example, the length of the first leg can section 11 along one longitudinal direction of the leg 10 is longer than the length of the second leg can section 12 along one longitudinal direction of the leg 10. ,long. This corresponds to the fact that the diameter of the first diagonal brace 40 connected to the first leg can part 11 is larger than the diameter of the second diagonal brace 50 connected to the second leg can part 12 (details will be described later). .

For example, the strength of the steel material of the first leg can part 11 is lower than the strength of the steel material of the second leg can part 12. Specifically, the above relationship is ensured as follows.
For example, the thickness of the first leg can part 11 is made thinner than the thickness of the second leg can part 12. For example, the first leg can part 11 is made of a steel material having lower strength than the second leg can part 12. In this case, the steel material of the first leg can portion 11 is, for example, SM490Y or SM520. The steel material of the second leg can portion 12 is, for example, SA440.
As described above, when different steel materials are used for the first leg can part 11 and the second leg can part 12, the first leg can part 11, the second leg can part 12, and the straight pipe part 13 are connected by, for example, welding. Ru.

Further, the outer diameters of the first leg can part 11 and the second leg can part 12 of the leg 10 are the same as those of the first leg vicinity part 43 of the first diagonal brace 40 and the second leg vicinity part 54 of the second diagonal brace 50, which will be described later. It is preferably larger than the outer diameter. With such a configuration, for example, as shown in FIG. That is, when the axial end of the first diagonal brace 40 or the axial end of the second diagonal brace 50 is brought into contact with the outer peripheral surface of the leg 10, the The radial end of the first diagonal brace 40 or the second diagonal brace 50 is located closer to the axial center of the leg 10 than the radial end of the first leg can portion 11 or the second leg can portion 12. becomes.

Then, for example, as shown in FIG. 4, in a direction orthogonal to both the axial direction of the first diagonal brace 40 and the axial direction of the leg 10, the radial end of the first diagonal brace 40 and the first leg can portion If the angle A formed by the outer circumferential surface of the first diagonal brace 40 and the first leg can portion 11 is 180° when the outer diameter of the first diagonal brace 40 and the outer diameter of the first leg can portion 11 are equal, the state is closer to a right angle. becomes. This is the angle between the radial end of the second diagonal brace 50 and the outer peripheral surface of the second leg can portion 12 in a direction perpendicular to both the axial direction of the second diagonal brace 50 and the axial direction of the leg 10. If the angle A is 180° when the outer diameter of the second diagonal brace 50 and the outer diameter of the second leg can portion 12 are equal, the angle A will be closer to a right angle. By adopting such a mode, it becomes easy to provide both side grooves or a K-shaped groove K at the end of the first diagonal brace 40 or the second diagonal brace 50.

As shown in FIG. 1, the offshore wind turbine 300 is installed on the platform 20. In addition, the stand 20 is supported by the first diagonal brace 40 , the second diagonal brace 50 , the third diagonal brace 60 , and the fourth diagonal brace 70 via the plurality of legs 10 . The platform 20 is a so-called transition piece in a known jacket structure used as a marine structure.

The skirt sleeve 30 is a part provided at the lower end of the leg 10 and used to connect the leg 10 and the stake L. Thereby, the offshore wind turbine jacket structure 100 is installed on the ocean via the pile L driven into the ground such as the seabed.

The first diagonal brace 40 is a cylindrical member. For example, a steel pipe is preferably used for the first diagonal brace 40. In this embodiment, the outer diameter of the first diagonal brace 40 is the same over the entire length of the first diagonal brace 40. The first diagonal brace 40 includes a first proximal portion 41, a first distal portion 42, a first leg proximal portion 43, and a first leg distal portion 44 (see FIGS. 2 and 5).

As shown in FIG. 5, the first neighboring portion 41 is a cylindrical portion of the first diagonal brace 40, and is a cylindrical portion within a predetermined range including the intersection of the first diagonal brace 40 and the second diagonal brace 50. It is. The predetermined range refers to the range in the longitudinal direction of the first diagonal brace 40. Preferably, the predetermined range is approximately 1.5 to 2.5 times the outer diameter of the first neighboring portion 41.
The first remote portion 42 is a cylindrical portion of the first diagonal brace 40 that is farther from the intersection than the first proximal portion 41 .

As shown in FIG. 2, the first leg vicinity portion 43 is a cylindrical portion of the first diagonal brace 40, and is a cylindrical portion within a predetermined range including the intersection of the first diagonal brace 40 and one of the legs 10. It is. The predetermined range refers to the range in the longitudinal direction of the first diagonal brace 40. The dimensions of the predetermined range can be appropriately set based on the cross-sectional force distribution and the brace diameter. The predetermined range is preferably 2.0 m or less in consideration of welding workability.
First leg distal portion 44 is a cylindrical portion of first diagonal brace 40 that is farther from the intersection of first diagonal brace 40 and one of the legs 10 than first leg proximal portion 43 .

The second diagonal brace 50 is a cylindrical member and intersects with the first diagonal brace 40. For example, a steel pipe is preferably used for the second diagonal brace 50. As shown in FIGS. 1 and 5, the second diagonal brace 50 includes two cylindrical members. In other words, the second diagonal brace 50 is divided into two. As shown in FIG. 1, the first diagonal brace 40 and the second diagonal brace 50 are arranged in an X-shape. For example, the X-shape may be provided in only one stage in the jacket structure 100 for an offshore wind turbine. In this embodiment, the X-shape is provided in two stages in the vertical direction (details will be described later). Furthermore, the X-shape may be provided in three or more stages in the vertical direction. In this embodiment, a double-sided welded portion BW is provided at the intersection of the first diagonal brace 40 and the second diagonal brace 50, as shown in FIG. That is, the first diagonal brace 40 and the second diagonal brace 50 are welded on both sides. More specifically, each of the cylindrical members included in the second diagonal brace 50 is joined to the first diagonal brace 40 at the intersection by double-sided welding. This ensures sufficient fatigue strength at the connection between the first diagonal brace 40 and the second diagonal brace 50. For example, as shown in FIG. 3, the double-sided welded portion BW is provided with both-side grooves or K-shaped grooves K.

The second diagonal brace 50 includes a second proximal portion 51, a second distal portion 52, a tapered portion 53, a second leg proximal portion 54, a second leg distal portion 55, and a leg tapered portion 56. (See Figures 5 and 6).
The second neighboring portion 51 is a cylindrical portion of the second diagonal brace 50, and is a cylindrical portion within a predetermined range including the intersection of the second diagonal brace 50 and the first diagonal brace 40. The predetermined range refers to the range in the longitudinal direction of the second diagonal brace 50. The dimensions of the predetermined range can be appropriately set based on the cross-sectional force distribution and the brace diameter. In consideration of welding workability, the predetermined range is preferably 2.0 m or less, more preferably 1.5 m or less.

The second remote portion 52 is a cylindrical portion of the second diagonal brace 50 that is farther from the intersection of the second diagonal brace 50 and the first diagonal brace 40 than the second proximal portion 51 . In this embodiment, a one-sided weld OW is provided between the second proximal portion 51 and the second remote portion 52. That is, the second proximate portion 51 and the second remote portion 52 are connected by one-sided welding (details will be described later).
The relationship between the outer diameter and inner diameter of each of the second proximal portion 51 and the second remote portion 52 is as follows.
That is, the outer diameter of the second proximate portion 51 is greater than or equal to the outer diameter of the second remote portion 52. That is, the outer diameter of the second proximal portion 51 is equal to or greater than the outer diameter of the second remote portion 52 . The outer circumferential surface of the second proximate portion 51 is flush with the outer circumferential surface of the second remote portion 52, or is located radially outward than the outer circumferential surface of the second remote portion 52. Here, being flush means that the outer circumferential surface of the second neighboring portion 51 is not located outside the outer circumferential surface of the second remote portion 52 and is located inside the outer circumferential surface of the second remote portion 52. means not located.

Further, the inner diameter of the second proximate portion 51 is at least equal to or smaller than the inner diameter of the second remote portion 52 . The inner circumferential surface of the second proximate portion 51 may be flush with the inner circumferential surface of the second remote portion 52 . Here, being flush means that, in the radial direction of the second diagonal brace 50, the inner circumferential surface of the second proximate portion 51 is not located inside the inner circumferential surface of the second remote portion 52, and This means that it is not located outside the inner circumferential surface of the second remote portion 52. That is, it means that the inner diameter of the second proximal portion 51 is equal to the inner diameter of the second remote portion 52. The inner circumferential surface of the second proximate portion 51 may be located radially inner than the inner circumferential surface of the second remote portion 52 .

For example, as shown in FIG. 5, in this embodiment, the outer circumferential surface of the second proximate portion 51 is flush with the outer circumferential surface of the second remote portion 52. The inner circumferential surface of the second proximate portion 51 is located radially inner than the inner circumferential surface of the second remote portion 52 . With such a relationship, the orthogonal projection of the second proximate portion 51 when projected onto a plane perpendicular to the longitudinal axis of the second diagonal brace 50 is the same as the orthogonal projection when the second remote portion 52 is projected onto the plane. Cover the orthographic projection. In other words, as shown in FIG. 7, when viewed from the axial direction of the second diagonal brace 50, the cross section of the second remote portion 52 is located within the cross section of the second proximal portion 51. Therefore, the cross-sectional area of the second proximal portion 51 in a plane orthogonal to the longitudinal axis of the second diagonal brace 50 is larger than the cross-sectional area of the second remote portion 52 . Further, the thickness of the second nearby portion 51 is greater than the thickness of the second remote portion 52.

A tapered portion 53 is provided between the inner surface of the second proximal portion 51 and the inner surface of the second distal portion 52 . More specifically, as shown in FIG. 5, the tapered portion 53 is a portion provided in an inclined manner so as to connect the inner surface of the second neighboring portion 51 and the inner surface of the second remote portion 52. be. The tapered portion 53 connects the second proximal portion 51 and the second distal portion 52 by varying continuously between the second proximal portion 51 and the second distal portion 52 .

In this embodiment, the tapered portion 53 is formed integrally with the second neighboring portion 51. The second proximal portion 51 and the second remote portion 52 are connected by welding the tapered portion 53 and the second remote portion 52. Note that the tapered portion 53 and the second remote portion 52 are welded on one side from the inside of the second diagonal brace 50. Further, as shown in FIG. 9, a V-shaped groove SB or a V-shaped groove is provided between the inner surface of the tapered portion 53 and the inner surface of the second remote portion 52. When the difference between the plate thickness of the second proximate portion 51 and the plate thickness of the second remote portion 52 is small, the second proximate portion 51 and the second remote portion 52 may be directly welded. In this case, the welded portion may be the tapered portion 53.

The second leg vicinity portion 54 is a cylindrical portion of the second diagonal brace 50, as shown in FIG. It is. The predetermined range refers to the range in the longitudinal direction of the second diagonal brace 50. The dimensions of the predetermined range can be appropriately set based on the cross-sectional force distribution and the brace diameter. The predetermined range is preferably 1.5 m or less in consideration of welding workability.

The second leg distal portion 55 is the cylindrical portion of the second diagonal brace 50 that is farther from the intersection of the second diagonal brace 50 and one of the legs 10 than the second leg proximal portion 54 . In this embodiment, a single-sided weld OW is provided between the second leg proximal portion 54 and the second leg remote portion 55. That is, the second leg near portion 54 and the second leg remote portion 55 are connected by one-sided welding (details will be described later).
The relationship between the outer diameter and inner diameter of the second leg near portion 54 and the second leg remote portion 55 is as follows.
That is, the outer circumferential surface of the second leg proximal portion 54 is located on the outer side in the radial direction than the outer circumferential surface of the second leg remote portion 55. That is, the outer diameter of the second leg proximal portion 54 is larger than the outer diameter of the second leg remote portion 55.

Further, the inner diameter of the second leg proximal portion 54 is at least equal to or smaller than the inner diameter of the second leg remote portion 55 . The inner circumferential surface of the second leg proximal portion 54 may be flush with the inner circumferential surface of the second leg remote portion 55 . Here, being flush means that in the radial direction of the second diagonal brace 50, the inner circumferential surface of the second leg near portion 54 is not located inside the inner circumferential surface of the second leg remote portion 55; This also means that it is not located outside the inner circumferential surface of the second leg remote portion 55. That is, it means that the inner diameter of the second leg proximal portion 54 is equal to the inner diameter of the second leg remote portion 55. The inner circumferential surface of the second leg proximal portion 54 may be located radially inner than the inner circumferential surface of the second leg remote portion 55.

For example, as shown in FIG. 6, in the present embodiment, the outer circumferential surface of the second leg near portion 54 is located on the outer side in the radial direction than the outer circumferential surface of the second leg remote portion 55. The inner circumferential surface of the second leg proximate portion 54 is flush with the inner circumferential surface of the second leg remote portion 55 . By having such a relationship, the orthogonal projection when the second leg near portion 54 is projected onto a plane perpendicular to the longitudinal axis of the second diagonal brace 50 is the same as the second leg remote portion 55 projected onto the plane. Covers the orthographic projection. In other words, as shown in FIG. 8, when viewed from the axial direction of the second diagonal brace 50, the cross section of the second leg distal portion 55 is located within the cross section of the second leg proximal portion 54. Therefore, the cross-sectional area of the second leg proximal portion 54 in a plane orthogonal to the longitudinal axis of the second diagonal brace 50 is larger than the cross-sectional area of the second leg remote portion 55 . Further, the thickness of the second leg near portion 54 is greater than the thickness of the second leg remote portion 55.

As shown in FIG. 6, the leg tapered portion 56 is a portion provided in an inclined manner so as to connect the outer surface of the second leg near portion 54 and the outer surface of the second leg remote portion 55. The leg tapered portion 56 connects the second leg proximal portion 54 and the second leg distal portion 55 by varying continuously between the second leg proximal portion 54 and the second leg distal portion 55 .

In this embodiment, the leg tapered portion 56 is formed integrally with the second leg vicinity portion 54. The second leg near portion 54 and the second leg remote portion 55 are connected by welding the leg tapered portion 56 and the second leg remote portion 55. Note that the leg tapered portion 56 and the second leg remote portion 55 are welded on one side from the outside of the second diagonal brace 50. Further, as shown in FIG. 9, a V-shaped groove SB or a V-shaped groove is provided between the outer surface of the leg tapered portion 56 and the outer surface of the second leg remote portion 55. If the difference between the thickness of the second leg near portion 54 and the second leg remote portion 55 is small, the second leg near portion 54 and the second leg remote portion 55 may be directly welded. In this case, the welded portion may be the leg tapered portion 56.

As described above, the intersection of the first diagonal brace 40 and the second diagonal brace 50 is double-sided welded. This ensures sufficient strength at the connection between the first diagonal brace 40 and the second diagonal brace 50. At this time, as shown in FIG. 3, a double-sided groove or a K-shaped groove K is provided at the intersection of the first diagonal brace 40 and the second diagonal brace 50.

Further, as shown in FIG. 5, the outer diameter of the first diagonal brace 40 is larger than the outer diameter of the second diagonal brace 50. That is, the outer diameter of the first diagonal brace 40 is larger than at least the outer diameter of the second neighboring portion 51 of the second diagonal brace 50. With such a configuration, when the second neighboring part 51 is aligned with the side surface of the first neighboring part 41, as shown in FIG. 50 in the radial direction (that is, in the vertical direction in the drawing) is located closer to the axial center of the first neighboring portion 41 than the radial end of the first neighboring portion 41.

Then, for example, as shown in FIG. 10, when viewed along the axial direction of the first diagonal brace 40, the radial end of the second diagonal brace 50 and the outer circumferential surface of the first neighboring portion 41 form a When the angle B is 180° when the outer diameter of the second diagonal brace 50 and the outer diameter of the first neighboring portion 41 are equal, the state becomes closer to a right angle. With this configuration, it is easy to provide both side grooves or K-shaped grooves K at the end portions of the second diagonal brace 50.

The third diagonal brace 60 is a cylindrical member, as shown in FIG. For example, a steel pipe is preferably used for the third diagonal brace 60. As mentioned above, the third diagonal brace 60 is connected to the first leg can portion 11 of the leg 10 along with the first diagonal brace 40, as shown in FIG. As described above, in this embodiment, the number of legs 10 in the offshore wind turbine jacket structure 100 is four. Therefore, for example, as shown in FIG. 4, the third diagonal brace 60 and the first diagonal brace 40 are substantially perpendicular to each other when viewed from the axial direction of the leg 10. For example, in FIG. 1, when the first diagonal brace 40 is located in the left-right direction in the paper, the third diagonal brace 60 is located in the depth direction in the paper.

As shown in FIGS. 1 and 4, the third diagonal brace 60 is connected to the first leg can portion 11 to which the first leg vicinity portion 43 of the first diagonal brace 40 is connected.
The configuration of the third diagonal brace 60 is, for example, similar to the configuration of the first diagonal brace 40 described above. For example, in this embodiment, the outer diameter of the third diagonal brace 60 is larger than the outer diameter of the second diagonal brace 50. The outer diameter of the third diagonal brace 60 may be the same over the entire length of the third diagonal brace 60.

The fourth diagonal brace 70 is a cylindrical member. For example, a steel pipe is preferably used for the fourth diagonal brace 70. As mentioned above, the fourth diagonal brace 70 is connected to the second leg can portion 12 of the leg 10 along with the second diagonal brace 50. As described above, in this embodiment, the number of legs 10 in the offshore wind turbine jacket structure 100 is four. Therefore, for example, as shown in FIG. 4, when viewed from the axial direction of the leg 10, the fourth diagonal brace 70 is orthogonal to the second diagonal brace 50. For example, in FIG. 1, when the second diagonal brace 50 is located in the left-right direction in the paper, the fourth diagonal brace 70 is located in the depth direction in the paper.

As shown in FIGS. 1 and 4, the fourth diagonal brace 70 is connected to the second leg can portion 12 to which the second leg vicinity portion 54 of the second diagonal brace 50 is connected.
The configuration of the fourth diagonal brace 70 is, for example, similar to the configuration of the second diagonal brace 50 described above. For example, in this embodiment, the outer diameter of the fourth diagonal brace 70 is smaller than the outer diameter of the first diagonal brace 40. The fourth diagonal brace 70 includes two cylindrical members. In other words, the fourth diagonal brace 70 is divided into two.
Each of the above configurations constitutes the offshore wind turbine jacket structure 100 according to the present embodiment.

As described above, according to the jacket structure 100 for an offshore wind turbine according to the present embodiment, the intersection between the first diagonal brace 40 and the second diagonal brace 50 is double-sided welded. Thereby, sufficient fatigue strength can be ensured at the connection portion between the first diagonal brace 40 and the second diagonal brace 50.

Further, the outer diameter of the first diagonal brace 40 is larger than the outer diameter of the second diagonal brace 50. Thereby, the intersection between the first diagonal brace 40 and the second diagonal brace 50 can be easily welded on both sides.

Further, the thickness of the first leg can portion 11 including the intersection between one of the plurality of legs 10 and the end of the first diagonal brace 40 is equal to It is thinner than the plate thickness of the second leg can part 12 including the intersection with the part. Thereby, the thickness of the first leg can portion 11 can be suppressed. Therefore, the material cost of the leg 10 can be suppressed.

Further, the strength of the steel material of the first leg can portion 11 including the intersection point between one of the plurality of legs 10 and the end of the first diagonal brace 40 is determined by The strength is lower than the strength of the steel material of the second leg can portion 12 including the intersection with the end portion. Thereby, an inexpensive material can be used for the first leg can portion 11. Therefore, the material cost of the leg 10 can be suppressed.

Further, the steel material of the first leg can part 11 is SM490Y or SM520, and the steel material of the second leg can part 12 is SA440. Thereby, the strength of the steel material of the first leg can part 11 can be made weaker than the strength of the steel material of the second leg can part 12. Therefore, the material cost of the leg 10 can be suppressed.

Further, the length of the first leg can portion 11 along one longitudinal direction is longer than the length of the second leg can portion 12 along the longitudinal direction. Thereby, for example, when the outer diameter of the first diagonal brace 40 is larger than the outer diameter of the second diagonal brace 50, the length of the second leg can portion 12 can be increased while the length of the first leg can portion 11 is sufficient. can be suppressed. Therefore, the material cost of the leg 10 can be suppressed.

Further, a third diagonal brace 60 is connected to the first leg can portion 11 including the intersection of one of the plurality of legs 10 and the end of the first diagonal brace 40, and the outer diameter of the third diagonal brace 60 is , larger than the outer diameter of the second diagonal brace 50. Thereby, for example, when the outer diameter of the first diagonal brace 40 and the outer diameter of the third diagonal brace 60 are made the same, the first diagonal brace 40 and the third diagonal brace 60 connected to the first leg can portion 11 The cross sections of can be unified. Therefore, it is possible to easily manage parts when manufacturing the jacket structure. Moreover, structural calculation of the jacket structure can be facilitated.

Further, a fourth diagonal brace 70 is connected to the second leg can portion 12 including the intersection between one of the plurality of legs 10 and the end of the second diagonal brace 50, and the outer diameter of the fourth diagonal brace 70 is , smaller than the outer diameter of the first diagonal brace 40. Thereby, for example, when the outer diameter of the second diagonal brace 50 and the outer diameter of the fourth diagonal brace 70 are made the same, the second diagonal brace 50 and the fourth diagonal brace 70 connected to the second leg can portion 12 The cross sections of can be unified. Therefore, it is possible to easily manage parts when manufacturing the jacket structure. Moreover, structural calculation of the jacket structure can be facilitated.

Further, the outer diameter of the second proximate portion 51 is greater than or equal to the outer diameter of the second remote portion 52, and the inner diameter of the second proximate portion 51 is less than or equal to the inner diameter of the second distal portion 52. Therefore, the plate thickness of the second proximate portion 51 is at least the same as or larger than the second remote portion 52 . Thereby, the strength of the intersection in the second diagonal brace 50 can be ensured. Further, when the plate thickness of the second neighboring portion 51 is increased, it is possible to more easily double-sided weld the second neighboring portion 51 at the intersection with the first neighboring portion 41. This makes it possible to improve fatigue strength.
Furthermore, by making the plate thickness of the second remote portion 52 smaller than that of the second proximate portion 51, the weight of the entire second diagonal brace 50 can be reduced while ensuring sufficient strength against bending moments etc. in the second proximate portion 51. This can prevent it from increasing more than necessary.

It also includes a tapered portion 53 provided between the inner surface of the second proximal portion 51 and the inner surface of the second remote portion 52 . Thereby, the second nearby portion 51 and the second remote portion 52 can be connected by continuously changing the distance between the second nearby portion 51 and the second remote portion 52. Therefore, it is possible to suppress stress concentration occurring at the connection portion between the second nearby portion 51 and the second remote portion 52.

Additionally, the tapered portion 53 and the second remote portion 52 are welded on one side from the inside of the second diagonal brace 50. Here, if the inner diameter of the second proximate portion 51 is less than or equal to the inner diameter of the second remote portion 52, stress concentration occurs on the inner surface of the second diagonal brace 50 at the boundary between the tapered portion 53 and the second remote portion 52. It's easy to do. Weld defects are particularly likely to occur at the root portion of the weld. By performing single-sided welding from the inside of the second diagonal brace 50, the root portion can be placed outside the second diagonal brace 50. Therefore, at the boundary between the tapered portion 53 and the second remote portion 52, the welding root portion can be moved away from a location where stress concentration is likely to occur. Therefore, the decrease in fatigue life at the boundary can be suppressed.

Further, the outer diameter of the first diagonal brace 40 is the same over the entire length of the first diagonal brace 40. Thereby, for example, it is possible to easily provide a stainless steel plate or the like for rust prevention on the outer peripheral surface of the first diagonal brace 40.

Further, double-sided welds BW are provided at the intersection between the first diagonal brace 40 and the second diagonal brace 50, and at the intersection between the second diagonal brace 50 and one of the legs 10. That is, the intersection between the first diagonal brace 40 and the second diagonal brace 50 and the intersection between the second diagonal brace 50 and one of the legs 10 are welded on both sides. Thereby, sufficient fatigue strength can be ensured at the intersection between the first diagonal brace 40 and the second diagonal brace 50 and at the intersection between the second diagonal brace 50 and one of the legs 10.

A single-sided weld OW is provided between the near part of the brace and the far part of the brace, and between the near part of the leg 10 and the far part of the leg 10. In other words, the portion near the brace and the remote portion of the brace, and the portion near the leg 10 and the remote portion of the leg 10 are welded on one side. Thereby, for example, by double-sided welding each welding part in the jacket structure, it is possible to avoid leaving the operator behind inside the jacket structure.

(Second embodiment)
Next, a second offshore wind turbine jacket structure 200 according to a second embodiment of the present invention will be described with reference to FIGS. 11 and 12.
In addition, in this 2nd embodiment, the same code|symbol is attached|subjected to the same component as the component in 1st Embodiment, the description is abbreviate|omitted, and only a different point will be described.

The second offshore wind turbine jacket structure 200 differs from the offshore wind turbine jacket structure 100, particularly in the aspect of the second diagonal brace 50.
Specifically, in the second diagonal brace 50 of the second offshore wind turbine jacket structure 200, the outer diameter of the second remote portion 52 is equal to or larger than the outer diameter of the second neighboring portion 51, and The inner diameter is less than or equal to the inner diameter of the second neighboring portion 51 . That is, for example, as shown in FIG. 11, the outer circumferential surface of the second proximate portion 51 is located on the inner side of the outer circumferential surface than the outer circumferential surface of the second remote portion 52. The inner circumferential surface of the second proximate portion 51 is flush with the inner circumferential surface of the second remote portion 52 . A tapered portion 53 is provided between the outer surface of the second proximal portion 51 and the outer surface of the second remote portion 52 . A tapered portion 53 is then integrally formed with the second remote portion 52. In these respects, it is different from the second diagonal brace 50 of the jacket structure 100 for an offshore wind turbine. The second proximal portion 51 and the second remote portion 52 are connected by welding the tapered portion 53 and the second proximal portion 51 on one side from the outside of the second diagonal brace 50 .

Accordingly, in the second diagonal brace 50 of the second offshore wind turbine jacket structure 200, the outer diameter of the second leg remote portion 55 is equal to or larger than the outer diameter of the second leg neighboring portion 54, and the second leg remote portion 55 is smaller than the inner diameter of the second leg vicinity portion 54. That is, for example, as shown in FIG. 12, the outer circumferential surface of the second leg near portion 54 is located radially inner than the outer circumferential surface of the second leg remote portion 55. The inner circumferential surface of the second leg proximate portion 54 is flush with the inner circumferential surface of the second leg remote portion 55 . Additionally, the leg tapered portion 56 is integrally formed with the second leg remote portion 55. The second leg vicinity portion 54 and the second leg remote portion 55 are connected by welding the leg tapered portion 56 and the second leg vicinity portion 54 on one side.

As explained above, according to the second offshore wind turbine jacket structure 200 according to the present embodiment, the outer diameter of the second remote portion 52 is equal to or larger than the outer diameter of the second neighboring portion 51, and the second remote portion The inner diameter of 52 is less than or equal to the inner diameter of second neighboring portion 51 . Therefore, the plate thickness of the second remote portion 52 is at least the same as or larger than the second nearby portion 51 . This ensures that the second remote portion 52 has sufficient strength against bending moments and the like.

It also includes a tapered portion 53 provided between the outer surface of the second proximal portion 51 and the outer surface of the second remote portion 52 . Thereby, the second nearby portion 51 and the second remote portion 52 can be connected by continuously changing the distance between the second nearby portion 51 and the second remote portion 52. Therefore, it is possible to suppress stress concentration occurring at the connection portion between the second nearby portion 51 and the second remote portion 52.

Further, the tapered portion 53 and the second neighboring portion 51 are welded on one side from the outside of the second diagonal brace 50. Here, if the outer diameter of the second remote portion 52 is greater than or equal to the outer diameter of the second proximate portion 51, the boundary between the tapered portion 53 and the second proximate portion 51 is where stress is concentrated on the outer surface of the second diagonal brace 50. is likely to occur. Weld defects are particularly likely to occur at the root portion of the weld. By performing single-sided welding from the outside of the second diagonal brace 50, the root portion can be placed inside the second diagonal brace 50. Therefore, at the boundary between the tapered portion 53 and the second neighboring portion 51, the welding root portion can be moved away from a location where stress concentration is likely to occur. Therefore, the decrease in fatigue life at the boundary can be suppressed.

(About welding method of offshore wind turbine jacket structure 100)
Next, a welding method for the offshore wind turbine jacket structure 100 according to the first embodiment and the second embodiment described above will be described. The welding method described below prevents a worker from being left behind inside the jacket structure 100 for an offshore wind turbine.
Hereinafter, the cylindrical portion of the second diagonal brace 50 within a predetermined range including the intersection of the second diagonal brace 50 and the first diagonal brace 40 will be referred to as a portion near the brace. In other words, the second neighborhood portion 51 is referred to as a brace neighborhood portion.
A cylindrical portion of the second diagonal brace 50 that is farther from the intersection of the second diagonal brace 50 and the first diagonal brace 40 than a portion near the brace is referred to as a brace remote portion. Thus, the second remote portion 52 is referred to as a brace remote portion.

A cylindrical portion of the second diagonal brace 50 within a predetermined range including the intersection of the second diagonal brace 50 and one of the legs 10 is referred to as a portion near the leg 10. In other words, the second leg vicinity portion 54 is referred to as the leg 10 vicinity portion.
A cylindrical portion of the second diagonal brace 50 that is farther from the intersection of the second diagonal brace 50 and one of the legs 10 than a portion near the leg 10 is referred to as a remote portion of the leg 10. That is, the second leg remote portion 55 is referred to as the leg 10 remote portion.

The welding method according to this embodiment includes a double-sided welding process and a single-sided welding process.
In the double-sided welding process, the intersections of the first diagonal brace 40 and the second diagonal brace 50 are welded on both sides. Also, the intersection between the second diagonal brace 50 and one of the legs 10 is welded on both sides.
The single-sided welding process is performed after the double-sided welding process. The single-sided welding process performs a single-sided weld between a portion near the brace and a portion remote from the brace. Also, one-sided welding is performed between the near leg part and the far away part of the leg.
The above steps constitute the offshore wind turbine jacket structure 100 according to the present embodiment.

As explained above, according to the method of welding the offshore wind turbine jacket structure 100 according to the present embodiment, the intersection between the first diagonal brace 40 and the second diagonal brace 50 and the intersection between the second diagonal brace 50 and the leg 10 After the double-sided welding process, one-sided welding is performed between the near part of the brace and the far part of the brace, and the near part of leg 10 and the far part of leg 10 are welded on both sides. , a single-sided welding step of performing single-sided welding between .

Here, when the first diagonal brace 40 is an integral cylindrical member, double-sided welding of both ends of the first diagonal brace 40 to the leg 10 means that the inside of the first diagonal brace 40 is welded after welding. This is not possible as it would leave many people behind. On the other hand, by performing the single-sided welding process after the double-sided welding process, the intersection between the first diagonal brace 40 and the second diagonal brace 50 and the second diagonal brace 50 can be and the intersection with one of the legs 10 can be welded on both sides. Therefore, it is possible to ensure the welding strength at each intersection point where both sides are welded.

Note that the technical scope of the present invention is not limited to the embodiments described above, and various changes can be made without departing from the spirit of the present invention.
For example, although it has been described that the outer diameter of the first diagonal brace 40 is the same over the entire length of the first diagonal brace 40, the outer diameter is not limited to this. For example, the outer diameter of the first proximal portion 41 may be greater than or equal to the outer diameter of the first remote portion 42. The outer diameter of the first remote portion 42 may be greater than or equal to the outer diameter of the first proximal portion 41 .
Further, each steel pipe member that constitutes the offshore wind turbine jacket structure 100 is not limited to a cylindrical shape, but may be a rectangular tube shape.
Further, the outer diameters of the first leg can portion 11 and the second leg can portion 12 of the leg 10 may be the same as, for example, the straight pipe portion 13. The outer diameters of the first leg can part 11 and the second leg can part 12 of the leg 10 may be larger than the straight pipe part 13, for example.
Additionally, the tapered portion 53 may be provided between the outer surface of the second proximal portion 51 and the outer surface of the second remote portion 52. That is, for example, as shown in FIG. 13, the outer circumferential surface of the second proximate portion 51 is located on the outer side in the radial direction than the outer circumferential surface of the second remote portion 52, and the inner circumferential surface of the second proximate portion 51 is located on the outer circumferential surface of the second proximal portion 52. 2 may be flush with the inner circumferential surface of the remote portion 52.
Further, the outer diameter of the second leg proximal portion 54 may be the same as the outer diameter of the second leg remote portion 55.
Additionally, the leg tapered portion 56 may be provided between the inner surface of the second leg proximal portion 54 and the inner surface of the second leg remote portion 55.

In addition, without departing from the spirit of the present invention, the components in the embodiments described above may be replaced with well-known components as appropriate, and the above-described modifications may be combined as appropriate.

10 leg 11 first leg can part 12 second leg can part 13 straight pipe part 20 stand 30 skirt sleeve 40 first diagonal brace 41 first proximal part 42 first remote part 43 first leg proximal part 44 first leg remote part 50 2 diagonal brace 51 2nd proximate portion 52 2nd remote portion 53 Tapered portion 54 2nd leg proximal portion 55 2nd leg remote portion 56 Leg tapered portion 60 3rd diagonal brace 70 4th diagonal brace 100 Offshore wind turbine jacket structure 200 2 Jacket structure for offshore wind turbine 300 Offshore wind turbine BW Double-sided welded part K K-shaped groove L Pile OW Single-sided welded part SB Rectangular groove

Claims (17)

a first diagonal brace that is a cylindrical member;
a second diagonal brace that is a cylindrical member and intersects with the first diagonal brace;
a platform on which an offshore wind turbine is installed and supported by the first diagonal brace and the second diagonal brace;
A jacket structure for an offshore wind turbine, comprising:
the intersection of the first diagonal brace and the second diagonal brace is welded;
The welding is double-sided welding,
A jacket structure for offshore wind turbines, which is characterized by: The outer diameter of the first diagonal brace is larger than the outer diameter of the second diagonal brace.
The jacket structure for an offshore wind turbine according to claim 1. The platform is supported by the first diagonal brace and the second diagonal brace via a plurality of legs,
The thickness of the first leg can portion, which is one of the plurality of legs, including the intersection of one of the plurality of legs and the end of the first diagonal brace is: , a plate thickness of a second leg can part that is one of the plurality of legs, the second leg can part including the intersection of one of the plurality of legs and the end of the second diagonal brace; thinner,
The jacket structure for an offshore wind turbine according to claim 2. The platform is supported by the first diagonal brace and the second diagonal brace via a plurality of legs,
The strength of the steel material of a first leg can part that is one of the plurality of legs, the first leg can part including the intersection of one of the plurality of legs and the end of the first diagonal brace. is a second leg can portion that is one of the plurality of legs , the steel material of the second leg can portion including the intersection of one of the plurality of legs and the end of the second diagonal brace; weaker than the strength of
The jacket structure for an offshore wind turbine according to claim 2. The steel material of the first leg can part is SM490Y or SM520,
The steel material of the second leg can part is SA440,
The jacket structure for an offshore wind turbine according to claim 4. The length of the first leg can portion along the longitudinal direction of one of the plurality of legs is longer than the length of the second leg can portion along the longitudinal direction. ,
The jacket structure for an offshore wind turbine according to any one of claims 3 to 5. third diagonal brace,
further comprising;
The platform is supported by the first diagonal brace, the second diagonal brace, and the third diagonal brace via a plurality of legs,
A first leg can portion that is one portion of the plurality of legs, the first leg can portion including an intersection of one of the plurality of legs and an end of the first diagonal brace includes the The third diagonal brace is connected,
The outer diameter of the third diagonal brace is larger than the outer diameter of the second diagonal brace.
The jacket structure for an offshore wind turbine according to claim 2. 4th diagonal brace,
further comprising;
The platform is supported by the first diagonal brace, the second diagonal brace, and the fourth diagonal brace via a plurality of legs,
A second leg can portion that is one portion of the plurality of legs, the second leg can portion including an intersection of one of the plurality of legs and an end of the second diagonal brace includes the The fourth diagonal brace is connected,
an outer diameter of the fourth diagonal brace is smaller than an outer diameter of the first diagonal brace;
The jacket structure for an offshore wind turbine according to claim 2. A cylindrical portion of the second diagonal brace, the cylindrical portion within a predetermined range including the intersection of the first diagonal brace and the second diagonal brace, as a second neighboring portion;
a cylindrical portion of the second diagonal brace that is farther from the intersection than the second neighboring portion is a second remote portion;
the outer diameter of the second proximate portion is greater than or equal to the outer diameter of the second remote portion;
the inner diameter of the second proximate portion is less than or equal to the inner diameter of the second remote portion;
The jacket structure for an offshore wind turbine according to claim 2. further comprising a tapered portion provided between an inner surface of the second proximal portion and an inner surface of the second remote portion;
The jacket structure for an offshore wind turbine according to claim 9. the tapered portion and the second remote portion are welded on one side from inside the second diagonal brace;
The jacket structure for an offshore wind turbine according to claim 10. A cylindrical portion of the second diagonal brace, the cylindrical portion within a predetermined range including the intersection of the first diagonal brace and the second diagonal brace, as a second neighboring portion;
a cylindrical portion of the second diagonal brace that is farther from the intersection than the second neighboring portion is a second remote portion;
The outer diameter of the second remote portion is greater than or equal to the outer diameter of the second neighboring portion,
an inner diameter of the second remote portion is less than or equal to an inner diameter of the second proximate portion;
The jacket structure for an offshore wind turbine according to claim 2. further comprising a tapered portion provided between an outer surface of the second proximal portion and an outer surface of the second remote portion;
The jacket structure for an offshore wind turbine according to claim 12. the tapered portion and the second neighboring portion are welded on one side from the outside of the second diagonal brace;
The jacket structure for an offshore wind turbine according to claim 13. The outer diameter of the first diagonal brace is the same over the entire length of the first diagonal brace.
The jacket structure for an offshore wind turbine according to any one of claims 1 to 5 and 7 to 14. multiple cylindrical legs;
a first diagonal brace that is a cylindrical member and is connected to the leg;
a second diagonal brace that is a cylindrical member, is connected to the leg, and intersects with the first diagonal brace;
a stand supported by the leg, the first diagonal brace, and the second diagonal brace, and on which an offshore wind turbine is installed;
A jacket structure for an offshore wind turbine, comprising:
The outer diameter of the first diagonal brace is larger than the outer diameter of the second diagonal brace,
an intersection of the first diagonal brace and the second diagonal brace;
an intersection of the second diagonal brace and one of the plurality of legs;
A double-sided welded part provided on the
a cylindrical portion of the second diagonal brace, which is a cylindrical portion within a predetermined range including the intersection of the second diagonal brace and the first diagonal brace, and a cylindrical portion of the second diagonal brace; a brace remote portion, which is a cylindrical portion farther from the intersection of the second diagonal brace and the first diagonal brace than the brace proximal portion;
a cylindrical portion of the second diagonal brace, which is a cylindrical portion within a predetermined range including an intersection of the second diagonal brace and one of the plurality of legs; a cylindrical portion of a brace, the leg distal portion being a cylindrical portion further from the intersection of the second diagonal brace and one of the plurality of legs than the leg proximal portion;
A single-sided welded part provided on the
A jacket structure for an offshore wind turbine, comprising: multiple cylindrical legs;
a first diagonal brace that is a cylindrical member and is connected to the leg;
a second diagonal brace that is a cylindrical member, is connected to the leg, and intersects with the first diagonal brace;
a stand supported by the leg, the first diagonal brace, and the second diagonal brace, and on which an offshore wind turbine is installed;
A method for welding a jacket structure for an offshore wind turbine, comprising:
The outer diameter of the first diagonal brace is larger than the outer diameter of the second diagonal brace,
an intersection of the first diagonal brace and the second diagonal brace;
an intersection of the second diagonal brace and one of the plurality of legs;
A double-sided welding process that welds both sides of the
After the double-sided welding process,
a cylindrical portion of the second diagonal brace, a portion near the brace that is within a predetermined range including the intersection of the second diagonal brace and the first diagonal brace;
a cylindrical portion of the second diagonal brace, the brace remote portion being a cylindrical portion farther from the intersection of the second diagonal brace and the first diagonal brace than the brace proximal portion;
In addition to welding on one side between
a cylindrical portion of the second diagonal brace, a portion near the leg that is within a predetermined range including an intersection of the second diagonal brace and one of the plurality of legs ;
a cylindrical portion of the second diagonal brace, the remote leg portion being a cylindrical portion farther from the intersection of the second diagonal brace and one of the plurality of legs than the proximal leg portion;
A single-sided welding process in which one side is welded between the
A method for welding a jacket structure for an offshore wind turbine, comprising:

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