Spar-type floating body for ocean wind power generation facility and construction method for the same

Abstract

To construct a spar type floating body effectively and at low cost as well as solving problems such as temperature cracking or cracking by bending of concrete at once.SOLUTION: A spar-type floating body 4 has a lower half side being a steel-concrete composite structure 4A with concrete C installed at prescribed thickness on an inner surface side of an outer shell steel member 10 covering an outer periphery, and an upper half side being a steel structure 4B having an outer shell steel member 12 covering the outer periphery and entirely made of steel members. The outer shell steel member 10 of the steel-concrete composite structure 4A has the same plate thickness as the outer shell steel member 12 of the steel structure 4B in a boundary part between the steel-concrete composite structure 4A on the lower half side and the steel structure 4B on the upper half side, and the outer shell steel member 10 of the steel-concrete composite structure 4A is extended for a prescribed length, and joined by welding with the outer shell steel member 12 of the steel structure 4B in a position separated from the concrete C.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a spar-type floating body for an offshore wind power generation facility that can be constructed efficiently and at low cost, and a method for constructing the same. [Background technology]

[0002] Traditionally, hydroelectric, thermal and nuclear power generation have been the main power generation methods used, but in recent years, wind power generation, which uses natural wind to generate electricity, has been attracting attention from the perspective of the environment and the effective use of natural energy. Wind power generation facilities can be installed on land or on water (mainly offshore), but in Japan, which has mountainous terrain behind its coasts, there are few plains in coastal areas where stable winds can be expected. On the other hand, Japan is surrounded by sea on all sides, and has the advantage that winds suitable for generating electricity can be easily obtained on the sea and there are fewer restrictions on installation. For this reason, many different types of offshore wind power generation facilities and floating structures have been proposed in recent years.

[0003] The floating structure can be broadly classified into a barge type float, which floats on the water surface, a semi-submersible type float, which floats in a semi-submerged state by submerging the lower part of the float below the water surface, and a spar type float, which floats in an upright position like a fishing float.

[0004] With regard to the spar-type float, in Patent Document 1 listed below, the applicant has proposed a spar-type float 50 consisting of a lower concrete floating structure 50A (hereinafter referred to as the concrete floating structure) in which concrete precast cylindrical bodies 51, 51... are stacked vertically in multiple tiers and each precast cylindrical body 51, 51... is fastened and integrated with PC steel rods 52, 52..., as shown in FIG. 11, and an upper steel floating structure 50B (hereinafter referred to as the steel floating structure) connected to the upper side of this concrete floating structure 50A.

[0005] The method of constructing the concrete floating section 50A is as follows: with the spar-type floating body 50 laid horizontally, the precast cylindrical bodies 51, 51 are connected together while the PC steel rods 52 extending upward from the precast cylindrical bodies 51 are inserted into the sheaths 53 as shown in Fig. 12(A), and then an anchor plate 54 is fitted into the box-opening portion, and tension is applied to the PC steel rods 52 by means of a nut member 55 to integrate them. Then, grout material is injected into the sheaths 53 from the grout injection holes 54a.

[0006] 12(B), a coupler 56 is screwed onto the protruding portion of the PC steel rod 52 to connect the upper PC steel rod 52, and the PC steel rod 52 is inserted into the sheath 53 of the next precast cylindrical body 51 and set in place. Also, grout material is injected into the sheath 53 through the grout injection hole 57. By repeating this procedure in sequence, the concrete floating body section 50A is constructed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5274329 Summary of the Invention [Problem to be solved by the invention]

[0008] However, since the concrete floating body portion 50A of the spar-type float is constructed bit by bit by sequentially connecting the precast cylindrical bodies 51 with the PC steel bars 52, it takes a lot of time, effort and cost to construct the float. In addition, as the size of offshore wind power generation facilities increases, the size of the spar-type float also increases, and there is a problem that the increase in the thickness of the concrete members and the number of PC steel bars requires even more time, effort and cost.

[0009] Furthermore, if offshore wind power generation facilities become larger and their generating capacity reaches 15 MW, it is estimated that the diameter of the concrete floating section will be 15 m or more and the concrete components will be 90 cm or more thick, which will cause problems such as temperature cracks during construction and bending cracks during erection in the concrete sections.

[0010] Therefore, the main object of the present invention is to provide a spar-type float for an offshore wind power generation facility and a construction method thereof that can construct the spar-type float efficiently and at low cost, while simultaneously solving problems such as thermal cracking and bending cracking of concrete. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention as claimed in claim 1 provides a spar-type floating body for offshore wind power generation equipment, characterized in that the lower half is a steel-concrete composite structural part in which concrete is poured at a predetermined thickness on the inner side of an outer shell steel member covering the outer periphery, and the upper half is a steel structural part having an outer shell steel member covering the outer periphery and made entirely of steel members.

[0012] In the invention described in claim 1 above, the lower half of the spar-type float is replaced by a conventional concrete float, and is made into a steel-concrete composite structural part in which concrete is poured to a predetermined thickness on the inner side of the outer steel shell member covering the periphery.

[0013] By using a steel-concrete composite structural section, efficient and low-cost manufacturing is possible using the construction method of claim 5 described below. In addition, because the thickness of the concrete members can be made thin, thermal cracks are less likely to occur, and because the outer shell is covered with steel members, bending cracks are also less likely to occur. Even if thermal cracks or bending cracks do occur, they will not cause water leakage or the like. In addition, the weight of the entire floating body can be reduced, making it an economical floating body.

[0014] The present invention according to claim 2 provides a spar-type float for offshore wind power generation equipment as described in claim 1, in which prestress is introduced into the steel-concrete composite structural part by PC steel members arranged at predetermined intervals along the longitudinal direction of the float and around the circumferential direction to the concrete poured to a predetermined thickness.

[0015] The invention described in claim 2 above is such that in the steel-concrete composite structure, prestress is introduced to the concrete poured to a specified thickness by PC steel members arranged along the longitudinal direction of the floating body and at specified intervals along the circumferential direction. By introducing prestress to the concrete, it becomes possible to further prevent cracks from occurring in the concrete and to increase the strength against external bending forces.

[0016] The present invention relates to claim 3, and provides a spar-type floating body for offshore wind power generation equipment as described in either claim 1 or 2, wherein at the boundary between the lower half of the steel-concrete composite structural part and the upper half of the steel structural part, the plate thicknesses of the outer steel members of the steel-concrete composite structural part and the outer steel members of the steel structural part are the same.

[0017] In the invention described in claim 3 above, the plate thicknesses of the outer shell steel members of the steel concrete composite structural section and the outer shell steel members of the steel structural section are made the same so that the load from the steel structural section can be easily transmitted.

[0018] The present invention as claimed in claim 4 provides a spar-type floating body for offshore wind power generation equipment as claimed in either claim 1 or 2, wherein at the boundary between the lower half steel-concrete composite structural part and the upper half steel structural part, the outer shell steel member of the steel-concrete composite structural part extends a predetermined length and is joined to the outer shell steel member of the steel structural part by welding at a position away from the concrete.

[0019] The invention described in claim 4 above is such that when a steel-concrete composite structural section and a steel structural section are joined by welding, the welding is performed at a position separated from the concrete so that the concrete does not explode due to heat input during welding.

[0020] As a fifth aspect of the present invention, there is provided a method for constructing a spar-type floating body of an offshore wind power generation facility according to the first aspect of the present invention, comprising the steps of: A mobile form device including a form support device having a slide guide provided horizontally between a front support leg and a rear support leg, and a circular form device provided to fit around the slide guide and movable along the slide guide, and capable of installing form plates in a circular shape at a predetermined radial position all around, is brought to a construction site of the spar-type floating offshore wind power generation facility; a first step of installing the outer shell steel members of the steel-concrete composite structure of the spar-type floating body in a horizontal orientation, providing an opening at the bottom, installing the movable formwork device with a slide guide penetrating the opening, and positioning the circular formwork device at the bottommost position of the steel-concrete composite structure to install formwork plates so that concrete can be poured to a predetermined thickness on the inner side of the outer shell steel members that cover the entire periphery; A second step of pouring concrete into a space between the outer steel member of the steel concrete composite structure and the formwork plate; a third step of moving the form support device to an inner space side of the steel concrete composite structure while maintaining the circular form device in position; a fourth step of moving the circular form device to the interior of the steel-concrete composite structure while maintaining the form support device in position, and installing a form plate adjacent to the poured concrete on the inner surface of the outer shell steel member that covers the entire periphery so that concrete can be poured to a predetermined thickness; and a fifth step of pouring concrete into the space between the outer steel member of the steel-concrete composite structural part and the formwork plate, wherein by repeating the second to fourth steps, concrete is sequentially poured to a predetermined thickness onto the inner surface side of the outer steel member of the steel-concrete composite structural part, and after the mobile formwork device has completely entered the interior of the steel-concrete composite structural part, the opening formed in the bottom of the steel-concrete composite structural part is closed.

[0021] The invention described in claim 5 above shows an efficient method for constructing a spar-type floating body. Specifically, the mobile formwork device is brought to the construction site of the spar-type floating offshore wind power generation facility. In order to pour concrete from the bottommost part of the steel-concrete composite structure, an opening is provided at the bottom of the steel-concrete composite structure, and the mobile formwork device is installed with the slide guide penetrating the opening. A circular formwork device is installed at a predetermined position, and formwork plates are installed so that concrete can be poured to a predetermined thickness on the inner side of the outer shell steel member that covers the entire periphery (first step). Next, once concrete has been poured into the space between the outer steel member of the steel-concrete composite structure and the formwork plate (second step), the formwork support device is moved to the interior space of the steel-concrete composite structure while maintaining the circular formwork device in its position (third step), and then, while maintaining the formwork support device in its position, the circular formwork device is moved to the interior space of the steel-concrete composite structure, and the formwork plate is installed in a position adjacent to the poured concrete so that concrete can be poured to a predetermined thickness on the inner side of the outer steel member that covers the entire perimeter (fourth step).

[0022] Thereafter, by repeating the second to fourth steps, concrete is poured in a predetermined thickness sequentially onto the inner surface of the outer steel shell members of the steel-concrete composite structure, and after the mobile formwork device has completely entered the interior of the steel-concrete composite structure, the opening formed at the bottom of the steel-concrete composite structure is closed.

[0023] The above construction method makes it possible to pour concrete in one span of about 6 to 12 m in one go, enabling the steel-concrete composite structural parts of spar-type floating structures to be produced efficiently and at low cost.

[0024] According to a sixth aspect of the present invention, there is provided a method for constructing a spar-type floating body for an offshore wind power generation facility according to the second aspect of the present invention, comprising the steps of: A movable form device is carried to a construction site of the spar-type floating body, the movable form device being composed of a form support device having a slide guide provided between the front support leg and the rear support leg along the horizontal direction, and a circular form device provided to be fitted onto the slide guide, movable along the slide guide, and capable of installing form plates in a circular shape at a predetermined radial position all around the circumference. a first step of installing the outer shell steel members of the steel-concrete composite structure of the spar-type floating body in a horizontal orientation, providing an opening at the bottom, installing the movable formwork device with a slide guide penetrating the opening, disposing a sheath for inserting and installing PC steel members over the installation range of the circular formwork device in the longitudinal direction of the floating body, positioning the circular formwork device at the bottommost position of the steel-concrete composite structure, and installing formwork plates so that concrete can be poured to a predetermined thickness on the inner side of the outer shell steel members that cover the entire periphery; A second step of pouring concrete into a space between the outer steel member of the steel concrete composite structure and the formwork plate; a third step of moving the form support device to an inner space side of the steel concrete composite structure while maintaining the circular form device in position; a fourth step of moving the circular formwork device to the inner space of the steel concrete composite structure while holding the formwork support device in position, disposing a sheath for inserting and installing PC steel members over the floating body longitudinal installation range of the circular formwork device at a position adjacent to the poured concrete, and installing a formwork plate on the inner surface side of the outer shell steel member covering the entire periphery so that concrete can be poured to a predetermined thickness; A fifth step of pouring concrete in a predetermined thickness in sequence on the inner surface side of the outer steel member of the steel concrete composite structure by repeating the second step to the fourth step, and closing the opening formed in the bottom of the steel concrete composite structure after the movable formwork device has completely entered the interior of the steel concrete composite structure; The present invention provides a method for constructing a spar-type floating body for an offshore wind power generation facility, characterized in having a sixth step of inserting PC steel into a sheath arranged over the entire length of the concrete in the steel-concrete composite structure, and then introducing tension into and fixing the PC steel.

[0025] The invention described in claim 6 above is a method for constructing a spar-type floating body, in which prestress is introduced into the steel-concrete composite structural section by means of PC steel members arranged at predetermined intervals along the longitudinal direction of the float and around the circumferential direction to concrete poured to a predetermined thickness.

[0026] In this case, when the circular formwork device is installed, a sheath for inserting and installing the PC steel is arranged in advance over the longitudinal installation range of the floating body, and after all the concrete has been poured, the PC steel is inserted into the sheath arranged over the entire length of the concrete, and then tension is introduced to the PC steel and it is fixed in place.

[0027] The present invention as claimed in claim 7 provides a method for constructing a spar-type floater for an offshore wind power generation facility as claimed in either claim 5 or 6, wherein, once concrete has been poured to a predetermined thickness on the inner side of the outer steel shell member covering the outer periphery in the steel-concrete composite structural section, the steel structural section is joined by full-circumference welding to complete the spar-type floater.

[0028] According to the invention described in claim 7 above, once the fabrication of the steel-concrete composite structural section is completed, the steel structural section is joined by all-around welding to complete the spar-type floating structure. Effect of the Invention

[0029] As explained above in detail, according to the present invention, a spar-type floating body can be constructed efficiently and at low cost, and problems such as thermal cracking and bending cracking of concrete can be solved at once. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is an overall view of a spar-type offshore wind power generation facility 1. [Diagram 2] FIG. [Diagram 3] 1 shows a movable formwork device 9, in which (A) is a side view and (B) is a cross-sectional view taken along line BB. [Figure 4] (A) to (D) show the manufacturing method (part 1) of the bottom part of the steel-concrete composite structural section 4A. [Diagram 5] (E) to (G) show the manufacturing method (part 2) of the bottom part of the steel-concrete composite structural section 4A. [Figure 6] (A) to (C) show the manufacturing procedures for the general parts of the steel-concrete composite structural section 4A. [Figure 7] 1 is an enlarged cross-sectional view of a main part of a spar-type floating body 4 according to a second embodiment. FIG. [Figure 8] 13(A) to 13(D) show manufacturing procedures for the bottom portion of a steel-concrete composite structural section 4A according to the second embodiment. [Figure 9] 13(A) to 13(C) show manufacturing procedures for the general parts of a steel-concrete composite structural section 4A according to the second embodiment. [Figure 10] 2 is a diagram showing how to insert PC steel material 16 into sheath 15. FIG. [Figure 11] FIG. 1 is a cross-sectional view of a conventional spar-type float 50, the lower half of which is a concrete float section 50A and the upper half of which is a steel float section 50B. [Figure 12] 13A and 13B are diagrams showing the procedure for connecting a precast cylindrical body 51 to a concrete floating body section 50A using PC steel bars 52. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0032] [Spar-type floating offshore wind turbine 1] First, a spar-type floating offshore wind power generation facility 1 according to the present invention will be described in detail with reference to Figs. 1 and 2.

[0033] As shown in Figure 1, the spar-type floating offshore wind power generation facility 1 is composed of a spar-type float 4, a plurality of mooring lines 5 connected to the spar-type float 4, a tower 6 connected to the top of the spar-type float 4, and a nacelle 7 and a plurality of blades 8, 8... mounted on the top of the tower 6.

[0034] As shown in FIG. 2, the lower half of the spar-type floating body 4 is a steel-concrete composite structural section 4A in which concrete 11 is poured to a predetermined thickness on the inner side of the outer periphery of the outer shell steel member 10, and the upper half is a steel structural section 4B in which the entire body is made of steel members and has the outer periphery covered by the outer shell steel member 12.

[0035] Ballast materials such as water, gravel, fine aggregate, coarse aggregate, and metal particles can be charged or discharged into or from the hollow portion of the spar-type floating body 4, making the buoyancy (draft) adjustable. The charging / discharging of ballast materials is possible by employing the fluid transport method previously proposed by the applicant in JP 2012-201217 A.

[0036] The steel-concrete composite structure 4A uses steel members (steel plates) 10 for the outer periphery, and in manufacturing it, the steel rings divided in the longitudinal direction are manufactured separately, and these are oriented horizontally and then each divided steel ring is welded in sequence to construct a steel outer shell of a specified length. Note that a number of ribs are provided on the inner side of the outer shell steel members 10 for reinforcement.

[0037] The concrete poured on the inner side of the outer shell steel member 10 is basically unreinforced concrete, but since a certain amount of tensile stress is expected to occur due to temperature, drying shrinkage, and external forces during construction, it may be acceptable to arrange relatively small diameter reinforcing bars at predetermined intervals to prevent cracking.

[0038] Similarly, the bottom of the steel-concrete composite structure 4A is preferably a composite structure in which concrete C0 is poured on the inner side of the bottom steel plate 11. As will be described later, for manufacturing reasons, an opening 30 is provided in this bottom, which is closed after the pouring of the concrete C on the bottom side is completed.

[0039] The steel structural part 4B is a cylindrical body whose outer periphery is surrounded by the outer shell steel member 12, and is composed of a steel cylindrical body 17 located relatively on the lower stage side and a steel cylindrical body 18 located relatively on the upper stage side. The lower part of the steel cylindrical body 17 on the lower stage side has the same outer diameter as the outer shell steel member 10 of the steel-concrete composite structural part 4A. The upper part of the steel cylindrical body 17 has a truncated cone shape with a gradually narrowing diameter. The steel cylindrical body 18 on the upper stage side is a cylindrical body whose outer diameter is continuous with the upper outer diameter of the steel cylindrical body 17 on the lower stage side, and is connected to the steel cylindrical body 17 on the lower stage side by bolts or welding (bolt fastening in the illustrated example). These steel cylindrical bodies 17, 18 are composed of steel rings divided for each predetermined weight, and each steel ring is integrated by welding in the circumferential direction.

[0040] At the boundary between the steel-concrete composite structural portion 4A and the steel structure 4B, it is desirable to make the plate thickness of the outer shell steel member 10 of the steel-concrete composite structural portion 4A the same as that of the outer shell steel member 12 of the steel structural portion 4B, as shown in Fig. 2. This makes it easier for the load to be transmitted from the steel structural portion 4B to the steel-concrete composite structural portion 4A.

[0041] 2, it is preferable to extend the outer steel shell member 10 of the steel-concrete composite structural section 4A toward the steel structural section 4B by a predetermined length and join it to the outer steel shell member 12 of the steel structural section 4B by welding at a position spaced a distance S from the concrete C (weld section 19). This makes it possible to prevent the concrete C from exploding due to heat input during welding.

[0042] On the other hand, the tower 6 is made of steel, concrete or PRC (prestressed reinforced concrete), but it is preferable to use one made of steel so that the total weight is small. The outer diameter of the tower 6 and the outer diameter of the upper steel cylindrical body 18 are almost the same, and the outer shape is continuous in the vertical direction without any steps.

[0043] As shown in Fig. 1, the mooring point P of the mooring line 5 to the float 4 is set below the sea surface and at a position higher than the center of gravity G of the float 4. This makes it possible to prevent a ship from coming into contact with the mooring line 5. Also, since a resistance moment is generated around the center of gravity G of the float 4 at the mooring point P so as to prevent the float 4 from tipping over too much, the tilting attitude of the tower 6 can be appropriately maintained.

[0044] On the other hand, the nacelle 7 is a device equipped with a generator that converts the rotation of the wind turbine into electricity, a controller that can automatically change the angle of the blades 8, and the like.

[0045] [About the mobile formwork device 9] Before describing in detail the method for constructing the spar-type floating body 4 of the offshore wind power generation facility 1, a mobile formwork device 9 used for pouring concrete inside the outer shell steel member 10 will be described in detail with reference to FIG. 3.

[0046] The movable formwork device 9 is composed of a formwork support device 13 having a slide guide 23 provided between a front support leg 20 and a rear support leg 21 along the horizontal direction, and a circular formwork device 14 that is fitted around the slide guide 23, can move along the slide guide 23, and can install formwork plates in a circular shape at a predetermined radial position all around. The movable formwork device 9 is set inside the shell steel member 10 with the shell steel member 10 of the steel concrete composite structure 4A installed in a horizontal position, and concrete is poured inside the shell steel member 10 of the steel concrete composite structure 4A in the all-around direction. One span is about 6 to 12 m, and concrete is poured over the entire length of the steel concrete composite structure 4A by repeatedly moving and pouring concrete.

[0047] This will be described in more detail below.

[0048] The front support leg 20 and the rear support leg 21 have a jack-type leg 24 on the lower side that is extendable and retractable, and the height direction position is adjustable. A slide guide 23 is installed between the front support leg 20 and the rear support leg 21. In the illustrated example, the slide guide 23 has a rectangular shape.

[0049] The circular formwork device 14 has a rectangular sleeve 24 fitted around the slide guide 23 and is movable along the slide guide 23. The sleeve 24 has jack support rods 26, 26... protruding outward at appropriate intervals around the entire circumference on its outer surface, and has formwork plates 27, 27... supported by the jack support rods 26, 26... and divided into a plurality of plates in the circumferential direction. When these formwork plates 27, 27... are positioned at predetermined positions, they form a perfect circle, forming a concrete pouring space of a certain thickness between the outer shell steel member 10. The formwork plates 27, 27... are movable in the outer circumferential direction by a jack provided on the jack support rod 26, so that they can be easily removed after pouring concrete. The circular formwork device 14 has a formwork distance L in the direction of the slide guide 23. It is preferable that the formwork distance L is about 6 to 12 m.

[0050] Fixing jack fixtures 28, 29 are provided at the upper front and upper rear sides of the circular form apparatus 14 for supporting members extending in the front-rear direction from the circular form apparatus 14. These fixing jack fixtures 28, 29 enable the circular form apparatus 14 to be firmly supported in a predetermined position.

[0051] [Construction method of spar-type floating body 4] Next, a method for constructing the spar-type floating body 4 using the circular formwork device 14 will be described in detail with reference to Figures 4 to 7. Figures 4 and 5 show the concrete pouring procedure for the bottom part of the steel-concrete composite structural section 4A, and Figures 6 and 7 show the concrete pouring procedure for the general part of the steel-concrete composite structural section 4A.

[0052] <Concrete pouring procedure for the bottom part of steel-concrete composite structure 4A> (First Step) As shown in Fig. 4(A), the outer shell steel members 10 of the steel-concrete composite structural section 4A are installed in a horizontal orientation. At this time, an opening 30 large enough to allow the movable formwork device 9 to pass through is provided at the bottom of the steel-concrete composite structural section 4A. The outer periphery of the opening 30 is preferably a composite structure of steel and concrete.

[0053] The movable form device 9 is installed with its slide guide 23 penetrating the opening 30, and the circular form device 14 is positioned at the bottommost position of the steel-concrete composite structural section 4A, and form plates 27, 27... are installed so that concrete can be poured at a predetermined thickness on the inner surface of the outer shell steel member 10 that covers the entire periphery. The circular form device 14 is supported so as not to move by the fixing jack equipment 28, 29, and a gable form 31 is installed around the entire periphery at the front ends (right side of the drawing) of the form plates 27, 27... to close the concrete pouring space.

[0054] (Second step) As shown in FIG. 4(B), concrete C1 is poured into the spaces between the outer steel members 10 of the steel-concrete composite structural portion 4A and the formwork plates 27, 27 . . .

[0055] (Third Step) As shown in Fig. 4(C), while the circular form device 14 is held in position, the form support device 13 is moved to the interior space of the steel-concrete composite structure section 4A (to the right in the drawing). The movement is performed with the front support leg 20 and the rear support leg 21 of the form support device 13 in an open state, and only the form support device 13 is moved by human power. After the movement is completed, the jack-type legs 24 of the front support leg 20 and the rear support leg 2 are extended and placed on the ground as shown in the drawing.

[0056] (Fourth step) As shown in Fig. 4(D), the circular formwork device 14 is removed from the concrete C1, and while the formwork support device 13 is held in position, the circular formwork device 14 is moved to the inner space side of the steel-concrete composite structure section 4A. Then, formwork plates 27, 27... are installed adjacent to the poured concrete C1 so that concrete can be poured to a predetermined thickness on the inner surface side of the outer shell steel member 10 that covers the entire circumference. Also, as shown in Fig. 5(E), the circular formwork device 14 is supported so as not to move by the fixing jack equipment 28, 29, and a gable formwork 31 is installed around the entire circumference at the front ends (front ends in the direction of travel) of the formwork plates 27, 27... to close the concrete pouring space.

[0057] (5th step) As shown in FIG. 5(F), concrete C2 is poured into the spaces between the outer steel members 10 of the steel-concrete composite structural portion 4A and the formwork plates 27, 27 . . .

[0058] (Next process step) By repeating the second to fourth steps, concrete is successively poured to a predetermined thickness onto the inner surface of the outer steel member 10 of the steel-concrete composite structure 4A, and when the movable formwork device 9 has completely entered the interior of the steel-concrete composite structure 4A, the opening 30 formed at the bottom of the steel-concrete composite structure 4A is closed as shown in Fig. 5(G). Specifically, for example, as shown in Fig. 5(G), the inner side of the ring-shaped steel plate 32 provided on the outer periphery of the opening 30 is closed with a circular steel plate 33, and then concrete 34 is poured on the inner side, so that the opening 30 is closed by the composite structure of steel and concrete.

[0059] <Concrete pouring procedure for steel-concrete composite structural section 4A general section> (First Step) As shown in FIG. 6(A), concrete C is poured into the spaces between the outer steel members 10 of the steel-concrete composite structural portion 4A and the formwork plates 27, 27 . . .

[0060] (Second step) As shown in Fig. 6(B), while the circular form device 14 is held in position, the form support device 13 is moved to the interior space of the steel-concrete composite structural section 4A (the right side of the drawing, toward the steel structural section 4B). The movement is performed with the front support leg 20 and rear support leg 21 of the form support device 13 in an open state, and only the form support device 13 is moved by human power. Once the movement is complete, the jack-type legs 24 of the front support leg 20 and rear support leg 21 are extended and placed on the ground, as shown in the drawing.

[0061] (Third Step) As shown in Fig. 6(C), with the formwork support device 13 held in position, the circular formwork device 14 is moved to the inner space side of the steel-concrete composite structural section 4A (the right side of the drawing, toward the steel structural section 4B), and formwork plates 27, 27... are installed adjacent to the poured concrete so that concrete C can be poured to a predetermined thickness on the inner surface side of the outer shell steel member 10 that covers the entire periphery. Also, as shown in the same figure, the circular formwork device 14 is supported so as not to move by the fixing jack equipment 28, 29, and end formwork 31 is installed around the entire periphery at the front ends (front ends in the direction of travel) of the formwork plates 27, 27... to close the concrete pouring space.

[0062] (Further steps) By repeating the above first to third steps, concrete is successively poured to a predetermined thickness onto the inner surface side of the outer steel shell members 10 of the steel-concrete composite structural section 4A.

[0063] <Completion of Spar-type Floating Body 4> In the steel-concrete composite structural section 4A, once concrete C has been poured onto the inner surface of the outer steel shell member 10 that covers the outer periphery, the steel structural section 4B is joined by full perimeter welding, and the spar-type floating body 4 is completed.

[0064] [Spar-type floating body 4 according to the second embodiment and its construction method] As shown in FIG. 7, in the spar-type float 4' according to the second embodiment, prestress is introduced into the steel-concrete composite structural section 4A by means of PC steel members 16, 16... (mainly PC steel strands) arranged at predetermined intervals along the longitudinal direction of the float and around the circumferential direction in the concrete C poured to a predetermined thickness.

[0065] By introducing prestress into concrete C, it becomes possible to further prevent cracks from occurring in the concrete portion and to increase the strength against external bending forces.

[0066] [Construction method of spar-type floating body 4'] Next, a method for constructing a spar-type floating body 4' using the circular formwork device 14 will be described in detail with reference to Figs.

[0067] (First Step) As shown in Fig. 8(A), the outer shell steel members 10 of the steel-concrete composite structural section 4A are installed in a horizontal orientation. At this time, an opening 30 large enough for the movable formwork device 9 to pass through is provided at the bottom of the steel-concrete composite structural section 4A. It is desirable that the outer periphery of the opening 30 be a composite structure of steel and concrete.

[0068] The slide guide 23 of the movable formwork device 9 is installed in a state where it penetrates the opening 30, a sheath 15 for inserting and installing PC steel members is arranged over the installation range of the circular formwork device 9 in the longitudinal direction of the floating body, and the circular formwork device 14 is positioned at the bottommost position of the steel-concrete composite structure part 4A, and formwork plates 27, 27... are installed so that concrete can be poured at a predetermined thickness on the inner side of the outer shell steel member 10 that covers the entire periphery. The circular formwork device 14 is supported so as not to move by the fixing jack equipment 28, 29, and a gable formwork 31 is installed over the entire periphery at the front end (right side of the drawing) of the formwork plates 27, 27....

[0069] (Second step) As shown in FIG. 8(B), concrete C1 is poured into the spaces between the outer shell steel members 10 of the steel-concrete composite structural portion 4A and the formwork plates 27, 27 . . .

[0070] (Third Step) As shown in Figure 8 (C), while the circular form device 14 is held in position, the form support device 13 is moved to the interior space of the steel-concrete composite structure section 4A (to the right in the drawing). The movement is performed with the front support leg 20 and the rear support leg 21 of the form support device 13 in an open state, and only the form support device 13 is moved by human power. After the movement is completed, the jack-type legs 24 of the front support leg 20 and the rear support leg 2 are extended and placed on the ground as shown in the drawing.

[0071] (Fourth step) As shown in FIG. 8(D), the circular formwork device 14 is removed from the concrete C1, and while the formwork support device 13 is held in position, the circular formwork device 14 is moved to the inner space of the steel-concrete composite structure 4A. Then, a sheath 15 for inserting and installing the PC steel 16 is arranged at a position adjacent to the poured concrete C1 over the floating body longitudinal installation range of the circular formwork device, and formwork plates 27, 27... are installed so that concrete can be poured at a predetermined thickness on the inner side of the outer shell steel member 10 covering the entire circumference. The sheath 15 is placed in the same position as the sheath 15 arranged in the previous step, and is arranged so that the sheath 15 continues in the longitudinal direction. The circular formwork device 14 is supported so as not to move by the fixing jack equipment 28, 29, and a gable formwork 31 is installed over the entire circumference at the front end (front end in the traveling direction) of the formwork plates 27, 27... to close the concrete pouring space.

[0072] (5th step) As shown in FIG. 8(D), concrete C2 is poured into the spaces between the outer steel members 10 of the steel-concrete composite structural portion 4A and the formwork plates 27, 27 . . .

[0073] (Next process step) By repeating the second to fourth steps, concrete is successively poured to a predetermined thickness onto the inner surface of the outer steel member 10 of the steel-concrete composite structure 4A, and when the mobile formwork device 9 has completely entered the interior of the steel-concrete composite structure 4A as shown in Fig. 9(A), the opening 30 formed at the bottom of the steel-concrete composite structure 4A is closed. Specifically, the inner side of the ring-shaped steel plate 32 provided on the outer periphery of the opening 30 is closed with a circular steel plate 33, and then concrete 34 is poured on the inner side, so that the opening 30 is closed by the composite structure of steel and concrete.

[0074] <Concrete pouring procedure for steel-concrete composite structural section 4A general section> (First Step) As shown in FIG. 9(A), concrete C is poured into the spaces between the outer steel members 10 of the steel-concrete composite structural portion 4A and the formwork plates 27, 27 . . .

[0075] (Second step) As shown in Figure 9 (B), while the circular form device 14 is held in position, the form support device 13 is moved to the interior space of the steel concrete composite structural section 4A (the right side of the drawing, toward the steel structural section 4B). The movement is performed with the front support leg 20 and rear support leg 21 of the form support device 13 in an open state, and only the form support device 13 is moved by human power. Once the movement is completed, the jack-type legs 24 of the front support leg 20 and rear support leg 21 are extended and placed on the ground, as shown in the figure.

[0076] (Third Step) As shown in FIG. 9(C), while the formwork support device 13 is held in position, the circular formwork device 14 is moved to the inner space side of the steel concrete composite structure section 4A (the right side of the drawing, the steel structure section 4B side), and a sheath 15 for inserting and installing the PC steel material 16 is arranged in a position adjacent to the poured concrete over the installation range of the circular formwork device 14 in the longitudinal direction of the floating body, and formwork plates 27, 27... are installed so that concrete C can be poured with a predetermined thickness on the inner side of the outer shell steel member 10 covering the entire circumference. The sheath 15 is placed in the same position as the sheath 15 arranged in the previous step, and is arranged so that the sheath 15 continues in the longitudinal direction. Also, as shown in the same figure, the circular formwork device 14 is supported so as not to move by the fixing jack equipment 28, 29, and a gable formwork 31 is installed over the entire circumference at the front end (front end in the traveling direction) of the formwork plates 27, 27... to close the concrete pouring space.

[0077] (Further steps) By repeating the above first to third steps, concrete is successively poured to a predetermined thickness onto the inner surface side of the outer steel shell members 10 of the steel-concrete composite structural section 4A.

[0078] <Introduction of prestress to concrete C and its anchorage> After all the concrete C has been poured, as shown in Figure 10, PC steel bars 16 are inserted into the sheaths 15 arranged over the entire length of the concrete C, and then tension is introduced to the PC steel bars 16 and they are fixed in place.

[0079] <Completion of Spar-type Floating Body 4> In the steel-concrete composite structural section 4A, once concrete C has been poured onto the inner surface of the outer steel shell member 10 that covers the outer periphery, the steel structural section 4B is joined by full perimeter welding, and the spar-type floating body 4 is completed.

[0080] [Other form examples] (1) In the above embodiment, when pouring concrete into the bottom part of the steel-concrete composite structural section 4A, the opening 30 formed in the bottom part of the steel-concrete composite structural section 4A is closed immediately after the movable formwork device 9 has completely entered the interior of the steel-concrete composite structural section 4A as shown in Fig. 5(G), but the process of closing the opening 30 can be performed at any time after the movable formwork device 9 has completely entered the interior of the steel-concrete composite structural section 4A. For example, it may be performed after all the concrete has been poured on the inner side of the outer shell steel member 10, or after joining of the steel structural section 4B to the steel-concrete composite structural section 4A has been completed. [Explanation of symbols]

[0081] 1...Offshore wind power generation equipment, 4...Spar-type floating body, 4A...Steel concrete composite structural section, 4B...Steel structural section, 5...Mooring line, 6...Tower, 7...Nacelle, 8...Blade, 9...Mobile formwork device, 13...Formwork support device, 14...Circular formwork device, 15...Sheath, 16...PC steel, 20...Front support leg, 21...Rear support leg, 27...Formwork plate, 28, 29...Fixing jack equipment, 30...Opening, 31...Gable formwork

Claims

1. A spar-type floating body for offshore wind power generation equipment, characterized in that the lower half is a steel-concrete composite structural part in which concrete is poured to a predetermined thickness on the inner side of an outer shell steel member covering the periphery, and the upper half is a steel structural part having an outer shell steel member covering the periphery and made entirely of steel members.

2. 2. A spar-type float for an offshore wind power generation facility as described in claim 1, wherein in the steel-concrete composite structural section, prestress is introduced into the concrete poured to a predetermined thickness by PC steel members arranged along the longitudinal direction of the float and at predetermined intervals along the circumferential direction.

3. 3. A spar-type floating body for an offshore wind power generation facility as described in claim 1 or 2, wherein at the boundary between the lower half of the steel-concrete composite structural part and the upper half of the steel structural part, the plate thicknesses of the outer shell steel members of the steel-concrete composite structural part and the outer shell steel members of the steel structural part are the same.

4. 3. A spar-type floating body for an offshore wind power generation facility as described in claim 1 or 2, wherein at the boundary between the lower half of the steel-concrete composite structural part and the upper half of the steel structural part, the outer shell steel member of the steel-concrete composite structural part extends a predetermined length and is joined to the outer shell steel member of the steel structural part by welding at a position away from the concrete.

5. A method for constructing a spar-type floating body of an offshore wind power generation facility according to claim 1, A movable form device is carried to a construction site of the spar-type floating body, the movable form device being composed of a form support device having a slide guide provided between the front support leg and the rear support leg along the horizontal direction, and a circular form device provided to be fitted onto the slide guide, movable along the slide guide, and capable of installing form plates in a circular shape at a predetermined radial position all around the circumference. a first step of installing the outer shell steel members of the steel-concrete composite structure of the spar-type floating body in a horizontal orientation, providing an opening at the bottom, installing the movable formwork device with a slide guide penetrating the opening, and positioning the circular formwork device at the bottommost position of the steel-concrete composite structure, and installing formwork plates so that concrete can be poured to a predetermined thickness on the inner side of the outer shell steel members that cover the entire periphery; A second step of pouring concrete into a space between an outer steel member of the steel concrete composite structure and the formwork plate; a third step of moving the form support device to an inner space side of the steel concrete composite structure while maintaining the circular form device in position; a fourth step of moving the circular form device to the interior space of the steel-concrete composite structure while maintaining the form support device in position, and installing a form plate adjacent to the poured concrete on the inner surface of the outer shell steel member that covers the entire periphery so that concrete can be poured to a predetermined thickness; A method for constructing a spar-type floating body for an offshore wind power generation facility, characterized in that by repeating the second to fourth steps, concrete is sequentially poured to a predetermined thickness onto the inner surface side of the outer steel shell members of the steel-concrete composite structural part, and after the mobile formwork device has completely entered the interior of the steel-concrete composite structural part, the opening formed in the bottom of the steel-concrete composite structural part is sealed.

6. A method for constructing a spar-type floating body of an offshore wind power generation facility according to claim 2, A movable form device is carried to a construction site of the spar-type floating body, the movable form device being composed of a form support device having a slide guide provided between the front support leg and the rear support leg along the horizontal direction, and a circular form device provided to be fitted onto the slide guide, movable along the slide guide, and capable of installing form plates in a circular shape at a predetermined radial position all around the circumference. a first step of installing the outer shell steel members of the steel-concrete composite structure of the spar-type floating body in a horizontal orientation, providing an opening at the bottom, installing the movable formwork device with a slide guide penetrating the opening, disposing a sheath for inserting and installing PC steel members over the installation range of the circular formwork device in the longitudinal direction of the floating body, positioning the circular formwork device at the bottommost position of the steel-concrete composite structure, and installing formwork plates so that concrete can be poured to a predetermined thickness on the inner side of the outer shell steel members that cover the entire periphery; A second step of pouring concrete into a space between an outer steel member of the steel concrete composite structure and the formwork plate; a third step of moving the form support device to an inner space side of the steel concrete composite structure while maintaining the circular form device in position; a fourth step of moving the circular formwork device to the inner space of the steel concrete composite structure while the formwork support device is held in position, disposing a sheath for inserting and installing PC steel members over the installation range of the circular formwork device in the longitudinal direction of the float adjacent to the poured concrete, and installing a formwork plate on the inner surface side of the outer shell steel member covering the entire periphery so that concrete can be poured to a predetermined thickness; a fifth step of pouring concrete in a predetermined thickness in sequence on the inner surface side of the outer steel member of the steel concrete composite structure by repeating the second step to the fourth step, and closing the opening formed in the bottom of the steel concrete composite structure after the movable formwork device has completely entered the interior of the steel concrete composite structure; and a sixth step of inserting PC steel into a sheath arranged over the entire length of the concrete in the steel-concrete composite structure, and then introducing tension into and fixing the PC steel.

7. 7. The method for constructing a spar-type float for an offshore wind power generation facility according to claim 5 or 6, wherein, once concrete has been poured to a predetermined thickness on the inner side of the outer shell steel member covering the outer periphery in the steel-concrete composite structural section, the steel structural section is joined by full-circumference welding to complete the spar-type float.

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