Support structure for offshore wind turbines and process for installing the support structure.

Abstract

The present invention relates to a support structure (1) for an offshore wind turbine, and the support structure (1) is - A first structural part (A) to be fixed to the seabed (Sb), the first structural part (A) comprising at least three dummy legs (3) regularly distributed on a first circle (X1) centered on the longitudinal axis (Y) of the support structure (1) and extending along the longitudinal axis (Y) of the support structure (1), the dummy legs (3) comprising a lower end (3a) designed to face the seabed (Sb) and an upper end (3b) opposite to the lower end (3a), the first structural part (A) also comprising at least three anchor devices (5) to the seabed (Sb) connected to at least three dummy legs (3), - A second structural part (B) having at least three structural legs (4) having a lower end (Ba) facing the first structural part (A) and an upper end (Bb) configured to be positioned above the sea surface (S1) and The structure comprises, wherein at least one anchor device (5) of the first structural part (A) is positioned at an angle between two adjacent dummy legs (3) on a second circle (X2) centered on the longitudinal axis (Y) of the support structure (1), and at least one of the dummy legs (3) of the first structural part (A) and / or the structural legs of the second structural part (B) is filled at least partially with solid ballast (10).

Description

Technical Field

[0001] The present invention relates to a support structure for an offshore wind turbine and a process for installing such a support structure. More precisely, the present invention relates to a support structure that is placed and fixed on the seabed at an average water depth of about 80 to 150 m.

Background Art

[0002] In the case of shallower water depths of about 50 m, it is well known to use support structures such as jacket structures for offshore wind turbines. Such support structures are placed on the seabed and fixed to the ground using anchor devices. The support structure extends above the sea surface to receive the mast of the wind turbine. Generally, this support structure is made in one piece, and as the water depth increases, the support structure needs to be made higher.

[0003] In the case of deeper water depths of about 80 to 150 m, the support structure needs to be tall enough to reach such water depths. Such a height can pose a problem for the installation of the support structure on the seabed. In fact, the support structure is generally transported vertically to the site using a transport barge, lifted by a floating crane, and placed on the seabed. In such water depths, the transport barge and the floating crane become larger and heavier, which increases the cost and affects the installation plan, especially when continuously installing multiple support structures for wind power generation. Furthermore, depending on the anchor devices used, such as piles drilled into the seabed, the fixing can become more complicated depending on the water depth.

Summary of the Invention

[0004] One object of the present invention is to provide a support structure for an offshore wind turbine adapted to an average water depth of about 80 to 150 m and an improved anchor device. Another object of the present invention is to provide a suitable process for installing a support structure for wind power generation.

[0005] For this purpose, the present invention relates to a support structure for offshore wind turbines, the support structure being: - A first structural part intended to be fixed to the seabed, comprising at least three dummy legs regularly distributed on a first circle centered on the longitudinal axis of the support structure and extending along the longitudinal axis of the support structure, wherein each dummy leg has a lower end designed to face the seabed and an upper end opposite to the lower end, and the first structural part also comprises at least three anchor devices to the seabed connected to the at least three dummy legs, - A second structural part comprising at least three structural legs, each having a lower end facing the first structural part and an upper end configured to be positioned above sea level. The system comprises, wherein at least one anchor device of the first structural part is positioned at an angle between two adjacent dummy legs on a second circle centered on the longitudinal axis of the support structure, and at least one of the dummy legs of the first structural part and / or the structural legs of the second structural part is filled at least partially with solid ballast.

[0006] According to one aspect of the present invention, the dummy legs of the first structural part and / or the structural legs of the second structural part each comprise at least one hollow section filled with solid ballast over their length.

[0007] According to another aspect of the present invention, the dummy legs of the first structural part and / or the structural legs of the second structural part are filled with solid ballast over their entire length.

[0008] According to another aspect of the present invention, the upper ends of the dummy legs of the first structural part and / or the structural legs of the second structural part are open for filling with solid ballast.

[0009] According to another aspect of the present invention, in order to fill the dummy legs of the first structural part and / or the structural legs of the second structural part with solid ballast, the dummy legs of the first structural part and / or the structural legs of the second structural part are provided with at least one side opening that communicates with the hollow portion of the dummy legs of the first structural part and / or the structural legs of the second structural part.

[0010] According to another aspect of the present invention, the solid ballast comprises at least one of the following materials: sand, gravel, concrete grout, Magnadens, and materials recovered on site.

[0011] According to another aspect of the present invention, the support structure comprises at least one intermediate element positioned between a first structural part and a second structural part.

[0012] According to another aspect of the present invention, the first structural part and the second structural part have a standardized height, and at least one intermediate element has a variable height depending on the depth sounding.

[0013] According to another aspect of the present invention, at least one intermediate element is a metal extension welded to the upper end of a dummy leg of a first structural part and / or to the lower end of a structural leg of a second structural part.

[0014] According to another aspect of the present invention, at least one intermediate element is a concrete element positioned between the upper end of a dummy leg of a first structural part and the lower end of a structural leg of a second structural part.

[0015] According to another aspect of the present invention, the support structure comprises individual concrete elements between each individual dummy leg of the first structural part and each individual structural leg of the second structural part.

[0016] According to another aspect of the present invention, the concrete element is at least one concrete slab positioned between the structural legs of a first structural part and a second structural part.

[0017] According to another aspect of the present invention, at least one intermediate element is a steel intermediate frame that connects a dummy leg of a first structural part and a structural leg of a second structural part together.

[0018] The present invention also relates to a process for installing a support structure for wind power plant equipment, the process being: - A step of transporting at least one first structural part to the site, wherein the first structural part comprises at least three dummy legs that are regularly distributed on a first circle centered on the longitudinal axis of the support structure and extend along the longitudinal axis of the support structure, the dummy legs having a lower end designed to face the seabed and an upper end opposite to the lower end, and the first structural part also comprises at least three anchor devices to the seabed connected to the at least three dummy legs, the anchor device to the seabed of the first structural part being positioned at an angle between two adjacent dummy legs on a second circle centered on the longitudinal axis of the support structure, - Steps include installing the first structural part on the seabed, - A step of fixing at least one first structural part to the seabed using an anchor device, - A step of transporting at least one second structural upper section to the site, - A step of lifting and stacking at least one second structural part on top of at least one first structural part underwater, - The steps of fixing at least one second structural part (B) on top of the first structural part The process also includes the step of filling the first and / or second structural parts with solid ballast after installing the first and / or second structural parts on site.

[0019] According to one aspect of the process, the process also includes the step of installing at least one intermediate element designed to be positioned between a first structural part and a second structural part.

[0020] Further features and advantages of the present invention will become apparent from the following description given by way of non-limiting example, with reference to the accompanying drawings.

Brief Description of the Drawings

[0021] [Figure 1] It is a schematic side view of a support structure for an offshore wind turbine according to a first embodiment. [Figure 2] It is a schematic top view of a first structural part of a support structure according to a first embodiment. [Figure 3] It is a schematic top view of a first structural part of a support structure according to a second embodiment. [Figure 4] It is a schematic top view of a first structural part of a support structure according to a third embodiment. [Figure 5] It is a schematic top view of a first structural part of a support structure according to a fourth embodiment. [Figure 6-7] It is a side view of an anchor device according to two different embodiments. [Figure 8] It is a schematic side view of a joint between a first structural part and a second structural part according to a first embodiment. [Figure 9] It is a schematic side view of a support structure for an offshore wind turbine according to a second embodiment. [Figure 10] It is a schematic side view of a support structure for an offshore wind turbine according to a third embodiment. [Figure 11] It is a schematic side view of a joint between a first structural part and a second structural part according to a second embodiment. [Figure 12] It is a schematic side view of a joint between a first structural part and a second structural part according to a third embodiment. [Figure 13-14] They are two charts of a process for installing a support structure according to two different embodiments.

Modes for Carrying Out the Invention

[0022] In these figures, identical elements are given the same reference numeral. The following implementations are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment or that the features apply only to a single embodiment. Individual features from different embodiments can be combined or replaced to provide other embodiments.

[0023] Figure 1 shows a support structure 1 for an offshore wind turbine. This support structure 1 comprises at least a first structure A and a second structure B, which are designed to be stacked to form the support structure 1.

[0024] The first structural part A is configured to be fixed to the seabed Sb. The first structural part A comprises at least three dummy legs 3 regularly distributed on a first circle X1 centered on the longitudinal axis Y of the support structure 1. The dummy legs 3 extend along the longitudinal axis Y of the support structure 1. Figure 2 is a top view of a first example of the first structural part A having three dummy legs 3 arranged in a triangular pattern on the first circle X1. Figure 3 is a top view of a second example of the first structural part A having four dummy legs 3 arranged in a square pattern on the first circle X1. Other examples having four or more or five or more dummy legs are also possible.

[0025] As shown in Figure 1, the dummy leg 3 comprises a lower end 3a designed to face the seabed Sb and an upper end 3b opposite the lower end 3a. The dummy leg 3 can be parallel to the longitudinal axis Y of the support structure 1, or it can be inclined with respect to this longitudinal axis Y. If the dummy leg 3 is inclined, it is preferable that the lower end 3a of the dummy leg 3 is further from the central longitudinal axis Y than its upper end 3b. Whether the dummy leg 3 is parallel to the longitudinal axis Y or inclined with respect to the longitudinal axis Y, the first circle X1 may be defined by the lower end 3a of the dummy leg 3.

[0026] The first structural part A also includes at least three anchor devices 5 to the seabed Sb, connected to at least three dummy legs 3. As shown in Figures 2 and 3, at least one anchor device 5 of the first structural part A may be positioned at an angle between two adjacent dummy legs 3, i.e., within an arc defined by the radius connecting the longitudinal axis Y to the two adjacent dummy legs 3. At least one anchor device 5 may be positioned on a second circle X2 centered on the longitudinal axis Y of the support structure 1.

[0027] The fact that the anchor device 5 is offset compared to the dummy legs 3 reduces the risk of damage to the support structure 1, particularly the first structural part A, when the anchor device 5 is fixed to the seabed Sb. This is especially advantageous when the anchor device 5 is fixed using piles 7 driven into the seabed Sb. Furthermore, the fact that the anchor device 5 of the first structural part A is positioned at an angle between two adjacent dummy legs 3 is advantageous in that it reduces the weight and manufacturing cost of the structure compared to conventional skirt pile connections.

[0028] According to the first embodiment shown in Figures 2 and 3, the second circle X2, which includes the anchor device 5 for the first structural part A to the seabed Sb, and the first circle X1, which includes the dummy leg 3, have the same radius.

[0029] According to the second embodiment shown in Figure 4, the second circle X2, which includes the anchor device 5 of the first structural part A to the seabed Sb, has a larger radius than the first circle X1, which includes the dummy leg 3.

[0030] According to a third embodiment not shown, the second circle X2 comprising the anchor device 5 to the seabed Sb of the first structural part A has a smaller radius than the first circle X1 comprising the dummy leg 3.

[0031] In Figures 2 to 4, the first structural part A comprises only one anchor device 5 to the seabed Sb between two adjacent dummy legs 3. In this particular embodiment, as shown in Figure 3, the angle α between the radius (from axis Y) connecting the anchor devices 5 and the radius (from axis Y) connecting the two dummy legs 3 surrounding the anchor devices 5 is the same.

[0032] Another embodiment is possible in which the first structural part A comprises at least two anchor devices 5 between two adjacent dummy legs 3, for example, as shown in Figure 5. In the example shown in Figure 5, only two anchor devices 5 are shown, but three or more anchor devices 5 are also possible. In this embodiment, these at least two anchor devices 5 are preferably equidistant from the two dummy legs 3 and distributed symmetrically and / or linearly on each side on a central line passing through the longitudinal axis Y of the support structure 1. In this embodiment, the radius of the second circle X2 may be different from the radius of the first circle X1 in the first, second, and third embodiments described above.

[0033] As shown in Figures 6 and 7, the anchor device 5 may be a sleeve configured to receive and secure the pile 7. These piles are designed to be driven into or excavated into the seabed Sb. The sleeve 5 may have a lower end 5a designed to face the seabed Sb and an upper end 5b opposite the lower end 5b. The sleeve 5 may have a hollow shape complementary to the pile 7. The pile 7 is inserted into the hollow portion of the sleeve 5. The sleeve 5 and the pile 7 may be secured together by grout injection, for example, with cement grout 12. The securing of the sleeve 5 and the pile 7 can be achieved by welding these two elements together.

[0034] Another means of securing both the sleeve 5 and the pile 7 together can be achieved by swaging, for example, using a Hydra-Lok® structural connection solution. Using such a solution makes it possible to reduce connection time, and therefore installation time. The time from connecting the sleeve 5 and the pile 7 to installing the wind turbine on the support structure is also shorter compared to, for example, grouting.

[0035] To facilitate the insertion of the pile 7, the sleeve 5 may also be provided with guide portions at its upper end 5b and / or lower end 5a, depending on whether the pile 7 is inserted into the sleeve 5 from the upper end 5b or from the lower end 5a. These guide portions may be, for example, formed at the tips 5a and 5b of the sleeve 5, where a funnel is formed.

[0036] The anchor device 5 may also include other elements such as a suction bucket (not shown) or some concrete foundation as a gravity structure.

[0037] The first structural component A may preferably be a jacket structure consisting of a welded space frame with dummy legs 3 supported by a lateral bracing system.

[0038] As shown in Figure 1, the second structural part B comprises at least three structural legs 4. These structural legs 4 extend along the longitudinal axis Y of the support structure 1 and are supported by a lateral bracing system. Each structural leg 4 has a lower end Ba facing the first structural part A and an upper end Bb configured to be positioned above sea level Sl. The second structural part B may also preferably be a jacket structure composed of a welded space frame.

[0039] According to the first embodiment shown in Figure 8, the second structural part B may have a lower end Ba designed to connect to the upper end 3b of the dummy leg 3 of the first structural part A. The upper end 3b of the dummy leg 3 of the first structural part A is provided with either a receiving opening or a pin, and the lower end Ba of the second structural part B is provided with either a pin or a receiving opening. The pin and the receiving opening are configured to fit together. The pin may be fixed in the receiving opening by grout injection, for example, with cement grout 14. Fixation of the lower end Ba of the second structural part B and the upper end 3b of the dummy leg 3 can be performed by welding these two elements together.

[0040] Another means of securing the lower end Ba of the second structural part B and the upper end 3b of the dummy leg 3 together can be performed, for example, by swaging fixation using the Hydra-Lok® structural connection solution. Using such a solution makes it possible to reduce connection time, and therefore installation time. The time from connection of the lower end Ba of the second structural part B and the upper end 3b of the dummy leg 3 to the installation of the wind turbine on the support structure is also shorter compared to, for example, grout fixation.

[0041] To facilitate the insertion of the pin into the receiving opening, the receiving opening may be provided with a guide portion. This guide portion may be configured in a flared portion that forms a funnel at the entrance of the receiving opening. To enable the transmission of force between the upper end 3b of the dummy leg 3 and the lower end Ba of the second structural part B, the pin may also be provided with a stopper element 17 that contacts the receiving opening. In the example shown in Figure 8, the receiving opening is located at the upper end 3b of the dummy leg 3, and the pin is located at the lower end Ba of the second structural part B.

[0042] The upper end Bb of the second structural part B is located above sea level Sl and may also include a platform 8 for receiving the mast of an offshore turbine.

[0043] Furthermore, the cross-sectional dimension of the upper end Bb of the second structural part B may be smaller than the cross-sectional dimension of the lower end Ba. Therefore, the legs of the second structural part B may be inclined with respect to the longitudinal axis Y of the support structure 1.

[0044] As shown in Figures 1 and 8-12, the structural legs 4 of the first structural part A and / or the second structural part B are filled at least partially with solid ballast 10. For example, when wind forces exert a very large lever action on the seabed, thus causing a large overturning moment at its base level, resulting in large tensions, the addition of weight reduces the potential tension acting on the pile.

[0045] The combination of this at least partially ballasting and the fact that the first structural part A comprises at least three dummy legs 3 regularly distributed on the first circle X1 and at least one anchor device 5 positioned at an angle between two adjacent dummy legs 3 on the second circle X2, or equidistant from each other, increases the compressive force on the anchor device 5 and decreases the tensile force on the same anchor device 5 due to the increased weight of the support structure 1, especially when the second circle X2 has a larger radius than the first circle X1. In this case, the support structure 1 becomes more stable and more resistant to lateral forces and movements caused by flow or wind. This combination, in particular the fact that at least one anchor device 5 of the first structural part A is positioned at an angle between two adjacent dummy legs 3 or at an equidistant distance, also facilitates access to the anchor device 5 for driving the pile 7 with an anchor tool such as a hammer, and access to the dummy legs 3 for at least partially filling the dummy legs 3 with solid ballast 10.

[0046] Generally, the interaction capacity in tension between the pile 7 and the soil beneath the seabed Sb is smaller than the interaction capacity in compression, and the length of the pile 7 is often determined by the maximum tension acting on it. This means that the addition of weight in the supporting structure 1 reduces the penetration requirements of the pile 7. This is beneficial in reducing the steel and manufacturing costs, installation time, and overall costs of the pile 7 (especially when the pile 7 needs to be excavated, which is more costly and time-consuming than driving).

[0047] Ballast tuning of structural part A and / or structural part B, either entirely or partially, alters the dynamic response of support structure 1, providing the ability to fine-tune the overall dynamics of support structure 1 to wind turbine and wave excitation.

[0048] As shown in Figures 1 and 9, the dummy legs 3 of the first structural part A and / or the structural legs 4 of the second structural part B each have at least one hollow section filled with solid ballast 10 over their length. Partially or entirely filling the dummy legs 3 of the first structural part A and / or the structural legs 4 of the second structural part strengthens the nodes, in particular against fatigue and punching shear effects, and increases the ship's resistance to collisions.

[0049] According to the first embodiment shown in Figures 1 and 9, the dummy legs 3 of the first structural part A and / or the structural legs 4 of the second structural part B are filled with solid ballast 10 over their entire length.

[0050] To fill the dummy legs 3 of the first structural part A and / or the structural legs 4 of the second structural part B with solid ballast 10 over their entire length, the upper ends 3b, Bd of the dummy legs 3 and / or structural legs 4 can be opened to fill the dummy legs 3 and / or structural legs 4 with solid ballast 10, as shown in Figures 1 and 9.

[0051] According to the second embodiment shown in Figure 10, the dummy leg 3 of the first structural part A and / or the structural leg 4 of the second structural part B have hollow sections configured to be filled with solid ballast 10, and the dummy leg 3 and / or structural leg 4 have at least one side opening communicating with these hollow sections in order to fill these hollow sections with solid ballast 10. If one of these hollow sections is located at the upper end 3b, Bb of the dummy leg 3 and / or structural leg 4, this upper end 3b, Bb can be opened to fill this upper hollow section with solid ballast 10.

[0052] The solid ballast 10 may comprise at least one of the following materials: sand, gravel, concrete grout, Magnadens, and materials recovered on site.

[0053] By using Magnadens, preferably with a relative density of up to 5, or any pumpable derivative thereof, as the solid ballast 10, the solid ballast 10 can be removed, facilitating the dismantling of the support structure 1.

[0054] The support structure 1 is configured to be installed in a location with a water depth of 80 to 150 m. For example, at a water depth of approximately 100 m, the first structural part A may have a height of 30 to 40 m, and the second structural part B may have a height of 60 to 70 m. At greater water depths, the first structure may be taller.

[0055] As shown in Figures 1, 9, and 10, the second structural section B may be a single unit, for example, in the case of a second structural section B of 60m to 70m. In the case of a higher second structural section B, the second structural section B may be divided into two substructures not shown. During the installation of the support structure 1, the two substructures may be stacked and connected together. These two substructures may be attached together by means 10 similar to the means used to connect the first structural section A and the second structural section B. This division of the second structural section B is particularly advantageous in the transport and storage, as well as the installation of the second structural section B. In fact, because the substructures are lower and lighter, they can be transported by small transport barges, and they can be installed by small floating cranes.

[0056] To facilitate the manufacturing process of the support structure 1, the first structural part A and the second structural part B may be standardized and have a fixed height. This allows for the automation and standardization of the manufacturing of structural parts A and B, and enables the use of robotic means for their production. Thus, structural parts A and B can be mass-produced and stored so that they can be used in various fields or regions around the world.

[0057] To compensate for the depth measurement, the support structure 1 may include at least one intermediate element C positioned between the first structural part A and the second structural part B, as shown in Figures 11 and 12. More precisely, the at least one intermediate element C may be positioned between the upper end 3b of the dummy leg 3 of the first structural part A and the lower end Ba of the structural leg 4 of the second structural part B. The first structural part A and the second structural part B may have standardized heights, and the at least one intermediate element C may have a variable height depending on the depth measurement at the location of the support structure 1.

[0058] At least one intermediate element C may be a metal extension, for example, welded to the upper end 3b of the dummy leg 3 of the first structural part A and / or welded to the lower end Ba of the structural leg 4 of the second structural part B.

[0059] As shown in Figures 11 and 12, at least one intermediate element C may be a concrete element made of, for example, ultra-high performance fiber-reinforced concrete (UHPC), and may be positioned between the upper end 3b of the dummy leg 3 of the first structural part A and the lower end Ba of the structural leg 4 of the second structural part B.

[0060] As shown in Figure 11, the support structure 1 may include individual concrete elements 10 between each individual dummy leg 3 of the first structural part A and each individual structural leg 4 of the second structural part B.

[0061] Alternatively, concrete element C may be at least one concrete slab positioned between the structural legs 4 of the first structural part A and the second structural part B, as shown in Figure 12.

[0062] At least one intermediate element C may be a steel intermediate frame that connects both the dummy leg 3 of the first structural part A and the structural leg 4 of the second structural part B.

[0063] The present invention also relates to a process 100 for installing a support structure 1 for wind power plant equipment, as described above. Steps of such a process are shown in Figure 13.

[0064] The process comprises a first step 101 of transporting one or more first structural parts A to site. As described above, the first structural part A comprises at least three dummy legs 3 extending along the longitudinal axis Y of the support structure 1. These dummy legs 3 can be regularly distributed on a first circle X1 centered on the longitudinal axis Y of the support structure Y. Each dummy leg 3 comprises a lower end 3a designed to face the seabed Sb and an upper end 3b opposite the lower end 3a. The first structural part A also comprises at least three anchor devices 5 connected to at least three dummy legs 3. At least one anchor device 5 of the first structural part A may be positioned at an angle between two adjacent dummy legs 3, i.e., within an arc defined by the radius connecting the longitudinal axis Y to the two adjacent dummy legs 3. At least one anchor device 5 may be positioned on a second circle X2 centered on the longitudinal axis Y of the support structure A. As previously mentioned, the first structural part A can be transported to the site by a transport barge. Since the first structural part A is smaller and lighter, multiple first structural parts A can be placed on the same transport barge and can be arranged vertically to facilitate the next installation step.

[0065] The second step 102 is to install the first structural part A on the seabed Sb. This second step 102 can be carried out using a floating crane. Since the first structural part A is smaller and lighter, the floating crane can be made smaller to reduce costs.

[0066] The third step 103 is to secure the first structural part A to the seabed Sb using the anchor device 5. Depending on the anchor device 5, this third step 103 can be performed in different ways, for example, by using a pile 7 driven or excavated into the seabed, by a suction bucket, or by using some concrete foundation as a gravity structure. However, the risk of damage to the support structure 1 is reduced because the anchor device 5 may be offset compared to the dummy leg 3. This is particularly advantageous when the anchor device 5 is secured using a pile 7 driven into the seabed Sb.

[0067] These three steps 101, 102, and 103 may be performed during the same installation activity (campaign) of the first structural part A. Other subsequent steps in the installation of the second structural part B may be performed later or postponed during another installation activity that immediately follows the first activity.

[0068] The fourth step 104 is to transport one or more second structural parts B to the site. These second structural parts B comprise at least three structural legs 4, each having a lower end Ba facing the first structural part A and an upper end Bb configured to be positioned above sea level Sl. As previously stated, the second structural parts B can be transported to the site by a transport barge. Since the second structural parts B are smaller and lighter than the entire support structure 1, multiple second structural parts B can be placed on the same transport barge and may be positioned vertically to facilitate the next installation step.

[0069] The fifth step 105 is to lift and stack the second structural part B on top of the first structural part A underwater. This fifth step 105 can be performed using a floating crane. Since the second structural part B is smaller and lighter than the entire support structure 1, the floating crane can be made smaller to reduce costs.

[0070] The sixth step 106 is to fix the second structural part B onto the first structural part A. As previously mentioned, this fixing can be carried out by various means such as grout injection, welding, or swaging by hydraulic means.

[0071] Process 100 also includes the step of filling the first structural part A and / or the second structural part B with solid ballast 10 after they have been installed in site. This step can be performed at different points in the process. For example, if the dummy legs 3 of the first structural part A are to be filled with solid ballast 10, this step can be performed immediately after the second step 102 in which the first structural part A is installed on the seabed Sb. If the structural legs 4 of the second structural part B are to be filled with solid ballast 10, this step can be performed immediately after the fifth step 105 in which the second structural part B is lifted and stacked on top of the first structural part A underwater. Alternatively, structural part B may be partially filled with solid ballast 10 before the fifth step 105, and then the filling may be completed.

[0072] By increasing the weight of support structure 1 after its installation, support structure 1 becomes lighter during these steps, thereby reducing construction, transportation, and installation costs.

[0073] Process 100 may also include the step of installing at least one intermediate element C designed to be positioned between the first structural part A and the second structural part B. This step can be performed on site, on board a ship, underwater, or before the first or fourth step of transporting the first structural part A or the second structural part B.

[0074] Therefore, the fifth step 105, which involves lifting and stacking the second structural part B on top of the first structural part A, can be performed with the second structural part B already connected to at least one intermediate element C.

[0075] In another embodiment, at least one intermediate element C is transported and installed before the fifth step 105 in which the second structural part B is lifted and stacked on top of the first structural part A. For example, the three steps 101, 102, and 103 may be performed during the same first installation activity of the first structural part A. The step 104 in which one or more second structural parts B are transported to the site may be performed during the second installation activity. After this step 104, the second structural parts B may be stored at the site, for example, lying on the seabed. The step of installing at least one intermediate element C may be performed during the third installation activity, for example, immediately before or simultaneously with the fifth step 105.

[0076] This process 100 not only enables a reduction in installation costs, but also allows for the installation itself using, optionally, conventional transport barges or vessels equipped with standard cranes, slings, and winches, and optionally, with the help of a separate floating crane. In fact, a support structure 1 consisting of two parts, A and B, allows for the installation of a larger support structure 1 using much smaller transport barges and floating cranes than in the case of a single support structure. In addition, provided that the total height of the stacked parts A and / or B does not hinder the lifting, separation, and setup of individual parts A and / or B by the crane, it may be possible to stack multiple parts A and / or B, taking into consideration on-site transport and installation, depending on the loading capacity of the transport barge or vessel in question. This process is particularly useful for the installation of support structures 1 in water depths that have not been easily accessible using conventional means.

[0077] If the anchor device 5 is a sleeve, the process 100 may include a preliminary step 101a of inserting piles 7 into the seabed Sb to form a receiving area for each first structural part A, prior to step 101 of installing the first structural part A into the seabed Sb. In this case, step 101 of installing the first structural part A into the seabed Sb consists of docking the pre-installed piles 7 into the sleeve of the anchor device 5.

[0078] During the preliminary step 101a of inserting the pile 7, a template may be dropped onto the seabed Sb to guide the insertion of the pile 7. This template can be removed after forming a receiving area for a first structural part A and reused to form a receiving area for another first structural part A.

[0079] In another embodiment, shown in Figure 13, where the anchor device 5 is also a sleeve, the pile 7 is positioned after the installation of the first structural part A, rather than before. Thus, step 103 for fixing the first structural part A to the seabed Sb consists of a first substep 103a in which the pile 7 is inserted into the seabed Sb through the sleeve 5. In a second substep 103b, the sleeve 5 and the pile 7 are fixed together. In this embodiment, the first structural part A is used as a template for the pile 7.

Claims

1. A support structure (1) for an offshore wind turbine, - A first structural part (A) to be fixed to the seabed (Sb), the first structural part (A) comprising at least three dummy legs (3) regularly distributed on a first circle (X1) centered on the longitudinal axis (Y) of the support structure (1) and extending along the longitudinal axis (Y) of the support structure (1), the dummy legs (3) comprising a lower end (3a) designed to face the seabed (Sb) and an upper end (3b) opposite to the lower end (3a), the first structural part (A) also comprising at least three anchor devices (5) to the seabed (Sb) connected to the at least three dummy legs (3), - A second structural part (B) having at least three structural legs (4) having a lower end (Ba) facing the first structural part (A) and an upper end (Bb) configured to be positioned above the sea surface (S1) A support structure (1) comprising, wherein at least one anchor device (5) of the first structural part (A) is positioned at an angle between two adjacent dummy legs (3) on a second circle (X2) centered on the longitudinal axis (Y) of the support structure (1), and at least one of the dummy legs (3) of the first structural part (A) and / or the structural legs of the second structural part (B) is filled at least partially with solid ballast (10).

2. The support structure (1) according to claim 1, wherein the dummy leg (3) of the first structural part (A) and / or the structural leg (4) of the second structural part (B) each comprises at least one hollow portion filled with the solid ballast (10) over their respective lengths.

3. The support structure (1) according to claim 1, wherein the dummy legs (3) of the first structural part (A) and / or the structural legs (4) of the second structural part (B) are filled with the solid ballast (10) over their entire length.

4. The support structure (1) according to claim 2 or 3, wherein the upper ends (3b, Bb) of the dummy leg (3) of the first structural part (A) and / or the structural leg (4) of the second structural part (B) are open for filling with solid ballast (10).

5. Support structure (1) according to any one of claims 2 to 4, wherein the dummy leg (3) of the first structural part (A) and / or the structural leg (4) of the second structural part (B) are provided with at least one side opening that communicates with the hollow portion of the dummy leg (3) of the first structural part (A) and / or the structural leg (4) of the second structural part (B) in order to fill the dummy leg (3) of the first structural part (A) and / or the structural leg (4) of the second structural part (B) with solid ballast (10).

6. The support structure (1) according to any one of claims 1 to 5, wherein the solid ballast (10) comprises at least one of the following materials: sand, gravel, concrete grout, Magnadens, and materials recovered on site.

7. The support structure (1) according to any one of claims 1 to 6, wherein the support structure (1) comprises at least one intermediate element (C) disposed between the first structural part (A) and the second structural part (B).

8. The support structure (1) according to claim 7, wherein the first structural part (A) and the second structural part (B) have standardized heights, and the at least one intermediate element (C) has a variable height according to the depth measurement.

9. The support structure (1) according to claim 7 or 8, wherein the at least one intermediate element (C) is a metal extension welded to the upper end (3b) of the dummy leg (3) of the first structural part (A) and / or to the lower end (Ba) of the structural leg (4) of the second structural part (B).

10. The support structure (1) according to claim 7 or 8, wherein the at least one intermediate element (C) is a concrete element positioned between the upper end (3b) of the dummy leg (3) of the first structural part (A) and the lower end (Ba) of the structural leg (4) of the second structural part (B).

11. The support structure (1) according to claim 10, further comprising individual concrete elements (10) between each individual dummy leg (3) of the first structural part (A) and each individual structural leg (4) of the second structural part (B).

12. The support structure (1) according to claim 10, wherein the concrete element (C) is at least one concrete slab positioned between the first structural part (A) and the structural leg (4) of the second structural part (B).

13. The support structure (1) according to claim 7 or 8, wherein the at least one intermediate element (C) is a steel intermediate frame that connects the dummy leg (3) of the first structural part (A) and the structural leg (4) of the second structural part (B).

14. A process for installing a support structure (1) for wind power plant equipment, - A step of transporting at least one first structural part (A) to the site, wherein the first structural part (A) comprises at least three dummy legs (3) which are regularly distributed on a first circle (X1) centered on the longitudinal axis (Y) of the support structure (1) and extend along the longitudinal axis (Y) of the support structure (1), and the dummy legs (3) have a lower end (3a) designed to face the seabed (Sb) and an upper end opposite to the lower end (3a) (3b) and also comprising, the first structural part (A) also comprises at least three anchor devices (5) to the seabed (Sb) connected to the at least three dummy legs (3), wherein at least one anchor device (5) to the seabed (Sb) of the first structural part (A) is positioned at an angle between two adjacent dummy legs (3) on a second circle (X2) centered on the longitudinal axis (Y) of the support structure (A), - The step of installing the first structural part (A) on the seabed (Sb), - The steps of fixing the at least one first structural part (A) to the seabed (Sb) using the anchor device (5), - A step of transporting at least one second upper structural part (B) to the site, - The steps of lifting and stacking the at least one second structural part (B) on top of the at least one first structural part (A) underwater, - The step of fixing at least one second structural part (B) on the first structural part (A) A process comprising the steps of, after installing the first structural part (A) and / or the second structural part (B) on site, filling the first structural part (A) and / or the second structural part (B) with solid ballast (10).

15. The process according to claim 14, further comprising the step of installing at least one intermediate element (C) designed to be positioned between the first structural part (A) and the second structural part (B).

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