Support structure for an offshore wind turbine and process for installing the support structure

Abstract

The present invention relates to a support structure (1) for an offshore wind turbine, comprising a first structural part (A) adapted to be fixed to a seabed (Sb), said support structure (1) comprising at least three dummy legs (3) regularly distributed on a first circle (XI) having as its centre the longitudinal axis (Y) of the support structure (1) and extending along said longitudinal axis (Y) of the support structure (1), said dummy legs (3) comprising a lower end (3a) designed to face the seabed (Sb) and an upper end (3b) opposite said lower end (3a), said first structural part (A) comprising at least three dummy legs (3) regularly distributed on a first circle (XI) having as its centre the longitudinal axis (Y) of the support structure (1), said dummy legs (3) comprising at least three dummy legs (3) arranged along said longitudinal axis (Y) of the support structure (1), said dummy legs (3) each having a lower end (3a) designed to face the seabed (Sb) and an upper end (3b) opposite said lower end (3a), The support structure (1) also comprises a first structural part (A) with at least three anchoring devices (5) to the seabed (Sb) connected to at least three dummy legs (3) and a second structural part with a lower end (Ba) attached to the upper ends (3b) of the at least three dummy legs (3) of the first structural part (A), the at least one anchoring device (5) of the first structural part (A) being angularly positioned between two adjacent dummy legs (3) on a second circle (X2) centered on the longitudinal axis (Y) of the support structure (1). The present invention also relates to a process for installing said support structure (1) for wind power plant installation.

Description

[Technical field]

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

[0002] At shallower depths, around 50 m, it is well known to use support structures, such as jacket structures, for offshore wind turbines. Such support structures rest on the seabed and are fixed to the ground using anchoring devices. The support structure extends above the sea surface to receive the wind turbine mast. Generally, this support structure is made in one piece, and the deeper the depth, the higher the support structure must be.

[0003] For deeper depths, around 80-150 m, the support structure must be tall enough to reach such depths. Such height can be a problem when installing the support structure on the seabed. Indeed, the support structure is generally transported vertically on site with a transport barge and lifted by a floating crane to be placed on the seabed. For such depths, the transport barge and the floating crane must be bigger and heavier, which increases the cost and affects the planarity of the installation, especially in the case of successive installation of several support structures for a wind farm. Moreover, the fixing may be more complicated due to the depth, depending on which anchoring device is used, like piles drilled into the seabed.

[0004] One object of the present invention is to provide a support structure and enhanced anchoring device for offshore wind turbines adapted to an average depth of about 80-150 m. Another object of the present invention is also to provide an adapted installation process of the support structure for wind farms.

[0005] To this end, the present invention relates to a support structure for an offshore wind turbine, the support structure comprising: a first structural part adapted to be fixed to the seabed, said first structural part comprising at least three dummy legs regularly distributed on a first circle having a center on the longitudinal axis (Y) of the support structure and extending along said longitudinal axis of the support structure, said dummy legs comprising a lower end designed to face the seabed and an upper end opposite said lower end, said first structural part also comprising at least three anchoring devices to the seabed connected to the at least three dummy legs; a second structural portion having a lower end attached to the upper ends of the at least three dummy legs of the first structural portion; At least one anchoring device of the first structural portion is angularly disposed between two adjacent dummy legs on a second circle having a center about the longitudinal axis of the support structure.

[0006] The first structural part may comprise only one anchoring device to the seabed between two adjacent dummy legs, and the angle between the radius of the second circle joining the anchoring device and the radius of the first circle joining the two dummy legs surrounding the anchoring device may be the same.

[0007] The first structural part may comprise at least two anchoring devices to the seabed between two adjacent dummy legs, which may be distributed symmetrically on each side and / or directly on a central line equidistant from the two dummy legs and passing through the longitudinal axis of the support structure.

[0008] The second circle including the anchoring device of the first structural part to the seabed may have a larger radius than the first circle including the dummy leg.

[0009] The second circle including the anchoring device of the first structural part to the seabed may have a smaller radius than the first circle including the dummy leg.

[0010] The second circle including the anchoring device of the first structural part to the seabed and the first circle including the dummy leg may have the same radius.

[0011] The seabed anchoring device may be a sleeve configured to receive and be secured to a pile designed to be driven or drilled into the seabed.

[0012] At least one end of the sleeve may comprise a guide portion for the pile.

[0013] The anchoring device to the seabed may be a suction bucket.

[0014] The upper ends of the dummy legs of the first structural part may each include one of a receiving opening or a pin, and the lower ends of the second structural part may each include one of a pin or a receiving opening, and the pin and the receiving opening may be configured to mate together.

[0015] The invention also relates to a process for installing a support structure for a wind power plant installation, said process comprising: Transporting at the site at least one first structural part, said first structural part having at least three dummy legs regularly distributed on a first circle having a center on the longitudinal axis of the support structure and extending along said longitudinal axis of the support structure, said dummy legs having a lower end designed to face the seabed and an upper end opposite to said lower end, said first structural part also having at least three anchoring devices to the seabed connected to the at least three dummy legs, at least one anchoring device of the first structural part to the seabed being angularly arranged between two adjacent dummy legs on a second circle having a center on the longitudinal axis of the support structure; placing a first structural portion on the seabed; anchoring at least one first structure part to the seabed using an anchoring device; transporting at least one second structural upper portion at the site; Lifting and stacking at least one second structural part onto at least one first structural part underwater; and fixing at least one second structural portion onto the first structural portion.

[0016] The anchoring device may be a sleeve and the process may include a preliminary step of inserting a pile into the seabed to form a receiving area for each first structure part, before the step of installing the first structure part on the seabed; The step of installing the first structural part on the seabed may comprise inserting a pre-installed pile into a sleeve of the anchoring device.

[0017] A template may be dropped on the seabed to guide the insertion of the pile during a preliminary step of the pile insertion, the template may be removed after formation of the receiving area for the first structural part and may be reused to form another receiving area for another first structural part.

[0018] The anchoring device may be a sleeve, and the step of fixing the first structural part to the seabed may include: a first sub-step of inserting the pile through the sleeve into the seabed; and a second sub-step of fastening the sleeve to the pile.

[0019] Further characteristics and advantages of the invention will become more clearly apparent on reading the following description, given by way of illustrative and non-limiting example, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a side view of a schematic representation of a support structure for an offshore wind turbine. [Diagram 2] FIG. 2 is a top view of a schematic representation of a first structural part for a support structure according to a first embodiment; [Diagram 3]FIG. 11 is a top view of a schematic representation of a first structural part for a support structure according to a second embodiment; [Figure 4] FIG. 11 is a top view of a schematic representation of a first structural part for a support structure according to a third embodiment; [Diagram 5] FIG. 13 is a top view of a schematic representation of a first structural part for a support structure according to a fourth embodiment; [Figure 6] 1A-1D are side views of an anchoring device according to two different embodiments. [Figure 7] 1A-1D are side views of an anchoring device according to two different embodiments. [Figure 8] FIG. 2 is a side view of a schematic representation of a joint between a first structural portion and a second structural portion. [Figure 9] 1A-1D are side views of schematic representations of support structures for offshore wind turbines according to two different embodiments. [Figure 10] 1A-1D are side views of schematic representations of support structures for offshore wind turbines according to two different embodiments. [Figure 11] 2A-2C are two charts of a process for installing a support structure according to two different embodiments. [Figure 12] 2A-2C are two charts of a process for installing a support structure according to two different embodiments.

[0021] In these figures, identical elements are given the same reference numbers. The following implementations are examples. Although this specification refers to one or more embodiments, this does not mean that each reference refers to the same embodiment or that a feature applies only to a single embodiment. Individual features of different embodiments can also be combined or exchanged to provide other embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] 1 shows a support structure 1 for an offshore wind turbine. This support structure 1 comprises a first structure A and a second structure B designed to be stacked to form the support structure 1.

[0023] 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 having a center on the longitudinal axis Y of the support structure 1. The dummy legs 3 extend along said longitudinal axis Y of the support structure 1. Figure 2 shows a top view of a first example of the first structural part A with three dummy legs 3 arranged in a triangular pattern on the first circle X1. Figure 3 shows a top view of a second example of the first structural part A with four dummy legs 3 arranged in a square pattern on the first circle X1. Other examples with three or more than four dummy legs are also possible.

[0024] As shown in Fig. 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 may be parallel to the longitudinal axis Y of the support structure 1 or inclined relative to this longitudinal axis Y. If the dummy leg 3 is inclined, the lower end 3a of the dummy leg 3 is preferably farther from the central longitudinal axis Y than its upper end 3b. The first circle X1 may be defined by the lower end 3a of the dummy leg 3 whether the dummy leg 3 is parallel to the longitudinal axis Y or inclined relative to the longitudinal axis Y.

[0025] The first structural part A also comprises at least three anchoring devices 5 to the sea bed Sb connected to the at least three dummy legs 3. As shown in Figures 2 and 3, at least one anchoring device 5 of the first structural part A is arranged angularly between two adjacent dummy legs 3, i.e. in an arc defined by a radius connecting the longitudinal axis Y to the two adjacent dummy legs 3. The at least one anchoring device 5 is arranged on a second circle X2 having as its centre the longitudinal axis Y of the support structure 1.

[0026] The fact that the anchoring devices 5 are offset compared to the dummy legs 3 reduces the risk of damage to the support structure 1, in particular the first structural part A, when the anchoring devices 5 are fixed to the seabed Sb. This is particularly advantageous when the anchoring devices 5 are fixed with piles 7 driven into the seabed Sb. Furthermore, the fact that the anchoring devices 5 of the first structural part A are arranged at an angle between two adjacent dummy legs 3 advantageously reduces the weight and manufacturing costs of the structure compared to conventional skirt pile connections.

[0027] According to the first embodiment shown in Figures 2 and 3, the second circle X2 including the anchor device 5 of the first structural part A to the seabed Sb and the first circle X1 including the dummy leg 3 have the same radius.

[0028] According to the second embodiment shown in FIG. 4, the second circle X2 including the anchoring device 5 of the first structural part A to the seabed Sb has a larger radius than the first circle X1 including the dummy leg 3.

[0029] According to a third embodiment, not shown, the second circle X2 including the anchoring device 5 of the first structural part A to the seabed Sb has a smaller radius than the first circle X1 including the dummy leg 3.

[0030] 2 to 4, the first structural part A comprises only one anchoring device 5 to the sea bed Sb between two adjacent dummy legs 3. In this particular embodiment, as shown in Fig. 3, the angle α between the radius joining the anchoring device 5 (from axis Y) and the radius joining the two dummy legs 3 surrounding said anchoring device 5 (from axis Y) is the same.

[0031] Another embodiment is also possible, for example as shown in Fig. 5, in which the first structural part A comprises at least two anchoring devices 5 between two adjacent dummy legs 3. In the example shown in Fig. 5 only two anchoring devices 5 are represented, but three or more anchoring devices 5 are also possible. In this embodiment, these at least two anchoring devices 5 are preferably distributed symmetrically on each side and / or equidistant from the two dummy legs 3 and directly on a central line passing through the longitudinal axis Y of the support structure 1. A different radius of the second circle X2 compared to the radius of the first circle X1 of the first, second and third embodiments described above is also possible for this embodiment.

[0032] As shown in figures 6 and 7, the anchoring device 5 may be a sleeve configured to receive and be fixed to piles 7, which are designed to be driven or drilled into the seabed Sb. The sleeve 5 may comprise 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 piles 7. The piles 7 are inserted into the hollow part of the sleeve 5. The sleeve 5 and the piles 7 may be fixed to each other by grout, for example by cement grout 12, or by other means such as welding or swaging by hydraulic means.

[0033] The sleeve 5 may also be provided with a guide portion at its upper end 5b and / or at its lower end 5a to facilitate the insertion of the pile 7, depending on whether the pile 7 is inserted into the sleeve 5 by the upper end 5b or by the lower end 5a. This guide portion may for example consist of a flared portion forming a funnel at the ends 5a, 5b of the sleeve 5.

[0034] The anchoring device 5 may also include other elements such as a suction bucket (not shown) or some concrete foundation as a gravity based structure.

[0035] The first structural part A may preferably be a jacket structure consisting of a welded space frame with dummy legs 3 supported by a lateral bracing system.

[0036] As shown in Figure 1, the second structural part B comprises a lower end Ba attached to the upper ends 3b of at least three dummy legs 3 of the first structural part A. The second structural part B may also preferably be a jacket structure consisting of a welded space frame with legs extending along the longitudinal axis Y of the support structure 1 and supported by a lateral bracing system.

[0037] The second structural part B comprises a lower end Ba designed to be coupled to the upper end 3b of the dummy leg 3 of the first structural part A. As shown in FIG. 8, the upper end 3b of the dummy leg 3 of the first structural part A comprises one of a receiving opening or a pin, respectively, and the lower end Ba of the second structural part B comprises one of a pin or a receiving opening, respectively. The pin and the receiving opening are configured to fit together. The pin may be fixed in the receiving opening by grout, for example by cement grout 14, or by other means such as welding or swaging by hydraulic means. To facilitate the insertion of the pin into the receiving opening, said receiving opening may comprise a guide portion. This guide portion may consist of a flared portion forming a funnel at the entrance of the receiving opening. The pin may also comprise a stopper element 17 in contact with the receiving opening to allow the transmission of forces between the upper end 3b of the dummy leg 3 and the lower end Ba of the second structural part B. In the example shown in FIG. 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.

[0038] The upper end Bb of the second structural part B is adapted to be placed above the sea level S1 and may comprise a platform 8 for receiving the mast of an offshore turbine.

[0039] The second structural part B may have a surface with a smaller cross-sectional dimension at its upper end Bb than at its lower end Ba. The legs of the second structural part B may therefore be inclined compared to the longitudinal axis Y of the support structure 1.

[0040] The support structure 1 is configured to be placed at a location having a depth of 80-150 m. As an example, for a depth of about 100 m, the first structure part A may have a height of 30-40 m and the second structure part B may have a height of 60-70 m. At deeper depths, the first structure may be taller, as shown in FIG. 9.

[0041] As shown in Fig. 1 and Fig. 9, the second structural part B may be one piece, for example for second structural parts B between 60 m and 70 m. For higher second structural parts B, the second structural part B may be divided into two sub-structures B1, B2, as shown in Fig. 10. The two sub-structures B1 and B2 may be stacked and connected to each other during the installation of the support structure 1. These two sub-structures B1 and B2 may be attached to each other by means 10 similar to the means connecting the first structural part A and the second structural part B. This division of the second structural part B is particularly advantageous for the transportation and storage of the second structural part B, as well as for the installation. Indeed, the sub-structures B1 and B2 are lower and lighter, so that their transportation can be carried out by smaller transport barges and their installation can be carried out by smaller floating cranes.

[0042] To facilitate the manufacturing process of the support structure 1, the taller and more complex second structural parts B can be standardized and have a constant height. This allows the automation and standardization of the manufacturing of the second structural parts B and allows the use of robotic means for their manufacture. It is therefore possible to mass-produce the second structural parts B and to stock them for availability in different areas around the world or in a region. The first structural parts A, which are low in height and simple, can be easily adjusted to fit the depth of the site where the support structure 1 is to be installed. The first structural parts A can also be manufactured more locally, for example by local workers in a country close to the site of the support structure 1, and adapted to local specifications and depths.

[0043] The invention also relates to a process 100 for installing a support structure 1 for a wind power plant installation as described above. The steps of such a process are represented in FIG.

[0044] The process comprises a first step 101 of transport at the site of one or several first structural parts A. As mentioned above, the first structural part A comprises at least three dummy legs 3, which have as their centre the longitudinal axis Y of the support structure 1 and are regularly distributed on a first circle X1 extending along said longitudinal axis Y of the support structure 1. The dummy legs 3 comprise 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 anchoring devices 5 connected to the at least three dummy legs 3. At least one anchoring device 5 of the first structural part A is arranged angularly between two adjacent dummy legs 3, i.e. in an arc defined by a radius connecting the longitudinal axis Y to the two adjacent dummy legs 3. The at least one anchoring device 5 is also arranged on a second circle X2, which has as its centre the longitudinal axis Y of the support structure A. As mentioned above, 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, several first structural parts A can be placed on the same transport barge and they can be arranged vertically to facilitate the next installation step.

[0045] The second step 102 is the installation of the first structural part A on the seabed Sb. This second step 102 can be carried out by means of a floating crane. As the first structural part A is smaller and lighter, the floating crane can be smaller in order to limit and reduce costs.

[0046] The third step 103 is the fixing of the first structure part A to the seabed Sb by means of the anchoring device 5. Depending on the anchoring device 5, this third step 103 can be performed differently, for example by piles 7 being driven or drilled into the seabed, by means of a suction bucket or by some concrete foundation as a gravity-based structure. However, due to the fact that the anchoring device 5 is offset compared to the dummy leg 3, the risk of damage to the support structure 1 is reduced. This is particularly advantageous when the anchoring device 5 is fixed with piles 7 driven into the seabed Sb.

[0047] These three steps 101, 102 and 103 may be performed during the same campaign of installation of the first structural part A. The other subsequent steps of the installation of the second structural part B may be performed later during another campaign of installation immediately after the first campaign or may be delayed.

[0048] The fourth step 104 is transporting one or several second structure upper parts B at the site. As mentioned above, the second structure parts B can be brought to the site by a transport barge. Since the second structure parts B are small and light compared to the support structure 1 as a whole, several second structure parts B can be placed on the same transport barge and can be arranged vertically to facilitate the next installation step.

[0049] The fifth step (105) is to lift and stack the second structural part (B) on the first structural part (A) underwater. This fifth step 105 can be carried out using a floating crane. As the second structural part B is smaller and lighter compared to the support structure 1 as a whole, the floating crane can be smaller to limit costs.

[0050] The sixth step 106 is the fixing of the second structural part B onto the first structural part A. As mentioned before, this fixing can be performed by different means such as grouting, welding or swaging by hydraulic means.

[0051] This process 100 not only allows to reduce the cost of installation, but also allows the installation itself using a conventional transport barge or ship, optionally equipped with standard cranes, slings and winches, and optionally with the assistance of a separate floating crane. In fact, a support structure 1 consisting of two parts A and B allows a larger support structure 1 to be installed using a much smaller transport barge and floating crane than would be the case for a monolithic support structure. Furthermore, depending on the loading capacity of the transport barge or ship considered, it may be possible to stack multiple parts A and / or multiple parts B, taking into account transportation and installation at the site, if the total height of the stack of parts A and / or B does not prevent a crane from lifting, separating and setting up each individual part A and / or B, respectively. This process is particularly useful for the installation of the support structure 1 in water depths that were not previously easily accessible using conventional means.

[0052] If the anchoring device 5 is a sleeve, the process 100 may comprise, before the step 101 of installing the first structural parts A on the seabed Sb, a preliminary step 101a of inserting piles 7 into the seabed Sb to form a receiving area for each first structural part A. In this case, the step 101 of installing the first structural parts A on the seabed Sb consists of docking the pre-installed piles 7 into the sleeve of the anchoring device 5.

[0053] A template can be dropped onto the seabed Sb to guide the insertion of the pile (7) during the preliminary step 101a of the insertion of the pile 7. This template can be removed after the formation of the receiving area for the first structure part A and reused to form another receiving area for another first structure part A.

[0054] In another embodiment shown in figure 12, where the anchoring device 5 is also a sleeve, the pile 7 is placed after the installation of the first structural part A, rather than before. The step 103 of fixing the first structural part A to the seabed Sb therefore consists of a first sub-step 103a of inserting the pile 7 through the sleeve 5 into the seabed Sb. In a second sub-step 103b, the sleeve 5 and the pile 7 are fixed to each other. 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, said support structure (1) comprising: a first structural part (A) intended to be fixed to the seabed (Sb), 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) having 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 comprising at least three anchoring devices (5) to the seabed (Sb) connected to the at least three dummy legs (3); a second structural part (B) having lower ends (Ba) attached to the upper ends (3b) of the at least three dummy legs (3) of the first structural part (A); A support structure (1), wherein at least one anchoring device (5) of the first structural portion (A) is angularly disposed between two adjacent dummy legs (3) on a second circle (X2) having the longitudinal axis (Y) of the support structure (1) as its center.

2. 2. The support structure (1) according to claim 1, wherein the first structural part (A) comprises only one anchoring device (5) to the seabed (Sb) between two adjacent dummy legs (3), and the angle (α) between the radius of the second circle (X2) joining the anchoring devices (5) and the radius of the first circle (X1) joining the two dummy legs (3) surrounding the anchoring device (5) is the same.

3. 2. A support structure (1) according to claim 1, wherein the first structural part (A) comprises at least two anchoring devices (5) to the seabed (Sb) between two adjacent dummy legs (3), these at least two anchoring devices (5) being distributed symmetrically on each side and / or equidistant from the two dummy legs (3) and directly on a central line passing through the longitudinal axis (Y) of the support structure (1).

4. 4. A support structure (1) according to any one of claims 1 to 3, wherein the second circle (X2) including the anchoring device (5) of the first structural part (A) to the seabed (Sb) has a larger radius than the first circle (X1) including the dummy leg (3).

5. 4. A support structure (1) according to any one of claims 1 to 3, wherein the second circle (X2) including the anchoring device (5) of the first structural part (A) to the seabed (Sb) has a smaller radius than the first circle (X1) including the dummy leg (3).

6. 4. A support structure (1) according to any one of claims 1 to 3, wherein the second circle (X2) including the anchoring device (5) of the first structural part (A) to the seabed (Sb) and the first circle (X1) including the dummy leg (3) have the same radius.

7. 4. A support structure (1) according to any one of claims 1 to 3, wherein the anchoring device (5) to the seabed (Sb) is a sleeve configured to receive and be fixed to a pile (7) designed to be driven or drilled into the seabed.

8. 8. A support structure (1) according to claim 7, wherein at least one end (5a, 5b) of the sleeve comprises a guiding portion for the pile (7).

9. 4. The support structure (1) according to any one of claims 1 to 3, wherein the anchoring device (5) to the seabed (Sb) is a suction bucket.

10. 4. A support structure (1) according to any one of claims 1 to 3, wherein the upper ends (3b) of the dummy legs (3) of the first structural part (A) each comprise one of a receiving opening or a pin, and the lower ends (Ba) of the second structural part (B) each comprise one of a pin or a receiving opening, the pin and the receiving opening being configured to fit together.

11. A process for installing a support structure (1) for a wind power plant installation, said process comprising: a step of transporting at least one first structural part (A) at the site, said first structural part (A) being regularly distributed on a first circle (X1) having a center on the longitudinal axis (Y) of said support structure (1) and comprising at least three dummy legs (3) extending along said longitudinal axis (Y) of said support structure (1), said dummy legs (3) having a lower end (3a) designed to face the seabed (Sb) and an upper end opposite said lower end (3a); (3b), wherein the first structural part (A) also comprises at least three anchoring devices (5) for the seabed (Sb) connected to the at least three dummy legs (3), and at least one anchoring device (5) for the first structural part (A) for the seabed (Sb) is angularly positioned between two adjacent dummy legs (3) on a second circle (X2) centered on the longitudinal axis (Y) of the support structure (1); placing the first structural part (A) on the seabed (Sb); anchoring said at least one first structural part (A) to said seabed (Sb) using said anchoring device (5); transporting at the site at least one second structural upper portion (B); Lifting and stacking said at least one second structural part (B) on said at least one first structural part (A) underwater; and fixing said at least one second structural part (B) onto said first structural part (A).

12. a process, wherein the anchoring devices (5) are sleeves, the process comprising, before the step of installing the first structural parts (A) on the seabed (Sb), a preliminary step of inserting piles (7) into the seabed (Sb) to form a receiving area for each of the first structural parts (A), 12. The process according to claim 11, wherein the step of installing the first structural part (A) on the seabed (Sb) consists of inserting the pre-installed pile (7) into the sleeve of the anchoring device (5).

13. 13. The process according to claim 12, wherein a template is dropped onto the seabed (Sb) to guide the insertion of the piles (7) during a preliminary step of the insertion of the piles (7), and wherein the template is removed after the formation of a receiving area for a first structural part (A) and is reused to form another receiving area for another first structural part (A).

14. The anchoring device (5) is a sleeve, and the step of fixing the first structural part (A) to the seabed (Sb) comprises: a first sub-step of inserting the pile (7) through the sleeve into the seabed (Sb); and a second sub-step of fixing the sleeve onto the pile (7).

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