DK2940218T3

DK2940218T3 - Offshore foundation structure

Info

Publication number: DK2940218T3
Application number: DK14166638.8T
Authority: DK
Inventors: Bertomeo Emilio Reales
Original assignee: Maritime Offshore Group Gmbh
Priority date: 2014-04-30
Filing date: 2014-04-30
Publication date: 2018-09-17
Also published as: EP2940218A1; PL2940218T3; EP2940218B1; EP2940218B8

Description

The invention relates to an offshore foundation structure having a jacket portion, which has a plurality of struts connected to one another in a framework-like manner, and a receiver for a tower shaft, in particular for a tower shaft of a wind turbine.

Such foundation structures based on a jacket design are used in particular with the installation of wind turbines in offshore regions with a great body of water depth and are fundamentally known e.g. from the printed publication DE 20 2012 002 730 Ul. The jacket design has increased water permeability compared with conventional monopile designs, so that there is a reduction in the loads on the offshore foundation structure which are caused by the flow of the body of water.

Furthermore it has already been shown that the installation of jacket-based offshore foundation structures can be carried out with substantially lower emissions. Jacket designs permit the anchorage to the bottom of the body of water using a plurality of driven piles. The driving of a plurality of small driven piles into the bottom of the body of water can here be carried out with substantially lower emissions than the driving in of large monopile anchorages.

Owing to wind turbines which are continually becoming larger, there is likewise an increase in the demands made on the offshore foundation structures as regards their load-bearing capacity. Furthermore likewise considerable dynamic forces are transmitted into the offshore foundation structure by the tower of the wind turbine, which forces must support the offshore foundation structure with respect to the bottom of the body of water. In order to be able to use wind turbines in offshore areas with high wind strengths, there is likewise regularly a need for foundation structures with increased load-bearing capacity.

The object of the invention is therefore to specify an offshore foundation structure which has increased load-bearing capacity compared with the known foundation structures, wherein the increase in load-bearing capacity does not lead to a rise in the costs of manufacture, installation or maintenance.

The object is achieved by an offshore foundation structure of the type mentioned in the introduction, wherein the receiver for the tower shaft is arranged at least partially within the jacket portion.

The invention makes use of the awareness that through the arrangement of the receiver within the jacket portion there is a direct force transmission from the receiver into the individual struts of the jacket portion. The homogenous distribution of the forces to be supported is consequently implemented directly. Through the arrangement of the receiver for the tower shaft within the jacket portion, the load-bearing capacity of the offshore foundation structure can consequently be increased in a surprisingly simple manner, without a simultaneous increase in the costs of manufacture, installation or maintenance.

In a first preferred embodiment of the offshore foundation structure according to the invention, the receiver is adapted such that the tower shaft is arrangeable at least partially within the jacket portion. This can in particular be realised in that the receiver has an opening which extends at least partially into the jacket portion.

In a second preferred embodiment of the offshore foundation structure, the receiver comprises an opening which extends along a substantially vertical longitudinal axis. The opening extending along the longitudinal axis is preferably cylindrical. The opening is along its longitudinal axis arranged at least 25%, 50% or 75% within the jacket portion. The further the opening of the receiver projects into the jacket portion of the foundation structure, the more direct and advantageous is the force transmission to the individual struts of the jacket portion. An increase in the load-bearing capacity of the foundation structure can already be achieved when the opening is along its longitudinal axis arranged approximately 25% within the jacket portion. The load-bearing capacity of the foundation structure can be further increased, for instance through the arrangement of the opening approximately 50% or approximately 75% within the jacket portion.

The offshore foundation structure according to the invention is furthermore advantageously further developed in that the receiver is arranged completely within the jacket portion. Such a complete arrangement of the receiver within the jacket portion permits the direct distribution to the individual struts of the jacket portion of the entirety of the forces to be supported. Consequently the complete arrangement of the receiver within the jacket portion can maximize the load-bearing capacity of the foundation structure.

In a further preferred embodiment of the offshore foundation structure, a service platform is arranged on the jacket portion and/or the receiver. The service platform can for example be used during maintenance work on the wind turbine. Here the service platform is such that a substantially vertical access ladder can be secured to the service platform. The access ladder is here preferably connected to the jacket portion of the foundation structure via stabilizing struts and extends from the service platform approximately to the water surface of the body of water in question. The service platform can furthermore have an encircling railing, so that safety during use of the service platform is increased. It is furthermore preferred that the service platform has an inner access opening via which the service platform can be accessed by means of the access ladder.

Furthermore an offshore foundation structure is preferred with which the receiver and/or the jacket portion are, at a head end, connected to a connecting plate. The connecting plate connects the service platform to the jacket portion and/or the receiver. The connecting plate preferably has a circular opening whose diameter corresponds at least to the diameter of the tower shaft to be received. The mounting of the service platform is considerably simplified by the connecting plate. Furthermore a connecting ring can be arranged at the connecting plate, in the region of the circular opening. The tower shaft can be inserted into the receiver of the foundation structure through the connecting ring.

In a further preferred embodiment of the offshore foundation structure, the receiver comprises a cylindrical opening and the jacket portion has a plurality, in particular three, four, five, six, seven or eight, of substantially vertical outer struts. The outer struts are here preferably arranged along a substantially horizontal circular path, wherein the quotient of the diameter of the opening and the diameter of the circular path is greater than 0.5, preferably greater than 0.6. Through the relationship of opening diameter and circular path diameter there can be specified a characteristic which describes the horizontal spread of the jacket portion relative to the tower diameter. The greater this characteristic, the slimmer the jacket portion. This characteristic consequently likewise has an influence on the flow resistance for the water caused by the foundation structure. Through the use of appropriate struts within the jacket portion, there can consequently be a reduction in the forces acting upon the foundation structure by the flow of the body of water.

The offshore foundation structure is furthermore advantageously further developed in that the jacket portion has a plurality, in particular three, four, five, six, seven or eight, of outer struts which are inclined with respect to a vertical line in a range from 5 degrees to 30 degrees. The outer struts are preferably inclined with respect to the vertical line in a range from 5 degrees to 15 degrees. The load-bearing capacity of the foundation structure is further increased through the resultant conical basic structure of the jacket portion. Through the outwards spreading outer struts there is likewise an increase in the spacing of two adjacent foot-end outer struts ends, so that the anchorage of the foundation structure to the bottom of the body of water is simplified owing to the greater space available.

In a further preferred embodiment of the offshore foundation structure, in each case two adjacent outer struts are connected by means of at least one cross bracing. The cross bracings are preferably prefabricated strut segments which have four limbs arranged in an X-shape in relation to one another, the limbs being connected to one another directly or by means of a central joint piece. Through the use of cross bracings, the forces transmitted into the outer struts can be distributed at different sites of the jacket portion, so that the load-bearing capacity of the foundation structure is increased owing to the more homogenous force distribution produced. Two, three, four or a plurality of cross bracings are preferably arranged between adjacent outer struts in each case. It is furthermore preferred that a plurality of cross bracings of the jacket portion are arranged in a substantially horizontal plane.

The object of the invention is furthermore achieved by an offshore foundation structure of the type mentioned in the introduction, wherein the jacket portion has a plurality, in particular three, four, five, six, seven or eight, of outer struts, preferably substantially vertical outer struts, and wherein in each case two adjacent outer struts are connected by means of at least one curved strut element. Such a bracing of adjacent outer struts considerably reduces the manufacturing costs of the foundation structure, in particular of the jacket portion.

The offshore foundation structure according to the invention is advantageously further developed in that the curved strut element has one or a plurality of curved strut portions and one or a plurality of straight strut portions, wherein these are arranged in an alternating sequence. In particular, the strut element has a uniform meandering form formed from curved strut portions and straight strut portions.

In a further preferred embodiment of the offshore foundation structure according to the invention, the curved strut element is at a first curved strut portion connected to the first outer strut of two adjacent outer struts by means of a first securing plate and is at a second curved strut portion connected to the second outer strut of two adjacent outer struts by means of a second securing plate. In particular, the securing plates are welded to the curved strut element and the outer struts. Furthermore, it is particularly preferred that the curved strut element is at a plurality of curved strut portions connected to the first outer strut by means of a plurality of securing plates and is at a plurality of curved strut portions connected to the second outer strut by means of a plurality of securing plates. Such a connection between adjacent outer struts enables simplification of the manufacturing process of the foundation structure, in particular of the jacket portion, since the securing plates can be adapted to the contour of the curved strut element and the contour of the outer struts in a simple manner, e.g. by thermal, primary shaping or machining manufacturing processes, and consequently one can dispense with cost-intensive and time-intensive working and adaptation of the individual connecting struts between the outer struts. Furthermore, the manufacture of the curved strut elements can also be realized in a low-cost manner. The curvature of large pipes is not a technical problem, since suppliers from the steel pipe industry can manufacture and deliver these pipe portions to size in bulk. The costs associated with the pipe-portion curvature or the bending of pipe portions are considerably less than the costs for the manufacture of complex pipe joints. In addition the required regular examination of the weld seams for crack formation and corrosion is simplified by such bracing of adjacent outer struts. The weld seams are easily reachable and can be inspected more quickly, since the inspection tools are to be passed along a straight or merely slightly curved line. Automation of this inspection by robots at the underwater parts of the foundations can consequently be realised, this leading to considerable cost savings in the case of maintenance of the foundation structure. Such connections of two adjacent outer struts can be realised irrespective of the geometry, arrangement and number of the outer struts. This type of bracing can also be used in the case of foundation structures with which the outer struts are slightly inclined with respect to a vertical line, e.g. in order to achieve greater stability as can be necessary with greater water depths, since here too this type of bracing brings economic advantages.

Furthermore the offshore foundation structure according to the invention is advantageously further developed in that each outer strut is connected to the receiver by means of a cross strut, wherein the cross strut is inclined with respect to a vertical line in a range from 30 degrees to 60 degrees, preferably 45 degrees. Above all, these cross struts forward the gravitational force component, conveyed from the tower shaft to the receiver, to the outer struts. Alternatively, the cross struts are secured to an end ring made of pipes, which is mounted on the upper end of the outer struts.

Furthermore, an offshore foundation structure is preferred with which each outer strut is connected to the receiver by means of a horizontal strut. The horizontal struts preferably run radially outwards from the receiver in the direction of the outer struts or to the end ring. These struts forward the horizontally running force components from the receiver to the outer struts. The individual cross struts, horizontal struts and the walls of the receiver consequently form triangles which ensure stable support of the tower shaft.

The offshore foundation structure according to the invention is furthermore advantageously further developed in that the jacket portion has a plurality, in particular two, three, four, five, six, seven or eight, of preferably prefabricated and coaxially oriented annular structures, which in each case are arranged in parallel, substantially horizontal planes. The annular structures likewise support the homogenous force distribution and consequently increase the load-bearing capacity of the foundation structure. In the case of prefabricated annular structures, substantially vertically-running strut elements are placed upon these annular structures, wherein an outer strut of the jacket portion can have a plurality of substantially vertically-running strut segments.

In a further preferred embodiment of the offshore foundation structure according to the invention, at least one, preferably two or a plurality of annular structures run around the receiver and are connected thereto in a supporting manner. The forces introduced into the receiver from the tower shaft can consequently be transferred to the jacket portion of the foundation structure in an homogenous manner. If the foundation structure has two or a plurality of annular structures connected to the receiver in a supporting manner, then in additional planes there is a further homogenization of the force distribution.

The offshore foundation structure according to the invention is furthermore advantageously further developed in that at least one annular structure running around the receiver is connected to the receiver by means of a substantially horizontal supporting plate. The external contour of the supporting plate here preferably substantially corresponds to the internal contour of the annular structure. Furthermore it is preferred that the supporting plate has an opening whose contour substantially corresponds to the external contour of the receiver. The supporting plate constitutes the force route from the receiver to the annular structure. The use of a plate structure guarantees that the forces can be uniformly conveyed to the annular structure. The load-bearing capacity of the foundation structure is consequently further increased.

In a further preferred embodiment of the offshore foundation structure, a plurality, in particular three, four, five, six, seven or eight, of substantially vertical driven piles for driving into the bottom of the body of water are arranged at the foot end of the jacket portion. The outer struts of the jacket portion of the foundation structure preferably have a larger diameter than the driven piles. Consequently sealing of the driven piles within the outer struts by means of concrete (grouting) can be carried out. For this reason, the feed lines for the concrete, the so-called grout lines, are within the outer struts guided to the connecting sites between driven piles and outer struts. External guiding of the grout lines can consequently be prevented. The grout lines are protected from the influence of the water environment and can be used not only during the construction phase, but also upon renovation measures, e.g. when concrete sealing which has become cracked has to be repaired by fresh grout injections. This leads to simplified and faster installation and maintenance of the foundation structure. The grout lines can also be used after many years for servicing or repair of the foundation structure, since the grout lines have a considerably lengthened service life through the protection of the outer struts.

Furthermore there is preferred an offshore foundation structure with which the jacket portion has a plurality of pipes welded with a longitudinal seam or a spiral seam.

Further features and advantages of the invention emerge from the following description of preferred embodiments, with reference to drawings.

Fig. 1 shows an embodiment of the offshore foundation structure according to the invention;

Fig. 2 shows the embodiment shown in Fig. 1 of the offshore foundation structure according to the invention, without service platform;

Fig. 3 shows a further embodiment of the offshore foundation structure according to the invention;

Fig. 4 shows a further embodiment of the offshore foundation structure according to the invention;

Fig. 5 shows a lateral view of the embodiment shown in Fig. 4 of the offshore foundation structure according to the invention;

Fig. 6 shows a plan view of the embodiment shown in Fig. 4 and Fig. 5 of the offshore foundation structure according to the invention;

Fig. 7 shows a further embodiment of the offshore foundation structure according to the invention; and

Fig. 8 shows a detail of the embodiment shown in Fig. 7 of the offshore foundation structure according to the invention.

According to Fig. 1, the offshore foundation structure 1 according to the invention has a jacket portion 2 which comprises a plurality of struts connected to one another in a framework-like manner. A receiver 4 for a tower shaft 6 of a wind turbine is arranged within the jacket portion 2 of the offshore foundation structure 1. The receiver 4 has an opening (hidden) which extends along a substantially vertical longitudinal axis 8 and is cylindrica I. The opening of the receiver 4 enables the tower shaft 6 to be arranged partially within the jacket portion 2. A service platform 10 is arranged on the jacket portion 2. The service platform 10 has a circular opening 12 through which there extends the tower shaft 6. Furthermore a railing 14 is secured to the outer edges of the service platform 10 and completely encircles the service platform 10. In addition, the service platform 10 has an access opening 16 to which there is secured an access ladder 18. The access ladder 18 is connected to struts of the jacket portion 2 via stabilizing struts 20.

The jacket portion 2 has six parallel-running outer struts 22a, 22b, 22c, 22d, 22e, 22f which are substantially vertical. Furthermore, the jacket portion 2 has five prefabricated annular structures 24a, 24b, 24c, 24d, 24e, coaxial with one another, which are in each case arranged in parallel, substantially horizontal planes. Two annular structures 24a, 24b run around the receiver4 and are connected thereto in a supporting manner. The struts of the jacket portion 2 are partially in the form of pipes welded with a longitudinal seam or spirally welded. At the foot end of the jacket portion 2 there are arranged six substantially vertical driven piles 26a, 26b, 26c, 26d, 26e, 26f for driving into the bottom of the body of water.

Fig. 2 shows the offshore foundation structure 1 shown in Fig. 1, without service platform and access ladder. The receiver 4 and the jacket portion 2 are at a head end connected to a connecting plate 28 which connects the service platform (not shown) to the jacket portion 2 and the receiver 4. The connecting plate 28 has a circular opening 30 whose diameter substantially corresponds to the diameter of the tower shaft (not shown) to be received. In the region of the opening 30 of the connecting plate 28 there is furthermore arranged a connecting ring 32 which produces a connection between the connecting plate 28 and the tower shaft.

Fig. 3 shows a further embodiment of the offshore foundation structure 1 according to the invention. The shown embodiment differs from the embodiment of Fig. 1 and Fig. 2 through the design of the jacket portion 2 and the receiver 4. In this embodiment too the receiver 4 is arranged completely within the jacket portion 2 and has an opening in order to receive a tower shaft 6 of a wind turbine.

The receiver 4 is connected to the annular structures 24a, 24b (annular structure 24a is hidden) via two supporting plates 34a, 34b (supporting plate 34a is hidden). The external contour of the supporting plate 34a substantially corresponds to the internal contour of the annular structure 24a. The external contour of the supporting plate 34b substantially corresponds to the internal contour of the annular structure 24b. Furthermore the supporting plates 34a, 34b have openings 38a, 38b whose contours substantially correspond to the external contour of the receiver 4.

Adjacent outer struts 22a, 22b, 22c, 22d, 22e, 22fare in each case connected to one another by two cross bracings 36. The offshore foundation structure 1 has twelve cross bracings 36 in total, of which in each case six cross bracings 36 are arranged in a common, substantially horizontal plane. Furthermore, the jacket portion 2 has a further, lower annular structure 24c which is coaxial with the annular structures 24a, 24b and which just like the annular structures 24a, 24b is arranged in a substantially horizontal plane.

Fig. 4 shows a further embodiment of the offshore foundation structure 1 according to the invention. The receiver 4 is arranged completely within the jacket portion 2. The receiver 4 has a cylindrical opening which extends a long a substantially vertical longitudinal axis 8. The receiver is connected by means of horizontal supporting plates 34a, 34b to the substantially horizontally oriented and coaxially arranged annular structures 24a, 24b of the jacket portion 2. The external contour of the supporting plate 34a substantially corresponds to the internal contour of the annular structure 24a. The external contour of the supporting plate 34b substantially corresponds to the internal contour of the annular structure 24b. The horizontal supporting plates 34a, 34b furthermore have openings 38a, 38b whose contours substantially correspond to the external contour of the receiver 4. Furthermore the receiver 4 is connected to the outer struts 22a, 22b, 22c, 22d, 22e, 22f of the jacket portion 2 by six substantially vertical supporting plates 40a, 40b, 40c, 40d, 40e, 40f.

Fig. 5 shows a lateral view of the embodiment shown in Fig. 4 of the offshore foundation structure 1 according to the invention. The lateral view shows that the outer struts 22a, 22b, 22c, 22d, 22e, 22f of the jacket portion 2 are arranged substantially parallel to one another and are substantially vertical. The annular structures 24a, 24b, 24c, 24d, 24e are coaxial with one another and are in each case arranged in parallel, substantially horizontal planes.

Fig. 6 shows a plan view of the embodiment shown in Fig. 4 and Fig. 5 of the offshore foundation structure 1 according to the invention. The receiver 4 has a main body and comprises a cylindrical opening (according to a preferred configuration) and the six substantially vertical outer struts 22a, 22b, 22c, 22d, 22e, 22f of the jacket portion are arranged along a substantially horizontal circular path 42.

The quotient of the diameter of the cylindrical opening of the receiver 4 and the diameter of the circular path is > 0.5, preferably > 0.6. The relationship of opening diameter to circular path diameter describes the horizontal extension of the jacket portion with respect to the opening in the receiver 4 or the diameter of the tower of the wind turbine. The greater the ratio of opening diameter to circular path diameter, the slimmer the jacket portion with regard to the tower of the wind turbine or the opening of the receiver 4. The main body of the receiver 4 can e.g. be a steel cylinder.

Fig. 7 shows a further offshore foundation structure 1 according to the invention, with which the receiver 4 for the tower shaft is arranged completely within the jacket portion 2. The receiver 4 has an opening which extends along the substantially vertical longitudinal axis 8 and which is cylindrical. The opening is dimensioned and arranged in such a manner that the tower shaft 6 is arranged partially within the jacket portion 2.

The receiver 4 is connected to the outer struts 22a, 22b, 22c, 22d, 22e, 22f of the jacket portion 2 via six cross struts as well as six horizontal struts. Adjacent outer struts 22a, 22b, 22c, 22d, 22e, 22f are connected to one another via curved strut elements 44. The curved strut elements 44 have both curved strut portions 46 and straight strut portions 48. The curved strut portions 46 and the straight strut portions 48 of a curved strut element 44 are arranged in an alternating sequence, so that a curved strut element 44 has a substantially uniform meandering form. In the region of the curved strut portions 46, the curved strut elements 44 are connected to the outer struts 22a, 22b, 22c, 22d, 22e, 22f by means of securing plates 50. The shown embodiment has six curved strut elements 44 in total, which connect the adjacent outer struts 22a, 22b, 22c, 22d, 22e, 22f to one another. The curved strut elements 44 have in each case four straight strut portions 48 as well as six curved strut portions 46. In each case a curved strut portion 46 is here arranged at the foot end and at the head end of the curved strut element 44.

The driven piles 26a, 26b, 26c, 26d, 26e, 26f have a smaller diameter than the outer struts 22a, 22b, 22c, 22d, 22e, 22f. Grout material is arranged in the region in which driven piles 26a, 26b, 26c, 26d, 26e, 26f and outer struts 22a, 22b, 22c, 22d, 22e, 22f overlap or intersect, in order to produce a connection between the driven piles 26a, 26b, 26c, 26d, 26e, 26f and the outer struts 26a, 26b, 26c, 26d, 26e, 26f. Grout lines, by means of which grout material can be fed into the struts of the jacket portion 2, run within the outer struts 26a, 26b, 26c, 26d, 26e, 26f.

Fig. 8 shows a detail of the offshore foundation structure 1 shown in Fig. 7. The cross struts 52a, 52b, 52c, 52d, 52e, 52f arranged between the receiver 4 and the outer struts 22a, 22b, 22c, 22d, 22e, 22f have an inclination of approximately 45 degrees with respect to a vertical line. The cross struts 52a, 52b, 52c, 52d, 52e, 52f extend radially from the receiver 4 in the direction of the outer struts 22a, 22b, 22c, 22d, 22e, 22f and are arranged equidistantly spaced apart along a circular path. The diameter of the cross struts 52a, 52b, 52c, 52d, 52e, 52f substantially corresponds to the diameter of the outer struts 22a, 22b, 22c, 22d, 22e, 22f. The horizontal struts 54a, 54b, 54c, 54d, 54e, 54f, extending between the receiver and the outer struts 22a, 22b, 22c, 22d, 22e, 22f, have a smaller diameter. The six cross struts 52a, 52b, 52c, 52d, 52e, 52f form six triangles in conjunction with the six horizontal struts 54a, 54b, 54c, 54d, 54e, 54f and the outer shell of the receiver 4, both a vertical force component and horizontal force components being conveyable from the receiver 4 to the outer struts 22a, 22b, 22c, 22d, 22e, 22f by the six triangles.

Between adjacent outer struts 22a, 22b, 22c, 22d, 22e, 22f there are additionally arranged substantially horizontally-running connecting struts which in conjunction with the outer struts 22a, 22b, 22c, 22d, 22e, 22f form a substantially horizontal annular structure. At the head end of the receiver 4 there is furthermore arranged a connecting ring 32 which can produce a connection between the receiver 4 and a tower shaft.

Reference numerals 1. Offshore foundation structure 2. Jacket portion 4. Receiver 6. Tower shaft of a wind turbine 8. Vertical longitudinal axis 10. Service platform 12. Opening in the service platform 14. Railing of the service platform 16. Access opening 18. Access ladder 20. Stabilizing struts 22a, 22b, 22c, 22d, 22e, 22f outer struts 24a, 24b, 24c, 24d, 24e annular structures 26a, 26b, 26c, 26d, 26e, 26f driven piles 28 connecting plate 30 opening in the connecting plate 32 connecting ring 34a, 34b horizontal supporting plates 36 cross bracings 38a, 38b openings in the supporting plates 40a, 40b, 40c, 40d, 40e, 40f vertical supporting plates 42 circular path 44 curved strut elements 46 curved strut portions 48 straight strut portions 50 securing plates 52a, 52b, 52c, 52d, 52e, 52f cross struts 54a, 54b, 54c, 54d, 54e, 54f horizontal struts

Claims

An offshore foundation structure (1) having a Jacket section (2) comprising several struts connected to the grid like one another and an entrance (4) to a tower trunk (6), in particular a tower trunk of a wind power plant, characterized in that the recording (4) is at least partially arranged in the Jacket section (2).

The offshore foundation structure (1) according to claim 1, characterized in that the receptacle (4) is arranged so that the tower stem (6) can be at least partially placed in the Jacket section (2).

An offshore foundation structure (1) according to claim 1 or 2, wherein the receiving (4) comprises a recess extending along a substantially vertical longitudinal axis (8) and preferably cylindrical, characterized in that the recess is arranged. along its longitudinal axis (8) at least by 25%, 50% or 75% in the Jacket section (2).

An offshore foundation structure (1) according to claim 1 or 2, characterized in that the recess (4) is completely arranged in the Jacket section (2).

An offshore foundation structure (1) according to one of the preceding claims, characterized in that a service platform (10) is provided on the Jacket section (2) and / or on the recording (4), wherein the recording (4) and / or the Jacket section (2) is preferably connected at a top end to a connecting plate (28) connecting the service platform (10) to the Jacket section (2) and / or to the receptacle (4), and the connecting plate (28) preferably comprises a circular recess (30) whose diameter is at least equal to the diameter of the tower stem (6) to be accommodated.

An offshore foundation structure (1) according to any one of the preceding claims, wherein the recording (4) comprises a cylindrical recess and the Jacket section (2) comprises several, in particular three, four, five, six, seven or eight substantially. vertically oriented outer struts (22a, 22b, 22c, 22d, 22e, 22f), preferably arranged along a substantially horizontal circular path (42), characterized in that the quotient of the diameter of the recess and the diameter of the circular path (42) is greater than 0.5, preferably greater than 0.6.

An offshore foundation structure (1) according to one of claims 1 to 5, characterized in that the Jacket section (2) comprises several, in particular three, four, five, six, seven or eight external struts (22a, 22b, 22c). 22d, 22e, 22f) which inclines relative to a vertical line in a range of 5 degrees to 30 degrees, preferably in a range of 5 degrees to 15 degrees.

An offshore foundation structure (1) according to claim 6 or 7, characterized in that in each case two adjacent external struts (22a, 22b, 22c, 22d, 22e, 22f) are connected by at least one cross support (36).

The offshore foundation structure (1) of claim 1, wherein the Jacket section (2) comprises several, in particular three, four, five, six, seven or eight external struts (22a, 22b, 22c, 22d, 22e, 22f), preferably substantially vertically oriented exterior struts (22a, 22b, 22c, 22d, 22e, 22f), or offshore foundation structure (1) according to claim 6 or 7, characterized in that each has two adjacent outer struts (22a, 22b, 22c, 22d, 22e, 22f) are connected by at least one bent bracing element (44).

An offshore foundation structure (1) according to claim 9, characterized in that the bent stiffening element (44) comprises one or more bent stiffening sections (46) and one or more straight stiffening sections (48), where these are arranged in alternating order.

An offshore foundation structure (1) according to claim 9 or 10, characterized in that the bent stiffening element (44) is connected, at a first bent stiffening section (46), to the first outer strut of the two adjacent outer struts (22a, 22b). 22c, 22d, 22e, 22f) by means of the first fastening plate (50) and by a second bent stiffening section (46) are connected to the second outer strut of the two adjacent outer strut (22a, 22b, 22c, 22d, 22e, 22f) ) by means of another fastening plate (50).

An offshore foundation structure (1) according to one of claims 6 to 11, characterized in that each external strut (22a, 22b, 22c, 22d, 22e, 22f) is connected to the receiving (4) by means of a transverse strut ( 52a, 52b, 52c, 52d, 52e, 52f), wherein the transverse strut (52a, 52b, 52c, 52d, 52e, 52f), relative to a vertical line, is inclined in a range from 30 degrees to 60 degrees, preferably 45 degrees. .

An offshore foundation structure (1) according to one of claims 6 to 12, characterized in that each external strut (22a, 22b, 22c, 22d, 22e, 22) is connected to the receiving (4) by means of a horizontal strut ( 54a, 54b, 54c, 54d, 54e, 54f).

Offshore foundation structure (1) according to one of the preceding claims, characterized in that the Jacket section (2) comprises several, in particular two, three, four, five, six, seven or eight preferably pre-made ring structures (24a, 24b, 24c, 24d, 24e) which are coaxially oriented relative to each other and are each disposed in substantially horizontal planes parallel to each other.

An offshore foundation structure (1) according to claim 14, characterized in that at least one, preferably two or more ring structures (24a, 24b, 24c, 24d, 24e) extends around the receptacle (4) and is associated with it.

An offshore foundation structure (1) according to claim 15, characterized in that the at least one ring structure (24a, 24b) extending around the uptake (4) is connected to the uptake (4) by means of a substantially horizontal orientation. support plate (34a, 34b), wherein the outer contour of the support plate (34a, 34b) preferably corresponds substantially to the inner contour of the ring structure (24a, 24b) and further preferably comprises a recess (38a, 38b) whose contour substantially corresponds to the outer contour of the recess (4) or of the tower stem (6).