EP3121338B1 - Off-shore platform with movable connecting elements - Google Patents

Description

The invention relates to an offshore structure according to the preamble of claim 1. The invention also relates to a method for establishing an offshore structure.

Offshore structures are well known in the art. In the EP 2 204 497 A1 a method for installing a buoyant offshore arrangement is disclosed. In this case, four support legs are provided, which extend vertically from each one squeegee, wherein each of the support legs is arranged on the outside of the suction feet, so that a platform laterally to the support legs between a transport position between the Saugfüßen and an operating position at the free end of the support legs back and forth can be moved. For reasons of stability or for reasons of space, however, it may be disadvantageous in some applications that the suction feet arranged on the outside of the support legs occupy a particularly large cross-section. Disadvantageously, when they penetrate into the seabed, the suction feet generate torque on the support legs mounted on the outside thereof.

From the NL 2004357 is known a method for installing an offshore platform and an offshore platform. It is a self-installing platform (SIP) discloses that can be lowered by means of a positionally fixed to the platform connecting element in a transport position between suction feet. The platform is moved in the operating state together with the connecting elements upwards.

In the DE 1 484 525 There is described a method and apparatus for supporting and lifting a buoyant platform which is placed on the seabed.

In the US 2011/0129304 A1 is a floating platform with suction feet described, the platform is arranged on sliding cuffs on a support leg. The sleeves are provided fixed relative to the platform position.

It is therefore in a first aspect of the invention to provide an offshore structure which avoids the above-mentioned disadvantages and, in a second aspect, provides a method for establishing an offshore structure which avoids the above-mentioned disadvantages ,

In the first aspect, the object is achieved by an aforementioned offshore structure with the features of claim 1.

The offshore structure according to the invention has at least three support legs, wherein the structure may also have four, five or any higher number of support legs. At each of the support legs, a squeegee is arranged on a longitudinally lower, ie the seabed end facing and assigned to the respective support leg thereby. Each support leg is preferably assigned exactly one squeegee and vice versa. The squeegee is fixedly mounted at the lower end of the associated support leg. The offshore structure has a platform that reciprocates along both the support legs and the suction feet between a transport position and an operating position. The platform is arranged in the transport position between the suction feet, and the suction feet are preferably all arranged in the operating position in the longitudinal direction below the platform. According to the invention, each of the support legs is arranged in a cross section perpendicular to the longitudinal direction completely within an outer periphery of the associated suction foot. Thus, each of the support legs is not along the outer periphery of the Suction cup sideways. The outer circumference of the suction foot also determines along its virtual extension, preferably parallel to the longitudinal direction, the space in which the associated support leg can be arranged. Each of the support legs is not in a plan view laterally beyond the outer periphery of the associated squeegee. Preferably, each of the support legs is arranged centrally on the associated squeegee. In this case, each of the suction feet is preferably formed in a cross section, preferably each cross section perpendicular to the longitudinal direction in an outer circumference circular.

In a preferred embodiment of the invention, each of the support legs is arranged along each cross section perpendicular to the longitudinal direction along a stroke distance of the platform within the outer periphery or the longitudinally extended outer periphery of the associated suction foot.

Preferably, an underside of the platform in the transport position below a meeresbodenabseitigen wall of the suction cup, preferably each suction cup is arranged.

The offshore structure according to the invention makes use of the advantage of lowering the platform in the transport position very far in the direction of the seabed so that at least one underside of the platform is arranged between the suction feet, specifically beneath a sea floor-side wall of the respective associated suction foot. The platform itself is buoyant. The suction feet are, at least when they are filled with air, also designed buoyant, so that the offshore structure receives a buoyancy by the at least partially filled with air suction feet and the platform. The depth of the offshore structure in the transport position is crucially determined by how deep the platform can be lowered between the suction feet. A shallow draft is advantageous because the offshore structure can then be mounted in a conventional dock, the dock flooded, and the offshore structure then float out of the dock in the transport position.

Preferably, the buoyancy point of the platform and the buoyancy points of the suction feet fall in the same horizontal plane. Preferably, the underside of the platform in the transport position is flush with lower edges, preferably the deepest lower edge of the suction feet. In this constellation, the lowest draft of the buoyant offshore structure would be achieved.

Preferably, at least one of the support legs in a cross-sectional plane perpendicular to the longitudinal direction is mounted centrally on the associated squeegee. Particularly preferably, all support legs are mounted centrally on the squeegee. Due to the central arrangement of the support leg on the squeegee is advantageously ensured a uniform load on a skirt of the squeegee when sucking into the seabed.

In order to achieve the lowering of the platform between the suction feet in the inventive arrangement of the support legs on the squeegee, each of the support legs is connected via a connecting element to the platform. In this case, the platform is relative to the connecting elements and the connecting elements are designed to be movable relative to the associated support leg and forth. Conveniently, it is possible to individually lock the platform to each of the connecting elements and each of the connecting elements on the associated support leg, so that both the connecting elements relative to the platform can be moved back and forth as well as the platform against the locked to the support legs connecting elements can be movable back and forth.

Preferably, the connecting elements surround the associated support leg at least partially. Each of the connecting elements has the Umgriff opposite at least one guide for the platform. The guide may be in the form of one or more rails which extend in the longitudinal direction and along which the platform engages with corresponding counter-means.

Conveniently, each of the support legs and the platform are operatively connected via a first strand jack system, and the connection elements and the associated support legs are in operative connection with each other via a second strand jack system. Instead of stranded wire systems, other lifting / lowering systems can be chosen, but they must be designed to withstand the heavy loads of offshore foundation structures. These are preferably hydraulic or pneumatic lifting systems.

Conveniently, the encircling of the connecting element is formed semi-cylindrical, from the embrace is then preferably a truss structure inside to the platform down. However, the connecting elements can also be closed or partially closed, in particular with air-filled cavities, designed to generate additional buoyancy in the floating state and thus to reduce the draft.

In the second aspect, the object is achieved by a method having the features of claim 8.

The method is particularly suitable for carrying out with one of the abovementioned offshore structures by the platform is arranged in a transport position between the at least three suction feet and the floating offshore structure in the transport position on a water surface. It is 'swim up' as floating on its own without further buoyancy means like barges or the like meant. The building is floating on location, and on location the support legs are lowered to the seabed. Location means the place in the sea where the offshore structure is founded.

The method makes use of the idea to lower the platform between the suction feet even with centrally arranged on the squeegee support legs or only slightly eccentric, at least not over the outer periphery of the squeegee eccentrically protruding support legs, and thus to achieve the lowest possible draft, so that the The offshore structure floats independently and the draft is so low that the offshore structure can be built with the suction feet and the platform in a conventional dock, the dock can be flooded and after the platform is lowered between the suction feet, the building in the Transport position is simply pulled out of the dock with a tractor.

Preferably, connecting elements between the support legs and the platform along the longitudinal direction of the support legs are arranged to move back and forth, and the platform is moved by lowering the support legs first relative to the connecting elements in the longitudinal direction until the platform is arranged on the same height as the connecting elements. If the platform is located at the same horizontal height as the connectors, the connectors are locked to the platform.

Then, the connecting elements are moved together with the platform locked to them in the longitudinal direction, and in this way the support legs are further, preferably lowered to the seabed. The platform floats preferably still on the sea. The lowering of the support legs is preferably carried out simultaneously at all support legs.

The lowering of the support legs is thus divided into two process sections. In a first method section, the support leg is lowered together with the connecting element, as far as until the platform has reached a maximum longitudinal and maximum position relative to the connecting element. In this position, the platform is firmly connected to the connecting element, for. B. locked, and in a second step, the connecting elements are moved together with the platform relative to the support legs and thus lowered the support legs further to the seabed.
The suction feet are pressed into the seabed by creating a vacuum in the suction feet or by applying additional force to the suction feet.

The latter can be done by lifting the connecting elements together with the platform out of the sea.

After the suction feet are firmly anchored in the seabed, the platform is raised to the operating position out of the sea and moved to the upper free ends of the support legs.

Conveniently, the connecting elements are fixed relative to the support leg when the platform is moved relative to the connecting element, and the connecting elements are fixed relative to the platform position when the connecting elements are moved together with the platform relative to the support legs.

Preferably, the platform floats first on the water, and the support legs are lowered by means of a first Litzenhebersystems acting between support legs and platform to the seabed. There, the suction feet can be sucked into the seabed or be pressed in the further process by the weight of the building in the seabed. Conveniently, the platform is raised out of the water to an operating position by means of a second strand jack system which acts in each case between a support leg and a connecting element.

In the operating position, the platform is arranged at the longitudinal end of the outermost end of the support legs and is locked there.

Fig.1

eine vertikale Schnittansicht eines erfindungsgemäßen Offshore-Bauwerks in einer Transportposition in einem ersten Verfahrensschritt,

Fig.2

eine horizontale Schnittansicht entlang der Linie II- II in Fig. 1,

Fig.3a

eine Detailansicht in Fig. 1,

Fig.3b

die Detailansicht gemäß Fig. 3a ohne Eckstück und mit einem ersten und zweiten Litzen hebersystem,

Fig.4

eine Detailansicht in Fig. 2,

Fig.5a

eine Detailansicht gemäß Fig. 3a in einem zweiten Verfahrensschritt, in dem das Stützbein mit dem Saugfuß etwas zum Meeresboden herabgelassen wurde,

Fig.5b

die Ansicht gemäß Fig. 5a ohne Eckstück und mit den beiden Litzenhebersystemen,

Fig.6a

eine Detailansicht gemäß Fig. 3a in einem 3. Verfahrensschritt, in dem die Plattform fest mit einem Eckstück verbunden ist,

Fig.6b

die Ansicht gemäß Fig. 6a ohne Eckstück und mit den beiden Litzenhebersystemen,

Fig.7a

eine Detailansicht gemäß Fig. 3a in einem vierten Verfahrensschritt, in dem das Stützbein mit Saugfuß weiter zum Meeresboden herabgelassen wird,

Fig. 7b

die Ansicht gemäß Fig. 7a ohne Eckstück und mit den beiden Litzenhebersystemen,

Fign. 8a - 8g

acht Verfahrensschritte des erfindungsgemäßen Verfahrens, von denen die ersten vier Verfahrensschritte in den Figuren 1 bis 7b dargestellt sind.

The invention will be described with reference to an embodiment in 18 figures. Showing:

Fig.1

a vertical sectional view of an offshore structure according to the invention in a transport position in a first method step,

Fig.2

a horizontal sectional view taken along the line II-II in Fig. 1 .

3a

a detailed view in Fig. 1 .

3b

the detailed view according to Fig. 3a without corner piece and with a first and second strands lifting system,

Figure 4

a detailed view in Fig. 2 .

5a

a detailed view according Fig. 3a in a second process step, in which the support leg was lowered to the bottom of the sea with the suction foot,

5 b

the view according to Fig. 5a without corner piece and with the two stranded cable systems,

6a

a detailed view according Fig. 3a in a third method step, in which the platform is firmly connected to a corner piece,

Figure 6b

the view according to Fig. 6a without corner piece and with the two stranded cable systems,

7a

a detailed view according Fig. 3a in a fourth method step, in which the support leg with suction foot is lowered further to the seabed,

Fig. 7b

the view according to Fig. 7a without corner piece and with the two stranded cable systems,

FIGS. 8a - 8g

eight method steps of the method according to the invention, of which the first four method steps in the Figures 1 to 7b are shown.

Like in the Fig. 1 shown offshore structure has four support legs 1, of which in Fig.1 only the two front are shown. At each of the support legs 1, a squeegee 2 is arranged at a sea bottom end. Each of the suction feet 2 is circular in a horizontal cross section along its entire extension in a longitudinal direction L in an outer circumference. The support legs 1 are also circular in their cross-section along their entire extent in the longitudinal direction L in its outer periphery. A diameter of the support legs 1 and the suction feet 2 is in Lengthwise L always the same. Each of the support legs 1 is mounted centrally on a sea floor-side wall 3 of the associated squeegee 2. The support legs 1 are each additionally connected via a lateral truss structure 4 outside with the associated squeegee 2. The respective inner side of the four support legs 1 has no truss structure 4. Along the inner sides of the support legs 1, a corner piece 6 is arranged in the longitudinal direction L to move back and forth. However, each of the four corner pieces 6 can be locked in different positions along the associated support leg 1. In principle, it is also conceivable that instead of the four support legs 1 three, five or any higher number of support legs 1 is selected.

In the longitudinal direction L, a platform 7 which can be moved back and forth in the longitudinal direction L is provided between the support legs 1. The platform 7 has over its entire horizontal extent an approximately equal thickness, d. H. Extension in the longitudinal direction L on.

Fig. 1 shows the platform 7 in a transport position. In the transport position, the platform 7 is arranged between the four suction feet 2. The suction feet 2 are filled in the transport position at least in the longitudinal direction L upper portion with air. The platform 7 is buoyant alone, and in the transport position, the platform 7 as well as the four suction feet 2 are in the water and together generate a sufficiently large buoyancy to float the entire offshore structure on a sea surface 8.

It is essential that the platform 7 is moved in the transport position between the suction feet 2, d. H. an underside 9 of the platform 7 is disposed below the sea floor-side wall 3 of the four suction feet 2, and a buoyancy point of the platform 7 is also disposed below the sea bottom-side wall 3 of the suction feet 2.

Under a squeegee 2 is a hollow, open to a seabed 11 towards interior understood, which is surrounded by a skirt 12 and can be pressed under pressure into the seabed 11, but it can also be provided a pump, the air and water sucks the interior of the respective squeegee 2 and thus pulls the squeegee 2 during the formation process in the seabed 11.

The platform 7 has no direct connection with one of the four support legs 1 in the transport position. The underside 9 of the platform is arranged on the sea-bottom side below the four sea-bottom-side ends of the support legs 1.

The hatched area in the Fig. 1 is in the FIGS. 3a, 3b shown enlarged.

Fig. 2 shows the arrangement of Fig. 1 in a sectional view taken along the line II-II. The four support legs 1, which are circular in cross-section, are arranged in corners of an imaginary square and peripherally surrounded by a frame structure 13 which is fixedly connected to the four lateral framework structures 4. The frame structure 13 and the framework structures 4 give the foundation structure sufficient strength, in particular against loads acting laterally on the support legs 1.

On the inside, a corner piece 6 is provided on each of the support legs 1 in the longitudinal direction L to move back and forth along the associated support leg 1. Each of the corner pieces 6 has inwardly projecting arms. However, it is also completely different embodiments of the corner piece 6 conceivable. It can be a frame structure; However, the corner pieces 6 may also be formed closed or form a mixture of both.

The platform 7 is circumferentially adapted in its horizontal cross-section to an inner area formed between the suction feet 2, so that the platform 7 is lowered in the longitudinal direction L between all suction feet 2, so that a horizontal cross-section of each of the complete cross sections of the suction cups 2 as well complete cross section of the platform 7 detected.

In the Fig. 3a is part of the construction of the offshore structure in Fig. 1 shown. Each of the four corners of the foundation structure has the same structure as the partial construction of the Fig. 3a , The squeegee 2 is open to the seabed 11 cylindrical. However, the squeegee 2 can also be formed significantly longer or shorter than the illustrated suction 2 with respect to the relationships to each other and in relation to other components such as support leg 1 or platform 7. The squeegee 2 can also smaller or larger in relation to the other components Have diameter. The squeegee 2 also does not have to be circular in outer or inner circumference in the horizontal cross section, but may in principle have any shape.

The bottom of the seabed is mounted centrally in the longitudinal direction L on top of the squeegee 2, the support leg 1, which extends from the seabed 11 vertically upwards. On the outside of the offshore structure, the support leg 1 is connected to the truss structure 4 for reasons of stability in addition to the squeegee 2, preferably the skirt 12 and the meeresbodenabseitigen wall 3 fixed in position. On the inside of the support leg 1, the movable in the longitudinal direction L back and forth corner piece 6 is provided. The platform 7 is in the in Fig. 1 shown transport position lowered so far or the squeegee 1 raised so far that the Meeresbodenabseitige wall 3 of the squeegee 2 and an upper surface 14 of the platform 7 are arranged almost at the same height with each other. In fact, they can also be arranged exactly at the same height with each other, or the upper side 14 of the platform 7 can even be arranged lower than the sea floor-side wall 3 of the suction foot 2.

In the transport position, the platform 7 is fixed to the squeegee 2 at several points. For fixing bolts or similar fixatives may be provided, which can be solved later after the offshore structure is moved to location.

Also, the movable corner piece 6 is temporarily fixedly connected to a fixing means on the suction foot 2 or a reinforcing strut 15, which goes off from the suction 2. In the in Fig. 3a The entire offshore foundation structure floats on the water. Each of the four suction cups 2 is one according to Fig. 3 arranged transport position shown. Both the platform 7 and the four suction feet 2 contribute to the buoyancy. Together, they generate sufficient buoyancy for the structure.

The hatched area in the Fig. 2 is in the Fig. 4 shown enlarged.

In Fig. 3b is the inner life of the corner in Fig. 3a shown. In this case, the movable corner piece 6 is almost completely removed. First, it can be seen that the corner piece 6 has a semi-cylindrical shell 16, which is shown as part of the corner piece 6 and which engages around the support leg 1 from the inside. At a sea floor downstream end of the semi-cylindrical shell 16, a second arm 17 for fixing one end of a second strand jack system 18 is fixed, the first end of which is provided at the sea bottom-side end of the associated support leg 1. The second strand jack system 18 makes it possible to lift the movable corner piece 6 in the longitudinal direction L alone and / or together with the platform 7 or to lower the movable corner piece 6 by gravity counter to the longitudinal direction L.

In addition, a first strand lifter system 19 is provided between the suction foot 2 and the platform 7. The first Litzenhebersystem 19 is connected at a sea floor abseitigen end to the platform 7 with a first arm 21, which is derived from the platform 7, and fixedly connected at a sea bottom end with an outgoing from the squeegee 2 eyelet 22. The first strand jack system 19 makes it possible to lower the squeegee 2 together with the support leg 1 in the direction of the seabed 11, while the platform 7 floats on the sea. For this purpose, the squeegee 2 is flooded with water, for example, by opening an air outlet (not shown).

In Fig. 4 is part of Fig. 2 shown; this is a sectional view of Fig. 3a , The vertical sectional view shows the centrally arranged on the squeegee 2 support leg 1. The support leg 1 is only touched by the semi-cylindrical shell 16 of the support leg 1. A radial extent in the horizontal direction of the corner piece 6 corresponds to slightly more than a radius of the suction foot 2 in the horizontal direction, at least in a portion into which the platform 7 is lowered in the transport position. Rails 23 arranged on the inside of the corner piece 6 project beyond a radial outer circumference of the suction foot 2. The platform 7 has with the rails 23 corresponding counterparts. The platform 7 can be lowered with the rails 23 and corresponding counterparts with the aid of the first strand lifter system 19 between the suction feet 2. Fig. 4 shows two first strand lifters and four second strand lifters, which together form the first strand lifter system 19 and the second strand lifter system 18 respectively.

In Fig. 5a a second process step of the inventive foundation process is shown.

The offshore structure according to the invention has the great advantage over conventional alone floatable offshore structures that their draft is very low, since the platform 7 can be lowered between the suction feet 2 and thus in the transport position for transporting the offshore structure a small draft has, so that the offshore structure according to Fig. 1 In the case of conventional docks, the dock can then be completely flooded, the dock can then be flooded and the offshore structure floats independently in the transport position in the dock and can be pulled out of the dock by means of a tractor. To support the platform 7 can of course also be attacked at sea with a barge.

In the offshore construction towed to location are in a second step in accordance with Fig. 5a the fixing means of the platform 7 is released on the squeegee 2, and the first stranding system 19 lowers the support leg 1 with the squeegee 2 and together with the corner piece 6 fastened to the support leg 1 or squeegee 2. During the lowering of the support leg 1, the platform 7 slides in the rails 22 relative to the corner piece 6 in the longitudinal direction L upwards. The platform 7 floats during it's initial operation, such as Fig. 5a shows, on the sea surface 8 on. The second strand jack system 18 is not yet actuated at this time.

Fig. 5b shows in comparison to Fig. 3b in that the first strand jack system 19 is extended and that the suction foot 2 is lowered slightly below the sea surface 8. The entire support leg 1 is a piece far lowered together with the squeegee 2.

Fig. 6a shows a third process step. The platform 7 is further displaced in the longitudinal direction L relative to the support leg 1 and occupies its operating position with respect to the corner piece 6. It is displaced in the longitudinal direction L up to the uppermost end of the corner piece 6 and is firmly connected in the operating position with the corner piece 6. The corner piece 6 is still arranged opposite the support leg 1 in the transport position, ie in the lowermost position on the support leg 1.

Fig. 6b shows against the Fig. 5a in that the first strand jack system 19 has been further extended. The second strand jack system 18 is still not actuated.

In Fig. 7a In a fourth method step, the firm connection between the corner piece 6 and the support leg 1 is released, and the first stranded lifting system 19 is further extended, so that the support leg 1 with the squeegee 2 in the direction of the seabed 11 can sink down until the squeegee 2 the Ocean floor 11 has reached. The second strand jack system 18 is shortened, but without receiving load. This situation is in Fig. 7b shown. The second strand jack system 18 is shortened so far and the first strand jack system 19 extended until the squeegee 2 has reached the seabed 11. Depending on whether the squeegee 2 penetrates by force or by additional suction in the seabed 11, the first Litzenhebersystem 19 is further extended and the second Litzenhebersystem 18 further shortened.

In the further course of the process, not shown in detail, the first Litzhebersystem 19 is extended, but without load and the second Litzenhebersystem 18 further shortened, whereby the platform 7, which is fixedly connected to the corner piece 6, is lifted out of the water and thereby pressure on the suction feet 2 exerts, whereby they can be pressed firmly into the seabed 11, if no additional suction device is provided. The second strand jack system 18 is shortened until the platform 7 has reached its operating position relative to the support leg 1, d. H. is arranged completely at the sea bottom off end of the support leg 1.

The method can be found in the Figures 8a - 8g divided process steps are divided. The in the first four figures 8a to Fig. 8d illustrated method steps correspond to those in the FIGS. 3 . 5 . 6 , and 7 illustrated four process steps. The in the FIGS. 8e, 8f, 8g shown process steps are not shown in detail with reference to separate figures, but these are in connection with the description of Fig. 7b described. At the transition between 8e and 8f It can be seen that by lifting the platform 7 out of the sea an additional force is exerted on the support legs 1, which causes the suction feet 2 are pressed into the seabed 11.

LIST OF REFERENCE NUMBERS

1

outrigger

2

suction cup

3

sea-floor-side wall

4

lateral framework structure

6

corner

7

platform

8th

sea

9

Bottom of the platform

11

Seabed

12

apron

13

frame structure

14

Top of the platform

15

reinforcing strut

16

semi-cylindrical shell

17

second arm

18

second strand jack system

19

first stranded cable system

21

first arm

22

eyelet

23

rails

L

longitudinal direction

Claims (11)

1. Offshore construction with at least three supporting legs (1) and a respective suction foot (2) associated with each of the supporting legs (1) in a longitudinal direction (L) on a lower end, and a platform (7) which is movable back and forth along the supporting legs (1) and the suction feet (2) between a transport position, in which the platform (7) is arranged between the suction feet (2), and an operating position, in which the suction feet (2) are arranged below the platform (7), wherein in a cross-section perpendicular to the longitudinal direction (L) each of the supporting legs (1) is arranged completely inside an outer circumference of the associated suction foot (2), characterised in that each of the supporting legs (1) is connected by means of a connecting element (6) to the platform (7) and the platform (7) is designed to be movable back and forth relative to the connecting element (6) and the connecting element (6) is designed to be movable back and forth relative to the supporting leg (1).
2. Offshore construction according to claim 1, characterised in that each of the supporting legs (1) is arranged along each cross-section perpendicular to the longitudinal direction (L) along a maximum lifting distance of the platform (7) within an outer circumference, or an outer circumference lengthened in the longitudinal direction (L), of the associated suction foot (2).
3. Offshore construction according to claim 1 or 2, characterised in that an underside (9) the platform (7) in the transport position is arranged below a wall (3), remote from the seabed, of the associated suction foot (2).
4. Offshore construction according to claim 1, 2 or 3, characterised in that at least one of the supporting legs (1) is mounted centrally on the associated suction foot (2) in a cross-sectional plane perpendicular to the longitudinal direction (L).
5. Offshore construction according to claim 1, characterised in that the connecting element (6) at least partially wraps around the associated supporting leg (1) and has at least one guide (23) for the platform (7) opposite a wrap-around means (16).
6. Offshore construction according to claim 1 or 5, characterised in that the supporting leg (1) and the platform (7) are operatively connected by means of a first strand jack system (19), and the connecting element (6) and the supporting leg (1) are operatively connected to one another by means of a second strand jack system (18).
7. Offshore construction according to claim 1, 5 or 6, characterised in that the wrap-around means (16) is constructed in semi-cylindrical form, and in that the connecting element (6) comprises the wrap-around means (16) in semi-cylindrical form and a framework structure (4).
8. Method for foundation of an offshore construction, comprising at least three supporting legs (1) and a respective suction foot (2) arranged at a lower end on each of the supporting legs (1) in a longitudinal direction (L), wherein in a cross-section perpendicular to the longitudinal direction (L) each of the supporting legs (1) is arranged completely inside an outer circumference of the associated suction foot (2), a platform (7) being arranged in a transport position between the suction feet (2), and the offshore construction floating in the transport position on the surface of the water and the offshore construction being brought to a location and at the location the supporting legs (1) being lowered onto the seabed (11), characterised in that connecting elements (6) between the supporting legs (1) and the platform (7) are arranged movably back and forth in the longitudinal direction (L) of the supporting legs (1), the platform (7) is first of all moved relative to the connecting element (6) in the longitudinal direction (L), the supporting legs (1) with the connecting elements (6) being lowered until the platform (7) is arranged at the same height as the connecting elements (6), and then the connecting elements (6) are moved in the longitudinal direction (L), and in this way the supporting legs (1) are further lowered.
9. Method according to claim 8, characterised in that the connecting elements (6) are in fixed positions relative to the supporting legs (1) when the platform (7) is moved relative to the connecting elements (6) and the connecting elements (6) are in fixed positions relative to the platform (7) when the connecting elements (6) are moved together with the platform (7) relative to the supporting legs (1).
10. Method according to claim 8 or 9, characterised in that the platform (7) floats on the water and the supporting legs (1) are lowered to the seabed (11) by means of a first strand jack system (19) between the supporting legs (1) and the platform (2).
11. Method according to one of claims 8 to 10, characterised in that the platform (7) is lifted out of the water to an operating position by means of a second strand jack system (18) between the supporting legs (1) and the connecting elements (6).

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