Offshore platform with at least one pile

Abstract

An offshore platform with at least one pile of a pile foundation with an outer wall having an external diameter and with a tube (8, 12) with an inner wall having an internal diameter which is greater than the external diameter, on the exterior of which attachments are arranged, and which is slid over the pile (2, 3) driven into the seabed (4), wherein at least one spacer (20) is provided between the outer wall of the pile (2, 3) and the inner wall of the tube (8, 12).

Claims

1. Offshore platform with at least one pile of a pile foundation with an outer wall having an external diameter and with a tube (8, 12) with an inner wall having an internal diameter which is greater than the external diameter, on the exterior of which attachments are arranged, and which is slid over the pile (2, 3) driven into the seabed (4), characterised in that at least one spacer (20) is provided between the outer wall of the pile (2, 3) and the inner wall of the tube (8, 12).

2. Offshore platform according to claim 1, characterised in that the tube (8, 12) is connected to a support piece (11, 14) which is placed onto an upper end of the pile (2, 3).

3. Offshore platform according to claim 1, characterised in that the attachments (17, 19) have at least one cable guide (19).

4. Offshore platform according to claim 1, characterised in that the tube (8, 12) has openings in a longitudinal direction (L).

5. Offshore platform according to claim 1, characterised in that different tubes (8, 12) are connected to one another by means of a linkage (13) and have a spacing from one another which corresponds to the spacing of different piles (2, 3) over which they are slid.

6. Offshore platform according to claim 1, characterised in that a guide device is arranged on the end of the tube (8, 12) nearest to the seabed.

7. Offshore platform according to claim 1, characterised in that the tube (8, 12) which is slid on extends over the entire length of the portion of the driven pile projecting above the seabed (4).

8. Method for installation of an offshore platform, in which at least one pile (2, 3) of a pile foundation with an outer wall having an external diameter is driven into the seabed (4); a tube (8, 12) with an inner wall having an internal diameter which is greater than the external diameter is slid over a free end of the pile (2, 3) remote from the seabed, and attachments (17, 19) are fastened to the exterior of the tube (8, 12), characterised in that at least one spacer (20) is provided between the outer wall of the pile (2, 3) and the inner wall of the tube (8, 12).

9. Method according to claim 8, characterised in that the tube (8, 12) is pulled at least some way over the pile (2, 3) in the direction of the seabed (4).

10. Method according to claim 8, characterised in that the tube (8, 12) is connected to a fitting which is put in place after the tube (8, 12) is slid over the free end of the driven pile (2, 3).

11. Method according to claim 8, characterised in that a gap between the tube (8, 12) and the pile (2, 3) is sealed.

12. Method according to claim 8, characterised in that different tubes (8, 12) of different piles (2, 3) are connected to one another by a linkage (13).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention is described with reference to an embodiment with five drawings. In the drawings:

[0024] FIG. 1 shows a schematic side view of two driven piles, wherein a tube according to the invention is slid over one of them,

[0025] FIG. 2 shows a tube slid onto the pile in FIG. 1,

[0026] FIG. 3 shows tubes slid onto two driven piles of the pile foundation and a pontoon with a topsides,

[0027] FIG. 4 shows a pontoon with the topsides which has been positioned between the driven piles and has just been placed onto the ends of the piles,

[0028] FIG. 5 shows a longitudinal sectional view of the tube according to the invention.

DETAILED DESCRIPTION OF THE SEVERAL EMBODIMENTS

[0029] FIG. 1 shows a foundation of a transmission platform 1, in which a first pile 2 and a second pile 3 are driven into a seabed 4. A crane 7 arranged on a lifting platform 6 and a hammer (no shown) arranged on the crane 7 are used for driving the piles 2, 3 into the seabed 4. The two piles 2, 3 are driven into the seabed 4 to the same height, i.e. they each project by a portion of the same length above the surface of the water 10.

[0030] FIG. 1 shows a first method step in which a first tube 8 according to the invention is placed over the first pile 2. The first tube 8 is raised by means of the crane 7 and kept vertical. The first tube 8 has at its end nearest to the seabed end a guide 9 in the form of a funnel which is open towards the bottom, which simplifies the sliding of the first tube 8 over the first pile 2. Two cable guides 19 are arranged laterally opposite one another on the first tube 8. The first tube 8 has a length which substantially corresponds to the length of the portion of the first pile 2 above the seabed 4.

[0031] FIG. 2 shows the first tube 8 slid completely over the first pile 2. The guide 9 is spaced just above the seabed 4. The spacing is approximately 1 m, preferably 2 m. All intermediate values are also disclosed hereby.

[0032] A first support piece 11, which is connected in a fixed position to the first tube 8 and facilitates placement of the first tube 8 onto the first pile 2, is arranged at the end of the first tube 8 remote from the seabed. Slipping of the first tube 8 is prevented by the first support piece 11.

[0033] FIG. 3 shows a third method step in which a second tube 12 is already placed over the second pile 3, and a linkage 13 which connects the two tubes 8, 12 to one another in a fixed position is arranged between the two adjacent tubes 8, 12.

[0034] The first tube 8 is fitted on the first pile 2 by means of the first support piece 11, and the second tube 12 is fitted on the second pile 3 by means of the second support piece 14.

[0035] For final assembly of the transmission platform 1 a topsides, that is to say a platform superstructure 16, is shipped in one piece to its location by means of a pontoon 15. The platform superstructure 16 is arranged on a framework 18 on the pontoon 15. The pontoon 15 can be lowered by flooding of water tanks and can be raised by blowing out of the water tanks. The framework 18 has any height so that when the water tanks are filled with air the platform superstructure 16 can be arranged over upper ends of the driven piles 2, 3 above the support pieces 11, 14. This stage of the method is illustrated in FIG. 4.

[0036] According to FIG. 4 the platform superstructure 16 is moved over the upper ends of the piles 2, 3 remote from the seabed and also above the support pieces 11, 14 of the associated tubes 8, 12, and the pontoon 15 has a width such that it can be slid through between adjacent piles. In FIGS. 1, 2, 3 and 4 the transmission platform 1 has at least three, preferably four or six of the piles 2, 3. The drawings illustrate the first and the second piles 2, 3, and the other piles are arranged concealed by the first and the second piles 2, 3 in the drawings.

[0037] Due to flooding of the water tanks of the pontoon 15 the platform superstructure 16 is lowered and is then located on the piles 2, 3. Finally it can then be permanently fastened there.

[0038] FIG. 5 shows a detail of an end of the first tube 8 nearest to the seabed and an end remote from the seabed. The first tube 8 has, at its end nearest to the seabed, the guide 9 which is formed in one piece with the first tube 8 and widens towards the seabed 4 in the form of a funnel at the end of the first tube 8 nearest the seabed. The guide 9 facilitates the sliding of the first tube 8 by means of the crane 7 over the free upper end of the first pile 2 according to FIG. 1.

[0039] At least one spacer 20 is provided between the outer wall of the first pile 2 and the inner wall of the first tube 8. The spacers 20 can be individual, preferably resilient components or a circumferential ring. The spacer 20 can also be formed as filling material, such as concrete, poured into the gap.

[0040] The first support piece 11 for the platform superstructure 16 is provided at the end remote from the seabed. The first support piece 11 is connected in a fixed position to the first tube 8. The first support piece 11 can be an LMU or a transition piece. Mountings 17, which each have a sleeve through which a respective one of the cable guides 19 is guided on both sides, are arranged spaced apart from one another in the longitudinal direction L on the side of the first tube 8. After the erection of the transmission platform 1, various power cables can be passed through the cable guides 19. However, other attachments such as water pipes, landing stations for boats, ladders for the transfer of people, gangways etc. on the first tube 8 are also conceivable.