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Title:
APPARATUS AND METHODS FOR INSTALLING A SUBSTRUCTURE
Document Type and Number:
WIPO Patent Application WO/2016/144185
Kind Code:
A1
Abstract:
There is described apparatus for use in installing a substructure, and related methods. In embodiments of the invention, the apparatus comprises a positioning device attached to a leg of the substructure. The substructure comprises at least one leg to be mounted to at least one base, and the positioning device comprising at least one jack for supporting the leg upon the base, such that at least part of the weight of the substructure is supported on the base via the jack. In this way, relative movement between the leg and the base can be reduced, to allow permanent mounting of the leg to the base for example by using a curable material.

Inventors:
FOSS GUNNAR (NL)
OTHEGUY TORRES MARIANO ESTEBAN (NL)
Application Number:
PCT/NO2016/000011
Publication Date:
September 15, 2016
Filing Date:
March 08, 2016
Export Citation:
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Assignee:
OWEC TOWER AS (NO)
International Classes:
E02D13/04; E02B17/02; E02D27/42; E02D35/00
Foreign References:
EP2309063A12011-04-13
FR2607842A11988-06-10
EP2840185A12015-02-25
Attorney, Agent or Firm:
HÅMSØ PATENTBYRÅ ANS (4302 Sandnes, NO)
Download PDF:
Claims:
CLAIMS

1. Apparatus for use in installing a substructure, the substructure having a weight and comprising at least one leg to be mounted to at least one base, the apparatus being configured to be coupled to the leg and comprising at least one jack for supporting the leg upon the base, such that at least part of the weight of the substructure is supported on the base via the jack.

2. Apparatus as claimed in claim 1, wherein the jack is configured to be operable using a hydraulic fluid for supporting the leg upon the base.

3. Apparatus as claimed in claim 1 or 2, wherein the jack comprises at least one hydraulic actuator.

4. Apparatus as claimed in any preceding claim, wherein the jack is configured to be operable to elevate the leg upward with respect to the base, for stabilising the substructure.

5. Apparatus as claimed in any preceding claim, wherein the jack is configured to determine an elevation of the leg relative to the base, and is operable to maintain the leg at said elevation.

6. Apparatus as claimed in any preceding claim, wherein the jack is configured to limit movement between the leg and the base to within 10 mm or less during a curing period for curing the leg to the base in order to mount the leg to the base.

7. Apparatus as claimed in any preceding claim, wherein the base comprises a receptacle configured to receive an end of the leg.

8. Apparatus as claimed in claim 7, wherein the receptacle is provided In the seabed.

9. Apparatus as claimed in any preceding claim, wherein the jack comprises first and second portions wherein the second portion is movable relative to the first portion.

10. Apparatus as claimed in claim 9, wherein the first portion is fixed relative to the leg.

11. Apparatus as claimed in claim 9 or 10, wherein the second portion is arranged for engaging with the base.

12. Apparatus as claimed in any of claims 9 to 11, wherein the jack is configured to be operable to move the second portion relative to the first portion In order to configure the jack in a supporting configuration for supporting the leg upon the base.

13. Apparatus as claimed in any of claims 9 to 12, wherein the jack is configured to be operable to prevent movement between the first and second portions for holding the leg in position relative to the base and supporting the leg upon the base.

14. Apparatus as claimed In claim 9 or 13, wherein the jack is configured to be operable to move the second portion relative to the first portion to elevate the leg with respect to the base.

15. Apparatus as claimed in any of claims 9 to 14, wherein the second portion is movable relative to the first portion with a vertical component of movement.

16. Apparatus as claimed in any of claims 9 to 15, wherein either of first and second portions comprises a plunger, and the other of the first and second portions comprises a plunger housing.

17. Apparatus as claimed in claim 16, wherein the jack is configured with the plunger stroked out from the plunger housing in order to support the leg on the base.

18. Apparatus as claimed in any preceding claim, having a first configuration in which the jack is inactive, and a second configuration in which the jack is active to support the leg upon the base.

19. Apparatus as claimed in any preceding claim, wherein the jack is configured to be operable to cushion the substructure upon landing the leg upon the base.

20. Apparatus as claimed in any preceding claim, further comprising a landing member arranged to bear against the base upon landing the leg on the base.

21. Apparatus as claimed in claim 20, wherein the landing member comprises a gripping surface for contacting the base.

22. Apparatus as claimed In claim 21, wherein the landing member comprises a deformable material configured to deform upon landing the leg on the base.

23. Apparatus as claimed in any of claims 20 to 22, having a first configuration in which the landing member is arranged to support a part of the weight of the substructure, and a second configuration in which the landing member does not support any of the weight of the substructure or supports less of the weight of the substructure than in the first configuration.

24. Apparatus as claimed in claim 23, wherein in the first configuration the jack is inactive, and wherein in the second configuration the jack is active to support the leg upon the base.

25. Apparatus as claimed in any of claims 18, 23 or 24, wherein the jack is configured to be operable to reconfigure the apparatus from the first configuration into the second configuration.

26. Apparatus as claimed in any preceding claim, further comprising at least one bracket through which the jack is connected to the leg.

27. Apparatus as claimed in claim 26, wherein the bracket is arranged to project from a side of the leg.

28. Apparatus as claimed in claim 27, wherein the bracket comprises a fastening structure.

29. Apparatus as claimed in claim 28, wherein the fastening structure comprises at least one plate.

30. Apparatus as claimed in claim 29, wherein the plate comprises first and second radial plates, and at least one wall plate extending upward from the radial plates.

31. Apparatus as claimed in any preceding claim, wherein the jack comprises a plurality of actuators spaced apart from one another around the leg.

32. Apparatus as claimed in any preceding claim, wherein the jack comprises at least one actuator pair comprising a first actuator and a second actuator spaced apart from the first actuator, such that the first and second actuators can engage against the base on respective sides of an edge of the base.

33. A method of installing a substructure, the substructure having a weight, the method comprising the steps of:

(a) providing at least one base to which a leg of the substructure is to be mounted;

(b) operating at least one jack coupled to the leg; and

(c) supporting the leg on the base via the jack so that at least part of the weight of the substructure is supported by the jack.

34. A method as claimed in claim 33, which further comprises securing the leg to the base using a curable mass.

35. A method as claimed in claim 33 or 34, which further comprises supplying hydraulic fluid to operate the jack.

36. A method as claimed in any of claims 33 to 35, which further comprises moving the leg upward using the jack.

37. A method as claimed in any of claims 33 to 36, which further comprises positioning the leg such that the jack is arranged to engage with the base; and operating the jack to engage with the base to support the leg upon the base.

38. A method as claimed in any of claims 33 to 37, which further comprises landing the leg on the base, and moving the leg upward after the leg is landed on the base.

39. A method as claimed in any of claims 33 to 38, which further comprises using the jack to level the structure.

40. A method as claimed in any of claims 33 to 39, which further comprises landing the substructure on landing member of a positioning device, whereby a deformable material in the landing member is compressed, and using the jack to decompress the deformable material.

41. A method as claimed in claim 40, wherein the deformable material comprises an elastomeric material.

42. A method as claimed in any of claims 33 to 41, which further comprises landing the substructure upon the base, and using the jacks to cushion the substructure upon landing.

43. A method of using the apparatus as claimed in any of claims 1 to 32.

44. A method of providing the apparatus as claimed in any of claims 1 to 32.

45. A substructure provided with the apparatus as claimed in any of claims 1 to 32 for mounting the leg of the substructure to the base.

46. A method of providing the substructure as claimed in claim 44.

47. A wind turbine tower supported by a substructure installed either by using the apparatus as claimed in any of claims 1 to 32 or by performing the method of any of claims 33 to 42.

48. A substructure installed either by using the apparatus as claimed in any of claims 1 to 32 or by performing the method of any of claims 33 to 41.

49. Apparatus for use in installing a substructure, the substructure comprising at least one leg to be mounted to at least one base, the apparatus being configured to be coupled to the leg and comprising at least one jack for configured to cushion the substructure upon landing the substructure upon the base.

50. A method of installing a substructure, comprising the steps of:

(a) providing at least one base to which a leg of the substructure is to be mounted, the leg having at least one jack coupled thereto;

(b) landing the substructure upon the base; and

(c) using the jack to cushion the substructure during the landing.

Description:
APPARATUS AND METHODS FOR INSTALLING A SUBSTRUCTURE

Technical fle d,

The present Invention relates to the installation of substructures, in particular substructures such as for supporting for wind turbines and/or wind turbine towers, e.g. offshore.

PackgrQurtc:

In the installation of structures, appropriate foundations are needed so that the structures can withstand the forces to which they are to be subjected during use. Large scale industrial structures such as towers or masts and the like can be exposed to significant forces when installed from the environment. A wind turbine tower is an example of such a structure. Such a tower is typically placed in harsh locations and increasingly it is of interest install wind turbines in offshore environments. This provides significant challenges for installation, to ensure that a solid, durable foundation is obtained.

In the installation of a wind turbine tower, a substructure for the tower is typically installed before the upper tower structure is installed. Such a substructure is typically termed a "jacket" and comprises typically a trussed frame provided with a number of legs. A foundation is prepared, and it then is sought to lower the legs of the jacket onto the base, and mount these securely to the base.

One such technique is described in the patent publication WO2011/010937 that involves inserting the ends of the legs of the jacket into piles, and filling the pile with a curable mass to secure the legs in place on the piles. A positioning device is provided on the end of each leg to create an obstruction against the top of the respective pile and stop the leg from sliding further into the pile, and thereby keeping it in position, whilst the curable mass Is allowed to cure so as to bind the legs to the piles. The curable mass may comprise cementing or grouting material or other binding material to bind the legs to the base. Safety standards have set tolerance limits of only a few millimetres for the relative movement between the leg and the base during curing in such installation methods, in order for ensuring full bonding of the cement between the pile and the leg. There is therefore a need for supporting a jacket on a base such as a pile via a positioning device that allows adherence to such limits.

Ensuring adequate stability and support for the jacket upon the base during the curing period In the presence of the environmental forces experienced in harsh environments such as forces of wind, currents and waves can be a challenge. The solution described in WO2011/010937 uses an elastomeric material which can compress to a different extent on different legs to facilitate supporting the jacket. However, the loads induced on the elastomeric pads by environmental forces can give deflections resulting in relative movements between the leg and foundation pile, affecting in turn the grouting material placed between the leg and the pile. In particular, waves can dominate load fluctuations in the legs and cause significant deflections even in moderate sea states.

Such effects may be exacerbated in jackets with more than three legs, or where the positioning device is not accurately aligned, or there are differences in elevations between piles.

Summary of the invention

In light of the above, various aspects of the invention are provided as set out in the claims appended hereto.

Any of the aspects of the invention may include further features as described in relation to any other aspect, wherever described herein. Features described in one embodiment may be combined in other embodiments. For example, a selected feature from a first embodiment that is compatible with the arrangement in a second embodiment may be employed, e.g. as an additional, alternative or optional feature, e.g. inserted or exchanged for a similar or like feature, in the second embodiment to perform (in the second embodiment) in the same or corresponding manner as it does in the first embodiment. Embodiments of the invention are advantageous in various ways as will be apparent from the specification throughout.

Pescrlptton and drawings

There will now be described, by way of example only, embodiments of the invention with reference to the accompanying drawings, in which: Figures 1A and IB are schematic representations of a substructure in first and sec ¬ ond positions respectively during installation of the substructure, according to an embodiment of the invention;

Figure 2 is a perspective close-up representation of apparatus for use in installing the substructure of Figures 1A and IB according to an embodiment of the invention;

Figure 3 is a perspective representation of the apparatus of Figure 2 from below and in a smaller scale;

Figure 4 is a perspective representation of the underside of the apparatus of Figures 2 and 3 in another scale;

Figure 5 is a perspective representation from above of the apparatus of

Figures 2 to 4, with a resilient member omitted for clarity of illustration;

Figure 6 is a perspective representation from above of apparatus for use

In installing the substructure of Figures 1A to IB according to another embodiment of the invention;

Figure 7 is a perspective representation from above of the apparatus of

Figure 6 in a larger scale and with radial attaching plates omitted to illustrate a jack and landing member more clearly; Figure 8 Is a perspective representation from above, which is the same as

Figure 6 except that a resilient member is additionally omitted for clarity of illustration of the jack and landing member;

Figures 9A to 9B are schematic representations Illustrating the operation of jacks in the apparatus of Figures 3 to 8, in successive first, second, and third configurations respectively;

Figure 10 is a close-up perspective representation of apparatus for use in installing the substructure of Figures 1A to IB according to another embodiment of the invention;

Figure 11 is a perspective representation of the underside of the apparatus of Figure 10; and Figure 12 is a perspective representation of apparatus for use in installing a substructure in a yet further embodiment of the invention.

With reference first to Figures 1A and IB, there is shown a substructure 1 in this case for a wind turbine tower during a process of installing the substructure on piles 2a, 2b provided In the seabed 3. The piles 2a, 2b have tubular configurations having open ends at the seabed 3.

The substructure 1 (e.g. a jacket) has legs 4a, 4b each provided with a positioning device 10 near respective ends 5a, 5b of the legs 4a, 4b. The positioning devices 10 are fastened to the legs 4a, 4b and protrude radially outward from the legs 4a, 4b. During the installation, the substructure 1 is lowered toward and landed upon the piles 2a, 2b. The ends 5a, 5b of the legs 4a, 4b are lowered into the ends of the piles 2a, 2b, so that eventually the positioning device abuts against the ends of the piles 2a, 2b. The legs 4a, 4b are blocked by the positioning devices 10 from moving downward into the piles. The substructure 1 is thus supported by the positioning devices 10 in the "landed" position seen in Figure IB. Landing members in the positioning device 10 are provided with deformable elastomeric material (not shown) so that as the substructure 1 landed, the elastomeric material absorbs the impact load, and carries the weight of the substructure. The positioning device 10 is then activated using hydraulic jacks (not shown) to stabilise the legs 4a, 4b in position upon the piles 2a, 2b, such that the jacks support the weight of the substructure 1. The weight of the substructure is carried by the elastomeric rubber material until the jacks are activated and the weight is transferred onto hydraulic jacks. The jacks operate to elevate the substructure 1 and as such decompress the elastomeric material such that all weight is carried by jacks. This solidifies the support for the substructure 1 such that potential deflections due to fluctuating loads imparted to the legs 4a, 4b by environmental forces such as waves when supported using the elastomeric material can be avoided. Furthermore, the jacks allow the legs 4a, 4b to be elevated individually in order to level the entire substructure.

Various examples of the positioning device 10 and of the operation of the jacks are described in further detail below. With the positioning devices 10 activated using the jacks, the legs 4a, 4b are arranged stably positioned with respect to the piles 2a, 2b, for mounting the legs to the pile. The mounting process is typically performed by inserting curable material such as cement or grouting material into the piles 2a, 2b, between the leg and the pile, so that upon curing the curable material provides a strong, secure bond between the legs 4a, 4b and the pile 2a, 2b. After curing, the weight and loads exerted on the substructure 1 are carried through the bonded connection, and the jacks can be deactivated. The curing time of the curable material can typically be in the order of 24 hours, and the jacks are activated for helping to allow a high quality bond to be achieved. Preferably, the jacks are configured such that leg movement relative to a given pile 2a, 2b during this period of time cannot be more than 10 mm in moderate sea states i.e. is limited to 10 mm or less, for example not more than 5 mm, and most preferably not more than 1 mm in moderate sea states.

It will be noted that the substructure 1 normally has at least three or more legs, but only two such legs 4a, 4b are shown in Figures 1A and IB for Illustration purposes. Also, a positioning device may not necessarily be applied to all of the legs.

With reference to Figures 2 and 3, apparatus comprising a positioning device 110 in the form of a bracket is illustrated. The positioning device 110 is applied in the same way as the positioning device 10 described above. The positioning device 110 is provided on a leg 104 and supports the substructure (not shown) on a base in the form of a pile 102. The positioning device 110 Is fixed to the leg 104 through a fastening structure 111. The fastening structure 111 has an upper stiffener plate 112 and a lower load plate 114 surrounding and extending radially outward from the leg 104. The stiffener plate 112 and load plate 114 are spaced apart from one another along the leg 104. The fastening structure 111 includes a plurality of vertical walls 113 for strengthening the fastening structure 111. The walls 113 are arranged between stiffener plate 112 and load plate 114, to support the upper and lower ring plates with respect to one another. The walls 113 are spaced apart from one another around a circumference of the leg 104. The stiffener plate 112, the load plate 114, and the walls 113 are welded securely to an outer surface of the leg 104, and typically comprise a high-strength material such as for example steel or another metal.

The positioning device 110 has jacks, which in this example are in the form of hydraulic actuators 115 which are arranged to be activated to support the weight of the sub- Structure once the leg 104 has been landed upon the pile 102. The actuators 115 have a housing 115h inside of which a plunger 115p is arranged to be provided so as to be movable with respect to the housing 115h. Hydraulic fluid in the form of oil is used in the actuator for driving the plunger 115p. A plurality of the actuators 115 are provided around the leg 104 on the load plate 114.

Referring now additionally to Figure 4, an underside of the positioning device 110 is shown where it can be seen that the device 110 has landing members in the form of landing blocks 120, which are arranged to engage with the end 102e of the pile 102. The landing blocks 120 are connected to the fastening structure 111 on the underside of the load plate 114, such that they are configured to be disposed between the load plate 114 and the end of the pile 102, in use. The leg 104 is landed on the pile 102 via the blocks 120, and the blocks 120 act to provide some cushioning or shock absorption for the substructure against the pile 102 as it is landed thereupon.

The blocks 120 in this example each have inner ends 120i which are arranged adjacent to the leg 104 and outer ends 120e that extend outwardly from inner ends 120L The blocks 120 are spaced apart from each other around the leg 104. In this example, the actuators 115 are applied to selected "active" blocks 120a within the plurality of blocks 120. In this example, there are three active blocks 120a spaced equally apart clrcumferentially around the positioning device 110.

The landing blocks 120 each have a layered structure, having a contact plate 122 arranged bottom-most, followed upward in succession by a plate in the form of an engaging plate 123 with which the actuators can engage, a deformable pad 124, and a connecting plate 125. The connecting plate 125 is attached to the load plate 114 of the fastening structure 111 and to the deformable pad 124, for connecting the landing member to the fastening structure. The connecting plate 125 can thereby communicate force from the load plate 114 onto the landing blocks 120.

The contact plates 122 have contact surfaces 122s on the underside for contacting the pile 102. In the selected active blocks 120a, the contact plates 122 have a gripping surface 122a provided with gripping formations in the form of teeth 122t for contacting the pile and helping to create resistance against horizontal forces. In other variants, the gripping surface may be in the form of a friction material so that a significant frictional force is generated between the contact surface and the pile, for preventing slippage horizontally. The contact plate 122 in this example is a thin plate attached to an underside of the engaging plate 123 by welding, whereby the engaging plate 123 in effect connects the contact plate 122 with the deformable pad 124, but in other embodiments the engaging plate 123 and the contact plate 122 may be a single plate, which may be formed as one from the same material. In general, the engaging plate 123 and contact plate 122 may have a thickness adapted to known variations in height of the base e.g. between legs for facilitating levelling of the substructure and/or distribution of forces. The engaging plate 123 in the active blocks 120a is configured to engage with the plunger 115p of the actuator. When the actuators 115 are operated, the plunger 115p is urged downward to press against an upper part of the engaging plate 123. In particular variants, the plunger 115p can be attached to the engag- ing plate 123 and/or contact plate 122, so that the engaging plate 123 and/or contact plate 122 is in effect an extension of the plunger 115p.

The deformable pad 124 is formed of an elastomeric and/or resilient material such as rubber or the like, and is configured to be compressed together between the interfacing plate 125 and the engaging plate 123 under the weight of the substructure 1, e.g. when landed on the pile 102, prior to operating the actuators 115.

In this example, the deformable pad 124 is bonded to the interfacing plate 125 and to the engaging plate 123 and can be stretched and pressed together therebetween. Thus, the pad 124 allows some relative movement between the engaging plate 123, and the load plate 114 of the bracket 111.

Given the deformability of the of the pad 124, the active blocks 120a are also provided with an outer retaining member 126 arranged over the outer ends 120i of blocks 120a and an inner retaining member 127 for keeping the engaging plate 123, the contact plate 122 and the interfacing plate 125 aligned. The retaining members 126, 127 have lips 126p, 127p for preventing rotational movement of the engaging plate 123 and/or contact plate 122 relative to the load plate 114. This helps to ensure that the plunger 115p engages against the engaging plate 123 in the correct position upon the plate 123. The outer retaining member 126 in this example Is fastened to the interfacing plate 125 at an outer end of the interfacing plate 125 and extends downward therefrom over the end of the block 120a. In this way, the retaining members 126 also prevent radial movement of the engaging plate and or contact plate 122 relative to the load plate 114. The Inner retaining member 127 is attached to the leg 104. While the retaining members 126, 127 can in this way provide rotational and lateral alignment, It can be noted that the retaining members 126, 127 permit movement downwards or upwards of the deformable pad 124, engaging plate 123 and/or contact plate 122 relative to the load plate 114, e.g. during landing of the positioning device 110 on the pile 102, and/or upon actuation of the actuators 115.

With further reference to Figure 5, the actuators 115 of the positioning device 110 are visible in further detail, as the deformable pads 124 and retaining members 126 are not shown in the drawing, for the sake of clarity. In Figure 5, the actuators 115 are shown with the ends 115e of the plungers 115p in contact with upper surfaces 123u of the engaging plates 123. In each of the actuators 115, the actuator housing 115h is fixed onto the load plate 114. The plunger 115p is arranged to be movable In or out of the housing by supplying hydraulic power fluid into the housing 115h to exert pressure against a drive surface on the plunger 115p. The plungers 115p In this example move In a vertical direction (although more generally may be configured to move upwards or downwards). The actuator 115 is configured so that the plunger 115p is movable through the lower ring plate 114, the interfacing plate 125 and the deforma- ble pad 124 in order to allow the plunger 115p to contact the engaging plate 123. Accordingly, the deformable pad 124 includes a cut out through which the plunger 115p can pass through. Similarly, openings are provided in the load plate 114 and in the interfacing plate 125 for the plunger 115 to pass through .

The plunger 115p is movable out of the housing 115h so as to extend, and can be held in position once extended, by operation of the actuator. The plunger ends 115e may in general be configured to engage with an upper portion, e.g. upper surface 123u, of the engaging plate 123 so as to allow some degree of tilting or untilting of the landing member (and hence of the engaging plate 123) when engaged by the plunger 115p without the tilted upper surface 123u imparting damaging lateral forces on the actuator plunger 115p.

With the end 115e of the plunger 115p in contact with the engaging plate 123 [which in turn is supported on the end of the pile 102], the actuator 115 is operated so that it can support at least part of the weight of the substructure. Thus, the weight of the substructure can be carried through the actuator 115 and supported by the pile. The plungers 115p may extend from the respective housings 115h to provide an extended actuator length sufficient that the weight of substructure is supported by the actuator 115, and so that the weight is transferred through the actuator 115 and the engaging plate 123, into the pile 102. In order to do so, the plungers 115p can be moved from an initial position as seen in Figure 5 and further out of the housing 115h to extend the actuator length. This increases the distance between the load plate 114 and the contacting plate 122. Thus, it will be appreciated that the actuators are configured such that movement of the plunger 115p from the housing can generate movement upward of the load plate 114 with respect to the contacting plate 122, and, correspondingly, of the leg 104 relative to the pile 102, in order to place the apparatus in a configuration by which the leg is supported upon the pile by actuators 115 and can support the weight of the substructure. When landed on the pile 102, as mentioned above, the deformable pads 124 may be in compression, typically to varying degrees from one block 120 to another or from one leg 104 to another. The operation of the actuator 115 can therefore relieve the load exerted upon the pads 124 and movement of the plunger 115p out of the housing 115h may bring the pads 124 out of compression to a configuration in which they do not transmit any of the weight of substructure. Each of actuators 115 can be operated by power fluid, e.g. hydraulic oil, so that plunger is held in position relative to the housing, or so that the plunger 115p is moved controllably in or out of the housing 115h. In this example, two actuators 115 are applied to each of the active blocks 120a, as can be discerned in Figure 5, although it will be appreciated that in other embodiments, one such actuator per active block could be used. More than two actuators could be used. For example, it could be envisaged to apply four such actuators, placed near the corners of the block, for an even distribution of force. This may allow the weight of the substructure to be shared between the actuators, and the Individual actuator capacity to be reduced. It may also provide redundancy in the event of failure of a particular actuator. The bracket 111 is configured to be positioned concentrically with respect to the end of the pile 102e. The end 102e of the pile 102 defines an edge surface 102d on which the contacting plates 122 contact the pile 102. When located on the end of the pile 102 as shown in Figure 5, the blocks 120 contact the edge surface between the inner regions 120i and outer ends 120e of the blocks, defining a contact region between the block and the edge surface. For each active block 120a, one actuator 115 is provided laterally to the inside of the contact region and one laterally to the outside of the contact region. Accordingly, the two actuators 115 on the active block 120a are arranged to act on either side of the edge 102d, which can help to balance the loads in the positioning device and in particular the engaging plate 123 and the contacting plate 122. The two actuators 115 on given active block 120a are provided on opposite sides of a vertical stiffener 113.

It will be noted that in certain variants, the elastomer deformable plate 124 may be omitted altogether, in which case some other coupling arrangement is provided to connect the load plate 114 with the contacting plate 122, whilst allowing relative movement between the contacting plate 122 and the load plate 114 upon operating the actuators 115. For example, a lower end of the plunger 115p can be pre- connected to the engaging plate 123 in a first configuration and thereafter the actuator 115 may be activated to obtain a second, extended configuration after landing upon the pile 102. Alternatively, some other coupling to keep the contact plate 122 in place during the process of landing the leg 104 on the pile 102 could be used.

In such a variant, the actuators 115 may be used during the landing of the leg upon the pile to provide cushioning and absorption for the leg against the pile as it is landed (instead of the elastomeric material). The cushioning and shock absorption is then accommodated by the hydraulic oil in the actuator. With reference now to Figure 6, another positioning device 210 is depicted, which is applied in the same way as the positioning devices 10 and 110 described above.

The positioning device 210 has a fastening structure 211 attached to a leg 204 of a substructure (not shown). More specifically, the positioning device 210 has a stiffener plate 212, a load plate 214 spaced apart from the stiffener plate 212 along the leg, and walls 213 rising between the load plate 214 and the stiffener plate 212. The stiffener plate 212, the load plate 214 and the walls 213 are formed of steel and are welded to the leg 204.

The positioning device 210 includes, in this case, three landing member blocks 220 protruding downward on the underside of the load plate 214, for landing the substructure on the pile 202. The blocks 220 are attached to the load plate 214 and are spaced at 120 degree intervals around the load plate 214 (and hence around the leg 204). The blocks 220 each comprise from the bottom up in succession a contact plate 222, an engaging plate 223, and a deformable pad 224.

In this embodiment, no Interfacing plate is provided. The deformable pad 224 in each block 220 is bonded directly to the load plate 214 and to the adjacent engaging plate 223 for attaching the blocks 220 to the load plate 214. This provides a simpler structure on the underside of the load plate 214.

The actuators 215 are mounted to the load plate 214 and are arranged so that the plungers 215p extend out of the housings 215h through the load plate 214 and through the pad 224, so as to be able to engage with the engaging plates 223 in the underlying block 220.

With reference further to Figures 7 and 8, the arrangement of the actuators 215 on the underside of the fastening structure 211 and load plate 214 can be seen more clearly, since Figure 7 does not show the stiffener plate 212, load plate 214 or the walls 213, and Figure 8 additionally does not show the deformable pads 224 for the sake of clarity.

As seen in Figures 7 and 8, the plungers 215p are extended from the housings 215h and are located with their ends in contact with the engaging plate 223. In this configuration, they may be operated in the same way as in the actuators 115 of the positioning device 110 described above, In order to support the substructure upon the pile 202 via the actuators 115.

The landing blocks 220 are provided in this example with an outer retaining member 226 and an inner retaining member 227 for providing lateral support. Both the outer and the inner retaining members 226, 227 depend downward over outer and inner ends 220e, 220i of the blocks 220 and have lips 226p, 227p, so as to provide lateral support both radially and rotatlonally. The retaining members 226, 227 are attached to the load plate 214, whilst allowing upward or downward movement the engaging plate 223 and/or the contacting plate 224 relative to the load plate 214, e.g. when landing the positioning device 210 on the end of the pile and/or when engaging the actuators 215.

Each block 220 is configured to be engaged by two actuators 215 in the same way as the active blocks 120a in the positioning device 110 described above. The two actuators 215 acting on the given block are spaced apart from one another radially, such that one of the actuators 215 engages with the block 220 near an outer end 220e and the other of the actuators 215 engages with that block near an inner end 220i of the block 220, thus helping to balance loads. As can be seen, the actuators 215 act on opposite sides of a contact region 207 between the edge surface 202d of the pile 202 and the contact plate 222. They are also offset circumferentially and separated by one of the vertical radial walls 213 on the load plate.

In this example, three walls extend radially outward from an inner, central region adjacent to the leg, above each of the respective blocks 220. This arrangement provides additional bracing to withstand and transfer forces into the blocks 220 where the actuators 215 are to be activated.

Referring to Figures 9A to 9C, an operational sequence is illustrated showing the operation of actuators 315 for one of the active blocks 120a or blocks 220 in the positioning devices 110, 210 described above, in use.

Figure 9A shows an initial configuration, before the substructure has been landed, and before the contacting plate 322 has made contact with an end 302e the pile. The de- formable pad 324 is extended. The actuators 315 are not activated, and the plungers 315p are in a retracted position in the housing 315h. The engaging ends 315e of the plungers 315p are not In contact with the engaging plate 323.

In Figure 9B, the substructure has been landed, and the contacting plate 322 has been brought into contact with the end of 302e of the pile. The plate 314 is attached to a leg of the substructure. Upon landing the substructure, the 314 deformable pad 324 is compressed under the weight of the substructure, and the engaging plate 323 and contact plate 322 are moved closer to the plate 314. The actuators are inactive and configured to allow the movement of the engaging plate 323 and contact plate 322 closer to the plate 314. Once landed, the plungers 315p are moved outward from the housing 315h into the position seen in Figure 9B, so that the ends 315e of the plungers lie against the engaging plate 323. In this configuration, the weight of substructure is supported on the base mainly through the deformable pad 324, and not the actuators 315, and the deformable pad 324 remains compressed, as can be seen.

The actuators are then activated to move the plunger 315p into a further extended configuration, whereby the engaging plate 323 and contact plate 322 are moved away from the plate 314, bringing the actuators into the configuration shown in Figure 9C. In Figure 9C, the substructure is supported on the pile via the actuators 315 in which the plungers 315p are extended from the housing 315h, the ends 315e of the plungers 315p engaging with the engaging plate 323, The deformable pad 324 is extended and has no ability to transfer weight transfer between the plate 314 and the pile. In contrast, the weight is transferred through the actuator 315. In this configuration, the end of the leg 304 can be mounted to the pile by use of a curable material e.g. by cementation. After mounting, the hydraulic actuators 315 are deactivated.

With reference to Figures 10 and 11, a further example positioning device 410 is shown. Features in the present example which correspond with those in the earlier described examples are denoted by the same numerals, but are incremented by multiples of one hundred. The positioning device 410 operates generally in the same way as those described above, although in this example, the actuators 415 are separate from the landing members 420.

The positioning device 410 is provided on a leg 404 of the substructure through a fastening structure 411 comprising the stiffener plate 412, the load plate 414 and bracing walls 413. The walls 413 stand upward on the load plate 414 and are welded at an upper part to the stiffener plate 412 and at a lower part to the load plate 414. The stiffener plate 412, load plate 414 and bracing walls 413 are welded to the leg 404 to fix the positioning device 410 in place. The stiffener plate 412 and the load plate 414 extend out from an outer surface of the leg 404 and the stiffener place has a lesser radial extent than the load plate. The stiffener plate 412 and load plate 414 in this example are in the form of ring which encircle the leg 404 but in general these may have different shapes and may for example not fully encircle the leg.

The positioning device 410 includes landing members on the underside of the load plate 414 each including upwards in succession a contact plate 422 for making contact with the pile 402, a lower connecting plate 423, a deformable pad 424 comprising elastomeric material, and an upper connecting plate 425 for attaching the block to the load plate 414 of the fastening structure. These components within the blocks 420 are attached In the same way as the corresponding components In the examples described above (the corresponding features in the present example being denoted by the same numerals but incremented by multiples of one hundred).

The substructure rests upon the pile 402 via the landing members 420 when it is first landed, the elastomeric material of the deformable pads 414 providing a degree of cushioning and shock absorption of impact loads as the positioning device 410 makes contact with the pile 402. Thereafter, the actuators 415 are engaged, and push down upon the pile 402 at the edge surface 402d, so that the weight of the substructure is brought off the landing members 402 and transmitted through the actuators 415.

As can be seen, the plungers 415p are cylindrical with ends aligned over the edge surface 402d so that they bear against the edge surface when extended downwards from the housing 415h, in this case vertically. The ends of the plungers 415p have a rough gripping surface 415g comprising ridges to prevent slippage when pushing on the end of the pile 402. The housing 415h is fixedly attached to the load plate 414 (extending upward on an upper side thereof), and the plungers 415p pass downward through an opening in the load plate. The actuators 415 are arranged so that engagement against the end of the pile 402 occurs at three locations circumferentially around the edge of the pile, using one actuator 415 in each such location.

With reference to Figure 12, another example positioning device 510 is shown, having a fastening structure 511 comprising a stiffener plate 512, load plate 514 and bracing walls 513, arranged to secure the positioning device 510 to the leg 504. Actuators 515 each comprise a housing 515h attached onto the load plate 514, and plungers 515p extend below the load plate, for engaging with an upper end of the pile 502. Dedicated or separate landing blocks are not provided in this example.

In this case, the substructure rests upon the pile 502 via the actuators 515 when it is first landed. The actuators 515 are configured to provide cushioning or shock absorption, e.g. of impact loads as the substructure is landed. The cushioning is provided by way of hydraulic fluid, e.g. oil, in the actuator 515 acting between the housing 415h and the plunger 515p. The actuator 515 may be activated using a fluid supply circuit, so that the fluid in the housing 515h provides an appropriate resistance for cushioning the load. After landing, the actuators 515 are engaged, and push down upon the pile 502 at the periphery, in this example at the edge surface 502d, so that a rigid connection through the actuator between the pile and the leg, allowing the weight of the substructure to be transmitted through the actuators 515 to the pile, and/or the substructure to be levelled.

It will be appreciated that the surface of the pile onto which the positioning device is landed, may in practice be uneven (e.g. higher in certain parts of the surface than others) such that the different landing blocks in the positioning device may experience different forces depending upon where they are positioned. The actuators in different positions around the leg can be operated independently of each other and obtain different extensions, and by doing so, the weight of the substructure may be supported in more equal proportions through the actuators, providing more stable support for a given leg. In general, actuators may be used to engage the base in any number of locations circumferentially about the leg. Thus, any number (e.g. one or more) of the actuators, or active landing blocks such as described above, may be used on any giv ¬ en leg.

Furthermore, it can be noted that by providing positioning devices 10, 110, 210, 41, 510 of the kind described above on respective legs 4a, 4b, 104, 204, 404, 504 the elevation of each leg relative to the pile can be adjusted, independently for each leg, so as to level the substructure. This can be useful where base or bases for the legs are at slightly different elevations, e.g. may be sloped, such that the substructure may tilt or be unstable and tend to tip back and forth by external forces. By operating the actuators 115, 215, 415, 515 as described above the legs can be moved upward or downward, independently of each other for helping to stabilise the substructure.

Various modifications and improvements may be made without departing from the scope of the invention described herein. It can be noted that the positioning devices described can be applied for installing substructures on other bases than piles, such as gravity foundations. The base can be in the form of a receptacle for receiving a leg, and the receptacle and/or leg may have a square or circular cross section, or other shape. The devices may be applied both underwater and on land. It will also be noted that the jacks in general do not necessarily need to be operated hydraulically.