OFFSHORE PILE INSTALLATION METHOD AND SYSTEM

Abstract

A method for pile installation wherein use is made of a vessel for pile installation. A pile holding system is mounted to the hull of a vessel, e.g. on deck (2) of a vessel, which pile holding system is configured to hold the pile in an upright orientation at a pile installation location at least whilst suspended from a crane by means of one or more winch driven cables, e.g. for installation of a pile adapted to support an offshore wind turbine, the pile holding system comprises a pile holding tool (40). The pile holding tool (40) further comprises a damping system including at least one damping device (45) that is mounted to the base structure (42) and is configured to, in use, engage on the pile suspended from the crane at a location that is vertically spaced from the circumferential zone that is engaged by the plurality of pile engaging positioning devices (43) of the pile holding tool, and wherein the at least one damping device (45) is configured to dampen pendulum motion of the pile suspended from the crane.

Claims

1-32. (canceled)

33. A method for pile installation, wherein use is made of a vessel for pile installation, wherein the vessel has a hull, a crane mounted on the hull, and a pile holding system, wherein the pile holding system comprises: a pile holding tool comprising: a base structure; a support assembly mounted to the hull of the vessel, wherein the support assembly supports the base structure of the pile holding tool; a plurality of pile engaging positioning devices supported by the base structure and distributed in an annular array about a center axis of the pile holding tool and configured to engage on a circumferential zone of the pile so as to hold the pile in an upright orientation at a pile installation location; and a damping system including at least one damping device that is mounted to the base structure and is configured to, in use, engage on the pile suspended from the crane at a location that is vertically spaced from the circumferential zone that is engaged by the plurality of pile engaging positioning devices, the at least one damping device being configured to dampen pendulum motion of the pile suspended from the crane through said engagement on said vertically spaced location, wherein the method comprises holding the pile suspended from the crane by means of one or more winch driven cables, wherein the plurality of pile engaging positioning devices engage on the circumferential zone of the pile that is suspended from the crane so as to hold the pile in said upright orientation at the pile installation location, and wherein the at least one damping device engages on the pile suspended from the crane at the location that is vertically spaced from the circumferential zone and dampens pendulum motion of the pile suspended from the crane.

34. The method according to claim 33, wherein the at least one damping device is configured to dampen double pendulum motion of the pile suspended from the crane through said engagement on said vertically spaced location.

35. The method according to claim 33, wherein the pile engaging positioning devices engage and hold the pile during lowering of the pile towards the seabed, and wherein the at least one damping device dampens pendulum motion of the pile suspended from the crane during a lowering of the pile towards the seabed.

36. The method according to claim 35, further comprising lowering of the pile towards the seabed, wherein the engagement of the at least one damping device on the pile on said vertically spaced location is maintained during said lowering.

37. The method according to claim 33, wherein the configuration of the at least one damping device to dampen the pendulum motion includes at least a selected magnitude of the vertical spacing of the location from the circumferential zone at which the at least one damping device engages on the pile, and/or a selected stiffness of the at least one damping device between said location and the base structure of the pile holding tool.

38. The method according to claim 33, wherein the at least one damping device provides damping of pendulum motion of the pile suspended from the crane in at least two opposite directions.

39. A pile holding system configured to be mounted to the hull of a vessel, the pile holding system being configured to hold the pile in an upright orientation at a pile installation location at least whilst suspended from a crane by means of one or more winch driven cables, the pile holding system comprising: a pile holding tool comprising: a base structure; a support assembly to be mounted to the hull of the vessel, wherein the support assembly supports the base structure of the pile holding tool; a plurality of pile engaging positioning devices supported by the base structure and distributed in an annular array about a center axis of the pile holding tool and configured to engage on a circumferential zone of the pile so as to hold the pile in an upright orientation at a pile installation location; and a damping system including at least one damping device that is mounted to the base structure and is configured to, in use, engage on the pile suspended from the crane at a location that is vertically spaced from the circumferential zone that is engaged by the plurality of pile engaging positioning devices, the at least one damping device being configured to dampen pendulum motion of the pile suspended from the crane through said engagement on said vertically spaced location.

40. The pile holding system according to claim 39, wherein the at least one damping device is configured to dampen double pendulum motion of the pile suspended from the crane through said engagement on said vertically spaced location.

41. The pile holding system according to claim 39, wherein the pile engaging positioning devices are configured to engage and hold the pile during lowering of the pile towards the seabed, and wherein the at least one damping device is configured to dampen pendulum motion of the pile suspended from the crane during a lowering of the pile towards the seabed.

42. The pile holding system according to claim 39, wherein the configuration of the at least one damping device to dampen the pendulum motion includes at least a selected magnitude of the vertical spacing of the location from the circumferential zone at which the at least one damping device engages on the pile, and/or a selected stiffness of the at lease one damping device between said location and the base structure of the pile holding tool.

43. The pile holding system according to claim 39, wherein the at least one damping device is configured to provide damping of pendulum motion of the pile suspended from the crane in at least two opposite directions, the at least one damping device acting in two opposite horizontal directions on the pile.

44. The pile holding system according to claim 39, wherein a set of multiple damping devices is supported by the base structure and distributed in an annular array about a center axis of the pile holding tool and configured to engage on a circumferential zone of the pile that is vertically spaced from the circumferential zone that is engaged by the plurality of pile engaging positioning devices.

45. The pile holding system according to claim 39, wherein the at least one damping device each has a damping arm, the damping arm extending from the base structure, and wherein each damping device comprises: an engaging element, mounted on the damping arm and configured to engage a further circumference of the pile that is vertically spaced from the circumferential zone, the engaging element being configured to remain engaged to the pile while the pile is slid downwardly; and a damper element operative between the engaging element and the base structure.

46. The pile holding system according to claim 45, wherein multiple damping devices are provided, arranged and configured so that the two or more damping arms thereof act in two opposite horizontal directions on the pile to dampen pendulum motion of the pile suspended from the crane in at least two opposite directions,

47. The pile holding system according to claim 46, wherein two or more damping arms, extend in opposite vertical directions from the base structure, so the respective engaging elements engage on the pile at opposite vertical distances from the circumferential zone.

48. The pile holding system according to claim 46, wherein two of the damping arms extend from the base structure at opposite vertical sides of the base structure, both at the same angular position relative to the center axis at a rear or forward side of the base structure, and/or wherein two of the damping arms extend from the base structure both at the same vertical side of the base structure, at diametrically opposite angular positions at the rear and forward side of the base structure.

49. The pile holding system according to claim 39, wherein the damper device comprises or is a resilient element.

50. The pile holding system according to claim 39, wherein the damper device comprises or is a hydraulic or pneumatic damper.

51. The pile holding system according to claim 50, wherein the damper device is or comprises a hydraulic or pneumatic piston cylinder, combined with a hydraulic accumulator for generating pretensioning forces and/or for compensating possible volume differences in hydraulic cylinder chambers of the damper.

52. The pile holding system according to claim 39, wherein the damper device has a lower section connected to the base structure that is annularly wider than the width of the engaging element engaging the pile.

53. The pile holding system according to claim 39, wherein the pile holding tool is configured for supporting the pile during upending thereof from a horizontal orientation to the upright orientation, wherein the base structure is hingeable mounted on the support assembly, and is hingeable about a substantially horizontal hinge axis relative to the support assembly between a horizontal orientation, in which the pile holding tool is able to hold a pile in a substantially horizontal orientation, and a vertical orientation, in which the pile holding tool is able to hold the pile in the upright orientation.

54. The pile holding system according to claim 39, wherein the pile engaging positioning devices comprise controllable pile engaging device movement actuators.

55. The pile holding system according to claim 39, wherein the damping system comprises one or more sensors for detecting tilting of the suspended pile out of the upright orientation thereof, and wherein the at least one damping device are controllable damper devices configured to provide a controllable damping effect, and wherein the controllable damper devices are operably connected to the one or more sensors such as to adjust the damping effect in response to the sensor measurements.

56. A vessel for pile installation comprising: a hull; a crane mounted on the hull; and a pile holding system according to claim 39 mounted to the hull, the pile holding system being configured to hold the pile in an upright orientation at a pile installation location at least whilst suspended from the crane by means of one or more winch driven cables.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In the drawings:

[0063] FIG. 1 shows a vessel according to the invention in a perspective view from the top, while holding a pile in an upright orientation,

[0064] FIG. 2 shows, schematically, the arrangement of a holding tool with damper arms relative to the deck of the vessel, while holding a pile in the upright orientation,

[0065] FIGS. 3a, b shows in a schematic side and cross-sectional view of a pile holding tool according to a possible embodiment of the invention, the pendulum motion of the pile,

[0066] FIG. 4 shows in the same view a pile holding tool according to another possible embodiment,

[0067] FIGS. 5-9 show in the same view a pile holding tool according to other embodiments,

[0068] FIG. 10 shows yet another embodiment of a pile holding tool according to the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0069] FIG. 1 schematically depicts a vessel 1 while carrying out a method according to an embodiment of the invention.

[0070] In FIG. 2, a crane 10 is arranged on the vessel 1, more in particular on an upper deck 2 of the vessel 1. The vessel 1 is a jack-up type vessel in which legs 3 can be lowered into the water to lift the vessel 1 at least partially out of the water so that waves have a limited or minimal effect on the vessel 1.

[0071] The crane 10 as shown is a pedestal mounted crane, but it will be clear to the skilled person that the invention can also be used with other types of cranes, such as a mast crane. The crane 10 comprises a hoisting system with a hoisting cable 20, a load connector 21 connected to the hoisting cable and a hoisting winch (not shown) operating on the hoisting cable 20 to lower or lift the load connector 21.

[0072] The vessel further includes a pile holding tool 40 arranged on the upper deck 2. The pile holding tool 40 comprises a support assembly 41 and has one annular base structure 42 supported on the vessel 1 by the support assembly 41.

[0073] The pile holding tool 40 comprises, connected to the annular base structure 42, multiple pile engaging positioning devices 43 to engage with a pile 50 to hold the pile 50 and limit horizontal motion of a pile circumference or circumferential zone 51 engaged by the pile holding tool 42.

[0074] The pile engaging positioning devices 43 are distributed angularly with respect to a center axis 42a.

[0075] The pile engaging positioning devices 43 are provided with a plurality of rollers to engage with the pile 50 to hold the pile 50 while allowing the pile 50 to move in a direction parallel to the longitudinal axis of the pile 50, while limiting the sideways motion of the pile circumference 51. The rollers each have a horizontal roller axis.

[0076] The rollers are indicated in the schematic illustrations of the embodiments of FIGS. 3a, 3b, 4-9 of the pile holding tool 40.

[0077] Piles like the pile 50, in particular monopiles, adapted to support an offshore wind turbine, shown in FIG. 2, may be stored and/or transported on the vessel 1 or on a separate supply vessel in a horizontal orientation. Hence, in that situation, the crane 10 may be used to lift one end, i.e. an upper end of the pile 50, until the pile 50 is suspended from the hoisting cable in an upright orientation, that is, a substantially vertical orientation as shown in FIG. 2. To this end, a lifting tool 22 may be used as an interface between the pile 50 and the load connector 21.

[0078] After providing the pile 50 in the upright orientation, a lower portion or lower end of the pile 50 is provided in the annular base structure 42 of the pile holding tool 40. As such the position of the lower portion of the pile 50 is controlled by the pile holding system 40 and the position of the upper portion of the pile 50 is generally controlled using the crane and hoisting cable 20. The pile 50 is now held in an upright orientation at a pile installation location next to the vessel 1 by the pile holding tool 40.

[0079] FIG. 2 illustrates, schematically, the arrangement of the pile holding tool 40 relative to the deck, with the pile 50 held thereby in the upright orientation.

[0080] In a method for lowering the pile, the pile 50 is lowered by operating the crane paying out the hoisting cable 20 while the pile is being held by the pile holding tool 40. The pile 50 will first pass a splash zone of a body of water, which splash zone is the transition from air to water when lowering the pile 50 into the water and where the pile is subjected to waves. The pile 50 may also be subject to underwater currents, for example at lower depths, and to wind.

[0081] FIGS. 3a and 3b illustrate pendulum motion of the pile, on an extremely exaggerated scale, by the progression from FIG. 3a to FIG. 3b. The tilting or pendulum motion is indicated by the arrow labeled T.

[0082] To dampen out any such tilting or pendulum motion T of the suspended pile 50, a pushing or damping force F is exerted against the pile, as is indicated in FIG. 3a by means of an arrow.

[0083] Here, the force F is exerted on the pile by engaging element 44 of a damping device 45 having a pivotal damping arm 46.

[0084] The two damping arms 46 of the embodiment of FIGS. 3a and 3b extend upwardly and downwardly from the base structure 42, respectively.

[0085] The engaging elements 44 are in the form of a roller, that is rotatable about a horizontal axis.

[0086] The damping devices 45 each are provided with a damper 47, which is operative between the arm 46 and the base structure 42.

[0087] In the embodiment of the pile holding tool 40 shown in FIGS. 3a and 3b, which is also shown in FIG. 2, there are two damping devices 45 with arms 46.

[0088] Each damping device having an arm 46 extends at a respective vertical side of the annular base structure 42. The damping arm 46 extending above the annular base structure 42 engages a further circumference 52 for counteracting backwards tilting around the tilt axis, that is, with the top of the pile 50 towards the vessel 1, as shown in FIG. 3b. The damping arm 46 extending below the annular base structure 42 engages another further circumference 53 for counteracting pendulum motion.

[0089] Both damping arms 46 are both provided at the most backward angular location at the annular base structure 42. From the figures, it may be envisaged that damping arms may also both be provided at the frontmost angular location.

[0090] Furthermore, from the figures it may be envisaged that multiple damping devices 45, here with arms 46, may be provided around the central axis 42a, for example four, six, eight or ten damping arms may be provided. If, for example, in addition to the two damping arms of FIGS. 3a and 3b two similar damping arms 46 are provided extending above and below the base structure 42 at an angular location spaced 90 degrees therefrom.

[0091] An enhanced damping effect may be achieved by providing two more damping devices 45 at diametrically opposite angular locations in addition to those of FIGS. 3a and 3b, as shown in FIG. 4. The forces F exerted by damping arms 46 at diametrically and vertically opposed locations are added up to provide a force moment that counteracts the tilting motion T.

[0092] In the embodiments shown in FIGS. 3a, 3b, the pile engaging positioning devices 43 are connected to the annular base structure 42.

[0093] For each pile engaging device 43, a controllable pile engaging device movement actuator 43a is provided for independently moving the pile engaging element 44 with respect to the base structure 42, and therewith against the circumferential zone 51 of the pile 50.

[0094] In FIG. 1, it is visible that for the Y-direction, rails are provided via which the support assembly 41 is mounted to the deck 2 of the vessel 1. Though not shown here, such rails may be present for the X-direction as well. By means of such rails, or equivalent means, e.g. integrated in the support assembly, the pile holding tool 40 may be moveable relative to the vessel 1. The movement actuators of the pile engaging positioning devices 43 and/or the holding tool 40 may be controlled automatically e.g. by a control unit, e.g. based on sensor measurements indicating tilting of the pile 50, as discussed herein before.

[0095] In FIG. 5, an embodiment is shown wherein tilting T in opposite directions as in FIGS. 3a and 3b is counteracted by two damping devices 45, here with arms 46, which both extend at the same vertical side of the annular base structure 42, namely there above, engaging the same further circumference 52, and are provided at diametrically opposite angular locations, namely a frontmost and backmost angular location.

[0096] FIG. 6 shows a simple embodiment, wherein only one damping arm 46 is provided.

[0097] FIG. 7 shows an embodiment wherein the damper 47 is a piston cylinder, which is fixedly mounted to the ring. This piston cylinder 47 may form an active or passive damper meansin the latter case it may be connected to an accumulator providing a gas spring (not shown).

[0098] The piston cylinder 47 may, e.g. based on sensor measurements as described herein before, be automatically controlled e.g. by a control unit for dampening the tilting of the pile.

[0099] FIG. 8 shows a preferred embodiment, wherein the damper 47 comprises a piston cylinder, and a rigid elongate element via which the force which is involved with the extension of the piston cylinder is transferred to the engaging element 44. Another embodiment is envisaged wherein the piston cylinder is replaced by one or more blocks of resilient material, e.g. rubber, or an elastomeric material.

[0100] FIG. 9 shows an embodiment, wherein the damper 47 is a block of resilient material, e.g. rubber or an elastomeric material, or a stack of these resilient blocks.

[0101] In FIGS. 8 and 9, the engaging element 44 comprises two spaced parallel and interconnected rollers, so that two further circumferences 52, and two further circumferences 52 of the pile 50 are engaged thereby, and the pushing force is distributed over the rollers and circumferences 52, 53. The rollers each have a horizontal roller axis.

[0102] FIG. 10 shows yet another embodiment of a pile holding tool according to the invention. The tool has 40 comprising: [0103] an annular base structure 42, [0104] a motion-compensating support assembly 41 mounted to the hull, here on the deck 2, of the vessel 1, which support assembly 41 supports the base structure 42 of the pile holding tool.

[0105] Also shown is a plurality or set of pile engaging positioning devices 43 supported by the annular base structure 42 and distributed in an annular array about a center axis 42a of the pile holding tool 40.

[0106] These devices 43 are configured to engage on a circumferential zone 51 of the pile so as to hold the pile in an upright orientation at a pile installation location. Each positioning device 43 is provided with one or more pile guiding rollers. The rollers have a horizontal roller axis.

[0107] The pile holding tool of FIG. 10 further comprises a damping system including at least one damping device that is mounted to the base structure and is configured to, in use, engage on the pile suspended from the crane at a location that is vertically spaced from the circumferential zone that is engaged by the plurality of pile engaging positioning devices 43, and which at least one damping device is configured to dampen pendulum motion of the pile suspended from the crane.

[0108] In more detail, a set of multiple damping devices 45 is supported by the base structure 42 and distributed in an annular array about a center axis 42a of the pile holding tool and configured to engage on a circumferential zone of the pile that is vertically spaced from the circumferential zone that is engaged by the plurality of pile engaging positioning devices 43.

[0109] The base structure is provided with one annular carriers 42b vertically above the annular portion 42a of the base structure provided with the plurality of pile engaging positioning devices 43. The annular carrier 42b is provided with the set of multiple damping devices 45.

[0110] Both the carrier 423b and the annular portion of the base structure supporting the devices 43 are provided with one or more jaws to allow opening and closing of the annulus.

[0111] Each damping device 45 comprises a damping arm 46, which extends from the base structure 42, e.g. upward and/or downward, here pivotally mounted to the base structure 42b, and wherein each damping device comprises: [0112] an engaging element 44, e.g. a roller, mounted on the damping arm and configured to engage a further circumference of the pile that is vertically spaced from the circumferential zone associated with devices 43, and [0113] a damper element 47, here a hydraulic cylinder coupled with an associated hydraulic circuit, operative between the damping arm 45 and the base structure 42b.

[0114] The devices 45 of FIG. 10 provide damping of pendulum motion of the pile suspended from the crane in at least two opposite directions, as damping device will act in two opposite horizontal directions on the pile.

[0115] The pile holding tool 40 of FIG. 10 is furthermore configured for supporting the pile during upending thereof from a horizontal orientation to the upright orientation, wherein the base structure 42,42b is hingeable mounted on the support assembly 41, and is hingeable about a substantially horizontal hinge axis 55, e.g. the hinge axis being parallel to a X-axis of the vessel, relative to the support assembly 41 between a horizontal orientation, in which the pile holding tool 40 is able to hold a pile in a substantially horizontal orientation, and a vertical orientation, in which the pile holding tool 40 is able to hold the pile in the upright orientation.

[0116] The pile holder tool 40 is here provided with an actuable pile foot support 60, that avoids sliding of the pile during upending, and is released or opened for lowering of the pile.