Abstract
Various embodiments relate to a method and a harbour plant for mooring a floating body. The harbour plant includes a piled base structure provided with two upwards through sea level projecting sidewalls terminated above sea level and a laterally arranged bottom structure interconnecting the sidewalls, where a top surface of the bottom structure is arranged at a depth allowing the floating body to be floated in between the sidewalls, and where the floating body is arranged to be rigidly, but releasably supported by at least parts of the sidewalls. The method includes bringing the floating body into a position between the sidewalls and fixing rigidly the floating body to the vertical sidewalls of the base structure and still exposing the floating body more or less fully to buoyancy by allowing a water-filled gap at least between bottom of the floating body and a corresponding upper surface of the base structure.
Claims
1. A method for mooring a floating body (11) in a harbour plant, wherein the harbour plant comprises a piled base structure (10) provided with two side walls (22) projecting upwards through a sea level (29) and terminated above sea level (29); and a laterally arranged bottom structure (26) rigidly interconnecting the side walls (22), wherein a top surface of the bottom structure (26) is arranged at a depth allowing the floating body (11) to be floated in between the two side walls (22), and wherein the floating body (11) is provided with a sideways projecting part and is arranged to be rigidly, but releasably supported by at least parts of the side walls (22), the method comprising bringing the floating body (11) into a position between the side walls (22), with at least part of the sideways projecting part positioned above the side walls (22); and fixing rigidly the floating body (11) to the vertical side walls (22) of the base structure (10), while still exposing the floating body (11) fully to buoyancy by allowing a water filled gap at least between a bottom of the floating body (11) and a corresponding upper surface of the base structure (10), preventing relative vertical motion between the floating body (11) and the base structure (10), wherein fixing rigidly the floating body (11) to the vertical side walls (22) of the base structure (10) comprises fixing a bracket (51) and a complementary bracket (52) to each other, the bracket (51) being fixed to an interface surface of the sideways projecting part and the complementary bracket (52) being fixed to a supporting surface at a top of the side walls (22), in which the interface surface and the supporting surface are arranged to face each other and the supporting surface is positioned atop a pile of the piled base structure (10) or between adjacent piles of the piled base structure (10).
2. The method according to claim 1, wherein fixing rigidly the floating body (11) to the vertical side walls (22) of the base structure (10) further comprises arranging a number of tensioning devices (39) between the floating body (11) and an upper part of the side walls (22), the tensioning devices (39) being arranged to rigidly fix with one end to a strongpoint on a side wall of the sideways projecting part of the floating body (11) and the opposite end arranged to rigidly fix to the upper part of the side walls (22).
3. The method according to claim 2, wherein a part of the weight of the floating body (11) is supported by buoyancy and, when sea level increases, ballast water is added to the floating body and/or uplifting forces are compensated for by the tensioning devices (39).
4. The method according to claim 2, wherein tension in the tensioning devices (39) is adjustable in order to secure sufficient supporting and fixing force.
5. The method according to claim 1, further comprising allowing a surface on the floating body (11) to rest on an upper end surface of the side walls (22) in close association with upper ends of piles (25) supporting the base structure (10) and extending through the side walls (22) and into a sea bed (30).
6. The method according to claim 1, further comprising providing the floating body (11) with strongpoints on a bottom surface of the sideways projecting part of the floating body (11) and above the top of the side walls (22) of the base structure (10), wherein the top surface of the side walls (22) is provided with correspondingly arranged complementary strongpoints configured to carry at least a part of the weight of the floating body (11).
7. The method according to claim 6, wherein the strongpoints on the top surface of the side walls (22) are formed by a top end of piles (25) serving as a foundation for the base structure (10), allowing the weight from the supported floating body (11) to be transferred directly through the piles (25) into sea bed (30).
8. The method according to claim 6, wherein jacks are arranged between the strongpoints on top of the side walls (22) and below the bottom of the strongpoints on the bottom surface of the sideways projecting part of the floating body (11) to allow lifting of the floating body (11) in order to achieve optimal weight and/or buoyancy balance between the base structure (10) and the floating body (11); and between the assembled based structure (10) and the floating body (11) and the piled interface to the sea bed (30) and/or functioning as shock absorbers.
9. The method according to claim 1, wherein dampening devices are arranged on a top surface of the side walls (22), configured to serve as shock absorbers during mating of the floating body (11) on the base structure (10).
10. The method according to claim 3, further comprising allowing a surface on the floating body (11) to rest on a surface on an upper end surface of the side walls (22) in close association with upper ends of piles (25) supporting the base structure (10) and extending through the side walls (22) and into a sea bed (30).
11. The method according to claim 1, wherein the bracket (51) and the complementary bracket (52) are welded to each other.
12. A harbour plant for mooring of a floating body (11), the harbour plant comprising a piled base structure (10) provided with two side walls (22) projecting upwards through a sea level (29) and interconnected by a laterally arranged bottom structure (26), and a floating body (11), wherein the base structure (10) is configured to be supported by a sea bed by means of a number of piles (25) terminated at a top surface of the side walls (22) above the sea level (29) or within the side walls (22) below the sea level (29), the floating body (11) is provided with a sideways projecting part and is arranged to be rigidly, but releasably supported by at least parts of the top surface of the side walls (22), a top surface of the bottom structure (26) is arranged at a depth allowing the floating body (11) to be floated in between the two side walls (22) with at least part of the sideways projecting part positioned above the side walls (22), the side walls (22) are configured to carry the weight of the floating body (11) through a rigid, but releasable fixture and still allow a water filled gap at least between a bottom of the floating body (11) and a corresponding upper surface of the base structure (10), and the fixture comprises a bracket (51) and a complementary bracket (52) configured to be fixed to each other, the bracket (51) being fixed to an interface surface of the sideways projecting part and the complementary bracket (52) being fixed to a supporting surface at a top of the side walls (22), in which the interface surface and the supporting surface are arranged to face each other and the supporting surface is positioned atop a pile of the piled base structure (10) or between adjacent piles of the piled base structure (10).
13. The harbour plant according to claim 12, wherein strongpoints on the floating body (11) are arranged on a bottom surface of the sideways projecting part of the floating body (11) and above the top of the side walls (22) of the base structure (10), the top surface of the side walls (22) being provided with correspondingly arranged complementary strongpoints configured to carry at least a part of the weight of the floating body (11).
14. The harbour plant according to claim 12, wherein a number of tensioning devices (39) are arranged between the floating body (11) and the top of the side walls (22), preventing relative vertical motion between the floating body (11) and the base structure (10).
15. The harbour plant according to claim 14, wherein the tensioning devices (39) are rigidly fixed with one end to strongpoints on the floating body (11) and the opposite ends being rigidly fixed to strongpoints at the upper end of the side walls (22).
16. The harbour plant according to claim 14, wherein each tensioning device (39) is provided with a device for adjusting the tension in order to securing sufficient supporting and fixing force.
17. The harbour plant according to claim 15, wherein jacks are arranged between the strongpoints on top of the side walls (22) and below the bottom of the strongpoints on the bottom surface of the sideways projecting part of the floating body (11) to adjust the tension in the tensioning devices (39).
18. The harbour plant according to claim 12, wherein strongpoints on the top surface of the side walls (22) are formed by the top end of piles (25) serving as a foundation for the base structure (10), allowing the weight from the supported floating body (11) to be transferred directly through the piles (25) into the sea bed (30).
19. The harbour plant according to claim 12, wherein strongpoints on the top surface of the side walls (22) correspond to or are in close association with the upper end of piles (25) supporting the base structure (10) and extending through the side walls (22) and into the sea bed (30).
20. The harbour plant according to claim 18, wherein the piles (25) are arranged to terminate at the top surface of the side walls (22), above the sea level (29).
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) In the drawings, like reference characters generally refer to like parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. The detailed description will be better understood in conjunction with the accompanying drawings, where the drawings and description merely relate to preferred embodiments, as follows:
(2) FIG. 1 shows schematically a view in perspective, showing piling of an intermediate set of piles to support a base structure during installation and permanent piling operation.
(3) FIG. 2 shows schematically and in perspective a base structure in the mobilizing phase of being manoeuvred in over the intermediate piles.
(4) FIG. 3 shows schematically and in perspective the base structure installed and supported by the intermediate set of piles.
(5) FIG. 4 shows schematically and in perspective a mobilizing phase where a working barge is moored along one side of the base structure and with an additional stock of piles.
(6) FIG. 5 shows schematically and in perspective a view of the base structure during the piling phase of the permanent piles.
(7) FIG. 6 shows schematically the de-mobilizing stage where the piling of the permanent piles has been completed.
(8) FIG. 7 shows schematically and in perspective the base structure in its permanently piled position supported by the seabed by means of piles.
(9) FIG. 8 shows schematically and in perspective a stage where a floater is floated in and supported by the base structure.
(10) FIG. 9 shows schematically an end view of a base structure and a floating body docked in and supported by the base structure.
(11) FIG. 10 shows schematically and in perspective the base structure and floating structure shown in FIG. 9, also indication use of tension rods for fixing the floating body to the base structure.
(12) FIG. 11 shows schematically in enlarged scale an exemplary initial phase for using guiding pins, used for securing correct position of a floater in the dock.
(13) FIG. 12 shows schematically and in enlarged scale the exemplary guide pins in final position, the floater being in locked position supported by the dock.
(14) FIG. 13 shows schematically in enlarged scale a side view of a part of the top surface of the side wall and a corresponding complementary part of the bottom of the floating body.
(15) FIG. 14 shows schematically and in perspective a view of another embodiment of the base structure, in accordance with the present invention, where the base structure is opened for float in of a floater at two opposite ends.
(16) FIG. 15 shows schematically and in perspective a view of yet another embodiment of the base structure, in accordance with the present invention, where the base structure is provided with only one opening for float in of a floater.
(17) FIG. 16 shows schematically a side view of an alternative way of establishing a fixture between the floater and the top of the base structure.
(18) FIG. 17 shows schematically a side view of the fixture disclosed in FIG. 16, showing details of the position of the floater with respect to the pilings and with respect to the top surfaces of the base structure.
(19) FIG. 18A shows a cross-sectional side view of the floating module having an upper frustoconical portion and the base structure, in accordance with various embodiments.
(20) FIG. 18B shows a perspective view of the floating module of FIG. 18A having a circular top, in accordance with an embodiment.
(21) FIG. 18C shows a perspective view of the floating module of FIG. 18A having a square or rectangular top, in accordance with an embodiment.
(22) FIG. 19A shows a top view of the base structure having a U-shape, in accordance with an embodiment.
(23) FIG. 19B shows a top view of the base structure having a shape of partial hexagonal, in accordance with an embodiment.
DETAILED DESCRIPTION OF THE EMBODIMENTS
(24) The following description of the exemplary embodiment refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. The following embodiments are discussed, for simplicity, with regard to a method for installation of a base structure on a seabed in general and preferably, but not necessarily on a sloped seabed and/or on a seabed with a low bearing capacity.
(25) Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment.
(26) The key area for the invention is to provide a quick and safe installation of the storage module with topside equipment where the base structure is stably and rigidly supported during the piling operation of the permanent piles. By having a pre-installed base foundation, which is stabilized at least by means of piles and levelled in advance to the seabed, then the installation of the storage module can take place within a few hours.
(27) In addition, the present invention offers the possibility of establishing a seabed terminal on different soil conditions. The density, composition, consolidation and topography of seabed soil may vary significantly for one seabed location to another. This will have direct impact on the load bearing capacity of the seabed soil, and hence the possibility to find a predictable and reliable foundation solution for a seabed structure which shall be supported by the seabed. According to one embodiment, the based foundation may be in the form of a semi-submersible floating body, piled to the seabed. In this case the base substructure can be ballasted as a semi submersible structure and piled to the seabed through the base structure and possibly, but not necessary, the wall structure of the seabed substructure. It is important in these cases to have an efficient transfer of vertical structural forces, it is an advantage that the main structural beams of the base structure and the storage module has mirrored structural interfaces. This means that vertical forces from the bulkheads of the storage module are preferably transferred directly into the main structural beams of the base structure and into the piling structure and to the seabed. Calculations have shown that the piled seabed substructure must tolerate and stand a weight of 100 000-120 000 tons.
(28) FIG. 1 shows schematically a first stage of the installation procedure, where two rows of aligned piles 14 spaced apart are arranged, the last pile in the row 14′ being in process of being forced into the seabed 30 by means of a piling barge 15 with a crane 16 and a pile driving tool 17 suspended from the crane 16. During this stage the flat top barge 15 may be moored by means of conventional seabed anchors (not shown) and mooring lines 18 (two of which being shown). As indicated in the Figure the piles 14 are terminated at a predefined height above the sea level 29.
(29) FIG. 2 shows schematically a base structure 10 being towed into position between the two rows of aligned piles 14 by a towing vessel 19 and a pair of towing lines 20. The base structure 10 comprises two vertically arranged side walls 22, rigidly fixed to an intermediately arranged bottom structure, forming a dock structure with a U-shape, configured for berthing or docking a floating body 11. At the top of the vertically extending sidewalls 22, each side wall 22 is provided with an outwards projecting cantilever 21, 21′ extending outwards on each side of the base structure 10, extending laterally out from the top of the base structure 10 entirely along the two parallel side walls 22, each cantilever 21, 21′ being configured to rest on top of a corresponding row of piles 14. For such purpose the cantilevers 21, 21′ are provided with strong points 24 (not shown in FIG. 2), dimensioned and configured to transfer the weight of the base structure 10 temporarily and possible also carrying temporarily appearing loads, forces and bending moments introduced at least during the installation stage of the base structure 10 until the base structure is safely piled to the seabed 30.
(30) The base structure 10 is provided with a system (not shown) for ballasting and is preferably made from steel, although other materials can also be used, such as concrete. It should be appreciated that the base structure 10 according to the present invention may also be provided with auxiliary devices and systems, such as loading systems, cranes, winches, etc., arranged permanently or temporarily on top of the base structure 10. When a floating body or module 11 arrives at the site, it is manoeuvred in a floating state in between the two upwardly extending side walls 22. During this mating operation, the floating body 11 is manoeuvred in through the opening 23 at one end of the base structure 10 and in between the two parallel upwards extending side wall structures 22. The floating body 11 is guided in a way such that strongpoints on the floating body 11 are brought into vertical alignment with corresponding strongpoints arranged on the top surface of the side walls 22. Such strongpoints on the top surface of the two vertical walls 22 correspond with the top end of the piles 25, ended substantially at the top surface of the vertical walls 22. The floating module is then ballasted so that it rests stably on the upper end of the vertical walls 22 of the base structure 10. At sites where changes in sea water level are significant (or at challenging sites), compensation (e.g., by using ballast water, or active ballast) may be required. However, at sites where changes in sea water level are not significant, there may not be a need for compensation by, e.g., using ballast water, and the floating module may still rest stably on the upper end of the vertical walls 22 of the base structure 10. In any case, it should be appreciated that there should be a clearance between the upper surface of the interconnecting structure (base structure) and the bottom surface of the floating body 11. In other words, the upper surface of the interconnecting structure and the bottom surface of the floating body 11 are not in direct contact with each other.
(31) FIG. 3 shows schematically and in perspective an embodiment of the base structure 10, the base structure 10 being installed on top of and being and supported by the set of intermediate piles 14. As shown the temporary piles 14 are aligned with the strongpoints 24 projecting sideways out from the outer, upper part of the side walls 22. The base structure 10 comprises two vertically arranged walls 22 interconnected at the lower end by means of three horizontally arranged box beams 26, rigidly fixed to the side walls 22. Moreover, as indicated the base structure 10 is intended to be piled to the sea bed 30 by means of two rows of piles 14. For such purpose the vertical walls 22 are provided with two rows of casings 27 serving as guiding means to enabling piling operations to be performed above sea level 29, through the casings 27 in the vertical walls 22 and into the sea bed soil. According to the installation stage shown in FIG. 3, the permanent piling process has not yet been initiated. As further indicted, also the box beams 26 may be provided with casings 27 if required in order to obtain appropriate fixture of the base structure to the sea bed 30.
(32) FIG. 4 shows schematically and in perspective a mobilizing phase of the piling operation where a working barge 15′ is moored alongside the outer side of a vertical wall structure 22. On the deck of the flat top barge 15′ a stock 31 of piles to be piled is stored. In addition a hydraulic hammer 32 is indicated. Across the two vertical side walls 22, at one end of the base structure a temporary installed platform 33 is arranged storing yet another stock 31′ of piles to be piled.
(33) FIG. 5 shows schematically and in perspective a view of the base structure during a mobilization phase of the piling operation of the permanent piles 25 where a gantry platform 34. Each end of the gantry platform 34 runs on rails (not shown) arranged along each of the side walls 22, enabling the gantry platform to run along the length of the base structure 10. A crawler crane 35 is arranged on the gantry platform 34, the crawler crane 35 being configured to move back and forth on the gantry platform 34 to collect piles 25 from the stock of piles 31, 31′ and to install the piles 25 through the casings 27 by means of the hydraulic hammer 32. As indicated the hydraulic hammer 32 and a permanent pile 25 is suspended from the hook of the crawler crane 35, the pile 25 being in the process of being piled through the corresponding casing 27 through the side wall 22.
(34) Moreover, a railed welding station (not shown), running on a pair of rails (not shown) on each of the top sides of the side walls 22 may also be used for welding works related to fixing of the completed pile configuration.
(35) The base structure 10 may also be provided with a fender system (not shown) and a mooring and winching system (not shown) for mooring vessels at least along one side of the base structure 10.
(36) FIG. 6 shows schematically the de-mobilizing stage where the piling operation of the permanent piles 25 is completed, but prior to de-mobilizing the gantry platform 34 and crawler crane 35; the flat top barge 15′; and the additional storage platform 33.
(37) FIG. 7 shows schematically and in perspective the base structure 10 in its permanently piled position supported by the seabed 30 by means of piles 25. The piles 25 are terminated at the top of the upper surface of the side walls 22. As indicated upwards projecting ribs or fins 12 are arranged on each side of each pile, servings as support for the floating body 11 on the base structure 10. Moreover, in the space on the top surface of the upper walls a number of dampers 37 may be arranged. The fins or load transferring plates 12 are configured to take the loads and forces from the floating body 11 and transfer said loads and forces down and into the pile 25 immediately below and possibly into the neighbouring piles 25. For such purpose the side wall structure is configured and constructed in such way that the forces are transferred from the side wall 22 and into the pile(s) in a controlled and intended manner. The loads and forces may be transferred directly into the top end of a pile by direct vertical transfer arrangement and/or into the pile wall along the more or less entire interfacing length between the side wall 22 and the corresponding part of the pile 25.
(38) FIG. 8 shows schematically and in perspective a stage where a floating body 11 is manoeuvred in a floating state between the vertical side walls 22 of the base structure 10 to a position where strong points (not shown) on the bottom surface of the floating body are vertically aligned with the corresponding strongpoints on the upper surface of the side walls 22, whereupon the floating body 11 is lowered down until it rests on and is supported by the vertical walls 22. It should be appreciated that the floating body 11 is not limited to the shape or configuration shown, but may be varied without leaving the inventive idea.
(39) For example, the floating body 11 may have a T-shape cross-sectional side view, and a square or rectangular top view (as seen in FIG. 8). Another example may include a floating body 1800 having an upper frustoconcial portion 1802 when seen from a cross-sectional side view, as illustrated in FIG. 18A. The upper frustoconcial portion 1802 may be supported by the top edge of the base structure 1804 (which may be described in similar context to the base structure 10). Such an exemplary floating body 1800 may have a circular top view 1808 (as seen in FIG. 18B); or a square or rectangular top view 1810 (as seen in FIG. 18C). The floating body 1800 may include a lower portion 1806 that is configured to be arranged between the two opposing side walls of the base structure 1804. The lower portion 1806 may be cylindrical. The lower portion 1806 may, for example, have a square or rectangular cross-sectional shape when seen from the top. It should be appreciated that the lower portion 1806 may have a different cross-sectional shape when seen from the top.
(40) In order to allow the floating body 11 to be supported in an appropriate and adequate manner, the floating body 11 may be provided with a section projecting sideways out from the lower part of the floating body 11, said outwards projecting part having a lower surface provided with strongpoints (not shown) intended to be in vertical alignment and supporting contact with corresponding strongpoints on the upper surface of the side walls 22. Embodiments of such supporting contact will be described in further details below.
(41) FIG. 9 shows schematically an end view of a base structure 10 and a floating body 11 docked in and supported by the vertical side walls 22 of the base structure 10. As indicated the floating body 11 is only supported by the base structure 10 along the upper surface of the vertical side walls 22, leaving a gap 38 between the floating body 11 and the base structure 10 at the bottom and along the inner surface of the vertical side walls 22. Moreover, according to the embodiment disclosed in FIG. 9 the bottom surface of the base structure 10 is positioned above the sea bed 30. It should be appreciated, however, that the base structure may rest partly or fully on the sea bed 30, if required.
(42) FIG. 10 shows schematically and in perspective the base structure 10 and floating body 11 shown in FIG. 9, also indicating use of tension rods 39 for fixing and/or tying the floating body 11 to the base structure 10. The purpose of the tension rods 39 is to tie the floating body 11 down into adequate and safe supporting contact with the base structure 10. Moreover, as indicated in the Figure, the floating body 11 and the base structure 10 may be provided with guiding devices 40, preferably arranged at least at two diagonally opposed corners, so as to secure proper alignment of the floating body 11 during the mating on the base structure 10. Details of the guiding device will be described in more details below.
(43) FIGS. 11 and 12 show schematically in enlarged scale an exemplary initial and final phase of the use of the guiding device 40. The guiding device 40 comprises vertical pin 41 movably arranged in a vertical sleeve 42, rigidly fixed to the lower end of the floating body 11 by means of a structural frame element 43. On the top surface of the side wall 22 a corresponding seat 44 is provided, configured and dimensioned to receive the lower end of the vertically movable pin 41. The guiding device 40 is used for securing correct position of a floating body 11 to the base structure 10. When the floating structure 11 is brought into correct position floating above the upper surface of the side walls 22 and when the movable pin 41 or dowel is in alignment with its seat 44, the pin 41 or dowel is lowered down into the seat 44. With all pins 41 in seated position with respect to the seat 44 on the upper surface of the side walls 22, the floating body is in correct position and may be ballasted until supporting contact between the two is established. The final, accurate manoeuvring of the floating body 11 may be performed by towing vessels and/or a winching system (not shown).
(44) FIG. 13 shows schematically in enlarged scale a side view of a part of the top surface of the side wall 22 and a corresponding complementary part of the bottom of the floating body 11. As indicated a number of tension rods 39 are arranged along more or less the entire length of the floater's 11 side surface and the upper end of the external side of the side walls 22. It should be appreciated that other embodiments may include the tension rods 39 being arranged differently (not shown in Figures) and nevertheless provide fixing of the floating body 11 and the side wall 22 to each other. For example, one end of each tension rod 39 may be arranged at any position along the length of the floater's 11 side surface (or the top surface of the floater 11) and the opposite end of the tension rod 39 may be arranged at any position along the external side of the side walls. However, distribution of the tension rod 39 over the substantially entire length may provide more rigid fixation. The number of tension rods 39 used may also vary.
(45) At the upper end the tension rod 39 is rigidly fixed to the floating body 11 by means of a bracket 45 securely fixed to the sidewall of the floating body 11. Correspondingly, at the lower end the tension rod 39 is fixed to the outer surface of the side wall by a corresponding bracket 45′, securely fixed to said wall. At both ends the tension rod 39 is provided with a socket 46, such as for example a standard open spelter socket termination, and intermediately arranged rod or wire 47, rigidly fixed to the socket 46.
(46) The tension device may be a form of a connecting device or a connecting means.
(47) In the context of various embodiments, other forms of the connecting device or connecting means may include the tension rod 39, a bolted connection, or a welded connection, or a clamping connection, or any combination thereof.
(48) A turnbuckle 48 may be incorporated into each tension rod 39 in order to allow adjustment of the length of each individual tension rod 39 used, securing more or less equal tension in the tension rods and/or to control the tension when de-ballasting or ballasting the floating body 11, as the case may be.
(49) FIG. 13 discloses also the strongpoints 12 arranged along the upper surface of the side walls 22. The strongpoints 12 are in the form of upwards extending fins or ribs arranged along both side of the side wall 22 and placed between each upper end of a pile 25 (not shown in the Figure).
(50) FIG. 14 shows schematically and in perspective a view of another embodiment of the base structure 10, in accordance with the present invention, where the base structure 10 is opened for float-in of a floater 11 at two opposite ends. As shown, the base structure 10 comprises two parallel wall sections 22, arranged in spaced relation and interconnected by four laterally extending beams 26, fixing the lower ends of the walls 22 together, leaving open space between at the bottom surface of the base structure 10. According to the embodiment shown, only the vertical walls 22 extending up above the sea level when installed are provided with pile sleeves for receipt of the piles, allowing for dry piling above the sea level 29. In order to transfer forces appearing in the bottom section into the vertically extending side walls 22, the beams 26 may at each end be provided with an increasing larger vertical cross-sectional area towards the end of the beams and towards the corresponding inner side panel of the vertically extending side walls 22. At the upper end of the side walls 22, facing outwards, away from the side walls 22, the sidewalls are provided with strong points 24 to sit on pre-installed temporary piles (not shown). In principle the permanent piling is preferably performed only through the vertical walls 22.
(51) FIG. 15 shows schematically and in perspective a view of yet another embodiment of the base structure 10, in accordance with the present invention, where the base structure 10 is provided with only one opening for float-in of a floater 11 (not shown in FIG. 15). Apart from the fact that the base structure is provided with an opening for float-in of a floater from one side only, the embodiment disclosed is similar to the one disclosed in FIG. 14.
(52) In FIG. 15, the base structure 10 has three adjacent side walls forming a substantially rectangular shape when seen from the top. It should be appreciated that adjacent side walls may form other different shapes when seen from the top. For example, in FIG. 19A, the side walls of the base structure 1900 (which may be described in similar context to the base structure 10) may form a U-shape when seen from the top. In yet another example 1902 as seen in FIG. 19B, the shape formed may be partial hexagonal. It should be appreciated and understood that regardless of the shape formed by the side walls, there is an opening or gap to allow the floating structure to berth within the base structure, between the two opposing side walls. The base structure having a single opening (i.e., having at least three adjacent side walls) may be beneficial for breaking waves. The side walls may not need to be a solid structure. For example, the side walls may include holes or apertures, or sleeves above the waterline.
(53) FIG. 16 shows schematically an end view of an alternative way of establishing a fixture between the floater 11 and the top of the base structure 10 at the top surface of the vertically extending walls 22. As shown, the floater 11 is provided with a sideways projecting part, positioned above the side walls 22. The side wall 22 is provided with a sideways extending cantilevered section(s) 24 (not shown in FIG. 16, serving as strongpoints for support of the base structure during at least the installation phase, allowing the base structure 10 to rest on temporarily installed piles, prior to completing the permanent piling operations of the base structure 10. Moreover, the floater 11 is also provided with a cantilevered section 50, extending sideways out from the main body of the floater 11 above the sea level 29, the cantilevered section(s) 50 being configured to be rested on and be supported by the top surface of the vertical wall 22 on each side of the base structure 10. In order to secure a controlled transfer of loads and forces and in order to fix the floater 11 in a secure and safe manner to the base structure, brackets 51 are fixed to the interface surface on the cantilevered section(s) 50 on the floater 11, and corresponding, complementary brackets 52 are fixed to the supporting surface at the top of the walls 22. The two sets of brackets 51, 52 are bolted or fixed or welded together. It should be appreciated that the cantilevered section 50 may be a section extending along the entire length of the side of the floater, or as separate cantilevered units, placed apart in spaced relation along each side of the floater 11. As shown there is a certain spacing between the inner surface of the side wall 22 of the base structure 10 and the side wall of the floater 11.
(54) FIG. 17 shows schematically a side view of the fixture disclosed in FIG. 16, showing details of the position of the floater with respect to the pilings and with respect to the top surfaces of the base structure. As shown there is also a space between the upper surface of the beams 26 and the lower bottom surface of the floater, allowing the buoyancy of the floater to be varied by pumping ballast out or into the floater 11, the floater still being fixed to the base structure by means of the bracket connections 51, 52.
(55) As indicated in FIG. 17, the piles 25, which are piled from above sea level 29, are terminated below sea level 29, allowing a simple and effecting piling operations and also reducing the weight and the cost. The pile casing may be closed at the top by a plate structure and the bracket connections 51, 52 may either be positioned between two neighbouring pile casings, or on top of said pile casings.
(56) According to the embodiments disclosed, one or two rows of piles are disclosed. It should be appreciated, however, that the number of rows may be more than two.
(57) In the embodiments disclosed vertically oriented piles are shown. It should be appreciated, however, that one or more of the piles may be inclined downwards and laterally out from the base structure.
(58) According to the embodiments shown the piles are terminated at the upper end surface of the side walls 22. It should be appreciated, however, that the piles may be terminated inside the side walls 22 at a lower level than the upper surface, saving length of piles used.
