WO2013191558A1

WO2013191558A1 - Structure to anchor floating installations, and device of a floating bridge

Info

Publication number: WO2013191558A1
Application number: PCT/NO2013/000023
Authority: WO
Inventors: Tore SØREIDE
Original assignee: Reinertsen As
Priority date: 2012-05-26
Filing date: 2013-05-27
Publication date: 2013-12-27
Also published as: NO337262B1; NO20120623A1

Abstract

A construction (10) for the anchoring of floating constructions in connection to a fjord or a strait is described, and it is characterised in that it comprises first (20) and second (22) extended hollow elements that are fastened at each of their ends to respective land fastening points, where the elements are arranged in an arch shape so that their concave back sides face each other and the first and second elements (20,22) are mutually coupled together via a number of separated tie rods (40) fitted in between the elements (20,22). Also described is a floating bridge that is anchored in position across the strait/fjord between the land fastening points with the help of said construction.

Description

STRUCTU RE TO ANCHOR FLOATING INSTALLATIONS

AND DEVICE OF A FLOATING BRIDGE.

The present invention.

The present invention relates to a new construction for anchoring of floating installations in connection with a fjord or a strait as can be seen in the introduction to the subsequent claim 1 . In particular, the invention relates to a construction to anchor a floating bridge.

The invention also relates to a device for a floating bridge with an anchorage, where the bridge spans across a fjord or a strait between two land fastening points and comprises an extended carrier construction with an adapted roadway, and also pontoons that give the bridge the ability to float, and also that the floating bridge is connected to an anchoring construction as given above, for the positioning of the bridge as can be seen in the introduction to the subsequent claim 10.

Although the invention can be used for the anchoring of completely or partially floating installations on water in general, it has particular relevance to anchoring bridges across fjords and straits.

In more detail, the invention relates to a construction that can set up something which can be regarded as an artificial ocean bed to which , for example, anchorage lines from the installation can be secured. This is particularly relevant in cases of fjords or straits with crossing stretches of several kilometres and deep water, where the bottom can be several hundred meters down and possibly up to 1000 meters. These parameters have hitherto represented a limitation and blockage for the setting up of floating bridges across such wide fjords and straits, where the bridge shall, in addition, encompass sections above or below the surface of the water that permit passage of shipping traffic across the bridge span. There are known bridges that rest on poles and which run across fjords/straits that are several kilometres wide, but then in waters that are much shallower, only some tens of meters, so that the foundation poles are placed in a pre-prepared gravel/sand/clay base or they are inserted directly into a rock foundation.

When it comes to deeper fjords, the bottom is normally sold rock covered with a layer of clay/sand/gravel that is several hundred meters thick.

One aims that with the intended solution a classical and normally used floating bridge technology can be used in places where anchoring to the ocean bed was earlier not possible. This is relevant today as one can see the possibilities of crossing several deep fjords to set up road connections free of ferries, which has become a requirement for today's society and as a consequence of a considerable increase in traffic. One finds, for example, several such stretches of road along the west coast of Norway where it is appropriate to set up a series of crossings across fjords that are up to 5-6 kilometres wide. In more detail, this concerns the Norwegian European road E-39.

With regard to prior art, reference is made to the following patents NO-322.1 93, JP-1 1 1 52710, SE-462498 B, US 3,849,821 and US 3,038,224.

The former NO-322.193 relates to, and shows, a waist-formed construction of arch-formed cables/chains/wires 12 (figures 5a and 5b) that are held together with parallel, side-lying anchoring lines 1 1 , i.e. that two lines 1 1 are arranged perpendicularly extending from each pontoon. The straight structure in figure 5 represents the roadway that rests on a number of pontoons.

The disadvantage with this Norwegian solution is that both the arch-shaped line stretches 12 between the land fastening points and the straight, parallel tie rods 1 1 , are formed by chains or wires that thereby give the construction that runs across the strait a negative buoyancy. Besides, the floating bridge itself makes up an integral part of the construction. If one removes the floating bridge from the construction it will sink down in the middle and form a downward arch shape out from each side and lie deepest in the water at the middle of the stretch.

Aim of the invention.

It is an aim of the invention to provide a new construction for the anchoring of floating installations and, in particular, floating bridges. Meant by floating constructions are, for example, platforms for oil installations and aquaculture installations that can permanently, or temporarily, have a need for anchoring.

It is a further aim of the invention to provide an anchoring construction which lies below the waterline when assembled, and which does not influence or hinder the daily shipping traffic along, or across, the width or span of a fjord neither during, nor after, the installation of the construction.

Furthermore, it is an aim to provide an independent anchoring construction for a floating bridge, where the anchoring construction is assembled in the sea at the actual depth and is tested over time before the floating bridge itself is floated in place and is anchored to the construction.

Furthermore, it is an aim of the invention to provide a construction where its individual parts can easily be maintained or replaced, without the whole construction having to be dismantled.

It is a further aim of the invention to provide an anchoring construction with a pipe form that can be inspected from the inside by running monitoring instruments through the pipe.

The present invention.

The construction according to the invention for the anchoring of floating constructions is characterised in that it comprises first and second extended hollow elements that are fastened at each of their ends to two respective land fastening points, and the first and second hollow elements are mutually coupled together via a number of separated tie rods fitted in between the hollow elements so that the hollow elements form an arch shape and their concave back sides face each other.

According to a preferred embodiment the extended hollow elements are metal pipes that can be subjected to tensile forces and the construction of pipes and tie rods are set up to be installed in their entirety under water and dimensioned to have a neutral buoyancy.

According to yet another preferred embodiment the tie rods provide tensile forces that fix the arch-shaped pipes against each other. According to yet another preferred embodiment the construction of first and second pipes and also the tension struts are arranged in the same plane, preferably in a horizontal plane in the sea. According to yet another preferred embodiment, between the two arch-shaped pipes there are a number of largely mutually parallel, tie rods/tension struts of pipe inserted. The tie rods can be formed by massive rods or hollow pipes, as each end of these is fastened to respective arch shapes. According to yet another preferred embodiment the pipes are manufactured from metal, in particular steel, or from plastic or are composed from a composite material, with a sufficient tensile strength, or the arch shapes are formed by a wire bundle with a suitable thickness. According to yet another preferred embodiment the pipes are filled with air and/or they are filled with a lightweight foam, such as polystyrene, that forms isolated air bubbles.

According to a preferred embodiment the hollow arch shapes can be sectioned in that watertight bulkheads are inserted evenly spaced apart so that if a leakage should occur some place in the pipe, it is only the associated pipe section that is filled with water and not the whole length of the pipe.

According to yet another preferred embodiment the pipes are hollow all along their length and their land fastening points comprise means to inspect the pipe internally with the help of a remote controlled inspection tool, for example, video recorders that are placed in the pipe.

The floating bridge with anchoring, where the bridge spans across a fjord or a strait between two land fastening points, and comprises an extended carrier construction with an adapted roadway, and also pontoons that provide the floating ability for the bridge, and also that the floating bridge is connected to an anchoring construction for the positioning of the bridge, is characterised in that the anchoring construction comprises first and second extended hollow elements that are fastened at each of their ends to two respective land fastening points, where the elements are arranged in an arch shape so that their concave back sides face each other, and the first and second elements are mutually coupled together via a number of separate tie rods fitted in between the elements.

According to a preferred embodiment the bridge is arranged centrally, or in an arch shape, such as in an S-shape, along the anchoring construction between each landside and is connected to the pipes with the help of cross-struts, each fixed between a pontoon and the associated pipe arch.

According to yet another preferred embodiment the arch-shaped pipes are held together and set up with both the mentioned tie rods directly between the pipe arches and said cross-strut between the pontoon and pipe arch.

According to a preferred embodiment said tie rods directly between the pipe arches are replaced by said cross-struts between the pontoon and the nearest pipe arch to both hold the pipe arches in place against each other and to anchor the floating bridge.

According to yet another preferred embodiment the anchoring construction is installed between the landsides at a lower depth below the surface of the water than the necessary sailing draught for the ships passing the bridge crosswise. The installation depth can be 30 meters below the surface of the water.

Description of the figures.

The invention shall be explained and described in more detail with reference to the enclosed figures, in which :

Figure 1 shows an outline of a perspective crosswise from above of an anchoring construction according to the invention that spans across a fjord/strait 1 2 below the sea surface.

Figure 2 shows an outline in a plane diagram of the construction in figure 1 .

Figure 3 shows in a cross-section an alternative embodiment of the pipe-formed anchoring part composed of three parallel pipes fitted into a mounting bracket and strapped together into one unit.

Figure 4 shows an enlarged, real perspective of the one half of the construction with a floating bridge according to figure 1 . Figure 5 shows a different enlarged perspective of the cross-coupling between the pipe-formed, arch-formed anchoring parts, and also one of the pontoons of the floating bridge and its connection to said anchoring part.

Figure 6 shows an alternative solution where the anchoring construction is an integral part of the floating bridge and where the tie rods are connected to its pontoons. Figure 7 shows how the pipe construction can be connected to its land fastening points at each end, where the land fastening points comprise a chamber with a possibility to carry out inspections, both of the fastening construction to the landside and internally in the hollow pipes from the one landside to the other.

Figure 8 shows how the anchoring construction according to the invention can be fitted in-situ stepwise from a number of sections of anchoring pipes that are shipped to the installation site by barge. Initially, reference shall be made to figure 1 which is a slanted perspective from above of an anchoring construction 10 according to the invention that stretches across a fjord/strait 12 below the surface of the sea, between two fastening points on land 14 on each side of the fjord 12. Figure 1 also shows the floating bridge 30 itself that connects the two landsides 14, and figure 2 indicates also that the floating bridge floats on a number of pontoons 70 arranged equidistant or at varying distances apart along the bridge span according to the local conditions.

The anchoring construction 10 is composed of two arch-shaped anchoring bodies 20,22 with a pipe shape, hereafter denoted as the pipes in the construction.

The two arch-shaped anchoring pipes 20,22 are both placed in the sea in an arch shape so that their concave back sides face each other, or the convex belly sides face away from each other and they are mutually coupled together by a number of tie rods 40 that are fitted mutually spaced apart and thus form a grid structure with the pipes. The parallel rods 40 are preferably also formed by hollow pipe constructions with regard to a required buoyancy calculated in advance, but have smaller pipe diameter dimensions than the anchoring pipes 20,22. The rods can also be formed by solid, metal rods, preferably of steel. Each end of a rod 40 is fastened to respective anchoring pipes 20,22 via suitable casing constructions (not specifically shown) that surround the pipe circumference. Wire bundles can also be used as rods to hold the pipe arch tightly against each other. Furthermore, the tie rods, either in the form of pipes, solid struts or wires (for example, in bundles) are simpler to replace than parts of the pipe arch themselves. Each end of the pipe 20 is anchored to respective, specially adapted fastenings in solid land/rock on each side, indicated by 60 and 62, respectively, cf. figures 1 and 2. Each pipe is initially formed by welding together a number of pipe sections to a straight pipe length that is longer than the width of the fjord/strait. Thereby, the construction will be bent naturally in an arch shape when the pipe ends are fastened on land (for example, where there is the shortest distance across the fjord between the land fastening points) as shown in the figure. The fastening point is further organised with an outlet angle/length direction from land so that when the pipe sections in the arch-shapes are tied and pulled together, the pipe ends are subjected to a longitudinally running axial tension at the land fastening point.

The two pipes 20,22 and the tie rods 40 are calculated in advance with regard to buoyancy in the sea, i.e. weight per running meter and the volume of the body of water they displace so that the construction, when fastened on land via its four fastening points, has a balanced buoyancy and can float in the free body of water. The whole of the construction 10 is set up (fastened to land) so that it is positioned/floating in a horizontal plane. At least this horizontal position will be maintained when the pontoon 70 of the bridge 30 is connected to the construction 10.

With arch shape is meant that the two pipes 20 and 22, respectively, can form several possible rounded forms, but particularly preferred is an approximately oval or circle-like shape, so that the construction forms a smaller waist shape in the middle. Figure 2 indicates an embodiment where the construction 10 (the floating bridge 30) has a length of 3604 meters, there is a distance between the land fastening points of about 800 meters and the distance between the pipes 20 and 22, respectively, is about 80 meters at the narrowest. A land fastening point 62 for the pipes 20,22 shown in figure 7 can be formed with the help of conventional technology and comprises, according to the invention, a service chamber 80 inside the rock formation 14 where an access 82 to the entrance/mouth of the pipe 20 is arranged. The pipe can be inspected internally via this access 82 to monitor the state of possible formation of corrosion in the pipe material. This can be carried out in that an inspection tool, a robot with the necessary monitoring instruments, is driven into the pipe from one end to the other. According to an alternative embodiment each stretch of pipe 20,22 is made by a bundle of a number of pipes that are coupled together lengthwise with the help of straps that are placed around the bundle. As shown in figure 3, a such construction can comprise, for example, three parallel pipes 20a,20b,20c that are fitted in respective seats in a star-formed coupling piece 21 and bundled together by a belt/strap 23 or the like, i.e. that the pipes are bundled together with a number of coupling pieces a mutual distance apart along the pipe arch. This provides additional safety if one of the pipes become damaged, for example, by ingress of water (leakage). In this case the unit is formed such that one of the pipes, or all the pipes in turn can be dismantled and replaced by a new pipe material without preventing the intended use of the construction 1 0 and the floating bridge 30 for transport.

Pipe dimensions and alternatives.

According to one example pipe forms, with an outer diameter of about 1 .2 meters, an inner diameter of 1 meter, which means a wall thickness of about 20 cm, are used.

The pipes 20 and 22, respectively, are preferably hollow, air-filled pipes made of metal (steel) that can provide the necessary buoyancy. In special cases, the pipes can be made from plastic, or from a composite of different materials with a sufficiently large tensile strength. The pipes can also be filled with a lightweight foam material which means that a pipe will float even when it is damaged and water penetrates in. Foam materials that form air pockets do exist or are of a material that has a lower specific weight than water, for example, polystyrene. However, one then loses the inspection possibility one has with hollow, gas-filled pipes. According to a preferred embodiment inserted crosswise in the pipes 20,22 are separated watertight bulkheads, to form a number of separated hollow spaces along the pipe length. Thus, if leakage occurs some place in the pipe it is only the associated hollow space that will be filled with water and not the whole length of pipe. When the whole pipe stretch in the arch shape is formed by pipe sections welded together, each pipe section can be closed at each end by a plate that forms said bulkhead which thereby limits and defines the hollow sections. An alternative to the pipe form can be to replace the pipe forms 20,22 with bundles of cables or wires. However, wires are not preferred as they lead to a negative buoyancy for the construction and they are elongated when they are subjected to tensile stress. Steel pipes subjected to tension will also exhibit an elongation, but as long as the material does not enter into a so-called deformation flow, one has control over the elongation.

Fitting of the anchoring construction.

An assembly instruction for the anchoring construction is shown in figure 8. A number of pipe sections 120 are shown top left that are brought to the assembly location on board a barge 130. A land based welding station is shown by 140, where the pipe sections 1 20 are welded together into the whole pipe length 20, with Offer anodes 142 also being inserted. The pipe is continuously fed into the sea 12. Two manufactured units are then towed in place (bottom left in the figure) and the ends are fastened into the rock at 60 and 62, respectively, at the chosen depth for the formation of said arch shape. Thereafter, the pipes are subjected to tension in that they are pulled towards each other, whereupon the end sections of the tie rods 40 are coupled together with the pipes 20,22 and tighten/stretch these some more to form the arch shape. The buoyancy of the construction (of the pipes 20,22 and tie rods 40), together with its connection to the floating bridge, contribute to maintaining the horizontal position of the construction and that it is held approximately neutral, floating in the body of water.

Combination of anchoring structure and floating bridge.

The placing of the floating bridge 30 with its pontoons 70 relative to the anchoring construction 10 is shown schematically in the figures 1 and 2. Incidentally it is an advantage that the bridge is assembled in an S-shape along the anchoring construction, as it can then easier take up forces and movements, in particular sidewise, that arise as a consequence of waves, current, wind and the tidal movements over a 24 hour period. Reference is now made to the figures 4, 5 and 6 that illustrate in perspective how the floating bridge is coupled up. The figures 4 and 6 show this in two different versions.

Coupling of a floating bridge to a pre-assembled anchoring construction.

Figure 4 shows the floating bridge 30 placed with its pontoon 70 floating some distance above an underwater anchoring construction 10 set out in advance, where one half of this appears in the figure. The floating bridge is centred with regard to the unit 10 between the land fastening points. The tie rods 40 are shown lying horizontally across the longitudinal direction of the bridge down in the body of water 12, cf. the details also given in figure 5. The floating bridge 30 comprises an extended truss frame 31 that rests on a number of pontoons 70 and which carries a road way 32. Tilted anchoring struts 72 are inserted on each side between each pontoon 70 and the pipes 20 and 22, respectively, fastened in a conventional well-known way. As shown, particularly in figure 5, each strut 72 runs down at an angle to its fastening point in the pipe 20. The tilted struts 72 to each side are preferably fitted so that they run in parallel with the tie rods 40. But they can also be placed in a cross-shape, in that two cross- struts, for example, are fitted to the pipe 20 from each pontoon 70, one to each adjoining tie rod to each side of the pontoon 70 seen from above. Figure 5 also illustrates the waterline 1 1 and angle a that one of the cross-struts

72 forms with a tie rod 40. The waterline 1 1 is also schematically shown in figure 7.

Coupling up of a floating bridge simultaneously with, and integrated with, an anchoring construction.

This embodiment of the invention is shown in figure 6 and can be partially seen in figure 2 in a plane outline. A floating bridge 130 is formed with a high bridge part with two portals 134 for the passing of ships 200 across from the bridge. In this version the pontoons 70 of the bridge 130 are connected directly with the pipes 20 and 22, respectively, with the help of two separate tie rod sections 140a and 140b, respectively. This means that the tie rods 40 that hold together the pipes 20 and 22, respectively, in the solution described above are replaced by the two tie rod sections 140a and 140b, respectively, together with the pontoon. In the embodiment shown, each third pontoon 70 in the floating bridge, is in this way coupled together with the pipes 20 and 22, respectively. The two pontoons 1 36 that form the foundation for the vertical roadway-carrying columns 1 37 in the high bridge part 134, have larger dimensions (volume- height-width) than the other pontoons 70, and here two tie rods 141 to each side from each pontoon are coupled to their adjoining pipes 20 and 22, respectively.

In this solution the bridge is floated across the strait at the same time that the pipes 20 and 22, respectively, are placed in their respective land fastening points and form said arch shape. Thereafter, the two arch shapes are tightened against each other with the help of the strut sections that are fitted between the pipes and pontoons. While the construction according to the invention is described in connection with anchoring of floating bridges, it can of course be used for the anchoring of ships, platforms, aquaculture installations, constructions of pontoons or floats that shall carry harbour installations or support buildings and the like.

Claims

P A T E N T C L A I M S

1 . Construction (10) for the anchoring of floating constructions in connection to a fjord or a strait, characterised in that it comprises first (20) and second (22) extended hollow elements that are fastened at each of their ends to respective land fastening points, and the first and the second hollow elements (20,22) are mutually coupled together via a number of separate tie rods (40) fitted in between the hollow elements (20,22) so that the hollow elements form an arch shape and their concave back sides face each other.

2. Construction (10) according to claim 1 , characterised in that the extended hollow elements are pipes that can be subjected to tensile forces and the construction (1 0) of pipes (20,22) and tie rods (40) is set up to be installed in its entirety under water and be dimensioned to demonstrate a neutral buoyancy in water.

3. Construction (10) according to claims 1 -2, characterised in that the tie rods (40) provide tensile forces that tighten the arch-shaped pipes (20,22) against each other.

4. Construction (10) according to claims 1 -3, characterised in that the construction (10) of the first and second pipes (20,22) and also the tie rods (40) is arranged in the same plane preferably a horizontal plane

5. Construction (10) according to any of the preceding claims, characterised in that a number of mutually parallel tie rods (40) of pipes are fixed between the pipes (20,22).

6. Construction (10) according to any of the preceding claims, characterised in that the pipes (20,22) are manufactured from metal, in particular, steel or from plastic or made up from a composite material with a sufficient tensile strength.

7. Construction (10) according to any of the preceding claims, characterised in that the pipes are filled with air, or a lightweight foam, such as polystyrene.

8. Construction (10) according to any of the preceding claims, characterised in that the land fastening points (60,80) of the construction comprise means to inspect the pipes internally with the help of a remote controlled

5 inspection tool, such as a video recorder.

9. Construction (10) according to any of the preceding claims, characterised in that watertight bulkheads are inserted in the pipes (20,22) and spaced out crosswise to form a number of separate hollow spaces along the0 length of the pipe.

10. Construction (10) according to any of the preceding claims, characterised in that the pipe arches are defined by a number, preferably three, of mutually parallel pipes (20a,20b,20c) that are tied together with a strap/belt or5 the like, and each tube can also be lying in adapted seats in a number of coupling pieces (21 ) mutually spaced apart along the arch shape.

1 1 . Device for a floating bridge with anchorage where the bridge is stretched across a fjord or a strait between two land fastening points and comprises an o extended carrier construction with an adapted roadway, and also pontoons that provide the floating capability of the bridge, and also that the floating bridge is connected to an anchoring construction for the positioning of the bridge, characterised in that the anchoring construction comprises first (20) and second (22) extended hollow elements that are fastened at each of their ends 5 to respective land fastening points, where the elements are arranged in an arch shape so that their concave back sides face each other, and the first and second elements (20,22) are mutually coupled together via a number of separate tie rods (40) fitted in between the elements (20,22). 0

12. Device according to claim 1 1 , characterised in that the anchoring construction is formed as given in the claims 2-10.

13. Device according to claims 1 1 -12, characterised in that the bridge is arranged in a straight line between the two arch shapes, in the shape of an arch5 or an S, along the anchoring construction (1 0) between the land on each side and is connected with associated pipes (20,22) with the help of cross-struts (72) each set up between the end of a pontoon (70) and the adjoining pipe arch (20,22).

14. Device according to any of claims 1 1 -1 3, characterised in that the arch- shaped pipes are held together and are fixed by both said tie rods (40) directly between the pipe arches (20,22) and said cross-struts (72) between the pontoon (70) and the pipe arch.

15. Device according to any of claims 1 1 -14, characterised in that said tie rods (40) directly between the pipe arches (20,22) are replaced by said cross- struts (72) between the pontoon (70) and the nearest pipe arch (20 and 22, respectively)

16. Device according to any of claims 1 1 -15, characterised in that the anchoring construction (10) is installed between the stretches of land at a lower depth below the surface of the water than the necessary shipping draught for ships passing the bridge cross-wise.

17. Device according to any of claims 1 1 -16, characterised in that the depth of installation of the construction is up to 30 meters below the surface of the water.