US20120076590A1

US20120076590A1 - Protective device of the floating barrier type

Info

Publication number: US20120076590A1
Application number: US13/237,227
Authority: US
Inventors: Jean BRUDER
Original assignee: ENTREPRISE DE TRAVAUX PUBLICS DE L'OUEST; BOLINA Ltd
Current assignee: ENTREPRISE DE TRAVAUX PUBLICS DE L'OUEST; BOLINA Ltd
Priority date: 2010-09-20
Filing date: 2011-09-20
Publication date: 2012-03-29
Also published as: EP2431530A1; FR2964989B1; FR2964989A1

Abstract

A protective device (1) of the “floating barrier” type for preventing a floating body from colliding with a construction includes a barrier element (2) consisting of a cable provided with floats (4), each of the two ends (2 a) of which cable is connected to a respective one of the posts (3), and at least one of which ends is connected to the respective one of the posts (3) via an energy-dissipation system (5). The energy-dissipation system (5) advantageously includes: at least one chain having a segment that is folded in half, being made up of links that are connected together in pairs by breakable ties; and at least one spring member.

Description

The present invention relates to a protective device of the “floating barrier” type for preventing a moving floating body or obstacle (in particular a watercraft or a vessel) from colliding with a construction in such a manner as to protect said construction from any impact.
Barriers having similar purposes have been put in place on canals or rivers, using jacks or anchor systems dragging on the water bottom. Such devices have operating constraints, high implementation costs, and technical limitations.
Similarly, a device for stopping submarines and torpedoes is described in Document U.S. Pat. No. 1,151,607.
That device includes, in particular, an outer defense structure comprising an immersed rigid barrier that is carried by buoys and that is secured between two posts via intermediate elements in the form of flexible ties.
That device aims to destroy the body that it is to be retained. It does not enable said body to be captured while also preserving its structural integrity (or at least while also limiting damage to it).
The present invention provides a novel structure for a protective device of the “floating barrier” type.
This protective device is of the type comprising a barrier element that is mounted between two anchoring piles or posts and that is associated with a plurality of floats floating on the surface of the water.
According to the invention, the barrier element comprises a cable provided with the floats; said cable has two ends, each of which is connected to a respective one of the posts; and at least one of said ends of the cable is connected to the respective one of said posts via an energy-dissipation system.
Such a protective device offers particularly effective absorption of the kinetic energy of a floating body, thereby protecting a construction particularly effectively from any impact by said floating body.
This protective device also makes it possible not to damage the retained floating body, e.g. the hull of a boat or of a ship, and to keep it afloat some distance away from the construction to be protected.
Advantageously, each of the two ends of the cable is connected to the respective one of the posts via an energy-dissipation system.
In a preferred embodiment, the or each of the energy-dissipation systems comprises i) at least one chain having a segment that is folded in half, being made up of links that are connected together in pairs by breakable ties; and ii) at least one spring member.
The spring member is suitable for being moved between a rest configuration and a deformed configuration; and said spring member is advantageously associated with means for delivering a braking force designed to limit the speed at which the spring member moves from said deformed configuration to said rest configuration.
This characteristic makes it possible to avoid the links of the chain moving at excessive speed that might generate a dynamic effect conducive to causing a plurality of breakable ties to break simultaneously.
The spring member then advantageously consists of a compression spring suitable for being moved in compression and in decompression; said spring member is encased in a casing enclosing a piston that is movable in translation and that is made up of a head and of a rod, so as to form a damper assembly comprising the casing, the piston, and the spring member; the casing and the piston head form two surfaces holding said spring member captive; and the casing and the piston rod are provided with respective fastening points enabling them to be connected to the cable, to the chain, or to the post, as applicable.
The casing is then advantageously filled with liquid, advantageously water; and the piston head is provided with openings enabling the liquid to flow through, so as to deliver a braking force during the movements in compression and in decompression.
In a preferred embodiment, the chain of the energy-dissipation system is interposed between two spring members.
A first damper assembly is then connected at one end to the cable and at the other end to the chain, and a second damper assembly is connected at one end to the post and at the other end to the chain.
Also in the preferred embodiment, the breakable ties are constituted by metal ties or by ties of the rope type, e.g. made of synthetic polymer.
According to another characteristic, the energy-dissipation system is advantageously connected to the post via a collar mounted to move in vertical translation along said post, in order to enable the cable to remain floating in the event that the level of the water varies.
The present invention also provides an energy-dissipation system comprising:

- at least one chain having a segment that is folded in half, being made up of links that are connected together in pairs by breakable ties; and
- at least one spring member.

The spring member is then suitable for being moved between a rest configuration and a deformed configuration; and said spring member is advantageously associated with means for delivering a braking force designed to limit the speed at which the spring member moves from said deformed configuration to said rest configuration.
The spring member then advantageously consists of a compression spring suitable for being moved in compression and in decompression; said spring member is encased in a casing enclosing a piston that is movable in translation and that is made up of a head and of a rod, so as to form a damper assembly comprising the casing, the piston, and the spring member; the casing and the piston head form two surfaces holding said spring captive; and the casing and the piston rod are provided with respective fastening points enabling them to be connected to the cable, to the chain, or to the pile, as applicable.
In a preferred embodiment, the casing is then filled with liquid, which is advantageously constituted by water, and the piston head is provided with openings enabling the liquid to flow through.
Also in a preferred embodiment, the chain of the energy-dissipation system is interposed between two spring members.

The present invention is further illustrated, in a manner that is in no way limiting, by the following description given with reference to the accompanying drawing, in which:

FIG. 1 is a general diagrammatic view of the protective device of the invention, in its context as a floating barrier;

FIG. 2 is a diagrammatic view of one of the energy-dissipation systems equipping the protective device shown in FIG. 1;

FIG. 3 is a diagrammatic view of one of the damper assemblies making up the energy-dissipation system shown in FIG. 2; and

FIG. 4 is an end-on detail view of the head of a piston that is movable in translation and that equips the damper assembly shown in FIG. 3.

The protective device 1 shown in FIG. 1 is of the “floating barrier” type.
The protective device 1 is designed to retain a moving floating body (not shown), e.g. a watercraft or vessel, so as to prevent that body from colliding with a construction (not shown). For example, it is designed to be installed across a river for the purpose of protecting a construction situated downstream from it.
Conversely, and advantageously, the protective device 1 allows floating obstructions to pass through it so that they do not form jams.
For this purpose, the protective device 1 of the invention includes a barrier element 2, constituted by a cable in this example, that is arranged, in this example, to form a barrier across a river C and to retain the moving floating body (not shown).
The cable 2 is mounted, advantageously in tensioned or semi-tensioned manner, between two piles or posts 3 for anchoring it at the river banks.
The cable 2 has two ends 2 a, each of which is connected to a respective one of the posts 3.
The cable 2 is advantageously designed to extend horizontally, or at least approximately horizontally, between the posts 3.
Each post 3 advantageously has a cross-section that is constant, or at least approximately constant, over its entire height. Each post 3 is anchored into the ground S.
The cable 2 is associated with a plurality of floats 4 floating on the surface of the water E.
The floats 4 are suitably distributed over the length of the associated cable 2.
In this example, the floats 4 are of cylindrical shape, and the associated cable 2 passes axially through each of them.
In order to absorb the kinetic energy of a floating body retained by the protective device 1, each of the ends 2 a of the cable 2 is connected to a respective one of the posts 4 via an energy-dissipation system 5.
Each energy-dissipation system 5 is thus interposed between a respective one of the ends 2 a of the cable 2 and a respective one of the posts 3.
One of the energy-dissipation systems 5 is described below with reference to FIG. 2.
This energy-dissipation system 5 comprises an energy-dissipation loop 6 that is interposed between two spring members 7.
The energy-dissipation loop 6 consists of a chain 8 having a segment folded in half (in the general shape of a U) and made up of a plurality of links 9 that are connected together in pairs by breakable ties 10.
The breakable ties 10 form “fuses”, each of which interconnects two spaced-apart links 9.
The length of a breakable tie 10 is less than the length of the chain 8 between the two associated links 9 so that, when the protective device 1 is subjected to a thrust force generated by the moving body that is to be stopped, the breakable tie 10 breaking (or at least deforming) absorbs at least a fraction of the energy generated by the moving body.
In order to limit dynamic effects that are described in more detail below, the breakable ties 10 are chosen to be made of a material having a certain amount of elasticity.
The breakable ties 10 are advantageously made of a metal material or of rope (e.g. rope made of synthetic polymer), having a predefined breaking strength.
In this example, each spring member 7 consists of a compression spring suitable for being moved in compression (from a rest configuration to a deformed configuration) and in decompression (from a deformed configuration to a rest configuration).
In this example, each spring member 7 is engaged in a device 12 in the form of a hydraulic jack (FIG. 3) designed to limit the speed of its movements in compression and in decompression.
As shown in FIG. 3, this device in the form of a jack 12 comprises a casing 13 defining an internal volume 14 enclosing the spring member 7, and a piston 15 that is movable in translation.
The spring member 7 associated with the casing 13 and with the piston 15 form an assembly 16 referred to below as a “damper assembly”.
In this example, the casing 13 consists of a cylindrical tube, so that the internal volume 14 is also of generally cylindrical shape.
The piston 15 that is movable in translation is made up of:

- a disk-shaped head 15 a subdividing the internal volume 14 into two chambers 14 a and 14 b, a first chamber 14 a of which contains the spring member 7; and of
- a rod 15 b passing axially through the spring member 7 and said first chamber 14 a.

The piston 15 is mounted to move in translation inside the internal volume 14 and over its length.
The casing 13 and the piston head 15 a form two facing surfaces defining the first chamber 14 a and for holding the spring 7 captive, which faces are designated respectively by references 17 and 18 in FIG. 3.
In order to brake the movements in compression and in decompression of the spring member 7, the internal volume 14 of the casing 13 is filled with a liquid, which is advantageously constituted by water.
In addition, the piston head 15 a, against which one of the ends of the spring member 7 bears, is provided with through openings 19 (FIG. 4) allowing the liquid to pass through and to flow between the two chambers 14 a and 14 b.
Thus, the piston 15 that is movable in translation creates two chambers 14 a and 14 b between which liquid flows while its head 15 a is moving in translation. This liquid flow delivers a braking force that limits, in particular, the speed of the movement of the spring member 7 in decompression.
Finally, the casing 13 and the rod 15 b of the piston 15 that is movable in translation are provided with respective fastening points, referenced respectively 20 and 21 in FIG. 3, enabling them to be connected to the cable 2, to the chain 8, or to the pile 3, as applicable.
These two fastening points 20 and 21 are advantageously opposite from each other axially/longitudinally.
Thus, in each energy-dissipation system 5, an “inner” first damper assembly 16 (remote from the pile 3) is mounted so that:

- the fastening point 20 of its casing 13 is connected to the cable 2; and
- the fastening point 21 of the rod 15 b of its piston 15 is connected to the chain 8.

An “outer” second damper assembly 16 (in the vicinity of the pile 3) is mounted so that:

- the fastening point 20 of its casing 13 is connected to the chain 8; and
- the fastening point 21 of the rod 15 b of its piston 15 is connected to the pile 3.

In an alternative embodiment, the inner damper assembly 16 and/or the outer damper assembly 16 is/are mounted so that the fastening points 20 and 21 are secured the other way round from the configuration described above.
In an embodiment (not shown), the spring member or each of the spring members may equally well consist of a traction spring.
The traction spring may be incorporated into a device in the form of a jack as described above with reference to FIG. 3, in order to deliver a braking force that limits, in particular, the speed of movement from the lengthened deformed configuration to the rest configuration.
In this example, the coupling to each anchoring post 3 is via a sliding collar 25 (FIG. 1) suitable for travelling over the height of the associated post 3.
This characteristic enables the cable 2 with floats 4 to float continuously on the surface of the water E or just beneath the surface of the water E, regardless of the variations in the level of the surface of the water E.
In operation, when a floating body reaches the protective device 1 it exerts a thrust force on its cable 2.
The force of the moving body is transmitted from the cable 2 to the energy-dissipation systems 5.
Firstly, the work delivered by the spring members 7 being moved in compression absorbs a fraction of the kinetic energy of the floating body to be stopped.
This movement in compression is obtained by the surfaces 17 and 18 that hold the spring member 7 captive moving closer together.
Since the spring members 7 have strokes that are limited compared with the stopping distance of the floating body, the energy-dissipation loops 6 enable the cable 2 between the posts 3 to lengthen progressively, and they participate in dissipating the kinetic energy progressively.
For this purpose, when the spring members 7 come to the end of their movement in compression, continued traction on the energy-dissipation systems 5 causes one of their breakable ties 10 to break, thereby releasing a length enabling the spring members 7 to move in decompression.
The breakable ties 10 thus absorb a fraction of the kinetic energy of the moving body, so as to slow it down.
Advantageously, the speed of movement in decompression of the spring members 7 should not be excessive, in particular in order to avoid the speed at which the links 9 of the chain 8 are bust apart generating a dynamic effect leading to a plurality of successive breakable ties 10 all breaking simultaneously.
For this purpose, the movement of the spring members 7 is damped, in this example, by the flow of liquid through the orifices 19 in the associated piston head 15 a.
Once the movement in decompression is finished, the spring members 7 can start to move in compression again due to the continued thrust on the cable 2, possibly accompanied by another breakable tie 10 breaking, depending on the kinetic energy remaining to be dissipated.
Movements in compression and in decompression of the spring members 7, which movements being separated by the breaking of successive breakable ties 10, are repeated until the floating body stops.
The floating body is thus stopped, advantageously without suffering any damage, and with it being kept afloat some distance away from the construction.
Merely by way of example, the protective device 1 advantageously has the following characteristics:

- the anchoring posts 3 serving to retain the cable 2 withstand a horizontal force of about 100 metric tonnes (t);
- each of the spring members 7 has a weight of greater than 300 kilograms (kg) and a diameter of about 50 centimeters (cm), and presents a stroke of 24 cm for compression of 50 t;
- the chain 2 has a minimum breaking strength of 130 t;
- the breakable ties 10 have a minimum breaking strength of 50 t, and that strength should not exceed 70 t; and
- the cable 2 used has a minimum breaking strength of 200 t.

Claims

1. A protective device of the “floating barrier” type for preventing a floating body from colliding with a construction, which protective device (1) comprises a barrier element (2) that is mounted between two anchoring posts (3) and that is associated with a plurality of floats (4) designed to float on the surface of the water (E), said protective device being characterized in that said barrier element (2) comprises a cable provided with said floats (4), in that said cable (2) has two ends (2 a), each of which is connected to a respective one of said posts (3), and in that at least one of said ends (2 a) of said cable (2) is connected to the respective one of said posts (3) via an energy-dissipation system (5).

2. A protective device according to claim 1, characterized in that each of the two ends (2 a) of the cable (2) is connected to the respective one of the posts (3) via an energy-dissipation system (5).

3. A protective device according to claim 1, characterized in that each of the energy-dissipation systems (5) comprises:

at least one chain (8) having a segment that is folded in half, being made up of links (9) that are connected together in pairs by breakable ties (10); and

at least one spring member (7).

4. A protective device according to claim 3, characterized in that the spring member (7) is suitable for being moved between a rest configuration and a deformed configuration, and in that said spring member (7) is associated with means (12, 13, 14, 15) for delivering a braking force designed to limit the speed at which the spring member moves from said deformed configuration to said rest configuration.

5. A protective device according to claim 4, characterized in that the spring member (7) consists of a compression spring suitable for being moved in compression and in decompression, in that said spring member (7) is encased in a casing (13) enclosing a piston (15) that is movable in translation and that is made up of a head (15 a) and of a rod (15 b), so as to form a damper assembly (16) comprising said casing (13), said piston (15) that is movable in translation, and said spring member (7), which casing (13) and which piston head (15 a) form two surfaces (17, 18) holding said spring member (7) captive, and which casing (13) and which piston rod (15 b) are provided with respective fastening points (20, 21) enabling them to be connected to the cable (2), to the chain (8), or to the pile (3), as applicable.

6. A protective device according to claim 5, characterized in that the casing (13) is filled with liquid, and in that the piston head (15 a) is provided with openings (19) enabling the liquid to flow through.

7. A protective device according to claim 5, characterized in that the chain (8) of the energy-dissipation system (5) is interposed between two spring members (7).

8. A protective device according to claim 7, characterized in that a first damper assembly (16) is connected at one end to the cable (2) and at the other end to the chain (8), and in that a second damper assembly (16) is connected at one end to the post (3) and at the other end to the chain (8).

9. A protective device according to claim 3, characterized in that the breakable ties (10) are constituted by metal ties or by rope ties.

10. A protective device according to claim 1, characterized in that the energy-dissipation system (5) is connected to the post (3) via a collar (25) mounted to move in vertical translation along said post (3), in order to enable the cable (2) to remain floating in the event that the level of the water (E) varies.

11. An energy-dissipation system for a protective device according to claim 1, comprising:

at least one spring member (7).

12. An energy-dissipation system according to claim 11, characterized in that the spring member (7) is suitable for being moved between a rest configuration and a deformed configuration, and in that said spring member (7) is associated with means (12, 13, 14, 15) for delivering a braking force designed to limit the speed at which the spring member moves from said deformed configuration to said rest configuration.

13. An energy-dissipation system according to claim 12, characterized in that the spring member (7) consists of a compression spring suitable for being moved in compression and in decompression, and in that said spring member (7) is encased in a casing (13) enclosing a piston (15) that is movable in translation and that is made up of a head (15 a) and of a rod (15 b), so as to form a damper assembly (16) comprising said casing (13), said piston (15) that is movable in translation, and said spring member (7), which casing (13) and which piston head (15 a) form two surfaces (17, 18) holding said spring (7) captive, and which casing (13) and which piston rod (15 b) are provided with respective fastening points (20, 21) enabling them to be connected to the cable (2), to the chain (8), or to the post (3), as applicable.

14. An energy-dissipation system according to claim 13, characterized in that the casing (13) is filled with liquid, and in that the piston head (15 a) is provided with openings (19) enabling the liquid to flow through.

15. An energy-dissipation system according to claim 11, characterized in that the chain (8) of the energy-dissipation system (5) is interposed between two spring members (7).

16. A protective device according to claim 2, characterized in that each of the energy-dissipation systems (5) comprises:

at least one spring member (7).

17. A protective device according to claim 3, characterized in that the chain (8) of the energy-dissipation system (5) is interposed between two spring members (7).