FR2831192A1 - Boat arrester cable protecting fixed installations is made from synthetic material with very high resistance to traction - Google Patents

Abstract

The arrester cable consists of a flexible cable (122) deployed across a waterway (114) and connected at each end to an anchor (136, 137) on the bed of the waterway and a buoy (124, 125). Each buoy is attached to fixed lateral retaining points (126a, 126b; 127a, 127b) by V-shaped mooring lines (128a, 128b; 129a, 129b) of reduced resistance. The arrester cable is pre-tensioned by an elastic traction assembly (148, 149) in each of the forward mooring lines. A craft under way encountering the cable causes the mooring lines to break and is held by the arrester cable and anchors.

Description

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INSTALLATION FOR STOPPING PRE-TENTED CABLE BOATS
AND PRE-TENSIONING DEVICES FOR SECURITY CABLES
TECHNICAL FIELD The present invention relates to safety installations of the type comprising a safety cable arranged across a waterway so as to ensure the stopping of boats, including barges, barges, barges, convoys, etc., before these do not collide with engineering structures, such as dams, bridges, docks, port facilities, etc. located downstream.

The invention is also applicable to the production of pre-tensioning devices for safety cables intended to stop people or / moving objects.

 PRIOR ART The French patent published under the number FR 2.580. 691 in the name of the applicant describes an installation for stopping boats comprising a flexible stop cable arranged across all or part of a waterway and connected at each end to anchoring means arranged at the bottom of the track navigable and to a floating trunk itself attached to a lateral fixed point of retention by a connection assembly of less resistance, the installation being adapted, once the boat is caught in the stop cable and the rupture of the connection assemblies , to stop the boat using the anchoring means. The stop cable is made of steel and the anchoring means consist of a concrete dead body securely connected to the floating box by a mother chain and a set of anchors and chains attached to the dead body, the rupture of the connection assemblies following the impact or the impact with the boat releasing the cable end boxes so as to drag on the bottom of the body

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 dead, chains and anchors to absorb the kinetic energy of the boat and stop it.

The installation is replaced with replacement on the bottom of the dead bodies, chains and / or displaced anchors and replacement of the loosening and / or breaking elements of the connection assemblies (elements commonly called fuses).

If the installation presented above gives good results from the point of view of safety and stopping of boats in difficulty, its maintenance is delicate because of the floating objects likely to get caught in the stop cable and the holding floats. out of the water, especially during periods of flood during which we meet large floating objects such as branches and tree trunks. In particular in existing installations, the steel stop cable is hung on its end boxes about 1 meter above the water, however the vertical deflection due to the linear self-weight of the steel cable requires the installation of small intermediate floats (one float every 10 meters for a cable with a total length around 100 meters) to keep the vertical boom within 0.2 meters and the cable around a height of 0.6 meters from the water surface (the height necessary for a good grip of the boats by the stop cable).

This problem of involuntary recovery of floating objects is complicated and amplified by the relative displacements of the safes (and the resulting variations in tension of the stop cable) i) as a function of the water level of the waterway between the periods of floods and periods of unemployment (or emptying of the diversion bays), the sets of connections being of fixed length and ii) according to the current (a sufficiently strong current

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 being likely to create by spacing the floats a horizontal arrow having the consequence of raising the cable, conversely a weak current causes the approximation of the floats and the increase of the vertical arrow between floats). The relative movements of the boxes result in non-compliance with the minimum height of the stop cable of 0.6 meters.

 It also results from the above an almost permanent maintenance often delicate and sometimes dangerous in times of strong currents. To avoid inadvertent tripping of the security installation, hooks are releasable at the cable / boot attachment points and controlled remotely. This improvement does not, however, solve the problem of floating objects caught in the cable or that of the variations in the height of the cable relative to the water surface, consequences of variations in the force of the current and / or variations in height. water from the waterway.

 SUMMARY OF THE INVENTION It follows from the above that there is a need for a new installation for stopping boats with flexible stop cables which improves the maintenance of the cable at an adequate height above the water level. so as to eliminate or significantly reduce the limitations and other disadvantages presented above for existing installations.

To this end, the invention provides an installation for stopping boats with flexible stopping cables arranged across all or part of a waterway and connected at each end to anchoring means arranged at the bottom of the track. navigable and to a floating trunk itself attached to at least one lateral fixed point of restraint

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 by a connection assembly of lower resistance, the installation being adapted, once the boat caught in the stop cable and the rupture of the connection assemblies, to stop the boat using the anchoring means, the installation being characterized in that the stop cable is mainly made of synthetic material of very high tensile strength and in that the cable is pre-tensioned by at least one elastic traction assembly at a tension significantly lower than the value loosening and / or rupture of the connecting assemblies.

Thus the reduction in the linear gravity mass of the cable material (approximately 4 to 5 times compared to a steel cable) makes it possible to reduce the tension on the cable correspondingly to the height of the substantially equal arrow. It becomes, in these conditions, possible to give a pre-tension to the stop cable, without risking a release of loosening or a rupture of the connection assemblies, to put the cable at the right height out of water while reducing the number of floats and to absorb most of the pre-tension variations due to the relative movements of the boxes to keep the cable out of water at substantially the right height. This results in the reduction of the number of floats (3 floats instead of 10) and the keeping of the cable out at sufficient height with a significant reduction in the catch of floats whatever the current and water level conditions. of the waterway.

According to a first variant of the installation according to the invention, the stop cable is made of aramid and is optionally covered with a polyester sheath.

The choice of aramid for the cable (aromatic polyamide) is all the more advantageous when, in addition to a specific resistance in exceptional traction

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 (approximately 300 MPa with a longitudinal Young's modulus between 70 and 130 GPa) this fiber has a relatively low density (1.450 kg / m3).

It should also be noted that the modifications made in the invention with respect to the known installation of the prior art presented above in no way alter the ability of the new installation to stop boats, or even improve this function by allowing the cable to be positioned at the right height permanently. In addition, these technical modifications do not fundamentally change the overall structure of the safety installation and are relatively easy to perform, which allows replacement mounting of the cable and the connection assemblies without having to touch or move the elements. the heaviest in the installation such as dead bodies, chains and anchors.

According to a first embodiment of the installation according to the invention, each connection assembly comprises two moorings arranged in a V relative to the boot, the branches of the V being connected together by said elastic traction assembly arranged in the intermediate position. This embodiment, although simple in appearance, proves to be very effective in keeping the safes in place despite variations in the height of the water in the waterway.

Advantageously, each mooring comprises a portion of high strength and a portion of least resistance provided with a breaking assembly, the junction points between the portions of the moorings also serving as attachment points for said elastic traction assembly.

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 Equally advantageously, the portions of least resistance are each equipped with a mechanical tensioner for adjusting the length of the mooring lines, which facilitates the balancing of the connecting assemblies.

According to a particular variant of the installation according to the invention, the high strength portions are intended to be fixed to said fixed retaining points and in that the weakest portions are intended to be fixed to two attachment points on the corresponding trunk whose distance is substantially equal to the length of initial adjustment of the elastic traction assembly.

According to yet another particular variant of the installation according to the invention, the elastic traction assembly is produced by a tensioner of the type consisting of one or more bundles of elastomeric strands wrapped in a protective polyester sheath.

The invention also relates to a connection and pre-tensioning assembly with elastic traction assembly, whether or not mounted on a floating trunk, for installation for stopping boats according to the invention presented above and / or a replacement kit. consisting of a stopper cable made of synthetic material, preferably aramid, and two connection and pretensioning assemblies.

The invention can be simplified and applied to the production of a safety cable pre-tensioning device in synthetic material, characterized in that it comprises a connection assembly comprising two attachment links arranged in a V relative to each end of the cable, the branches of the V being connected together by an elastic traction assembly arranged in an intermediate position.

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A simple and effective device is thus obtained, of easy adjustment and well suited for laying temporary or permanent safety cables over relatively long lengths, exceeding 100 meters.

Advantageously, the two attachment links and the corresponding end of the cable are respectively fixed to the three vertices of a triangular spacer frame. In addition, the attachment links are equipped with mechanical tensioners for adjusting the length of the links to facilitate assembly and pre-tensioning of the cable.

Similarly optionally to improve the security provided by the cable depending on its use, each attachment link includes a portion of high resistance and a portion of lower resistance provided with a break or loosening assembly, the points of junction between the portions of the attachment links also serving as attachment points for said elastic traction assembly.

Other characteristics and advantages of the present invention will appear on reading the following description, by way of nonlimiting example, of a preferred embodiment of the invention of an installation for stopping boats in reference to the attached drawings.

 SUMMARY PRESENTATION OF THE DRAWINGS - Figure 1 shows a plan view of a safety installation for stopping boats according to the invention; - Figure 2 shows an enlarged longitudinal sectional view of the front of the convoy retained by the safety installation of Figure 1;

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 - Figure 3 shows an enlarged plan view of the cable and its connection assemblies used in the installation of Figure 1; - Figure 4 shows an enlarged plan view of a connecting half-assembly illustrated in Figure 3; and FIGS. 5a-5b, 6a-6b and 7a-7b show schematic representations of the elevation views and the corresponding plan views of a connection assembly used in the installation of FIG. 1 for three distinct levels of height d water from the waterway.

 BEST MODE FOR CARRYING OUT THE INVENTION By way of nonlimiting example, FIG. 1 represents a schematic plan view of a portion of waterway in which a lock head 10, 10 ′ separates the channel 12 leading to a lock (not shown) of a diversion channel 14 leading to a dam 16 extending through the channel 14 substantially between the head 10 and the bank 18 of the waterway. Upstream of the dam 16 (the direction of the current being represented by the arrow F) and across the channel 14 is arranged a safety installation for stopping the boats 20 according to the invention in order to protect the dam 16 downstream from the security facility 20 and boats. The term boats must be taken in its broadest sense and includes in particular any floating load or working machine such as barges, freighters, barges, ferries, barges, pontoons, ferries, etc. In this case Figure 1 shows a convoy in difficulty 21 consisting of a pusher 21a and a barge 21b and which, following a false maneuver or an engine failure, is in the channel 14 driven towards the dam 16.

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The safety installation mainly consists of a stop or guard cable 22 stretched across the channel 14 between two floating boxes 24 and 25 each attached to two fixed lateral retaining points 26-26 'and 27-27' respectively situated on the ground on the wall 10 ′ of the head or at the edge of the bank 18 by means of connection assemblies 28 and 29, the ends of the cable 22 being securely attached to anchoring means 30 and 31 disposed at the bottom 13 of the waterway.

More particularly, each end of the cable 22 is attached to the upper end of an axial tubular connecting spacer 41.61 (shown in FIGS. 2 and 3) passing through the corresponding trunk 24.25, the lower end of each tubular spacer being connected by a mother chain 32 (33) to anchoring means, in this case adapted to rocky bottoms, and comprising a dead concrete body 34 (35) to which is secured a bundle of large chains 36 (37 ) welded at their free ends to anchor sleepers 38 (39). In a variant (not shown) the anchoring means are adapted to muddy or sandy bottoms and each comprise a dead body made of concrete secured to a plurality of independent chains each carrying an anchor adapted to movable bottoms, for example a flat anchor.

According to one of the characteristics of the present invention, the cable 22 is made of aramid fibers, an aromatic polyamide of very high tensile strength. The aramid cable is advantageously mechanically protected and against UV radiation by a polyester sheath. Due to its relatively low linear mass, the cable 22 can be stretched over water at an average height of 0.6 meters using the pre-tensioning connection assemblies 28 and 29 described below and with a reduced number by floats

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 intermediaries 40, in this case two distant floats one, the other of about 30 meters.

FIG. 1 also illustrates the operating mode of the safety installation 20 by schematically showing two positions of the convoy 21, the first furthest to the right by looking at FIG. 1 (references in 'for the displaced elements) shows the end of the tensioning phase of the energy absorption installation (the anchoring means) under the effect of the advancement of the barge 21a with the deformation of the stop cable to take the form 22 ', the safes 24 'and 25' released from their connection assemblies allowing the direct transmission of the tensile forces of the stop cable to the dead bodies 32,33. The second position of the convoy (references in `` for the displaced elements) shows the latter in position 21 '' stopped by the cable 22 '', the trunks 24 '' and 25 '', the dead bodies 34 '' and 35 ' ', anchor chains 36' 'and 37' 'and anchor cross members 38' 'and 39' ', these latter elements having skidded on the bottom to absorb the kinetic energy of the convoy.

FIG. 2 illustrates the front of the convoy 21 '' (seen from the bank 18) in its stopped position with the cable 22 "out of water around the bow of the barge 21a '' (references 15, 15 ', 15' 'indistinguishable at three different heights the water level, the surface of the water body or the water line along the banks of the waterway), the intermediate float 40 ", the trunk 25 ", the main chain 33 stretched, the dead body 35", the bundle of chains 37 '' and the anchor cross member 39 '', these last three components constituting the anchoring means having dragged on the bottom 13. The reader may refer to French patent FR 2,580. 691 to obtain additional general information on mode operation

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   safety of this type of installation for stopping boats.

FIG. 3 shows an enlarged plan view of the cable 22 (without the floats 40) and of its connection assemblies 28 and 29. Each connection assembly 28, 29 has two moorings 28a-28b, 29a-29b arranged in V with respect to to the corresponding safe 24.25.

As shown in FIG. 4 representing an enlarged view of a mooring line (for example the mooring line 28b), each mooring line comprises a portion of high resistance 44b such as a mooring chain and a portion of lower resistance 46b carrying a breaking fuse 48b (in this case a cable calibrated for a given breaking voltage, for example 10,000 kg) and optionally a mechanical screw tensioner 52b capable of withstanding the breaking voltage of fuse 48b. The two portions 44b and 46b are connected to a triangular junction plate 50b, the last free vertex of which serves as an attachment point for one of the ends of the elastic traction assembly 42 disposed between the branches of the moorings 28a and 28b. Finally, the other end of the portion 28b is connected to the fixed point of retention 26b on the head 10, while the other end of the portion 46b is connected to a fastening tab 54b provided at the periphery of the trunk 24. As illustrated in Figure 3, each box has two legs 54a-54b and 55a-55b distant, in this case, about 2 meters.

Incidentally, part 44b carries a fuse 56b said to be loose, since the breaking of this fuse 56b calibrated for a lower voltage (for example 7,000 kg) than that of the breaking fuse 48b makes it possible to release a chain loop 64b (see the detail of FIG. 4) connecting the chain 44b to the plate 50b to release a little tension on the cable 22 in particular by

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 ice jams during flood periods. On the other hand, in the event of impact or impact with a boat in difficulty (see Figures 1 and 2), these are the four rupture fuses 48 which release releasing the safes 24 and 25 from their fixed retention points 26a-26b, 27a- 27b. It should also be noted that the cable 22 is equipped at the level of the trunk 24 with a release hook 62 controlled remotely.

Each elastic traction assembly mainly consists of a 42.43 tensioner of the SEAFLEX type from the Swedish company ANCRO MARIN AB made from one or more bundles of SBR rubber elastomer strands wrapped in a protective polyester sheath. These tensioners are capable of elastic elongation before rupture greater than 200%.

Each tensioner 42 (43) develops a tensile force by contraction tending to bring its free ends and the plates 50a-50b (5la-51b) to which they are attached. This has the effect of urging each trunk 24.25 towards its attachment edge 10.18 and of spreading them apart, and of putting the cable 22 under tension.

As can be seen in FIG. 3 corresponding to a normal situation of the installation 22 for an average low water level, the mounting of the cable part of the safety installation 20 is balanced substantially symmetrically with respect to the cable 22 so that the tensioners 42 and 43 are arranged substantially perpendicular to the cable and to the portions of least resistance 46a-46b, 47a-47b of the moorings (the useful length of the tensioners 42,43 and the junction plates 50a, 50b then being substantially equal to the distance between fastening tabs 54a-54b, 55a-55b on the boxes 24,25). The dimensions of the various components of the connection assemblies 28 and 29 are

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 such that for an average low water level of the waterway, the tensioners 42,43 are already stressed in tension so as to give the aramid cable 22 a pre-tension of the order of 1,000 to 1,500 kg (significantly lower than the breaking or loosening voltages of the corresponding fuses) ensuring that the cable 22 is kept at a good height relative to the water level.

Incidentally during assembly it is possible to measure the actual tension on the cable 22 with a dynamometer and to adjust this tension by acting on the mechanical tensioners 52a-52b and 53a-53b.

It should be noted that the operation in safety mode of the installation 20 is not disturbed by the relatively weak pre-tensioning of the cable 22 and conversely that the pre-tensioning device is not damaged by an impact of broken and can be replaced easily after replacing the fuses.

Among the advantages conferred by the introduction of the pre-tensioning device, it is noted that the cable remains stretched in a rectilinear manner whatever the speed of the current, the permanent pre-tension generated by the tensioners 42,43 easily countering the force. due to the current acting on the chests.

Furthermore, the pre-tensioning devices with variable geometry of the connection assemblies 28, 29 allow elastic deformation of the mooring of the safes 24 and 25 without appreciable lateral displacement for the latter despite the variations in the heights of water in the waterway. 14, as shown in FIGS. 5a-5b, 6a-6b and 7a-7b respectively representing the situations of average low water level 15, water level of high flood 15 'and water level of unemployment (emptying of the waterway) 15 ". Examination of

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 moorings shows that compared to the average low water situation (figures 5a-5b), the effective length of the moorings tends to lengthen to arrive at a position where the portions 44 and 46 come in alignment (figures 7a-7b) . This results in an elongation of the tensioners 42,43 (within acceptable limits) and an increase in the pre-tension acting on the boxes 24,25 so that the horizontal lateral position of the DL boxes is substantially invariable with the level of water in the waterway 14.

It is easily understood that the device for pre-tensioning the cable 22 illustrated in FIGS. 3 and 4 can be simplified for other uses, in particular the pre-tensioning of safety cables made of synthetic material by replacing the boxes 24.25 with triangular frames. spacing 124 and 125 (shown in dashes in Figure 3) or by directly connecting the mooring lines at the ends 41 and 43 of the cable; the triangular frame solution 124 (125) to the tops of which are attached two attachment links (replacing the mooring lines 28a-28b, 29a-29b) and the corresponding end of the cable facilitating the mounting and adjustment of the tensioners.

Of course, the above description is given only by way of nonlimiting examples and may be subject to modifications without departing from the scope of the invention defined by the claims below.

Claims (13)

CLAIMS: 1. Installation (20) for stopping boats comprising a flexible stop cable (22) placed across all or part of a waterway (14) and connected at each end to anchoring means (36,37) arranged at the bottom (13) of the waterway and to a floating trunk (24,25) itself attached to at least one lateral fixed point of restraint (26a-26b, 27a-27b) by a set of lower resistance connection (28,29), the installation (20) being adapted, once the boat (21) caught in the stop cable and the rupture of the connection assemblies (28,29), to stop the boat (21) using the anchoring means (36,37), characterized in that the stop cable (22) is mainly made of synthetic material of very high tensile strength and in that the cable (22) is pre-tensioned by at least one elastic traction assembly (42,43) at a tension clearly lower than the release and / or rupture value of the sets connecting wheat (28,29). 2. Installation according to claim 1, characterized in that the stop cable (22) is made of aramid and is optionally covered with a polyester sheath. 3. Installation according to one of the preceding claims, characterized in that each connection assembly (28,29) comprises two moorings (28a-28b, 29a-29b) arranged in V relative to the trunk (24,25), the branches of the V being interconnected by said elastic traction assembly (42,43) disposed in an intermediate position. 4. Installation according to claim 3, characterized in that each mooring (28b) comprises a portion of <Desc / Clms Page number 16>  high resistance (44b) and a portion of lower resistance (46b) provided with a rupture assembly (48b), the junction elements (50b) between the portions of the moorings also serving as attachment points for said elastic traction assembly (42). 5. Installation according to claim 4, characterized in that the portions of least resistance (46b) are each equipped with a mechanical tensioner (52b) for adjusting the length of the moorings. 6. Installation according to one of claims 3 to 5 characterized in that the high resistance portions (44b) are intended to be fixed to said fixed lateral retention points (26b) and in that the portions of less resistance (46b) are intended to be fixed to two attachment points (54a, 54b) on the corresponding trunk (24) distant by a distance substantially equal to the length of initial adjustment of the elastic traction assembly (42). 7. Installation according to one of the preceding claims, characterized in that each elastic traction assembly (42,43) consists of one or more bundles of elastomeric elongated strands wrapped in a protective polyester sheath. 8. Connection (28,29) and pre-tensioning assembly with elastic traction assembly (42,43), whether or not mounted on a floating box, for installation for stopping boats comprising a stop cable (22) made of material synthetic according to one of claims 1 to 7, characterized in that it comprises two moorings (28a-28b, 29a-29b) arranged in V with respect to each end of the cable, the branches of the V being connected together by a elastic traction assembly (42,43) disposed in an intermediate position. <Desc / Clms Page number 17>  9. Connection assembly (28,29) and pre-tensioning with elastic traction assembly (42,43) according to claim 8, characterized in that the two moorings (28a-28b, 29a-29b) and the end corresponding cable stop (22) are respectively fixed to a floating box (24,25). 10. Connection assembly (28,29) and pre-tensioning with elastic traction assembly (42,43) according to claim 8, characterized in that the two moorings (28a-28b, 29a-29b) and the end corresponding stop cable (22) are respectively fixed to the three vertices of a triangular spacer frame (124,125).  11. Connection assembly (28,29) and pre-tensioning with elastic traction assembly (42,43), according to one of claims 8 to 10, characterized in that each mooring (28b) has a portion of high resistance (44b) and a portion of lesser resistance (46b) provided with a breaking (48b) or loosening assembly, the junction elements between the portions of the moorings also serving as attachment points for said elastic traction assembly ( 42,43). 12. Connection assembly (28,29) and pre-tensioning with elastic traction assembly (42,43), according to one of claims 8 to 11, characterized in that the moorings (28a-28b, 29a-29b ) are each equipped with a mechanical tensioner (52b) for adjusting the length of the mooring lines and the cable (22). 13. Connection assembly (28,29) and pre-tensioning with elastic traction assembly (42,43), according to one of claims 8 to 12, characterized in that each elastic traction assembly (42,43) consists of one or more bundles of elastomeric strands wrapped in a protective polyester sheath.