Classifications

• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B1/00—Constructional features of ropes or cables
  • D07B1/16—Ropes or cables with an enveloping sheathing or inlays of rubber or plastics
  • D07B1/162—Ropes or cables with an enveloping sheathing or inlays of rubber or plastics characterised by a plastic or rubber enveloping sheathing
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B5/00—Making ropes or cables from special materials or of particular form
  • D07B5/002—Making parallel wire strands
• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
  • E01D19/00—Structural or constructional details of bridges
  • E01D19/16—Suspension cables; Cable clamps for suspension cables ; Pre- or post-stressed cables
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2201/00—Ropes or cables
  • D07B2201/20—Rope or cable components
  • D07B2201/2071—Spacers
  • D07B2201/2074—Spacers in radial direction

Definitions

• the present invention relates to a sheath for a cable composed of several independent strands, as well as a shroud comprising such a sheath.
• One field of application of the present invention is the construction of cable-stayed bridges and, more generally, the construction of any structure in which guy cables or other cables are provided to maintain, suspend or consolidate part of the work.
• the strands of a stay cable must be strictly parallel in the current part of the cable, that is to say in the part located between its two anchoring points. Indeed, entanglement of the strands would not ensure equal tension in the strands and could cause wear by small alternating movements, what those skilled in the art call "fretting corrosion" between the strands that cross. This is why all the known methods of fitting a stay cable composed of several independent strands offer various means for ensuring good storage of the strands of the cable inside the sheath.
• a first known technique in which, here again, the strands of the cable are successively pushed into the sheath, consists in using an element called "shell" which is fixed to the front end of the pushed strand. Thanks to its shape, the shell prevents the pushed strand from rotating around the strands already placed in the sheath.
• stay cables on a bridge are generally identical, in the sense that, apart from the fact that they do not have the same length, the number of strands can vary from cable stay cable to l 'other, therefore also the diameter of the cable sheath
• bare strands are used, that is to say without individual sheath.
• corrosion corrosion by humidity and / or "fretting corrosion"
• This filling material is or was usually a cement grout, a wax, a grease, petroleum jelly or a pitch-epoxy resin. Again, the injection of the filling material poses various problems to the point that the use of cement grout has been abandoned. As for the other fillers mentioned above, not only must they be heated to make them fluid, but also their implementation is difficult and / or delicate, in particular because of the risks, in cold weather, of creating plugs of frozen material which prevent a good filling of all the empty spaces, or because of their toxicity. In addition, the fact that these materials are injected hot, they induce in the outer tubular envelope, thermal stresses to which are added mechanical stresses due to dynamic pressure and / or hydrostatic pressure, in particular for the shrouds of great length and great difference in height between their two anchors.
• a sheath for a cable in particular a stay cable composed of several independent strands, of the type comprising an outer tubular envelope in one or more parts, which contains, in its internal volume, guide channels which extend from one end to the other of the sheath and which are at least equal in number to that of the strands of the cable intended to be housed in the sheath.
• a known sheath is used in the guy cable system 200 SSI from the company VSL, Lyssach. Swiss. This known system was used in particular for the construction of the BATAM-TONTON bridge in Singapore.
• each strand is greased and individually provided with an extruded plastic sheath which closely surrounds the greased strand.
• the guide channels of the individual strands are circular section tubes of HDPE (high density polyethylene) which extend continuously from one anchorage to the other of the stay so as to form, with the individual sheath of each greased strand and with the outer tubular casing common to all the strands of the stay cable, multi-layer anti-corrosion protection.
• No filler or corrosion protection agent is injected into the voids between the outer tubular casing and the guide tubes of the strands, neither between the guide tubes themselves, nor between each guide tube and the individual sheath of the sheathed strand housed in said tube.
• the present invention therefore aims to provide a sheath of the above-mentioned type, with several guide channels, which can be used with galvanized or bare strands, that is to say not individually sheathed, while ensuring parallelism rigorous said strands and allowing effective anti-corrosion protection thereof by injecting an appropriate filling material into all the empty spaces inside the outer tubular casing of the sheath after installation of a multi-strand cable in it.
• the sheath according to the invention is characterized in that said channels constitute a coherent beam in which the channels are arranged parallel to each other in an arrangement forming a mesh network, and in that said beam consists of a succession of beam segments which are kept spaced apart longitudinally from one another with an interval between a few millimeters and a few tens of centimeters, and whose individual homologous channels are kept aligned with respect to each other. Under these conditions, the parallelism of the strands is ensured by the coherence of the beam.
• said anti-corrosion material or agent can penetrate in all the empty spaces inside said outer tubular envelope and said guide channels thanks to the presence of the intervals between the successive segments of the channel bundle, thus ensuring good protection of the bare strands against corrosion.
• each segment of the bundle can be composed of several tubes of equal length, which have a relatively thin wall compared to that of the outer tubular envelope and which are assembled and linked together, by example by gluing, so as to form a bundle segment of parallel tubes.
• each segment of the bundle can be composed of several multichannel sections of equal length, which have a relatively thin wall compared to that of the tubular envelope. external, and which each comprise a number of channels equal to a fraction of the total number of channels of the beam, said multi-channel profiles being juxtaposed and linked together, for example by gluing to form the beam segment.
• each channel of the bundle has a hexagonal cross section, so that the bundle has, in cross section, a honeycomb shape.
• said outer tubular envelope may be composed, in a manner known per se, of a succession of tubes arranged and fixed to each other end to end.
• said bundle segments have a length corresponding to that of the tubes forming the outer tubular envelope or to a sub-multiple of that of the tubes forming said outer tubular envelope.
• the sheath according to the invention may also have the following characteristics: - at least two tubes, groups of tubes and / or multichannel profiles, spaced transversely from one another, of each beam segment are offset longitudinally with respect to the remaining multichannel tubes and / or sections of said beam segment such that each of said longitudinally offset multi-channel tubes, groups of tubes and / or sections has one end projecting from the corresponding end of the beam segment and an opposite end set back from the corresponding opposite end of the beam segment; each recessed end forms in the corresponding end of the bundle segment a cell capable of receiving by interlocking a projecting end of a tube, group of tubes and / or multi-channel profile of a bundle segment following or preceding in said succession beam segments,
• - Said beam has an outside diameter smaller than the inside diameter of said tubular envelope, and means are provided for centering at least approximately said beam in said external tubular envelope and providing an annular space between them, - said centering means are constituted by a wire helically surrounding the beam or each beam segment, - Said tubes, groups of tubes and / or multichannel profiles which are offset longitudinally with respect to the remaining multichannel tubes and / or profiles of each beam segment are located within the periphery of the mesh network formed by said channels; parts of the protruding ends of said tubes, groups of tubes and / or multichannel sections offset longitudinally, which cross each interval between two successive segments of the bundle, have openings putting the interior of the corresponding channels of the guide in communication with said interval,
• the invention also provides a stay comprising a cable composed of several independent strands housed in a sheath according to the invention, having one or more of the characteristics defined above, each strand of the cable being housed in a respective channel of said bundle of guide channels. .
• the sheath and its channels contain, as a corrosion protection agent, a filling material which is injected in the fluid state into the empty spaces between the outer tubular envelope of the sheath and its channels and between them and the strands of the cable,
• the corrosion protection agent is a composition based on monomer or prepolymer reagents capable of slowly polymerizing in situ, at room temperature, after injection into the sheath, in the presence of a solvent for swelling,
• FIG. 1 is a cross-sectional view of a sheath according to the present invention, the section being taken along line I-I of Figure 2;
• FIG. 2 is a longitudinal sectional view of part of the sheath of Figure 1. the section being taken along line II-II of Figure 1 and showing more particularly the region of the junction between two sheath segments ;
• FIGS. 3 and 4 are partial perspective views showing the two opposite ends of the same sheath segment
• Figures 5a to 5d are partial views in longitudinal section showing, on a smaller scale than Figure 2, how the assembly of two successive adjacent sheath segments is carried out;
• FIG. 6 and 7 are views corresponding respectively to Figures 3 and 4 and showing an alternative embodiment
• FIG. 8 is a cross-sectional view of a cable comprising several independent strands and provided with a sheath according to the invention.
• the sheath 1 which is shown in cross section in Figure 1 and in longitudinal section in Figure 2, essentially comprises an outer tubular casing 2 and a multi-channel guide 3 comprising a number of channels at least equal to the number of strands 4 (FIG. 8) of a cable with several independent strands, which is intended to be threaded into the sheath 1, at the rate of one strand 4 per channel of the guide 3.
• the guide 3 comprises fifty five channels, so that it can receive a cable comprising a maximum of fifty five strands 4 having for example seven wires each as shown in FIG. 8.
• the invention is not limited to a sheath whose guide 3 comprises such a number of channels, the number of channels of the guide 3 being determined as a function of the number of strands of the cable to be sheathed.
• the outer tubular casing 2 could be constituted by a continuous tube extending over the entire length of the cable to be sheathed, it is preferably constituted by a succession of tubes arranged and fixed to each other end to end. o end, such as for example the tubes 2i and 2j in FIG. 2. All the tubes making up the outer tubular casing 2 can for example be HDPE tubes and they preferably all have the same length, for example 12 m, with the exception of the last tube of the succession which can be cut to a shorter length if the length of the cable to be sheathed does not correspond to a multiple of the length of the individual tubes.
• the multichannel guide 3 constitutes a coherent bundle of channels in which the channels are arranged parallel to one another in an arrangement forming a mesh network.
• the coherent bundle of channels is constituted by a succession of bundle segments, like the segments 3i and 3j of FIG. 2, which are kept spaced apart longitudinally from one another with an interval e of between a few millimeters and a few tens of centimeters.
• the interval e can be between 5 mm and 50 cm, and it is preferably between 2 cm and 20 cm.
• the multi-channel guide 3 can be formed from separate elements and the beam segments of said succession of beam segments are spaced longitudinally apart from each other at a distance e, the individual homologous channels of said beam segments are kept aligned with each other in a manner which will now be described, so that each strand 4 of the cable can be threaded without snagging in the respective channel of the multichannel guide 3.
• Each segment 3i, 3j, ... of the multichannel guide may be composed of several tubes 5, for example fifty five tubes in the embodiment shown in the drawings, or of several multichannel profiles which each have a number of channels equal to one fraction of the total number of channels of the multichannel guide or bundle 3, or of a combination of individual tubes and multichannel profiles.
• the tubes 5 and / or the multi-channel profiles may for example be tubes or profiles in PNC having a relatively thin wall compared to that of the tubular casing 2, in order to minimize the diameter of the multi-channel guide 3, therefore also that of the outer tubular casing 2.
• the tubes 5 and / or the multi-channel profiles which are part of the same segment 3i or 3j of the multichannel guides all have the same length and they are assembled and linked together, for example by gluing, so as to form a bundle of tubes or channels having the form of a mesh network such as that shown in FIG. 1.
• each tube 5 and / or each channel of a multichannel profile has a hexagonal cross section, so that the multichannel bundle or guide 3 has, in cross section, a honeycomb shape.
• This hexagonal shape facilitates the positioning of the tubes and / or the multichannel profiles with respect to each other during their assembly in a bundle, and it makes it possible to minimize the empty spaces in the mesh network formed by the channels of the multichannel guide 3.
• each of said segments of the guide have a length corresponding to that of the tubes 2i, 2j forming the outer tubular envelope 2.
• the length of each tube 5 is slightly smaller, by a quantity a little greater than e, than the length of each tube 2i, 2j, ... so that, after assembly of successive tubes 2i and 2j in a manner which will be described later, there remains the interval e between two successive segments 3i and 3j of the guide 3.
• a convenient solution consists in longitudinally shifting at least two tubes 5 and / or multichannel profiles, spaced transversely from each other, of each segment 3i, 3j, ... relative to the tubes 5 and / or remaining multichannel profiles from said segment.
• three groups 5A, 5B and 5C of three tubes 5 each are offset longitudinally, by a quantity substantially greater than the interval e, compared to the remaining tubes 5 of the segment 3i or 3j considered.
• the tubes 5 or the groups 5A, 5B and 5C of tubes 5 which are offset longitudinally have one end 6A. 6B or 6C ( Figure 4) which protrudes relative to the corresponding end of the segment considered, for example segment 3i.
• the opposite end of the tubes 5 or groups 5A, 5B and 5C of tubes 5 which are longitudinally offset is set back with respect to the corresponding opposite end of the same segment 3i and defines a cell 7 A, 7B or 7C (FIG.
• Each segment 3i, 3j, ... of the multi-channel guide 3 preferably has an outside diameter smaller than the inside diameter of the tubes 2i, 2j, ... constituting
• the outer tubular casing 2 in order to facilitate the positioning of the said segments of the guide 3 in the said tubes of the outer tubular casing.
• Centering means are then provided to center at least approximately each segment
• the above-mentioned centering means may for example consist of a wire 8, metallic or made of plastic, helically surrounding each segment 3i, 3j, ... of the guide
• the diameter of the wire 8 is slightly smaller than the radial width of the annular space between the guide 3 and the outer tubular envelope 2.
• the manufacture of a sheath 1 according to the invention, for a given cable, for example a stay cable having a given number of independent strands and a given length, can be carried out in the following manner.
• the segments 3i, 3j, ... of the multichannel guide 3 are manufactured in a desired number, for example in the factory.
• Each segment is produced by assembling and fixing to each other, for example by gluing, the desired number of tubes 5 corresponding to the number of strands 4 of the cable.
• some of the tubes 5, such as groups 5A, 5B, and 5C of tubes 5, are fixed with a longitudinal offset with respect to the other tubes as indicated above.
• the wire 8 is then placed around each segment 3i, 3j, ...
• each segment lined with its wire 8 is threaded into a corresponding tube 2i, 2j, ... of the outer tubular casing 2.
• the tubes 2i, 2j, ... internally lined with their respective segment 3i, 3j, ... of the multi-channel guide 3 can be then delivered to the construction site of the structure and assembled to each other at this location, or they can be assembled and fixed to each other, also at the factory, then wound up in the form of a coil which is then delivered to the construction site.
• the assembly and fixing of the tubes 2i, 2j, ... internally lined with segments 3i, 3j .... of the multi-channel guide 3 can be carried out for example by a succession of operating steps such as those illustrated in FIGS. 5a to 5d.
• step 5a the projecting ends 6A, 6B and 6C of the guide segment 3j contained in the tube 2j are pre-glued and placed opposite the respective cells 7A. 7B and 7C of the guide segment 3i of the tube 2i, then they are partially engaged in said cells as shown in FIG. 5b.
• steps 5c and 5d the mutually opposite ends of the two tubes 2i and 2j are fixed to each other for example by a known welding technique called “mirror welding".
• This welding technique consists in placing between the opposite ends of the tubes 2i and 2j an annular heating mirror 9 (FIG. 5c) in two separable parts, and in lightly pressing said ends of the tubes 2i and 2j against the opposite faces of said annular mirror. .
• annular heating mirror 9 FIG. 5c
• annular bead 11 is formed at the junction of the two tubes 2i and 2j.
• This bead 11 projects radially inwards and outwards relative to the wall of the tubular casing 2 and it forms, on the inside of the latter, a stop capable of cooperating with stop elements 12 which had been fixed beforehand, in the factory, on the periphery of each of the segments 2i, 2j, ... of the multi-channel guide 3, at the two ends thereof. While the ends of the two tubes 2i and 2j are pressed against each other, the projecting ends 6A, 6B, 6C of groups 5A, 5B and 5C of tubes 5 of the guide segment 3j penetrate further into the corresponding cells 7A , 7B and 7C of the guide segment 3i.
• the annular bead 1 1 and the abutment elements 12 ensure that an interval at least equal to the width of said annular bead will be maintained between the two segments of 3i and 3j and that, in service, when the sheath 1 is put in place between the two anchor points of the stay cable that it is intended to be contained, the guide segments 3i, 3j, ... of the multichannel guide will remain respectively in place in the tubes 2i, 2j, ... of the outer tubular casing 2.
• the guide segment 3j is at a higher level than that of guide segment 3i
• the abutment elements 12 which are at the lower end of the guide segment 3j will abut against the annular bead 11 as shown in the figure 2.
• the projection formed by the bead 1 1 can be achieved by other arrangements, such as by inserting a brass ring, HDPE or any other solid material, inside the tubular casing.
• a stop member 12 may be provided at each end of each guide segment 3i, 3j, ... a number of short pieces of tubes, for example three pieces of tube fixed to the guide segment in positions spaced angularly by 120 ° as shown in FIG. 1.
• Each piece of tube 12 can for example be cut from a profile with a hexagonal PVC section identical to those used to form the tubes 5.
• the pieces of tube constituting the stop elements 12 are elastically deformed and flattened at the time of the positioning of each guide segment 3i, 3j, ...
• the pieces of tube constituting the stop elements 12 contribute, with the wire 8, to ensure the centering of each guide segment in the corresponding tube of the envelope tu outer bular.
• the stops can also be produced by adopting other forms or other materials than those mentioned above.
• the segments 3i, 3j of the multi-channel guide are assembled directly together, for example by bonding the ends 6A, 6B, 6C of the groups 5A, 5B, 5C of tubes of the segment 3j in the cells 7A , 7B, 7C of segment 3i. In this case, it is no longer necessary to link the segments 3i, 3j of the multichannel guide with the outer tubular envelope 2.
• the strands 4 of the cable are threaded, by pushing or by pulling, into the respective channels of the multi-channel guide. 3, from one end of the sheath to the other, also passing the strands through the holes of any deflectors and anchor heads provided in the region of the two anchor points of the guy cable on the structure to be built.
• the sheath 1 which has been described above is particularly suitable for cables whose strands 4 are bare or galvanized, that is to say without individual sheath.
• the strands 4 once the strands 4 have been placed in the sheath and tensioned, they can be easily and effectively protected against corrosion due to humidity, by injecting a filling material in the state fluid in the empty spaces 13 ( Figure 8) between the outer tubular casing 2 of the sheath 1 and the multichannel guide 3 and in the channels of the latter, between their wall and the strands 4 of the cable.
• the progression of the filling material injected into the sheath 1 takes place more rapidly in the first empty spaces than in the second empty spaces mentioned above. and it could result therefrom that the second empty spaces are incompletely filled with the material injected over the entire length of the sheath 1.
• the projecting ends 6A, 6B and 6C of the tubes 5 of the groups of tubes 5A, 5B and 5C are located within the periphery of the mesh network formed by the channels of the multichannel guide 3, as in the embodiment of the Figures 1 to 4, in order to guarantee that the filling material can also penetrate from said intervals into the tubes 5 of said groups 5A, 5B and 5C, parts of said projecting ends 6A, 6B and 6C which cross each interval e between two segments any successive 3i and 3j of the guide 3, have openings 14 in their side wall, which put the inside of the channels correspondents of guide 3 in communication with the interval e considered. As shown in Figure 4, the openings 14 may be formed by a series of holes, but they could also be formed for example by slots.
• each of the groups 5A, 5B and 5C of tubes 5 comprises five tubes instead of three tubes per group.
• a filler to be injected into the sheath 1 it is possible to use, according to one embodiment of the present invention, a composition based on monomer or prepolymer reagents capable of polymerizing slowly in situ, at room temperature, after injection.
• composition for protecting strands of cables for engineering structures is described in document FR-A 99.02754 filed on March 5, 1999 and having as its title "composition for protecting strands of cables for engineering structures".
• a viscoelastic gel is obtained which significantly improves the damping characteristics of the sheathed cable in the presence of vibrations or other oscillations generated by wind, rain or other dynamic loads to which the 'structure is submitted in service.
• the outer tubular casing 2 and the tubes 5 of the multi-channel guide 3 can be made of materials other than HDPE and that of the PVC indicated above.
• the tubes 5 and / or the multichannel profiles constituting the guide segments 3i, 3j, ... can be of a metal such as aluminum, galvanized steel, zinc ..., or others plastics than PVC.
• each tube 2i, 2j, ... of the outer tubular casing 2 can be constituted by two half-shells assembled together.
• the guide segments 3i, 3j, ... can have a length corresponding to a submultiple of the length of each tube of the outer tubular envelope 2.
• each tube of the envelope 2 will contain two or more than two guide segments, which are assembled each time with a spacing e between two successive segments.
• galvanized strands are preferably used for the cable, it can also use bare strands.

Landscapes

• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Bridges Or Land Bridges (AREA)
• Rigid Pipes And Flexible Pipes (AREA)
• Media Introduction/Drainage Providing Device (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=9542903

Family Applications (1)

Country Status (7)

Families Citing this family (5)

Family Cites Families (3)

• 1999
  • 1999-03-05 FR FR9902799A patent/FR2790491B1/fr not_active Expired - Fee Related
• 2000
  • 2000-02-28 EP EP00907736A patent/EP1159490A1/fr not_active Withdrawn
  • 2000-02-28 JP JP2000603465A patent/JP2008518124A/ja active Pending
  • 2000-02-28 CA CA002364994A patent/CA2364994A1/fr not_active Abandoned
  • 2000-02-28 WO PCT/FR2000/000487 patent/WO2000053850A1/fr active Search and Examination
  • 2000-02-28 KR KR1020007011662A patent/KR100610720B1/ko not_active IP Right Cessation
  • 2000-03-03 TW TW089103837A patent/TW467986B/zh not_active IP Right Cessation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events