EP1129264B1 - Cable with parallel wires for building works structure, anchoring for said cable, and anchoring method - Google Patents

Abstract

A reinforcement for a building works structure comprising an assembly of solid wires. The wires are mutually parallel to form a bundle and the reinforcement comprises a sheath made of plastic material enclosing the bundle and providing it with cohesion.

Description

The present invention relates to the field of reinforcements used in structures of construction work.

The invention aims particularly, but not exclusively, among these structures, those that are intended to equip cable stayed bridges, suspended or otherwise. The frames usually encountered in such structures include a number of wires.

In the known embodiments of the armatures of the kind in question, see for example EP-A-0855471, the various constituent son are generally twisted around a central wire. This arrangement is used to make a strand, also called strand, from reduced diameter wires. The mechanical characteristics of the strand obtained are higher than those of a single-strand wire whose section is equivalent to that of said strand.

Twisting the peripheral threads around a central thread makes the strand or strand wires integral with one another and reduces the bending inertia of the assembly. This gives a reinforcement unit from very high strength son.

However, the embodiment of the twisted strand or strand requires a particular stranding operation which is expensive. In addition, this operation causes a differential elongation between the central wire and the peripheral wires. The peripheral wires are then less stressed than the central wire, inducing an apparent modulus of elasticity of the lower strand than that of each constituent wire.

In addition, the fatigue behavior of a strand as defined above is less efficient than that of the wire that constitutes it. The differential elongation between the peripheral wires and the central wire indeed causes differential movements with the radial pressure and therefore a friction between the son unfavorable to fatigue.

A further disadvantage lies in the work hardening resulting from the stranding which creates a steep steel with residual internal stresses making it less ductile and therefore susceptible to creep or relaxation depending on the type of stress. In an attempt to reduce this disadvantage, an operation is performed consisting in exerting a high temperature voltage close to 400 ° C. This operation generates an additional cost and can be delicate because it requires a high temperature accuracy when the son are galvanized son or galfanisés. It must not exceed the melting temperature of zinc while not reducing the temperature too much otherwise the operation will be ineffective.

In addition, in order to obtain good protection against corrosion, it is customary to extrude a film of plastic material onto the strand. Prior to this extrusion operation, a spacer device makes it possible to fill the spaces between the threads around the central thread with a flexible product such as grease or wax. This operation creates, because of the need to untwist and twist the son again, a new hardening by deformation of the peripheral son, which reduces the ductility of the strand.

The invention aims to overcome the aforementioned drawbacks by providing an armature whose mechanical performance is equivalent to and equal to that of each of the son that constitute it.

For this purpose, according to the invention, an armature of the kind in question is essentially characterized in that the son are substantially parallel to each other to form a bundle and in that it comprises a plastic sheath which has a lobed inner wall which is provided with depressions and projections, the peripheral wires being housed in the recess and the projections extending into the grooves.

With this arrangement, the cohesion of the armature obtained is preserved while the mechanical characteristics of the armature are equivalent to or equal to those of a constituent wire.

• les fils pleins sont des fils métalliques ;
• les fils pleins sont des fils en matériau composite ;
• la gaine possède une paroi extérieure de forme circulaire en section transversale ;
• la gaine possède une paroi extérieure de forme lobée en section transversale ;
• la gaine possède une paroi extérieure de forme sensiblement polygonale en section transversale ;
• la gaine et les fils délimitent des interstices qui sont remplis d'un lubrifiant choisi parmi la cire et la graisse ; et
• la gaine et les fils délimitent des interstices qui sont remplis par un dispositif de collage.

In preferred embodiments of the reinforcement according to the invention, use is also made of one and / or the other of the following provisions:

• the solid wires are metallic wires;
• the solid wires are wires made of composite material;
• the sheath has an outer wall of circular shape in cross section;
• the sheath has an outer wall of lobed form in cross section;
• the sheath has an outer wall of substantially polygonal shape in cross section;
• the sheath and the wires delimit interstices which are filled with a lubricant chosen from wax and grease; and
• the sheath and the wires delimit interstices which are filled by a gluing device.

In addition, the subject of the invention is also a cable for a construction structure structure comprising at least two reinforcements as defined above.

The invention further relates to a method of conditioning an armature as defined above, by parallel winding on a drum by performing a complete twist on a lathe.

Finally, the subject of the invention is a method for implementing a construction structure of an armature as defined above, consisting in that, in at least a portion of the armature, the wires are stripped. solid and anchored stripped son to at least one constituent part of the construction work so as to work the armature in traction.

Advantageously, all the solid wires of the armature are collectively jammed in an anchor jaw.

• la figure 1 est une vue schématique générale d'un pont suspendu comprenant des armatures selon la présente invention ; et
• les figures 2 à 6 sont respectivement des vues en coupe transversale d'une armature selon une première, deuxième, troisième, quatrième et cinquième formes de réalisation.

Other characteristics and advantages of the invention will emerge during the following detailed description of several of its embodiments, given by way of non-limiting examples, with reference to the appended drawings, in which:

• Figure 1 is a general schematic view of a suspension bridge comprising reinforcements according to the present invention; and
• Figures 2 to 6 are respectively cross-sectional views of a frame according to a first, second, third, fourth and fifth embodiment.

The structure of building structure 1 shown in Figure 1 is for example a suspension bridge. This bridge conventionally comprises an apron 2, two pylons 3, two parallel carrying cables 4, only one being visible in the figure, and a plurality of lines 5 which are attached to the cables 4, and which carry the deck 2.

The carrying cables 4 are stretched between two ground anchors 6 located at both ends of the bridge, and they are supported by the two pylons 3.

Each carrier cable 4 consists of one or more armatures 10 according to a first embodiment of the invention such as that represented in FIG.

Each armature 10 consists of a set of solid wires 11 which form a bundle wrapped in a sheath 12. The armature 10 thus formed is also called strand, and can be joined to other strands to form the cable 4. On thus understands that, by armature, is meant a flexible assembly that can be rolled up to be stored and transported, and then unrolled to be installed in a construction work.

In one strand, the son 11 are generally seven in number and comprise a central wire 13 around which are disposed six peripheral son 14. The son 13 and 14 extend parallel to each other and are for example made of steel.

The son 13 and 14 are mutually in contact according to their generator. Only the central wire 13 is in contact with all the other peripheral wires 14. The wires The peripherals 14 are mutually spaced apart and define grooves 15 which face towards the outside of the wire bundle 13, 14.

All the son 13 and 14 is extruded with the sheath 12. This sheath forms an outer flexible plastic envelope which may be HDPE or amorphous polypropylene. The sheath 12 ensures the cohesion of all the son 13 and 14.

The sheath 12 is of hollow cylindrical shape and has an outer wall 16 and an inner wall 17. The thickness of the sheath is small relative to its length.

In the first embodiment (Figure 2), the outer wall 16 is, in cross section, circular while the inner wall 17 is, in cross section, lobed. This wall thus has recesses 18 and projections 19 which alternate alternately along the circumference of the inner wall.

The peripheral cables 14 are housed in the recesses 18 and the projections 19 extend between the cables 14 in the grooves 15. Thus, the peripheral cables are firmly held by the sheath.

In a second embodiment, such as that represented in FIG. 3, the armature 20 is distinguished from the armature 10 only by the shape of the outer wall of the sheath or sheath 22. This sheath has an outer wall 26 and an inner wall 27 which are in cross-section, both of lobed form.

The inner wall 27 is similar to the inner wall 17 of the sheath 12 of the first embodiment and is provided with recesses 28 and projections 29. The outer wall 26 has recesses and projections respectively in correspondence of the projections and recesses of the inner wall 27.

The armature 30 of the third embodiment shown in FIG. 4, differs from the previously described armature 20 only in that the wires 13 and 14 are embedded in an elastomeric matrix 31 such as polybutadiene or the like. This matrix occupies the interstices between the wires 13, 14. The elastomer 31 adheres to the yarns, by surface adhesion, preferably by chemical bonding with the sheath 22 to increase this adhesion. Alternatively, the matrix may be a lubricant such as wax or grease to reduce friction between the wires and the sheath.

In the fourth embodiment shown in FIG. 5, the armature 40 differs from the armature 30 described with reference to FIG. 4 by the external shape of the sheath 42. The outer wall 46 of this sheath is no longer lobed shape in cross section, but of polygonal shape. This shape facilitates the juxtaposition of the reinforcements or strands in order to constitute a cable 50 such as that shown in FIG. 6. The spaces between the strands 40 may be occupied by a matrix similar to that described above.

Alternatively, it is possible to juxtapose reinforcements 40 whose son are of different diameters from one armature to another.

The strand thus obtained according to one of the embodiments has a mechanical strength, a modulus of elasticity, fatigue performance and ductility of equivalent values and even equal to those of each wire constituting it.

In order to be packaged and transported into the area of the construction work, the strand is wound on a drum by performing a complete twist on a lathe. The pitch is of the order of one to three meters so that residual stresses in the elastic domain are stored in each constituent wire.

Furthermore, the reinforcement obtained according to one of the embodiments is implemented within the structure 1 to have the function of one of the cables 4 or lines 5. For this purpose, a portion the armature, for example the end, is stripped by removing the sheath. The son thus stripped are fixed by means of jaws, for example in the ground anchors 6, and the rest of the armature extends towards the pillars 3 so as to work the armature in traction.

The set of son 13,14 are for example collectively stuck in the anchor jaw.

Claims (12)

1. Reinforcement (10; 20; 30; 40) for a structure of a permanent construction (1), comprising an assembly of solid wires (13, 14) forming a bundle comprising a central wire (13) and peripheral wires (14) surrounded by a sheath (12; 22; 42) made from plastic material, which peripheral wires (14) are tangential to the central wire (13) and mutually spaced to bound grooves (15), and the sheath (12; 22; 42) is made from flexible plastic material extruded onto the bundle, which sheath (12; 22; 42) has a cylindrical external shape, characterised in that the wires (13, 14) are substantially parallel with one another and the sheath (12; 22; 42) has a lobed internal wall (17; 27) incorporating hollows (18; 28) and projections (19; 29) so that the peripheral wires (14) are accommodated in the hollows (18; 28) and the projections (19; 29) extend through the grooves (15).
2. Reinforcement (10; 20; 30; 40) as claimed in claim 1, in which the solid wires (13, 14) are metal wires.
3. Reinforcement (10; 20; 30; 40) as claimed in claim 1, in which the solid wires (13, 14) are wires made from a composite material.
4. Reinforcement (10; 20; 30; 40) as claimed in claim 1, in which the sheath (12) has an external wall (16) with a circular shape in cross-section.
5. Reinforcement (10; 20; 30; 40) as claimed in claim 1, in which the sheath (22) has an external wall (26) with a lobed shape in cross-section.
6. Reinforcement (10; 20; 30; 40) as claimed in claim 1, in which the sheath (42) has an external wall (46) with a substantially polygonal shape in cross-section.
7. Reinforcement (10; 20; 30; 40) as claimed in claim 1, in which the sheath (12; 22; 42) and the wires (13, 14) bound interstices which are filled with a lubricant selected from wax and grease.
8. Reinforcement (10; 20; 30; 40) as claimed in claim 1, in which the sheath (12; 22; 42) and the wires (13, 14) bound the interstices which are filled by means of a bonding device.
9. Cable (4; 5; 50) for a structure of permanent construction comprising at least two reinforcements (10; 20; 30; 40) as claimed in claim 1.
10. Method of packaging a reinforcement as claimed in claim 1 by a parallel winding of the reinforcement (10; 20; 30; 40) onto a drum, making a full twist in one turn.
11. Method of employing a reinforcement as claimed in claim 1 in a permanent construction, characterised in that the solid wires (13, 14) are stripped in at least one portion of the reinforcement (10; 20; 30; 40) and the stripped wires are anchored to at least one constituent part (6) of the permanent construction (1) to make the reinforcement (10; 20; 30; 40) work under traction.
12. Method of employment as claimed in claim 11, in which the solid wires (13, 14) of the reinforcement (10; 20; 30; 40) are collectively clamped in an anchoring jaw as a unit.

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