EP1689951B1 - Method for production of a block of concrete and a block of concrete - Google Patents

Method for production of a block of concrete and a block of concrete Download PDF

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Publication number
EP1689951B1
EP1689951B1 EP04805843A EP04805843A EP1689951B1 EP 1689951 B1 EP1689951 B1 EP 1689951B1 EP 04805843 A EP04805843 A EP 04805843A EP 04805843 A EP04805843 A EP 04805843A EP 1689951 B1 EP1689951 B1 EP 1689951B1
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EP
European Patent Office
Prior art keywords
concrete
band
stretched
longitudinal
twisted
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EP04805843A
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German (de)
French (fr)
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EP1689951A1 (en
Inventor
Marcel Matiere
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Societe Civile de Brevets Matiere
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Societe Civile de Brevets Matiere
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Priority to EP09173849.2A priority Critical patent/EP2141300B1/en
Publication of EP1689951A1 publication Critical patent/EP1689951A1/en
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Publication of EP1689951B1 publication Critical patent/EP1689951B1/en
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    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
    • E04C5/06—Reinforcing elements of metal, e.g. with non-structural coatings of high bending resistance, i.e. of essentially three-dimensional extent, e.g. lattice girders
    • E04C5/0604—Prismatic or cylindrical reinforcement cages composed of longitudinal bars and open or closed stirrup rods
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C1/00—Building elements of block or other shape for the construction of parts of buildings
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
    • E04C5/06—Reinforcing elements of metal, e.g. with non-structural coatings of high bending resistance, i.e. of essentially three-dimensional extent, e.g. lattice girders
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
    • E04C5/06—Reinforcing elements of metal, e.g. with non-structural coatings of high bending resistance, i.e. of essentially three-dimensional extent, e.g. lattice girders
    • E04C5/065—Light-weight girders, e.g. with precast parts

Definitions

  • the subject of the invention is a method for producing a concrete part and relates more specifically to a concrete part provided with a reinforcement cage having multiple advantages and allowing, in particular, to considerably increase the level of stress. from which detrimental cracks may form.
  • reinforced concrete is based on the combination of two materials with complementary properties, concrete which has a high compressive strength, but a very low tensile strength, and steel, which has excellent tensile strength and is protected from corrosion in the air when it is embedded in the concrete.
  • the two materials having, in addition, adjacent expansion coefficients, their combination allows to achieve composite parts having the durability qualities of concrete and can, however, withstand moments or bending forces.
  • Such a part comprises, under the effect of the applied stresses, two parts located on either side of a neutral axis, respectively a compressed part subjected to compression forces absorbed mainly by the concrete and a stretched part subjected to tensile stresses absorbed mainly by at least one stretched longitudinal reinforcement of the reinforcement cage embedded in the concrete.
  • This reinforcement cage comprises, usually, two layers of longitudinal bars, extending respectively along the stretched face and the compressed face of the part and connected by transverse reinforcements called stirrups.
  • the reinforcements must be located at a minimum distance from the outer surface of the part, called the "embedding distance".
  • the stirrups are smaller diameter threads which turn around the bars and it is therefore with respect to these stirrups that a minimum coating distance must be left, which increases the distance between the center of gravity of the longitudinal bar and the corresponding facing face.
  • stirrups also consisting of flat bands, can be welded to the inner faces of the longitudinal bars, which allows, for equal strength, to reduce the overall thickness of the part.
  • the document US-A-887,863 also discloses a reinforcing cage consisting of flat bars of rectangular section and describes a method according to the preamble of claim 1 and a concrete piece according to the preamble of claim 10. In this case, to reduce the amount of metal required, produces a triangular cage with, in the stretched portion, two lower frames spaced from each other and, in the compressed portion, a single upper frame.
  • Each lower reinforcement comprises a longitudinal flat strip extending over the entire length of the part and perpendicular to the facing face thereof, this longitudinal strip being associated with several strips of different lengths each comprising a central portion contiguous to the strip longitudinal and two inclined parts which form stirrups of connection with the upper armature and which are twisted by rotation about their longitudinal axis, to allow the change of orientation and the attachment of these inclined portions on the upper frame also consists of a flat strip perpendicular to the facing face of the workpiece.
  • this twisting ensures the anchoring in concrete of these inclined portions that resist shear forces and deviate towards the ends of the piece, in the upper part thereof. Because of the different lengths of the contiguous strips, the thickness of steel resistant to tensile stresses is greater in the central part and decreases towards the ends.
  • the part is more heavily armed in the most stressed parts, which allows, overall, to reduce the amount of steel needed.
  • the reinforcement cage comprises two plies spaced from intersecting flat bars, between which are placed two other intersecting webs of flat bars twisted along their entire length.
  • This document therefore aims to achieve a thick wall extremely resistant, which behaves absolutely not like a conventional piece of reinforced concrete of the usual type, such as a slab or a beam, to withstand especially bending forces.
  • a reinforced concrete part behaves like a composite part that deforms in a block with transfer of forces between the two components.
  • it is usually sought to improve the transfer bond between the reinforcement and the concrete, for example by using so-called high-adhesion bars, which are notched on their entire surface. length.
  • the ends of these bars are usually bent to form anchoring butts that increase the reinforcement length embedded in the concrete and, therefore, the transfer length of the internal forces between the reinforcement and the concrete .
  • high-adhesion bars which are notched on their entire surface. length.
  • the ends of these bars are usually bent to form anchoring butts that increase the reinforcement length embedded in the concrete and, therefore, the transfer length of the internal forces between the reinforcement and the concrete .
  • These cracks unavoidable in practice, may be admitted as long as their width is fairly small, for example less than 3/10 of a millimeter, to prevent the penetration of air and water until contact with the armature.
  • the subject of the invention is a new method for producing concrete moldings that makes it possible to solve such problems by using a new type of reinforcement reinforcement, which makes it possible in particular to reduce the risk of cracking at equal solicitations.
  • the method makes it possible to considerably improve the resistance to extreme stresses, the concrete parts thus produced being able to have a very high degree of flexibility and benefit from a high degree of safety between the appearance of the first cracks and the complete failure of the cracks. 'work.
  • This advantage is particularly interesting for the construction of structures or buildings in areas subject to seismic risk.
  • the invention therefore applies, in a general manner, to the production of a concrete part according to claim 1.
  • the idea of the invention is, on the contrary, to make separate locking zones, in which the reinforcement, because it consists of a flat strip, is supported in the concrete by a wide face, without risk of exceeding the permissible limit of concrete compression and, from a certain level of stress, to leave the part of the reinforcement comprised between two compression zones, free to slide slightly with respect to the concrete which surrounds it, after detachment thereof, so that the effect of elongation of the reinforcement resulting from the traction forces applied is always distributed over the entire length between two blocking zones, which avoids stress concentrations that can lead to a rupture of the armature in case of extreme stress.
  • the width and the thickness of a stretched longitudinal reinforcement in the form of a strip can be determined according to a maximum tensile force to be absorbed, on the one hand in order to obtain a cross-section sufficient for the absorption said maximum force remaining in the elastic range and secondly, so that, in each blocking zone, the part of the concrete on which the band bears by its wide face, is subjected to a compressive stress not exceeding one allowable limit.
  • the central portion of the stretched strip between two twisted parts is oriented so that its broad face is substantially parallel to the taut longitudinal face of the workpiece.
  • each blocking zone is made by curving the flat strip around a transverse axis, so as to form an anchoring buttstock bearing on the concrete by a wide face.
  • This crossbar may consist of a distribution thread.
  • the reinforcement cage usually comprises several longitudinal sectors interconnected by distribution threads consisting of bars perpendicular to the longitudinal main bars, the assembly constituting a sheet of reinforcement.
  • These distribution threads can be welded to the longitudinal bars, whose flat strip shape allows for particularly strong welds.
  • Each welded junction may constitute a blocking zone, the distribution thread being supported in the concrete on either side of the longitudinal bar.
  • each sector of the reinforcement cage comprises at least two longitudinal bars respectively compressed and tensioned and interconnected by connecting stirrups.
  • the compressed frames also consist of flat strips.
  • the connecting stirrups may each consist of at least one flat strip secured to the reinforcements by welding beads or glued portions extending over a length equal to the width of the band, and therefore, particularly resistant.
  • each band constituting a stirrup is inclined relative to the direction of the tensioned bar and the whole of the welded joint between these two flat strips of different orientation, forms a kind of corner bearing on the concrete.
  • each blocking zone between the tensile reinforcement and the concrete may be constituted by a joining junction between the tensioned frame and a band-shaped connecting stirrup.
  • the strip-shaped tensile reinforcement can be split axially over a certain length, the two band portions thus formed being spaced apart from one another to form a transverse passage opening of at least one rigid bar section likely to bear on the concrete on both sides of the longitudinal strip, in the opposite direction to the tensile force applied to the longitudinal reinforcement.
  • This embodiment is not part of the invention.
  • This rigid bar may be a distribution wire passing through the longitudinal strip in the plane thereof, or a simple bar section passing through the longitudinal strip perpendicular to its plane.
  • each longitudinal reinforcement may comprise at least two contiguous strips extending longitudinally, substantially in the extension of one another and subjected to traction forces in opposite directions, the two contiguous strips overlapping on a certain length and ending respectively, on both sides of the cover, by two sticks facing towards each other, which thus tend to get closer under the effect of the opposite tensile forces applied to the two corresponding bands, by inducing the compression of a concrete core between the two ends, on said lap length.
  • the reinforcement cage consists of parallel sectors connected by distribution threads
  • the latter can pass inside the ends of two neighboring sectors, so as to transmit to the concrete part between said sectors, the compression efforts induced, in each sector, by the tendency towards the opposite ends.
  • the two contiguous strips forming the longitudinal reinforcement of each sector of the cage may constitute two strands of a single band ending in opposite butts and forming a loop between two separated levels, so as to surround a concrete core set in compression by clamping said loop under the effect of traction forces applied in opposite directions on the two strands of the longitudinal reinforcement.
  • the longitudinal reinforcement may consist of a series of consecutive strips each having two curved ends in the form of a butt, the adjacent ends of two consecutive strips being placed next to the other partially overlapping so as to limit a passage space, in the transverse direction, of at least one bar section forming a connecting key between the two consecutive strips.
  • the longitudinal reinforcement then behaves like a tensioned chain consisting of a series of links each formed of a band and connected in pairs by pairs of adjacent sticks keyed together.
  • the longitudinal reinforcement comprises a stack of flat strips arranged on at least two superimposed levels, respectively a first level, the closest to a stretched longitudinal face of the piece comprising a band, with two stick-shaped ends turned towards the inside of the piece and at least a second level comprising at least two substantially parallel flat strips arranged side by side with each two end-shaped sticks, respectively internal and external, and said strips of the second level overlap over a certain length, so that their inner ends in the form of sticks are turned towards each other.
  • the part thus comprises at least one portion forming a core between the inner ends of the two strips and set in compression by the tendency towards the one towards the other of said internal butts under the effect of the tensile forces applied in the directions opposing on the corresponding bands, and two extreme parts each included between the outer hooks of the bands of the first and the second level and put in compression by the tendency to inward approximation of each external butt of the band of the first level under the effect of the tensile force supported by said band. It is thus possible to compress the entire concrete of the room.
  • this concrete part 1 which constitutes, in the example shown in the drawings, a slab having two planar faces, respectively bottom and top 21, is a molded part made by casting a mass of concrete 2 in a formwork, after placing in it a reinforcement cage 3 comprising two reinforcement plies, respectively lower and upper 30 ', substantially parallel to the two faces 20, 21 of the slab 1.
  • the reinforcement cage 3 normally consists of several sectors S1, S2, ... centered, respectively, in planes P1, P2 ... parallel to a longitudinal axis of the part 1, that is to say in terms of figure 1 and each comprising a lower longitudinal reinforcement 31 and an upper longitudinal reinforcement 31 'which are interconnected in the plane P1, P2 of the sector S1, S2 by transverse reinforcements called stirrups, which are not shown on the Figures 1 and 2 .
  • the part in concrete 1 can be divided into two parts located on either side of a neutral axis 10 respectively a compressed portion 11 'between the neutral axis 10 and the face 21 on which the forces are applied and a stretched portion 11 s extending to face 20 opposed to efforts.
  • the reinforcement cage 3 differs from the cages usually produced by the fact that, according to a provision described in the patent application FR-A-2,814,480 of the same inventor, at least the longitudinal reinforcements 31 situated in the stretched portion 11 of the part and extending at a short distance from the bottom face 20 are constituted by flat metal bars 4 with a rectangular section, with one face wide 41 and a narrow face 42, each flat bar thus consisting of a metal strip having a width I substantially greater than its thickness e.
  • the compressed armatures 31 ' are also constituted by flat bars but, for economy, it would also be possible to use conventional round bars.
  • the cross section (lxe) of the strip 4 is calculated, conventionally, as a function of the tensile forces to bear in view of the stresses applied to the part 1. Indeed, under the effect of the load M the part 1 tends to bend slightly, each longitudinal reinforcement 31 of the lower ply 30 being subjected to a tensile stress which tends to lengthen it.
  • notched reinforcement bars are generally used in order to improve the transfer bond between the reinforcement and the concrete, thereby producing a composite part which is usually sought after. increase rigidity to avoid the appearance of harmful cracks.
  • each blocking area B, B ' can be achieved simply by deflecting the corresponding part of the stretched reinforcement 31, which is gradually and progressively varied. continues the orientation of its wide face relative to the longitudinal stretched face 20 of the part so that, in this area, the band 4 forming the frame 31 is supported in the concrete, mainly by its wide side 41, in the opposite direction to the tensile force absorbed.
  • each locking zone B, B ' is made by twisting the strip 4 over a certain length L1, with a progressive rotation of its wide face 41 about its longitudinal axis 40.
  • the band is twisted on a complete turn. If we consider a horizontal band 4 subjected to a tensile force T directed to the right and having a part 43 twisted on a complete turn on either side of a median plane P, the tensile force T applied on the band 4 determines, as in a corkscrew, a support of this band 4 in the concrete by its two faces 41, 41 '. Because the band is flat and bears in the concrete by two faces wide, the concrete is not likely to shear, the compression stress is low. Moreover, the width I of the band 4 can be determined according to the stresses applied, so that the compressive stress applied to the concrete remains below a permissible limit.
  • each band 4 constituting a longitudinal reinforcement 31 is secured to the concrete only in the two blocking zones B, B 'which are separated from each other and the tendency to extension of the reinforcement under the effect of the applied tension can be distributed uniformly over the entire length L 2 of the central portion 44 between the two twisted parts 43, 43 ', this central portion 44 being able to be detached from the concrete from a certain level of solicitation.
  • the concrete 2 can not deform in the same way as the reinforcement and therefore we can not avoid the appearance of cracks but this risk of cracking is distributed uniformly over the entire length L 2 of the central portion 44 and more cracks may have a width that is small enough not to be detrimental.
  • the piece behaves, as usual, as a piece composite, the concrete deforming in the same way as the reinforcement.
  • the reinforcement remains secured to the concrete only in its blocking parts 43, 43 'and its central portion 44 can, on the contrary, peel off the concrete which coats it and slide slightly in relation to this one.
  • the tension and, consequently, the tendency for the elongation of the reinforcement is therefore distributed substantially uniformly over the entire length L 2 of the central portion 44. This avoids a concentration of the tensile stress on a low length of the armature and, therefore, it reduces the risk of rupture of the armature at a crack, under the effect of excessive stresses.
  • slabs made according to the invention have been subjected to progressive flexural tests with increasing load, and it has been found that a slab thus produced could, surprisingly, admit a very narrow deflection. important before the slab breaks and with relatively small width cracks.
  • the stretched longitudinal bars must be curved in the shape of a butt at their ends in order to increase the transfer length between the reinforcement and the concrete.
  • the curvature that can be given to a bar is necessarily limited and regulations require, moreover, to give the stick a diameter of at least 10 times the diameter of the bar.
  • a concrete part must have a minimum thickness of twelve times the diameter of the tension bars, to which must be added twice the minimum thickness of the coating.
  • each butt 5 also constitutes a blocking zone B1 in the concrete 2.
  • the longitudinal reinforcement is attached to the concrete in the locking zones 43, 5 while the central portion 44 is free to stretch, the stresses applied by the reinforcement on the concrete are more strong than in the case of a conventional reinforcement where one seeks to achieve a solid connection over the entire length of the frame.
  • the band 4 is subjected to a large tensile force T which is concealed by the blocking zone B1 located inside the butt 5, it may tend to unfold if the adhesion between the bar 4 is the concrete is not enough.
  • each tension bar 31 consisting of a flat strip 4 is oriented so that its wide face 41 is substantially parallel to the taut face 20 of the workpiece.
  • Such an arrangement increases the flexibility of the slab because the bar 4 thus oriented has a low resistance to bending and the bending of the piece simply results in an elongation of the frame.
  • each reinforcing strip 4 is twisted in two parts 43, 43 'spaced apart from each other, but only over a quarter of a turn so that in the central portion 44' and along the entire length thereof the wide side 41 of the strip 4 is located in a plane orthogonal to the stretched face 20 of the part.
  • the blocking of the strip 4 in the concrete is essentially achieved at the level of the zones B1, B'1, inside the butts 5, 5 ', formed at the ends of the band 4, the locking effect of the twisted portions 43, 43 'being decreased.
  • the longitudinal bars 31, 31 'of the two plies, respectively lower and upper 30' can be connected by stirrups which, as described in the document FR-A-2,814,480 , advantageously consist of corrugated flat strips 13 secured to the longitudinal reinforcements, at the top of the corrugations, by welding or gluing.
  • the welds between the corrugated strips 13 and the strips 4 constituting the tensile plates 31, are made only near the two ends of the part 1 so that the central portion 44 of each band 4 can lie freely.
  • stirrups may be welded or glued to the compressed bars 31 'at the top of each corrugation.
  • each compressed bar 31 ' also consists of at least one flat strip, in order to produce a weld bead over the entire width of the corrugated strip 13.
  • each welded or glued joint 34 between a bar 4 and the corresponding part of the stirrup 13 which forms an angle with this bar 4 constitutes, by wedge effect, a blocking zone B. It is therefore unnecessary, in this case, provide the band 4 twisted parts.
  • this method may be the subject of other variants, in particular by taking advantage of the support forces exerted in the concrete by the longitudinal reinforcement locking zones, for example as shown schematically on the Figures 10 to 20 which illustrate various variants.
  • each sector of the reinforcement cage 3 comprises a longitudinal reinforcement 31 consisting of a flat band which extends over the entire length of the workpiece 1 and whose ends 5, 5 'are curved in the shape of a stick as indicated above.
  • longitudinal bars 31 are associated with a second level of longitudinal bars offset upwards and comprising, in each sector of the cage, two bars 33, 34 each formed of a flat strip and placed side by side, each of these bars. 33, 34 being provided with curved ends in the form of hooks 51, 51 ', 52, 52'.
  • the two contiguous strips 33, 34 of the same sector are offset longitudinally relative to each other so that the two brackets 51, 51 '(52, 52') formed at the ends of each strip 33 (34) are placed at different distances from the transverse median plane Q of the part 1, on both sides of it.
  • the outer stock 51 of the bar 33 placed on the left on the figure 10 is farther from the median plane Q than the outer stock 51 'of the same band 31, placed on the right and the disposition is reversed for the second longitudinal band 34.
  • the lengths of the longitudinal bars 33, 34 are determined from way that the different sticks 5, 51, 52 placed on the same side of the transverse median plane Q are distributed over a certain length of the piece 1 from its end 11.
  • the longitudinal reinforcements are subjected to tensile forces and are supported in the concrete by their ends in the form of sticks which are therefore urged inwards .
  • the longitudinal reinforcements 33, 34 which overlap in the central part of the part, are stretched in different directions and the central blocking area B3 is therefore compressed by the tendency towards the one towards the other of the internal butts 51 ' , 52 of the two frames 33, 34.
  • end zones B1, B'1 are also put in compression by the butts 5, 5 'which oppose the tensile forces applied to the frame 31.
  • the piece 1 is put into compression practically over its entire length by the tendency towards the inward approach of the butts of the various reinforcements and this compression effect is exerted over the entire thickness of the concrete limited by the butts and not only, as usual, above the neutral axis 10.
  • the tensile reinforcement of the cage 3 may also consist of a simple stack of longitudinal strips of different lengths, respectively a first band 35 extending over a length I 1 slightly less than that of the piece and a second band 36 extending over a length I 2 less than I 1 , each band being provided with ends in the form of brackets turned towards the interior of the room.
  • the concrete is put in compression by the butts 5, 5 ', 51, 51' which absorb the tensile forces applied on the strips 35, 36 because of the bending of the part.
  • the metal strips having different mechanical characteristics so as to modulate the compression forces applied by the butts according to the distribution of forces applied to the workpiece.
  • FIGS. 12 and 13 show a variant of the embodiment of the figure 10 wherein the two adjacent strips 33, 34 constitute two strands of a single band forming a closed loop, the two opposite brackets 51 ', 52 being connected by a portion 37 of the band located at the upper level 30' of the cage 3.
  • Each longitudinal reinforcement thus consists of a single band 33, 37, 34 surrounding a concrete core B3 which is compressed by clamping of the loop thus formed under the effect of traction forces applied in opposite directions on both strands 33, 34 of the longitudinal reinforcement when the part 1 is subjected to a vertical load.
  • each longitudinal reinforcement in the form of a loop may form part of the upper ply 30 'of the reinforcement cage 3.
  • the opposing brackets 51 ', 52 which tend to compress a concrete core B3, are not necessarily spaced symmetrically on either side of the transverse median plane Q of the piece 1. Indeed, depending on the loading mode of the part, it is possible to determine certain parts of the part 1 in which the tensile forces induced in the concrete by the applied stresses are maximum and have the reinforcements and their butts so that the tensile forces resulting from the stresses are at least partially offset by the compression in the same areas of a concrete core between two butts solicited one towards the other by the tensile forces applied on the frame.
  • each of the figures described above shows a sector of the reinforcement cage centered in a vertical plane parallel to the longitudinal axis and the butts formed on the reinforcements of two adjacent sectors are placed substantially at the same level so as to passing, in the aligned locking zones of the sectors S 1 , S 2 , S 3 , transverse threads 32 which are also biased inwards and thus distribute on the concrete between two adjacent sectors, the compression forces applied by the crossheads 5, 51, 52.
  • These distribution threads may have a round or rectangular section, as shown in the figures.
  • the use of flat bars makes it easier to produce a weld bead between the longitudinal and transverse bars.
  • each stretched longitudinal reinforcement 6 of the cage 3 is constituted by a series of consecutive strips 6a, 6b .... each having two ends curved in the form of hooks 5a, 5'a, 5b, 5'b ... and these bars are arranged so that the pairs of adjacent sticks 5'a, 5b of two successive bands 6a, 6b are located substantially at the same level, overlapping slightly so as to surround a space E in which is passed a bar 38 which can constitute a transversal thread of distribution.
  • Each bar 38 passing through a space E placed in compression by the two opposite brackets 5'a, 5b constitutes a connecting key between the two consecutive strips 6a, 6b.
  • Each longitudinal reinforcement 6 consists of a series of strips 6a, 6b, 6c .... thus behaves like a chain whose links 6a, 6b, 6c ... are stretched under the effect of the charges applied on the part 1.
  • each blocking zone could be obtained simply by means of a transverse bar passing through an orifice formed on the longitudinal reinforcing bar.
  • a flat strip 4 as a longitudinal reinforcing bar makes it possible to fit therein a median slot 45 extending over a certain length and limiting two lateral parts 46, 47 which can be spaced apart from each other. the other so as to open a hole 45 'for passage of a transverse bar 48.
  • a tensile force for example in the direction of the arrow indicated on the figure 16 , it is supported on the crossbar 48 which itself is supported in the concrete, thus realizing the blocking of the band 4.
  • transverse bar 48 which, in this case, is parallel to the plane of the strip.
  • This bar could therefore constitute a transverse thread 32 of distribution between several sectors of the reinforcement cage.
  • this twisted part 43 could also be provided with a median slot allowing the two parts of the band to be separated from one another to provide an opening 45 ' passage of a distribution thread 32, as shown in FIG. figure 18 .
  • the use of flat strips 4 to form the longitudinal reinforcing bars makes it possible to vary the orientation of the butt formed at the end of such a bar.
  • the flat strip 4 can be easily bent around an axis parallel to its plane. It would therefore be possible, as shown in figure 20 twist a quarter turn the end of a strip 4 so that the butt 5 rotates about a vertical axis 50. This would give the same locking effect by giving the stock a height limited to the width e
  • This arrangement could be advantageous for making particularly thin pieces or, for example, for thinning the ends of a slab.
  • the use of a flat strip 4 allows, if necessary, to vary the orientation thereof, as shown in FIG. figure 20 for example, to thin some parts of the room.
  • the flat strips constituting the longitudinal and transverse reinforcements could even be curved in opposite directions so as to adapt to a left profile in the transverse direction, such as a regulated surface having non parallel parallel generatrices. This is the case, for example, the decking of a laterally inclined bridge of variable angle from one end to the other and whose reinforcement is difficult to achieve by conventional methods.
  • the invention is especially adapted to the realization of crossing structures buried under an embankment and having a curved profile allowing them to slightly deform under the load applied to support the side embankments by their sides.
  • the blocking zones between which the concrete is placed in compression can be placed at locations, determined by calculation, in which the concrete is subjected to a tensile stress maximum and where the risk of cracking is greatest.
  • the invention therefore makes it possible, from a standard model, to adapt the reinforcement of each part to the predictable distribution of the stresses, taking into account the loads applied.
  • the arrangement of the compression zones is not necessarily symmetrical with respect to the median plane of the part.
  • the arrangements according to the invention therefore make it possible to vary the shape of the reinforcement cage so as to modulate the action of the reinforcements as a function of the stresses applied in use on the part.

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Abstract

The method involves casting a cement mass (2) in a casing after setting a reinforcing housing (3) in the mass, to fabricate a slab (1). The housing has lower longitudinal frameworks (31) and upper longitudinal frameworks (31) connected with each other. Each framework (31) has locking parts (43, 43) supported in the mass at respective locking zones (B, B) formed inside the slab, in direction opposite to absorbed tensile stress. An independent claim is also included for a reinforced concrete piece comprising a reinforcing housing.

Description

L'invention a pour objet un procédé de réalisation d'une pièce en béton et porte plus spécialement sur une pièce en béton munie d'une cage de ferraillage présentant de multiples avantages et permettant, en particulier, d'augmenter considérablement le niveau de sollicitation à partir duquel des fissures préjudiciables risquent de se former.The subject of the invention is a method for producing a concrete part and relates more specifically to a concrete part provided with a reinforcement cage having multiple advantages and allowing, in particular, to considerably increase the level of stress. from which detrimental cracks may form.

On sait que le principe du béton armé repose sur l'association de deux matériaux ayant des propriétés complémentaires, le béton qui présente une résistance à la compression importante, mais une résistance à la traction très faible, et l'acier, qui présente une excellente résistance à la traction et se trouve protégé de la corrosion à l'air lorsqu'il est noyé dans le béton. Les deux matériaux ayant, en outre, des coefficients de dilatation voisins, leur association permet de réaliser des pièces composites ayant les qualités de durabilité du béton et pouvant, cependant, résister à des moments ou des efforts de flexion. Une telle pièce comporte, en effet, sous l'effet des sollicitations appliquées, deux parties situées de part et d'autre d'un axe neutre, respectivement une partie comprimée soumise à des efforts de compression absorbés principalement par le béton et une partie tendue soumise à des efforts de traction absorbés principalement par au moins une armature longitudinale tendue de la cage de ferraillage noyée dans le béton.It is known that the principle of reinforced concrete is based on the combination of two materials with complementary properties, concrete which has a high compressive strength, but a very low tensile strength, and steel, which has excellent tensile strength and is protected from corrosion in the air when it is embedded in the concrete. The two materials having, in addition, adjacent expansion coefficients, their combination allows to achieve composite parts having the durability qualities of concrete and can, however, withstand moments or bending forces. Such a part comprises, under the effect of the applied stresses, two parts located on either side of a neutral axis, respectively a compressed part subjected to compression forces absorbed mainly by the concrete and a stretched part subjected to tensile stresses absorbed mainly by at least one stretched longitudinal reinforcement of the reinforcement cage embedded in the concrete.

Cette cage de ferraillage comporte, habituellement, deux nappes de barres longitudinales, s'étendant respectivement le long de la face tendue et de la face comprimée de la pièce et reliées par des armatures transversales appelées étriers.This reinforcement cage comprises, usually, two layers of longitudinal bars, extending respectively along the stretched face and the compressed face of the part and connected by transverse reinforcements called stirrups.

Cependant, pour rester à l'abri de l'air et éviter la corrosion, les armatures doivent être situées à une distance minimale de la face externe de la pièce, appelée « distance d'enrobage ».However, to keep out of the air and to avoid corrosion, the reinforcements must be located at a minimum distance from the outer surface of the part, called the "embedding distance".

Lorsque les armatures sont constituées, comme habituellement, de barres rondes, les étriers sont des fils de plus faible diamètre qui tournent autour des barres et c'est donc par rapport à ces étriers qu'il faut laisser une distance minimale d'enrobage, ce qui augmente la distance entre le centre de gravité de la barre longitudinale et la face de parement correspondante.When the reinforcements are formed, as usual, of round bars, the stirrups are smaller diameter threads which turn around the bars and it is therefore with respect to these stirrups that a minimum coating distance must be left, which increases the distance between the center of gravity of the longitudinal bar and the corresponding facing face.

Pour réduire cette distance, la société déposante a déjà proposé, dans le document FR-A-2 814 480 , d'utiliser comme barres d'armature des bandes plates avant une section transversale rectangulaire déterminée, comme habituellement, en fonction des efforts induits par la sollicitation appliquée sur la pièce. De ce fait, les étriers, constitués également de bandes plates, peuvent être soudés sur les faces internes des barres longitudinales, ce qui permet, à résistance égale, de diminuer l'épaisseur globale de la pièce.To reduce this distance, the applicant company has already proposed in the document FR-A-2,814,480 , to use as rebars flat strips before a given rectangular cross section, as usually, depending on the forces induced by the bias applied to the piece. Therefore, the stirrups, also consisting of flat bands, can be welded to the inner faces of the longitudinal bars, which allows, for equal strength, to reduce the overall thickness of the part.

L'utilisation de barres d'armature à section carrée ou rectangulaire avait déjà été prévue dans le document GB-A-410 886 . Dans ce cas, cependant, les étriers transversaux tournent encore autour des barres longitudinales qui sont munies, sur une face latérale, de parties en saillie formant des butées permettant de solidariser l'ensemble.The use of square or rectangular section bars had already been included in the document GB-A-410 886 . In this case, however, the transverse stirrups still rotate around the longitudinal bars which are provided on a lateral face, projecting portions forming stops to secure the assembly.

Le document US-A-887 863 décrit également une cage de ferraillage constituée de barres plates à section rectangulaire et décrit un procédé selon le préambule de la revendication 1 et une pièce en béton selon le préambule de la revendication 10. Dans ce cas, pour réduire la quantité de métal nécessaire, on réalise une cage de forme triangulaire avec, dans la partie tendue, deux armatures inférieures écartées l'une de l'autre et, dans la partie comprimée, une seule armature supérieure. Chaque armature inférieure comprend une bande plate longitudinale s'étendant sur toute la longueur de la pièce et perpendiculaire à la face de parement de celle-ci, cette bande longitudinale étant associée à plusieurs bandes de longueurs différentes comportant chacune une partie centrale accolée à la bande longitudinale et deux parties inclinées qui forment des étriers de liaison avec l'armature supérieure et qui sont vrillées par rotation autour de leur axe longitudinal, afin de permettre le changement d'orientation et la fixation de ces parties inclinées sur l'armature supérieure également constituée d'une bande plate perpendiculaire à la face de parement de la pièce.The document US-A-887,863 also discloses a reinforcing cage consisting of flat bars of rectangular section and describes a method according to the preamble of claim 1 and a concrete piece according to the preamble of claim 10. In this case, to reduce the amount of metal required, produces a triangular cage with, in the stretched portion, two lower frames spaced from each other and, in the compressed portion, a single upper frame. Each lower reinforcement comprises a longitudinal flat strip extending over the entire length of the part and perpendicular to the facing face thereof, this longitudinal strip being associated with several strips of different lengths each comprising a central portion contiguous to the strip longitudinal and two inclined parts which form stirrups of connection with the upper armature and which are twisted by rotation about their longitudinal axis, to allow the change of orientation and the attachment of these inclined portions on the upper frame also consists of a flat strip perpendicular to the facing face of the workpiece.

En outre, ce vrillage assure l'ancrage dans le béton de ces parties inclinées qui résistent aux efforts tranchants et s'écartent vers les extrémités de la pièce, dans la partie supérieure de celle-ci. En raison des longueurs différentes des bandes accolées, l'épaisseur d'acier résistant aux efforts de traction est plus importante dans la partie centrale et diminue vers les extrémités.In addition, this twisting ensures the anchoring in concrete of these inclined portions that resist shear forces and deviate towards the ends of the piece, in the upper part thereof. Because of the different lengths of the contiguous strips, the thickness of steel resistant to tensile stresses is greater in the central part and decreases towards the ends.

Ainsi, la pièce est plus fortement armée dans les parties les plus sollicitées, ce qui permet, globalement, de réduire la quantité d'acier nécessaire.Thus, the part is more heavily armed in the most stressed parts, which allows, overall, to reduce the amount of steel needed.

Le document DE-A-35 41 875 prévoit également d'utiliser comme armatures des bandes plates vrillées par rotation autour de leur axe longitudinal, mais dans le but de réaliser une paroi de chambre forte, capable de résister aux risques de forages et d'explosions.The document DE-A-35 41 875 It also plans to use flat belts twisted around their longitudinal axis as reinforcements, but with the aim of making a vault wall capable of withstanding the risk of drilling and explosions.

Selon ce document, la cage de ferraillage comporte deux nappes espacées de barres plates entrecroisées, entre lesquelles sont placées deux autres nappes entrecroisées de barres plates vrillées sur toute leur longueur.According to this document, the reinforcement cage comprises two plies spaced from intersecting flat bars, between which are placed two other intersecting webs of flat bars twisted along their entire length.

Ce document a donc pour objet de réaliser ainsi une paroi épaisse extrêmement résistante, qui ne se comporte absolument pas comme une pièce classique en béton armé de type habituel, telle qu'une dalle ou une poutre, devant résister notamment à des efforts de flexion.This document therefore aims to achieve a thick wall extremely resistant, which behaves absolutely not like a conventional piece of reinforced concrete of the usual type, such as a slab or a beam, to withstand especially bending forces.

Or, on sait que tant que les sollicitations appliquées ne dépassent pas une certaine limite, une pièce en béton armé se comporte comme une pièce composite se déformant en bloc avec transfert des efforts entre les deux composants. Pour cela on cherche, habituellement, à améliorer la liaison de transfert entre l'armature et le béton, par exemple en utilisant des barres dites à haute adhérence, qui sont crantées sur toute leur longueur. D'autre part, les extrémités de ces barres sont habituellement recourbées pour former des crosses d'ancrage qui augmentent la longueur d'armature noyée dans le béton et, par conséquent, la longueur de transfert des efforts internes entre l'armature et le béton.
Cependant, sous l'effet des sollicitations, on ne peut éviter une déformation de la pièce avec un allongement de la partie tendue qui provoque l'apparition de fissures dans le béton d'enrobage. Ces fissures, inévitables en pratique, peuvent être admises tant que leur largeur est assez faible, par exemple inférieure à 3/10 de millimètre, pour interdire la pénétration de l'air et de l'eau jusqu'au contact de l'armature.Now, it is known that as long as the stresses applied do not exceed a certain limit, a reinforced concrete part behaves like a composite part that deforms in a block with transfer of forces between the two components. For this purpose, it is usually sought to improve the transfer bond between the reinforcement and the concrete, for example by using so-called high-adhesion bars, which are notched on their entire surface. length. On the other hand, the ends of these bars are usually bent to form anchoring butts that increase the reinforcement length embedded in the concrete and, therefore, the transfer length of the internal forces between the reinforcement and the concrete .
However, under the effect of the stresses, one can not avoid deformation of the part with an elongation of the stretched part which causes the appearance of cracks in the concrete coating. These cracks, unavoidable in practice, may be admitted as long as their width is fairly small, for example less than 3/10 of a millimeter, to prevent the penetration of air and water until contact with the armature.

Cependant, si la charge dépasse une certaine limite, les fissures s'élargissent et la partie libre, de faible longueur, de l'armature tendue qui s'étend entre les faces opposées d'une fissure, supporte seule l'allongement correspondant à l'épaisseur de cette fissure, alors que les parties voisines sont bloquées dans le béton. La tendance à l'allongement de la face tendue sous l'effet des sollicitations appliquées se concentre donc sur les parties libres de l'armature et, en raison de leur faible longueur, l'allongement appliqué peut faire dépasser la limite élastique du métal, ce qui provoque la striction de l'armature et la ruine de l'ouvrage.However, if the load exceeds a certain limit, the cracks widen and the free part, of short length, of the stretched reinforcement which extends between the opposite faces of a crack, only supports the elongation corresponding to the The thickness of this crack, while the neighboring parts are blocked in the concrete. The tendency of the stretched face to stretch under the effect of the stresses applied is therefore concentrated on the free parts of the reinforcement and, because of their short length, the elongation applied may cause the elastic limit of the metal to exceed which causes the narrowing of the frame and the ruin of the work.

L'invention a pour objet un nouveau procédé de réalisation de pièces moulées en béton permettant de résoudre de tels problèmes grâce à l'utilisation d'un nouveau type d'armature de ferraillage, permettant, en particulier, de diminuer le risque de fissuration à sollicitations égales. En outre, le procédé permet d'améliorer considérablement la résistance aux sollicitations extrêmes, les pièces en béton ainsi réalisées pouvant avoir une très grande souplesse et bénéficier d'un grand coefficient de sécurité entre l'apparition des premières fissures et la ruine complète de l'ouvrage. Un tel avantage est particulièrement intéressant pour la construction d'ouvrages d'art ou de bâtiments dans les régions soumises à un risque sismique.The subject of the invention is a new method for producing concrete moldings that makes it possible to solve such problems by using a new type of reinforcement reinforcement, which makes it possible in particular to reduce the risk of cracking at equal solicitations. In addition, the method makes it possible to considerably improve the resistance to extreme stresses, the concrete parts thus produced being able to have a very high degree of flexibility and benefit from a high degree of safety between the appearance of the first cracks and the complete failure of the cracks. 'work. Such This advantage is particularly interesting for the construction of structures or buildings in areas subject to seismic risk.

L'invention s'applique donc, d'une façon générale, à la réalisation d'une pièce en béton selon la revendication 1.The invention therefore applies, in a general manner, to the production of a concrete part according to claim 1.

Comme on le verra plus en détail par la suite, alors que la technique du béton armé a pour objet, d'une façon générale, de solidariser sur toute sa longueur chaque armature avec le béton qui l'enrobe, afin de réaliser une pièce composite se déformant en bloc sous l'effet des sollicitations, l'idée de l'invention est, au contraire, de réaliser des zones de blocage écartées, dans lesquelles l'armature, du fait qu'elle est constituée d'une bande plate, prend appui dans le béton par une face large, sans risque de dépasser la limite admissible de compression du béton et, à partir d'un certain niveau de sollicitation, de laisser la partie de l'armature comprise entre deux zones de compression, libre de glisser légèrement par rapport au béton qui l'enrobe, après décollement de celui-ci, afin que l'effet d'allongement de l'armature résultant des efforts de traction appliqués soit toujours réparti sur toute la longueur comprise entre deux zones de blocage, ce qui permet d'éviter les concentrations de contraintes pouvant conduire à une rupture de l'armature en cas de sollicitations extrêmes.As will be seen in more detail later, while the purpose of the reinforced concrete technique is, in general, to secure along its entire length each reinforcement with the concrete that surrounds it, in order to produce a composite part. being deformed as a block under the effect of the stresses, the idea of the invention is, on the contrary, to make separate locking zones, in which the reinforcement, because it consists of a flat strip, is supported in the concrete by a wide face, without risk of exceeding the permissible limit of concrete compression and, from a certain level of stress, to leave the part of the reinforcement comprised between two compression zones, free to slide slightly with respect to the concrete which surrounds it, after detachment thereof, so that the effect of elongation of the reinforcement resulting from the traction forces applied is always distributed over the entire length between two blocking zones, which avoids stress concentrations that can lead to a rupture of the armature in case of extreme stress.

En effet, la largeur et l'épaisseur d'une armature longitudinale tendue en forme de bande peuvent être déterminées en fonction d'un effort de traction maximal à absorber, d'une part afin d'obtenir une section transversale suffisante pour l'absorption dudit effort maximal en restant dans le domaine élastique et d'autre part, pour que, dans chaque zone de blocage, la partie du béton sur laquelle la bande prend appui par sa face large, soit soumise à une contrainte de compression ne dépassant pas une limite admissible.Indeed, the width and the thickness of a stretched longitudinal reinforcement in the form of a strip can be determined according to a maximum tensile force to be absorbed, on the one hand in order to obtain a cross-section sufficient for the absorption said maximum force remaining in the elastic range and secondly, so that, in each blocking zone, the part of the concrete on which the band bears by its wide face, is subjected to a compressive stress not exceeding one allowable limit.

De façon particulièrement avantageuse, la partie centrale de la bande tendue comprise entre deux parties vrillées est orientée de façon que sa face large soit sensiblement parallèle à la face longitudinale tendue de la pièce.Particularly advantageously, the central portion of the stretched strip between two twisted parts is oriented so that its broad face is substantially parallel to the taut longitudinal face of the workpiece.

Dans un autre mode de réalisation, qui ne fait pas partie de l'invention, chaque zone de blocage est réalisée par courbure de la bande plate autour d'un axe transversal, de façon à former une crosse d'ancrage prenant appui sur le béton par une face large.In another embodiment, which does not form part of the invention, each blocking zone is made by curving the flat strip around a transverse axis, so as to form an anchoring buttstock bearing on the concrete by a wide face.

Mais il est possible également de réaliser une zone de blocage en fixant sur la bande plate; à l'endroit voulu, au moins un tronçon de barre rigide s'étendant transversalement de façon à prendre appui dans le béton de part et d'autre de la bande plate. Ce mode de réalisation ne fait pas non plus partie de l'invention.But it is also possible to achieve a locking zone by fixing on the flat strip; at the desired location, at least one rigid bar section extending transversely so as to bear in the concrete on both sides of the flat strip. This embodiment is not part of the invention either.

Cette barre transversale peut être constituée d'un filant de répartition.This crossbar may consist of a distribution thread.

En effet, de façon classique, la cage de ferraillage comporte, habituellement, plusieurs secteurs longitudinaux reliés entre eux par des filants de répartition constitués de barres perpendiculaires aux barres principales longitudinales, l'ensemble constituant une nappe de ferraillage.In fact, in a conventional manner, the reinforcement cage usually comprises several longitudinal sectors interconnected by distribution threads consisting of bars perpendicular to the longitudinal main bars, the assembly constituting a sheet of reinforcement.

Ces filants de répartition peuvent être soudés sur les barres longitudinales, dont la forme de bande plate permet de réaliser des soudures particulièrement résistantes.These distribution threads can be welded to the longitudinal bars, whose flat strip shape allows for particularly strong welds.

Chaque jonction soudée peut constituer une zone de blocage, le filant de répartition prenant appui dans le béton de part et d'autre de la barre longitudinale. Par ailleurs, habituellement, chaque secteur de la cage de ferraillage comporte au moins deux barres longitudinales respectivement comprimée et tendue et reliées entre elles par des étriers de liaison.Each welded junction may constitute a blocking zone, the distribution thread being supported in the concrete on either side of the longitudinal bar. Furthermore, usually, each sector of the reinforcement cage comprises at least two longitudinal bars respectively compressed and tensioned and interconnected by connecting stirrups.

De préférence, les armatures comprimées sont également constituées de bandes plates.Preferably, the compressed frames also consist of flat strips.

De même, selon une autre disposition avantageuse, qui ne fait pas partie de l'invention, les étriers de liaison peuvent être constitués chacun d'au moins une bande plate solidarisée avec les armatures par des cordons de soudure ou des parties collées s'étendant sur une longueur égale à la largeur de la bande, et donc, particulièrement résistants.Similarly, according to another advantageous arrangement, which does not form part of the invention, the connecting stirrups may each consist of at least one flat strip secured to the reinforcements by welding beads or glued portions extending over a length equal to the width of the band, and therefore, particularly resistant.

En outre, chaque bande constituant un étrier est incliné par rapport à la direction de la barre tendue et l'ensemble de la jonction soudée entre ces deux bandes plates d'orientation différente, forme une sorte de coin prenant appui sur le béton.In addition, each band constituting a stirrup is inclined relative to the direction of the tensioned bar and the whole of the welded joint between these two flat strips of different orientation, forms a kind of corner bearing on the concrete.

De ce fait, chaque zone de blocage entre l'armature tendue et le béton peut être constituée par une jonction de solidarisation entre cette armature tendue et un étrier de liaison en forme de bande.Therefore, each blocking zone between the tensile reinforcement and the concrete may be constituted by a joining junction between the tensioned frame and a band-shaped connecting stirrup.

Mais l'utilisation de bandes plates pour réaliser au moins les armatures tendues donne encore d'autres possibilités.But the use of flat strips to achieve at least tensile frames gives further possibilities.

Ainsi, pour former une zone de blocage, l'armature tendue en forme de bande peut être fendue axialement sur une certaine longueur, les deux parties de bande ainsi constituées étant écartées l'une de l'autre pour former une ouverture de passage transversal d'au moins un tronçon de barre rigide susceptible de prendre appui sur le béton de part et d'autre de la bande longitudinale, dans le sens opposé à l'effort de traction appliqué sur l'armature longitudinale. Ce mode de réalisation ne fait pas partie de l'invention.Thus, to form a locking zone, the strip-shaped tensile reinforcement can be split axially over a certain length, the two band portions thus formed being spaced apart from one another to form a transverse passage opening of at least one rigid bar section likely to bear on the concrete on both sides of the longitudinal strip, in the opposite direction to the tensile force applied to the longitudinal reinforcement. This embodiment is not part of the invention.

Cette barre rigide peut être un filant de répartition traversant la bande longitudinale dans le plan de celle-ci, ou bien un simple tronçon de barre traversant la bande longitudinale perpendiculairement à son plan.This rigid bar may be a distribution wire passing through the longitudinal strip in the plane thereof, or a simple bar section passing through the longitudinal strip perpendicular to its plane.

Par ailleurs, l'utilisation de bandes plates permet de multiples possibilités pour la mise en oeuvre du procédé selon l'invention.Furthermore, the use of flat strips allows multiple possibilities for the implementation of the method according to the invention.

En particulier, chaque armature longitudinale peut comporter au moins deux bandes accolées s'étendant longitudinalement, sensiblement dans le prolongement l'une de l'autre et soumises à des efforts de traction en des sens opposés, les deux bandes accolées se recouvrant sur une certaine longueur et se terminant respectivement, de part et d'autre du recouvrement, par deux crosses tournées l'une vers l'autre, qui ont ainsi tendance à se rapprocher sous l'effet des efforts de traction opposés appliqués sur les deux bandes correspondantes, en induisant la mise en compression d'un noyau de béton compris entre les deux crosses, sur ladite longueur de recouvrement.In particular, each longitudinal reinforcement may comprise at least two contiguous strips extending longitudinally, substantially in the extension of one another and subjected to traction forces in opposite directions, the two contiguous strips overlapping on a certain length and ending respectively, on both sides of the cover, by two sticks facing towards each other, which thus tend to get closer under the effect of the opposite tensile forces applied to the two corresponding bands, by inducing the compression of a concrete core between the two ends, on said lap length.

Dans le cas habituel où la cage de ferraillage est constituée de secteurs parallèles reliés par des filants de répartition, ces derniers peuvent passer à l'intérieur des crosses de deux secteurs voisins, de façon à transmettre à la partie du béton comprise entre lesdits secteurs, les efforts de compression induits, dans chaque secteur, par la tendance au rapprochement des crosses opposées.In the usual case where the reinforcement cage consists of parallel sectors connected by distribution threads, the latter can pass inside the ends of two neighboring sectors, so as to transmit to the concrete part between said sectors, the compression efforts induced, in each sector, by the tendency towards the opposite ends.

Selon une disposition particulière, les deux bandes accolées formant l'armature longitudinale de chaque secteur de la cage, peuvent constituer deux brins d'une bande unique se terminant par des crosses opposées et formant une boucle entre deux niveaux écartés, de façon à entourer un noyau de béton mis en compression par serrage de ladite boucle sous l'effet des efforts de traction appliqués en des sens opposés sur les deux brins de l'armature longitudinale.According to a particular arrangement, the two contiguous strips forming the longitudinal reinforcement of each sector of the cage, may constitute two strands of a single band ending in opposite butts and forming a loop between two separated levels, so as to surround a concrete core set in compression by clamping said loop under the effect of traction forces applied in opposite directions on the two strands of the longitudinal reinforcement.

De façon particulièrement avantageuse, dans chaque secteur, l'armature longitudinale peut être constituée d'une série de bandes consécutives ayant chacune deux extrémités courbées en forme de crosse, les crosses adjacentes de deux bandes consécutives étant placées l'une à côté de l'autre en se chevauchant partiellement de façon à limiter un espace de passage, dans le sens transversal, d'au moins un tronçon de barre formant une clavette de liaison entre les deux bandes consécutives. L'armature longitudinale se comporte alors comme une chaîne tendue constituée d'une série de maillons formés chacun d'une bande et reliés deux à deux par des paires de crosses adjacentes clavetées entre elles.Particularly advantageously, in each sector, the longitudinal reinforcement may consist of a series of consecutive strips each having two curved ends in the form of a butt, the adjacent ends of two consecutive strips being placed next to the other partially overlapping so as to limit a passage space, in the transverse direction, of at least one bar section forming a connecting key between the two consecutive strips. The longitudinal reinforcement then behaves like a tensioned chain consisting of a series of links each formed of a band and connected in pairs by pairs of adjacent sticks keyed together.

Dans un autre mode de réalisation également avantageux, dans chaque secteur, l'armature longitudinale comprend un empilement de bandes plates, disposées sur au moins deux niveaux superposés, respectivement un premier niveau, le plus proche d'une face longitudinale tendue de la pièce comportant une bande, avec deux extrémités en forme de crosses tournées vers l'intérieur de la pièce et au moins un second niveau comportant au moins deux bandes plates sensiblement parallèles disposées côte à côte avec, chacune, deux extrémités en forme de crosses, respectivement interne et externe, et lesdites bandes du second niveau se chevauchent sur une certaine longueur, de façon que leurs extrémités internes en forme de crosses soient tournées l'une vers l'autre. La pièce comporte ainsi au moins une partie formant un noyau compris entre les crosses internes des deux bandes et mis en compression par la tendance au rapprochement l'une vers l'autre desdites crosses internes sous l'effet des efforts de traction appliqués en des sens opposés sur les bandes correspondantes, et deux parties extrêmes comprises chacune entre les crosses externes des bandes du premier et du second niveau et mises en compression par la tendance au rapprochement vers l'intérieur de chaque crosse externe de la bande du premier niveau sous l'effet de l'effort de traction supporté par ladite bande. Il est ainsi possible de mettre en compression l'ensemble du béton de la pièce.In another equally advantageous embodiment, in each sector, the longitudinal reinforcement comprises a stack of flat strips arranged on at least two superimposed levels, respectively a first level, the closest to a stretched longitudinal face of the piece comprising a band, with two stick-shaped ends turned towards the inside of the piece and at least a second level comprising at least two substantially parallel flat strips arranged side by side with each two end-shaped sticks, respectively internal and external, and said strips of the second level overlap over a certain length, so that their inner ends in the form of sticks are turned towards each other. The part thus comprises at least one portion forming a core between the inner ends of the two strips and set in compression by the tendency towards the one towards the other of said internal butts under the effect of the tensile forces applied in the directions opposing on the corresponding bands, and two extreme parts each included between the outer hooks of the bands of the first and the second level and put in compression by the tendency to inward approximation of each external butt of the band of the first level under the effect of the tensile force supported by said band. It is thus possible to compress the entire concrete of the room.

Mais l'invention permet encore d'autres dispositions et couvre de nombreuses caractéristiques avantageuses qui apparaîtront dans la description qui va suivre de certains modes de réalisation donnés à titre d'exemples non limitatifs illustrés par les Figures 1 à 8, 19 et 20 annexées. Les figures 9 à 17 montrent des modes de réalisation, dans lesquels les zones de blocage ne sont pas formées par des parties vrillées des bandes plates. Par conséquent, ces figures 9 à 17 ne forment pas partie de l'invention.

  • La figure 1 est une vue schématique, en coupe longitudinale, d'une pièce en béton réalisée selon l'invention.
  • La figure 2 est une vue partielle en coupe transversale selon II-II de la figure 1.
  • La figure 3 est une vue en perspective d'une partie vrillée de l'armature.
  • La figure 4 est une vue en coupe, selon un plan médian transversal, de la partie vrillée.
  • La figure 5 est une vue partielle, en perspective, d'une partie en forme de crosse.
  • La figure 6 est une vue partielle de côté, d'une crosse double.
  • La figure 7 est une vue en coupe longitudinale d'une pièce réalisée selon une variante de l'invention.
  • La figure 8 montre, en perspective, une partie vrillée appliquée au mode de réalisation de la figure 7.
  • La figure 9 montre, en coupe longitudinale, une pièce réalisée selon une autre variante, qui ne fait pas partie de l'invention.
  • Les figures 10 et 11 montrent, en coupe longitudinale, d'autres variantes, qui ne font pas partie de l'invention, avec plusieurs nappes d'armatures.
  • La figure 12 montre, en coupe longitudinale, une pièce du type représenté sur la figure 10, avec une armature en boucle fermée.
  • La figure 13 est une vue en perspective d'une armature en boucle fermée.
  • La figure 14 montre, en coupe longitudinale, une autre variante, qui ne fait pas partie de l'invention, avec une armature en forme de chaîne.
  • La figure 15 montre, en perspective, la jonction entre deux éléments de l'armature du type représenté sur la figure 14.
  • Les figures 16, 17, 18 montrent, en perspective, d'autres modes de réalisation d'une zone de blocage.
  • La figure 19 montre, en perspective, une zone de blocage en forme de crosse.
  • La figure 20 montre, en perspective, un autre mode de réalisation d'une extrémité d'armature en forme de crosse.
But the invention still allows other provisions and covers many advantageous features which will appear in the following description of certain embodiments given by way of non-limiting examples illustrated by the Figures 1 to 8 , 19 and 20 attached. The Figures 9 to 17 show embodiments, in which the locking zones are not formed by twisted portions of the flat strips. Therefore, these Figures 9 to 17 do not form part of the invention.
  • The figure 1 is a schematic view, in longitudinal section, of a concrete part made according to the invention.
  • The figure 2 is a partial cross sectional view along II-II of the figure 1 .
  • The figure 3 is a perspective view of a twisted part of the frame.
  • The figure 4 is a sectional view, along a transverse median plane, of the twisted part.
  • The figure 5 is a partial view, in perspective, of a part in the shape of a stick.
  • The figure 6 is a partial side view of a double butt.
  • The figure 7 is a longitudinal sectional view of a part made according to a variant of the invention.
  • The figure 8 shows, in perspective, a twisted part applied to the embodiment of the figure 7 .
  • The figure 9 shows, in longitudinal section, a part made according to another variant, which does not form part of the invention.
  • The Figures 10 and 11 show, in longitudinal section, other variants, which do not form part of the invention, with several plies of reinforcement.
  • The figure 12 shows, in longitudinal section, a part of the type shown on the figure 10 , with a closed loop frame.
  • The figure 13 is a perspective view of a closed-loop frame.
  • The figure 14 shows, in longitudinal section, another variant, which does not form part of the invention, with a chain-like reinforcement.
  • The figure 15 shows, in perspective, the junction between two elements of the armature of the type represented on the figure 14 .
  • The Figures 16, 17, 18 show, in perspective, other embodiments of a blocking zone.
  • The figure 19 shows, in perspective, a locking zone in the shape of a stick.
  • The figure 20 shows, in perspective, another embodiment of a butt-shaped frame end.

Sur les figures 1 et 2, on a représenté, respectivement en coupe longitudinale et en coupe transversale, une pièce en béton réalisée selon l'invention.On the Figures 1 and 2 in longitudinal section and in cross-section, a concrete part made according to the invention is shown respectively.

Comme habituellement, cette pièce en béton 1 qui constitue, dans l'exemple représenté sur les dessins, une dalle ayant deux faces planes, respectivement inférieure 20 et supérieure 21, est une pièce moulée réalisée par coulée d'une masse de béton 2 dans un coffrage, après mise en place, dans celui-ci d'une cage de ferraillage 3 comportant deux nappes d'armature, respectivement inférieure 30 et supérieure 30', sensiblement parallèles aux deux faces 20, 21 de la dalle 1.As usual, this concrete part 1 which constitutes, in the example shown in the drawings, a slab having two planar faces, respectively bottom and top 21, is a molded part made by casting a mass of concrete 2 in a formwork, after placing in it a reinforcement cage 3 comprising two reinforcement plies, respectively lower and upper 30 ', substantially parallel to the two faces 20, 21 of the slab 1.

La cage de ferraillage 3 est constituée, normalement, de plusieurs secteurs S1, S2,... centrés, respectivement, dans des plans P1, P2... parallèles à un axe longitudinal de la pièce 1, c'est-à-dire au plan de la figure 1, et comprenant chacun une armature longitudinale inférieure 31 et une armature longitudinale supérieure 31' qui sont reliées entre elles, dans le plan P1, P2 du secteur S1, S2 par des armatures transversales appelées étriers, qui ne sont pas représentées sur les figures 1 et 2.The reinforcement cage 3 normally consists of several sectors S1, S2, ... centered, respectively, in planes P1, P2 ... parallel to a longitudinal axis of the part 1, that is to say in terms of figure 1 and each comprising a lower longitudinal reinforcement 31 and an upper longitudinal reinforcement 31 'which are interconnected in the plane P1, P2 of the sector S1, S2 by transverse reinforcements called stirrups, which are not shown on the Figures 1 and 2 .

De plus, les différents secteurs S1, S2... de la cage sont reliés entre eux par des filants transversaux 32, 32' perpendiculaires au plan de la figure 1.In addition, the different sectors S1, S2... Of the cage are interconnected by transverse threads 32, 32 'perpendicular to the plane of the figure 1 .

Comme on le sait, sous l'effet, par exemple, d'une charge verticale M appliquée sur sa face supérieure 20', la pièce en béton 1 peut être divisée en deux parties situées de part et d'autre d'un axe neutre 10 respectivement une partie comprimée 11' comprise entre l'axe neutre 10 et la face 21 sur laquelle sont appliqués les efforts et une partie tendue 11 s'étendant jusqu'à la face 20 opposée aux efforts.As is known, under the effect, for example, of a vertical load M applied on its upper face 20 ', the part in concrete 1 can be divided into two parts located on either side of a neutral axis 10 respectively a compressed portion 11 'between the neutral axis 10 and the face 21 on which the forces are applied and a stretched portion 11 s extending to face 20 opposed to efforts.

Toutes ces dispositions sont classiques et ne nécessitent pas une description détaillée.All these arrangements are conventional and do not require a detailed description.

Cependant, la cage de ferraillage 3 se distingue des cages réalisées habituellement par le fait que, selon une disposition décrite dans la demande de brevet FR-A-2 814 480 du même inventeur, au moins les armatures longitudinales 31 situées dans la partie tendue 11 de la pièce et s'étendant à une faible distance d'enrobage de la face inférieure 20, sont constituées de barres métalliques plates 4 à section rectangulaire, avec une face large 41 et une face étroite 42, chaque barre plate étant ainsi constituée d'une bande métallique ayant une largeur I sensiblement supérieure à son épaisseur e.However, the reinforcement cage 3 differs from the cages usually produced by the fact that, according to a provision described in the patent application FR-A-2,814,480 of the same inventor, at least the longitudinal reinforcements 31 situated in the stretched portion 11 of the part and extending at a short distance from the bottom face 20 are constituted by flat metal bars 4 with a rectangular section, with one face wide 41 and a narrow face 42, each flat bar thus consisting of a metal strip having a width I substantially greater than its thickness e.

De préférence, les armatures comprimées 31' sont également constituées de barres plates mais, par économie, on pourrait aussi utiliser des barres rondes classiques.Preferably, the compressed armatures 31 'are also constituted by flat bars but, for economy, it would also be possible to use conventional round bars.

Comme l'indique le brevet précédent FR-A-2,814,480 du même inventeur, la section transversale (l x e) de la bande 4 est calculée, de façon classique, en fonction des efforts de traction à supporter compte tenu des sollicitations appliquées sur la pièce 1. En effet, sous l'effet de la charge M, la pièce 1 a tendance à fléchir légèrement, chaque armature longitudinale 31 de la nappe inférieure 30 étant soumise à un effort de traction qui tend à l'allonger.As indicated in the previous patent FR-A-2814480 of the same inventor, the cross section (lxe) of the strip 4 is calculated, conventionally, as a function of the tensile forces to bear in view of the stresses applied to the part 1. Indeed, under the effect of the load M the part 1 tends to bend slightly, each longitudinal reinforcement 31 of the lower ply 30 being subjected to a tensile stress which tends to lengthen it.

Dans la technique classique du béton armé, on utilise, généralement, des barres d'armature crantées afin d'améliorer la liaison de transfert entre l'armature et le béton et l'on réalise ainsi une pièce composite dont on cherche, habituellement, à augmenter la rigidité afin d'éviter l'apparition de fissures préjudiciables. Cependant, on ne peut éviter une déformation même minime de la pièce avec un allongement des armatures tendues ainsi que du béton qui les enrobe, dont la résistance à la traction est minime. Il en résulte donc l'apparition de fissures à partir d'une certaine charge.In the conventional reinforced concrete technique, notched reinforcement bars are generally used in order to improve the transfer bond between the reinforcement and the concrete, thereby producing a composite part which is usually sought after. increase rigidity to avoid the appearance of harmful cracks. However, we can not avoid a deformation even minimal of the piece with an elongation of tensioned reinforcements as well as the concrete which coats them, whose resistance to traction is minimal. This results in the appearance of cracks from a certain load.

Dans l'invention, au contraire, on ne cherche pas, comme habituellement, à solidariser l'armature avec le béton sur toute sa longueur mais, au contraire, on ménage dans le béton 2, le long de chaque armature longitudinale tendue 31, deux zones de blocage B, B' écartées de part et d'autre du plan médian transversal Q de la pièce, entre lesquelles s'étend une zone centrale C dans laquelle l'armature 31 est libre de s'allonger sous l'effet des efforts appliqués, en glissant par rapport au béton qui l'enrobe.In the invention, on the contrary, it is not sought, as usually, to secure the reinforcement with the concrete over its entire length but, on the contrary, it is cleaned in the concrete 2, along each stretched longitudinal reinforcement 31, two blocking zones B, B 'spaced apart on both sides of the transverse median plane Q of the part, between which extends a central zone C in which the armature 31 is free to stretch under the effect of the forces applied, sliding with respect to the concrete which enrobe it.

Du fait que l'on utilise, comme armature longitudinale, des bandes plates, chaque zone de blocage B, B', peut être réalisée simplement par déviation de la partie correspondante de l'armature tendue 31, dont on fait varier progressivement et de façon continue l'orientation de sa face large par rapport à la face longitudinale tendue 20 de la pièce afin que, dans cette zone, la bande 4 formant l'armature 31 prenne appui dans le béton, principalement, par son côté large 41, dans le sens opposé à l'effort de traction absorbé.Due to the fact that flat strips are used as longitudinal reinforcement, each blocking area B, B 'can be achieved simply by deflecting the corresponding part of the stretched reinforcement 31, which is gradually and progressively varied. continues the orientation of its wide face relative to the longitudinal stretched face 20 of the part so that, in this area, the band 4 forming the frame 31 is supported in the concrete, mainly by its wide side 41, in the opposite direction to the tensile force absorbed.

Dans l'exemple de réalisation représentée sur les figures 1 à 4, chaque zone de blocage B, B' est réalisée par vrillage de la bande 4 sur une certaine longueur L1, avec une rotation progressive de sa face large 41 autour de son axe longitudinale 40.In the exemplary embodiment shown on the Figures 1 to 4 each locking zone B, B 'is made by twisting the strip 4 over a certain length L1, with a progressive rotation of its wide face 41 about its longitudinal axis 40.

Dans le cas représenté sur la figure 3, la bande est vrillée sur un tour complet. Si l'on considère une bande horizontale 4 soumise à un effort de traction T dirigé vers la droite et ayant une partie 43 vrillée sur un tour complet de part et d'autre d'un plan médian P, l'effort de traction T appliqué sur la bande 4 détermine, comme dans un tire-bouchon, un appui de cette bande 4 dans le béton par ses deux faces 41, 41'. Du fait que la bande est plate et prend appui dans le béton par deux faces larges, le béton ne risque pas de se cisailler, la contrainte de compression étant faible. D'ailleurs, la largeur I de la bande 4 peut être déterminée en fonction des sollicitations appliquées, de façon à ce que la contrainte de compression appliquée sur le béton reste inférieure à une limite admissible.In the case shown on the figure 3 , the band is twisted on a complete turn. If we consider a horizontal band 4 subjected to a tensile force T directed to the right and having a part 43 twisted on a complete turn on either side of a median plane P, the tensile force T applied on the band 4 determines, as in a corkscrew, a support of this band 4 in the concrete by its two faces 41, 41 '. Because the band is flat and bears in the concrete by two faces wide, the concrete is not likely to shear, the compression stress is low. Moreover, the width I of the band 4 can be determined according to the stresses applied, so that the compressive stress applied to the concrete remains below a permissible limit.

La bande d'armature 4 ainsi solidarisée avec le béton par ses deux parties vrillées 43, 43' qui constituent des zones de blocage B et B' peut, en revanche, s'allonger librement dans sa partie centrale 44 comprise entre les deux parties vrillées 43, 43'.The reinforcing strip 4 thus secured to the concrete by its two twisted parts 43, 43 'which constitute blocking areas B and B' may, on the other hand, freely elongate in its central portion 44 between the two twisted parts. 43, 43 '.

Certes, après le bétonnage, il existe une liaison d'adhérence entre le béton et l'armature sur toute la longueur de celle-ci. Cependant, on évite, contrairement à la technique habituelle d'améliorer cette adhérence, par exemple au moyen de crans.Admittedly, after concreting, there is a bond of adhesion between the concrete and the reinforcement over the entire length of the latter. However, it is avoided, contrary to the usual technique to improve this adhesion, for example by means of notches.

Dans l'invention, en effet, chaque bande 4 constituant une armature longitudinale 31 n'est solidarisée avec le béton que dans les deux zones de blocage B, B' qui sont écartées l'une de l'autre et la tendance à l'allongement de l'armature sous l'effet de la tension appliquée peut se répartir uniformément sur toute la longueur L2 de la partie centrale 44 comprise entre les deux parties vrillées 43, 43', cette partie centrale 44 pouvant se décoller du béton à partir d'un certain niveau de sollicitation.In the invention, in fact, each band 4 constituting a longitudinal reinforcement 31 is secured to the concrete only in the two blocking zones B, B 'which are separated from each other and the tendency to extension of the reinforcement under the effect of the applied tension can be distributed uniformly over the entire length L 2 of the central portion 44 between the two twisted parts 43, 43 ', this central portion 44 being able to be detached from the concrete from a certain level of solicitation.

Certes, le béton 2 ne peut pas se déformer de la même façon que l'armature et l'on ne peut donc éviter l'apparition de fissures mais ce risque de fissuration se répartit uniformément sur toute la longueur L2 de la partie centrale 44 et les fissures plus nombreuses peuvent avoir une largeur assez réduite pour ne pas être préjudiciable.Admittedly, the concrete 2 can not deform in the same way as the reinforcement and therefore we can not avoid the appearance of cracks but this risk of cracking is distributed uniformly over the entire length L 2 of the central portion 44 and more cracks may have a width that is small enough not to be detrimental.

De la sorte, il n'est plus nécessaire, comme auparavant, d'augmenter la rigidité de la pièce en béton pour diminuer sa déformation et, au contraire, on peut réaliser des pièces en béton relativement souples.In this way, it is no longer necessary, as before, to increase the rigidity of the concrete part to reduce its deformation and, on the contrary, it is possible to make relatively flexible concrete parts.

Lorsque les sollicitations appliquées restent faibles, la pièce se comporte, comme habituellement, comme une pièce composite, le béton se déformant de la même façon que l'armature.When the applied stresses remain low, the piece behaves, as usual, as a piece composite, the concrete deforming in the same way as the reinforcement.

A partir d'un certain niveau de sollicitation, l'armature ne reste solidarisée avec le béton que dans ses parties de blocage 43, 43' et sa partie centrale 44 peut, au contraire, se décoller du béton qui l'enrobe et glisser légèrement par rapport à celui-ci. La tension et, par conséquent, la tendance à l'allongement de l'armature, se répartit donc de façon sensiblement uniforme sur toute la longueur L2 de la partie centrale 44. On évite ainsi une concentration de la contrainte de traction sur une faible longueur de l'armature et, par conséquent, on diminue le risque de rupture de l'armature au niveau d'une fissure, sous l'effet de sollicitations excessives.From a certain level of stress, the reinforcement remains secured to the concrete only in its blocking parts 43, 43 'and its central portion 44 can, on the contrary, peel off the concrete which coats it and slide slightly in relation to this one. The tension and, consequently, the tendency for the elongation of the reinforcement is therefore distributed substantially uniformly over the entire length L 2 of the central portion 44. This avoids a concentration of the tensile stress on a low length of the armature and, therefore, it reduces the risk of rupture of the armature at a crack, under the effect of excessive stresses.

A titre d'exemple on a soumis des dalles réalisées selon l'invention à des essais de flexion avec augmentation progressives, de la charge appliquée et l'on a constaté qu'une dalle ainsi réalisée pouvait, de façon surprenante, admettre une flèche très importante avant la rupture de la dalle et avec des fissures de largeur relativement faibles.By way of example, slabs made according to the invention have been subjected to progressive flexural tests with increasing load, and it has been found that a slab thus produced could, surprisingly, admit a very narrow deflection. important before the slab breaks and with relatively small width cracks.

Il est à noter, en outre, que comme on l'avait indiqué dans la demande de brevet FR-A-2 814 480 , l'utilisation, comme armatures, de bandes plates permet de réduire globalement l'épaisseur de la dalle car les étriers, qui sont également constitués d'une bande plate éventuellement ondulée, peuvent être soudés sur la face interne de chaque bande dont la face externe ne doit être séparée de la face de parement 20 de la dalle, que de la distance minimale d'enrobage imposée par la réglementation.It should be noted, moreover, that as stated in the patent application FR-A-2,814,480 the use, as reinforcements, of flat strips makes it possible to reduce overall the thickness of the slab because the stirrups, which are also constituted by a possibly corrugated flat strip, can be welded to the inside face of each strip whose face external should be separated from the facing face 20 of the slab, the minimum coating distance imposed by the regulations.

En outre, dans une pièce en béton armé réalisée de façon classique, les barres longitudinales tendues doivent être recourbées en forme de crosse à leurs extrémités afin d'augmenter la longueur de transfert entre l'armature et le béton. Or, compte tenu de la dureté de l'acier employé, la courbure que l'on peut donner à une barre est nécessairement limitée et la réglementation impose, d'ailleurs, de donner à la crosse un diamètre d'au moins 10 fois le diamètre de la barre. Pour cette seule raison, une pièce en béton doit avoir une épaisseur minimale de douze fois le diamètre des barres tendues à laquelle il faut ajouter deux fois l'épaisseur minimale d'enrobage.In addition, in a conventionally made reinforced concrete part, the stretched longitudinal bars must be curved in the shape of a butt at their ends in order to increase the transfer length between the reinforcement and the concrete. However, given the hardness of the steel used, the curvature that can be given to a bar is necessarily limited and regulations require, moreover, to give the stick a diameter of at least 10 times the diameter of the bar. For this reason alone, a concrete part must have a minimum thickness of twelve times the diameter of the tension bars, to which must be added twice the minimum thickness of the coating.

Si l'on utilise, comme dans l'invention, des barres plates, celles-ci peuvent également être munies à leurs extrémités, de crosses 5, de la façon représentée en perspective sur la figure 5, mais ces crosses 5 peuvent avoir un diamètre interne D plus faible que dans le cas d'une ou plusieurs barres rondes, du fait que l'épaisseur e d'une bande plate à section rectangulaire est inférieure au diamètre d'une ou même plusieurs barres rondes de même section équivalente.If, as in the invention, flat bars are used, these can also be provided at their ends with hooks 5, as shown in perspective on the figure 5 , but these sticks 5 may have a smaller internal diameter D than in the case of one or more round bars, because the thickness e of a rectangular section flat strip is smaller than the diameter of one or more round bars of the same equivalent section.

En outre, même si l'on utilise des aciers à limite élastique élevée, l'utilisation de bandes plates permet de réduire encore le diamètre D de la partie recourbée car celle-ci peut être plus facilement pliée autour d'un axe 50 parallèle au plan de la face large de la bande.In addition, even if high yielding steels are used, the use of flat belts makes it possible to further reduce the diameter D of the curved portion since it can be more easily folded around an axis 50 parallel to the plane of the broad side of the band.

De plus, comme le montre la figure 20, il est possible de faire tourner la crosse autour d'un axe vertical afin de réduire encore l'épaisseur de la dalle 1.In addition, as shown in figure 20 it is possible to rotate the stock around a vertical axis to further reduce the thickness of the slab 1.

Pour cette raison, il est possible à poids de ferraillage égal, de réaliser des pièces plus minces que les pièces réalisées de façon classique en béton armé.For this reason, it is possible for even reinforcement weight to produce thinner parts than those made in conventional reinforced concrete.

Par ailleurs, chaque crosse 5 constitue également une zone B1 de blocage dans le béton 2.Moreover, each butt 5 also constitutes a blocking zone B1 in the concrete 2.

Etant donné que, selon l'invention, l'armature longitudinale est accrochée au béton dans les zones de blocage 43, 5 alors que la partie centrale 44 est libre de s'allonger, les sollicitations appliquées par l'armature sur le béton sont plus fortes que dans le cas d'un ferraillage classique où l'on cherche à réaliser une solidarisation sur toute la longueur de l'armature. Bien entendu, ceci se traduit, dans les zones de blocage par un effort de compression plus important dans le béton mais, précisément, le béton présente une excellente résistance à la compression.Since, according to the invention, the longitudinal reinforcement is attached to the concrete in the locking zones 43, 5 while the central portion 44 is free to stretch, the stresses applied by the reinforcement on the concrete are more strong than in the case of a conventional reinforcement where one seeks to achieve a solid connection over the entire length of the frame. Of course, this results, in the locking zones by a compression effort more important in concrete but, precisely, the concrete has excellent compressive strength.

De plus, il n'y a pas à craindre comme dans le cas d'une barre ronde, un effet de cisaillement du béton, car la largeur I de chaque barre plate peut être déterminée en fonction des efforts appliqués de façon que la contrainte de compression du béton ne dépasse pas une limite donnée.In addition, there is no need to fear, as in the case of a round bar, a shearing effect of the concrete, since the width I of each flat bar can be determined according to the forces applied so that the stress of concrete compression does not exceed a given limit.

Du fait que la bande 4 est soumise à un effort important de traction T qui est encaissé par la zone de blocage B1 située à l'intérieur de la crosse 5, celle-ci peut avoir tendance à se dérouler si l'adhérence entre la barre 4 est le béton n'est pas suffisante.Because the band 4 is subjected to a large tensile force T which is concealed by the blocking zone B1 located inside the butt 5, it may tend to unfold if the adhesion between the bar 4 is the concrete is not enough.

Pour éviter un tel effet, il est possible d'adjoindre à la crosse 5 une crosse auxiliaire 51 tournée dans le sens opposé et ayant un diamètre un peu plus faible, afin d'éviter cet effet de déroulement.To avoid such an effect, it is possible to add to the butt 5 an auxiliary butt 51 turned in the opposite direction and having a slightly smaller diameter, to avoid this unwinding effect.

Il est à noter, par ailleurs, que dans le mode de réalisation préférentiel représenté sur la figure 1, chaque barre tendue 31 constituée d'une bande plate 4 est orientée de façon que sa face large 41 soit sensiblement parallèle à la face tendue 20 de la pièce. Une telle disposition augmente la souplesse de la dalle car la barre 4 ainsi orientée ne présente qu'une faible résistance à la flexion et le fléchissement de la pièce se traduit simplement par un allongement de l'armature.It should be noted, moreover, that in the preferred embodiment represented on the figure 1 each tension bar 31 consisting of a flat strip 4 is oriented so that its wide face 41 is substantially parallel to the taut face 20 of the workpiece. Such an arrangement increases the flexibility of the slab because the bar 4 thus oriented has a low resistance to bending and the bending of the piece simply results in an elongation of the frame.

Il est possible, cependant, si l'on souhaite augmenter la résistance au fléchissement, d'utiliser des bandes 4 orientées de la façon indiquée sur la figure 7. Dans ce cas, en effet, chaque bande d'armature 4 est vrillée dans deux parties 43, 43' écartées l'une de l'autre, mais seulement sur un quart de tour de telle sorte que, dans la partie centrale 44' et sur toute la longueur de celle-ci le côté large 41 de la bande 4 soit situé dans un plan orthogonal à la face tendue 20 de la pièce.It is possible, however, if one wishes to increase the resistance to bending, to use oriented strips 4 in the manner indicated on the figure 7 . In this case, indeed, each reinforcing strip 4 is twisted in two parts 43, 43 'spaced apart from each other, but only over a quarter of a turn so that in the central portion 44' and along the entire length thereof the wide side 41 of the strip 4 is located in a plane orthogonal to the stretched face 20 of the part.

Dans ce cas, le blocage de la bande 4 dans le béton est réalisé essentiellement au niveau des zones B1, B'1, à l'intérieur des crosses 5, 5', ménagées aux extrémités de la bande 4, l'effet de blocage des parties vrillées 43, 43' étant diminué.In this case, the blocking of the strip 4 in the concrete is essentially achieved at the level of the zones B1, B'1, inside the butts 5, 5 ', formed at the ends of the band 4, the locking effect of the twisted portions 43, 43 'being decreased.

En revanche, chaque bande d'armature 4 orientée, dans sa partie centrale 44', perpendiculairement à la face tendue 20, apporte par elle-même une certaine résistance à la flexion qui permet d'augmenter la rigidité de la pièce et de diminuer la flèche résultant des efforts appliqués.On the other hand, each reinforcing strip 4 oriented, in its central part 44 ', perpendicular to the stretched face 20, itself provides a certain resistance to bending which makes it possible to increase the rigidity of the part and to reduce the arrow resulting from the efforts applied.

Comme habituellement, les barres longitudinales 31, 31' des deux nappes, respectivement inférieures 30 et supérieures 30' peuvent être reliées par des étriers qui, de la façon décrite dans le document FR-A-2 814 480 , sont avantageusement constituées de bandes plates ondulées 13 solidarisées avec les armatures longitudinales, au sommet des ondulations, par soudage ou collage.As usual, the longitudinal bars 31, 31 'of the two plies, respectively lower and upper 30' can be connected by stirrups which, as described in the document FR-A-2,814,480 , advantageously consist of corrugated flat strips 13 secured to the longitudinal reinforcements, at the top of the corrugations, by welding or gluing.

Cependant, comme le montre la figure 9, pour la mise en oeuvre du procédé, il est préférable que les soudures entre les bandes ondulées 13 et les bandes 4 constituant les armatures tendues 31, soient effectuées seulement à proximité des deux extrémités de la pièce 1 de façon que la partie centrale 44 de chaque bande 4 puisse s'allonger librement.However, as shown in figure 9 for the implementation of the method, it is preferable that the welds between the corrugated strips 13 and the strips 4 constituting the tensile plates 31, are made only near the two ends of the part 1 so that the central portion 44 of each band 4 can lie freely.

En revanche, les étriers peuvent être soudés ou collés sur les barres comprimées 31' à la partie supérieure de chaque ondulation. Pour cela, il est préférable que chaque barre comprimée 31' soit également constituée d'au moins une bande plate, afin de réaliser un cordon de soudure sur toute la largeur de la bande ondulée 13.In contrast, the stirrups may be welded or glued to the compressed bars 31 'at the top of each corrugation. For this, it is preferable that each compressed bar 31 'also consists of at least one flat strip, in order to produce a weld bead over the entire width of the corrugated strip 13.

Il est à noter que chaque jonction soudée ou collée 34 entre une barre 4 et la partie correspondante de l'étrier 13 qui forme un angle avec cette barre 4 constitue, par effet de coin, une zone de blocage B. Il est donc inutile, dans ce cas, de munir la bande 4 de parties vrillées. En revanche, il est avantageux de recourber les extrémités en forme de crosses 5 afin de ménager, comme précédemment, des zones de blocage B1, B'1 aux deux extrémités de l'armature 31.It should be noted that each welded or glued joint 34 between a bar 4 and the corresponding part of the stirrup 13 which forms an angle with this bar 4 constitutes, by wedge effect, a blocking zone B. It is therefore unnecessary, in this case, provide the band 4 twisted parts. On the other hand, it is advantageous to bend the ends in the form of hooks 5 in order to provide, as previously, locking zones B1, B'1 at both ends of the frame 31.

Mais ce procédé peut faire l'objet d'autres variantes, en particulier en mettant à profit les efforts d'appui exercés dans le béton par les zones de blocage des armatures longitudinales, par exemple de la façon représentée schématiquement sur les figures 10 à 20 qui illustrent diverses variantes. Pour simplifier, les armatures comprimées 31' n'ont pas été représentées sur ces figures.However, this method may be the subject of other variants, in particular by taking advantage of the support forces exerted in the concrete by the longitudinal reinforcement locking zones, for example as shown schematically on the Figures 10 to 20 which illustrate various variants. For simplicity, the compressed frames 31 'have not been shown in these figures.

Dans une première variante représentée sur la figure 10, la nappe inférieure 30 de la cage de ferraillage 3 comporte deux niveaux superposés. Au niveau le plus bas, le plus proche de la face inférieure tendue 20 de la pièce, chaque secteur de la cage de ferraillage comporte une armature longitudinale 31 constituée d'une bande plate qui s'étend sur toute la longueur de la pièce 1 et dont les extrémités 5, 5' sont recourbées en forme de crosse comme indiqué précédemment.In a first variant represented on the figure 10 , the lower ply 30 of the reinforcement cage 3 comprises two superimposed levels. At the lowest level, the closest to the taut underside of the workpiece, each sector of the reinforcement cage comprises a longitudinal reinforcement 31 consisting of a flat band which extends over the entire length of the workpiece 1 and whose ends 5, 5 'are curved in the shape of a stick as indicated above.

Cependant ces barres longitudinales 31 sont associées à un second niveau de barres longitudinales décalées vers le haut et comprenant, dans chaque secteur de la cage, deux barres 33, 34 formées chacune d'une bande plate et posées côte à côte, chacune de ces barres 33, 34 étant munie d'extrémités recourbées en forme de crosses 51, 51', 52, 52'.However, these longitudinal bars 31 are associated with a second level of longitudinal bars offset upwards and comprising, in each sector of the cage, two bars 33, 34 each formed of a flat strip and placed side by side, each of these bars. 33, 34 being provided with curved ends in the form of hooks 51, 51 ', 52, 52'.

En outre, les deux bandes accolées 33, 34 d'un même secteur sont décalées longitudinalement l'une par rapport à l'autre de façon que les deux crosses 51, 51' (52, 52') ménagées aux extrémités de chaque bande 33 (34) soient placées à des distances différentes du plan médian transversal Q de la pièce 1, de part et d'autre de celui-ci.In addition, the two contiguous strips 33, 34 of the same sector are offset longitudinally relative to each other so that the two brackets 51, 51 '(52, 52') formed at the ends of each strip 33 (34) are placed at different distances from the transverse median plane Q of the part 1, on both sides of it.

Ainsi, la crosse externe 51 de la barre 33 placée à gauche sur la figure 10 est plus éloignée du plan médian Q que la crosse externe 51' de la même bande 31, placée à droite et la disposition est inversée pour la seconde bande longitudinale 34. D'autre part, les longueurs des barres longitudinales 33, 34 sont déterminées de façon que les différentes crosses 5, 51, 52 placées d'un même côté du plan médian transversal Q soient réparties sur une certaine longueur de la pièce 1 à partir de son extrémité 11.Thus, the outer stock 51 of the bar 33 placed on the left on the figure 10 is farther from the median plane Q than the outer stock 51 'of the same band 31, placed on the right and the disposition is reversed for the second longitudinal band 34. On the other hand, the lengths of the longitudinal bars 33, 34 are determined from way that the different sticks 5, 51, 52 placed on the same side of the transverse median plane Q are distributed over a certain length of the piece 1 from its end 11.

La pièce 1 est ainsi divisée en plusieurs zones adjacentes :

  • une zone centrale 83 comprise entre la crosse interne 51' de l'armature longitudinale 33 placée à droite du plan médian transversal Q et la crosse interne 52 de l'armature 34 placée à gauche de ce plan;
  • deux zones latérales B2, B'2 placées respectivement, à gauche et à droite du plan Q la zone de gauche B2 étant comprise entre la crosse externe 51 de la bande 33 et la crosse interne de la barre 34 et la zone de droite B'2 entre la crosse externe 52' de la bande 34 et la crosse interne 51' de la bande 33;
  • deux zones extrêmes B1 et B'1 comprises, respectivement à gauche et à droite, entre les crosses 5, 5' de la bande inférieure 31, et les crosses externes 51, 52' des bandes supérieures 33, 34.
Part 1 is thus divided into several adjacent zones:
  • a central zone 83 between the internal butt 51 'of the longitudinal reinforcement 33 placed to the right of the transverse median plane Q and the internal butt 52 of the armature 34 placed to the left of this plane;
  • two lateral zones B2, B'2 placed respectively to the left and to the right of the plane Q the left zone B2 being between the outer stick 51 of the band 33 and the inner butt of the bar 34 and the right zone B ' 2 between the external stick 52 'of the band 34 and the internal stock 51' of the band 33;
  • two extreme zones B1 and B'1 included, respectively on the left and on the right, between the butts 5, 5 'of the lower band 31, and the external butts 51, 52' of the upper bands 33, 34.

Lorsque la pièce 1 est soumise à une sollicitation ayant tendance à la faire fléchir vers le bas, les armatures longitudinales sont soumises à des efforts de traction et prennent appui dans le béton par leurs extrémités en forme de crosses qui sont donc sollicitées vers l'intérieur.When the part 1 is subjected to a bias tending to bend it downwards, the longitudinal reinforcements are subjected to tensile forces and are supported in the concrete by their ends in the form of sticks which are therefore urged inwards .

Les armatures longitudinales 33, 34 qui se chevauchent dans la partie centrale de la pièce, sont tendues dans des sens différents et la zone centrale de blocage B3 est donc comprimée par la tendance au rapprochement l'une vers l'autre des crosses internes 51', 52 des deux armatures 33, 34.The longitudinal reinforcements 33, 34 which overlap in the central part of the part, are stretched in different directions and the central blocking area B3 is therefore compressed by the tendency towards the one towards the other of the internal butts 51 ' , 52 of the two frames 33, 34.

De même, les crosses externes 51, 52' ont tendance à se rapprocher du plan Q sous l'effet des efforts de traction appliqués sur les barres 33, 34 et les zones latérales B2, B'2 sont ainsi mises en compression.Similarly, the external brackets 51, 52 'tend to approach the plane Q under the effect of tensile forces applied to the bars 33, 34 and the lateral zones B2, B'2 are thus put in compression.

Pour les mêmes raisons, les zones extrêmes B1, B'1 sont également mises en compression par les crosses 5, 5' qui s'opposent aux efforts de traction appliqués sur l'armature 31.For the same reasons, the end zones B1, B'1 are also put in compression by the butts 5, 5 'which oppose the tensile forces applied to the frame 31.

Ainsi, la pièce 1 est mise en compression pratiquement sur toute sa longueur par la tendance au rapprochement vers l'intérieur des crosses des différentes armatures et cet effet de compression s'exerce sur toute l'épaisseur du béton limitée par les crosses et non pas seulement, comme habituellement, au-dessus de l'axe neutre 10.Thus, the piece 1 is put into compression practically over its entire length by the tendency towards the inward approach of the butts of the various reinforcements and this compression effect is exerted over the entire thickness of the concrete limited by the butts and not only, as usual, above the neutral axis 10.

Le risque de fissuration de la pièce, même au voisinage de la face tendue 20 est donc considérablement diminué et des essais de chargement effectués sur une pièce ainsi réalisée ont montré qu'une telle pièce pouvait supporter, avant rupture, une flèche très importante et tout à fait inhabituelle pour une pièce en béton armé.The risk of cracking of the part, even in the vicinity of the tensioned face 20 is therefore considerably reduced and loading tests carried out on a part thus produced have shown that such a part could withstand, before rupture, a very large deflection and all unusual for a reinforced concrete part.

Dans le mode de réalisation qui vient d'être décrit, la mise en compression de la zone centrale B3 de la pièce entre les crosses internes 52, 51' des deux bandes accolées 33, 34 résulte du chevauchement de celles-ci qui sont tendues en des sens opposés de part et d'autre du plan médian transversal Q.In the embodiment which has just been described, the compression of the central zone B3 of the part between the inner butts 52, 51 'of the two contiguous strips 33, 34 results from the overlapping of these which are stretched in opposite directions on both sides of the transverse median plane Q.

Cependant, comme le montre la figure 11, l'armature tendue de la cage 3 peut aussi être constituée d'un simple empilement de bandes longitudinales de différentes longueurs, respectivement une première bande 35 s'étendant sur une longueur I1 un peu inférieure à celle de la pièce et une seconde bande 36 s'étendant sur une longueur I2 inférieure à I1, chaque bande étant munie d'extrémités en forme de crosses tournées vers l'intérieur de la pièce.However, as shown in figure 11 the tensile reinforcement of the cage 3 may also consist of a simple stack of longitudinal strips of different lengths, respectively a first band 35 extending over a length I 1 slightly less than that of the piece and a second band 36 extending over a length I 2 less than I 1 , each band being provided with ends in the form of brackets turned towards the interior of the room.

Dans ce cas, également, le béton est mis en compression par les crosses 5, 5', 51, 51' qui absorbent les efforts de traction appliqués sur les bandes 35, 36 en raison du fléchissement de la pièce.In this case, too, the concrete is put in compression by the butts 5, 5 ', 51, 51' which absorb the tensile forces applied on the strips 35, 36 because of the bending of the part.

A cet égard, il peut être avantageux de réaliser les bandes en métaux ayant des caractéristiques mécaniques différentes de façon à moduler les efforts de compression appliqués par les crosses en fonction de la répartition des efforts appliqués sur la pièce.In this regard, it may be advantageous to make the metal strips having different mechanical characteristics so as to modulate the compression forces applied by the butts according to the distribution of forces applied to the workpiece.

Il est à noter que l'utilisation de bandes plates comme barres d'armatures, permet assez facilement de faire varier leur module d'élasticité car les bandes plates peuvent être réalisées par refendage de tôles et l'on peut trouver sur le marché des tôles de caractéristiques différentes alors que les possibilités de choix sont plus réduites pour les ronds à béton.It should be noted that the use of flat strips as reinforcing bars, makes it quite easy to vary their modulus of elasticity because the flat strips can be made by slitting sheets and sheet metal can be found on the market. of different characteristics, whereas the possibilities of choice are smaller for concrete reinforcing bars.

Par ailleurs, du fait que, contrairement à la technique classique, on ne cherche pas à solidariser l'armature avec le béton qui l'enrobe, il est possible de placer l'une contre l'autre les deux bandes superposées 31, 35 qui se comportent alors comme une sorte de ressort à lames.Moreover, because, contrary to the conventional technique, it is not sought to join the reinforcement with the concrete that surrounds it, it is possible to place against one another the two superposed strips 31, 35 which then behave like a kind of leaf spring.

Les figures 12 et 13 montrent une variante du mode de réalisation de la figure 10 dans laquelle les deux bandes adjacentes 33, 34 constituent deux brins d'une bande unique formant une boucle fermée, les deux crosses opposées 51', 52 étant reliées par une partie 37 de la bande située au niveau supérieur 30' de la cage 3.The Figures 12 and 13 show a variant of the embodiment of the figure 10 wherein the two adjacent strips 33, 34 constitute two strands of a single band forming a closed loop, the two opposite brackets 51 ', 52 being connected by a portion 37 of the band located at the upper level 30' of the cage 3.

Chaque armature longitudinale est ainsi constituée d'une bande unique 33, 37, 34 entourant un noyau de béton B3 qui est mis en compression par serrage de la boucle ainsi formée sous l'effet des efforts de traction appliqués en des sens opposés sur les deux brins 33, 34 de l'armature longitudinale lorsque la pièce 1 est soumise à une charge verticale.Each longitudinal reinforcement thus consists of a single band 33, 37, 34 surrounding a concrete core B3 which is compressed by clamping of the loop thus formed under the effect of traction forces applied in opposite directions on both strands 33, 34 of the longitudinal reinforcement when the part 1 is subjected to a vertical load.

Il est à noter que dans ce cas, la partie supérieure 37 de chaque armature longitudinale en forme de boucle peut constituer une partie de la nappe supérieure 30' de la cage de ferraillage 3.It should be noted that in this case, the upper part 37 of each longitudinal reinforcement in the form of a loop may form part of the upper ply 30 'of the reinforcement cage 3.

D'autre part dans le cas de la figure 10 comme celui de la figure 12, les crosses opposées 51', 52 qui tendent à mettre en compression un noyau de béton B3, ne sont pas nécessairement écartées symétriquement de part et d'autre du plan médian transversal Q de la pièce 1. En effet, selon le mode de chargement de la pièce, il est possible de déterminer certaines parties de la pièce 1 dans lesquelles les efforts de traction induits dans le béton par les sollicitations appliquées sont maximaux et de disposer les armatures et leurs crosses de façon que les efforts de traction résultant des sollicitations soient compensés au moins partiellement par la mise en compression, dans les mêmes zones, d'un noyau de béton compris entre deux crosses sollicitées l'une vers l'autre par les efforts de traction appliqués sur l'armature.On the other hand in the case of figure 10 like that of the figure 12 , the opposing brackets 51 ', 52 which tend to compress a concrete core B3, are not necessarily spaced symmetrically on either side of the transverse median plane Q of the piece 1. Indeed, depending on the loading mode of the part, it is possible to determine certain parts of the part 1 in which the tensile forces induced in the concrete by the applied stresses are maximum and have the reinforcements and their butts so that the tensile forces resulting from the stresses are at least partially offset by the compression in the same areas of a concrete core between two butts solicited one towards the other by the tensile forces applied on the frame.

D'une façon générale, chacune des figures décrites précédemment montre un secteur de la cage de ferraillage centré dans un plan vertical parallèle à l'axe longitudinal et les crosses ménagées sur les armatures de deux secteurs voisins sont placées sensiblement au même niveau de façon à faire passer, dans les zones de blocage alignées des secteurs S1, S2, S3, de filants transversaux 32 qui sont également sollicités vers l'intérieur et répartissent donc sur le béton compris entre deux secteurs voisins, les efforts de compression appliqués par les crosses 5, 51, 52. Ces filants de répartitions peuvent avoir une section ronde ou rectangulaire, comme le montrent les figures. Cependant, l'utilisation de barres plates permet de faciliter la réalisation d'un cordon de soudure entre les barres longitudinales et transversales.In general, each of the figures described above shows a sector of the reinforcement cage centered in a vertical plane parallel to the longitudinal axis and the butts formed on the reinforcements of two adjacent sectors are placed substantially at the same level so as to passing, in the aligned locking zones of the sectors S 1 , S 2 , S 3 , transverse threads 32 which are also biased inwards and thus distribute on the concrete between two adjacent sectors, the compression forces applied by the crossheads 5, 51, 52. These distribution threads may have a round or rectangular section, as shown in the figures. However, the use of flat bars makes it easier to produce a weld bead between the longitudinal and transverse bars.

Dans un autre mode de réalisation représenté schématiquement sur la figure 14, chaque armature longitudinale tendue 6 de la cage 3 est constituée d'une série de bandes consécutives 6a, 6b.... ayant chacune deux extrémités recourbées en forme de crosses 5a, 5'a, 5b, 5'b... et ces barres sont disposées de façon que les paires de crosses adjacentes 5'a, 5b de deux bandes successives 6a, 6b soient situées sensiblement au même niveau, en se chevauchant légèrement de façon à entourer un espace E dans lequel on fait passer une barre 38 qui peut constituer un filant transversal de répartition.In another embodiment shown schematically on the figure 14 each stretched longitudinal reinforcement 6 of the cage 3 is constituted by a series of consecutive strips 6a, 6b .... each having two ends curved in the form of hooks 5a, 5'a, 5b, 5'b ... and these bars are arranged so that the pairs of adjacent sticks 5'a, 5b of two successive bands 6a, 6b are located substantially at the same level, overlapping slightly so as to surround a space E in which is passed a bar 38 which can constitute a transversal thread of distribution.

Chaque barre 38 passant dans un espace E mis en compression par les deux crosses opposées 5'a, 5b constitue une clavette de liaison entre les deux bandes consécutives 6a, 6b. Chaque armature longitudinale 6 constituée d'une série de bandes 6a, 6b, 6c.... se comporte ainsi comme une chaîne dont les maillons 6a, 6b, 6c... sont tendus sous l'effet des charges appliquées sur la pièce 1.Each bar 38 passing through a space E placed in compression by the two opposite brackets 5'a, 5b constitutes a connecting key between the two consecutive strips 6a, 6b. Each longitudinal reinforcement 6 consists of a series of strips 6a, 6b, 6c .... thus behaves like a chain whose links 6a, 6b, 6c ... are stretched under the effect of the charges applied on the part 1.

Mais l'invention ne se limite pas aux détails des divers modes de réalisation qui viennent d'être décrits, et pourrait encore faire l'objet d'autres variantes, sans s'écarter du cadre de protection de l'invention comme défini par les revendications.But the invention is not limited to the details of the various embodiments which have just been described, and could still be the subject of other variants, without departing from the scope of protection of the invention as defined by the claims.

Par exemple, chaque zone de blocage pourrait être obtenue simplement au moyen d'une barre transversale passant dans un orifice ménagé sur la barre d'armature longitudinale.For example, each blocking zone could be obtained simply by means of a transverse bar passing through an orifice formed on the longitudinal reinforcing bar.

En effet, comme on l'a représenté sur la figure 17, l'utilisation d'une bande plate 4 comme barre d'armature longitudinale permet de ménager dans celle-ci une fente médiane 45 s'étendant sur une certaine longueur et limitant deux parties latérales 46, 47 qui peuvent être écartées l'une de l'autre de façon à ouvrir un orifice 45' de passage d'une barre transversale 48. Lorsque la bande 4 est soumise à un effort de traction, par exemple dans le sens de la flèche indiquée sur la figure 16, elle prend appui sur la barre transversale 48 qui, elle-même, prend appui dans le béton, en réalisant ainsi le blocage de la bande 4.Indeed, as shown on the figure 17 , the use of a flat strip 4 as a longitudinal reinforcing bar makes it possible to fit therein a median slot 45 extending over a certain length and limiting two lateral parts 46, 47 which can be spaced apart from each other. the other so as to open a hole 45 'for passage of a transverse bar 48. When the strip 4 is subjected to a tensile force, for example in the direction of the arrow indicated on the figure 16 , it is supported on the crossbar 48 which itself is supported in the concrete, thus realizing the blocking of the band 4.

Dans le cas de la figure 16, les deux parties 46, 47 de la bande sont étirées en restant dans le plan de celle-ci, la barre transversale 48 étant ainsi orthogonale à ce plan.In the case of figure 16 , the two parts 46, 47 of the strip are stretched while remaining in the plane thereof, the transverse bar 48 thus being orthogonal to this plane.

Mais il est possible également, comme on l'a représenté sur la figure 17, d'écarter les deux parties 46, 47 perpendiculairement au plan S de la bande, pour permettre le passage d'une barre transversale 48 qui, dans ce cas, est parallèle au plan de la bande. Cette barre pourrait donc constituer un filant transversal 32 de répartition entre plusieurs secteurs de la cage d'armature.But it is also possible, as we have shown on the figure 17 , to separate the two parts 46, 47 perpendicularly to the plane S of the strip, to allow the passage of a transverse bar 48 which, in this case, is parallel to the plane of the strip. This bar could therefore constitute a transverse thread 32 of distribution between several sectors of the reinforcement cage.

Dans le cas où la bande est vrillée pour constituer une zone de blocage, cette partie vrillée 43 pourrait également être munie d'une fente médiane permettant d'écarter l'une de l'autre les deux parties de la bande afin de ménager une ouverture 45' de passage d'un filant de répartition 32, de la façon représentée sur la figure 18.In the case where the band is twisted to form a locking zone, this twisted part 43 could also be provided with a median slot allowing the two parts of the band to be separated from one another to provide an opening 45 ' passage of a distribution thread 32, as shown in FIG. figure 18 .

Par ailleurs, comme on l'a représenté sur la figure 19, on pourrait aussi améliorer l'effet de blocage d'une crosse 5 en ménageant sur les deux parties de celle-ci des orifices 45' de passage d'une barre transversale 52 qui, en outre, empêcherait la crosse de se dérouler sous l'effet de la traction appliquée sur la bande 4.Moreover, as shown on the figure 19 it would also be possible to improve the blocking effect of a stock 5 by providing on the two parts of the latter holes 45 'for the passage of a transverse bar 52 which, moreover, would prevent the stock from taking place under the effect of traction applied to the strip 4.

Il est à noter, par ailleurs, que l'utilisation de bandes plates 4 pour constituer les barres d'armature longitudinales permet de faire varier l'orientation de la crosse ménagée à l'extrémité d'une telle barre. En effet, d'une façon générale, la bande plate 4 peut être facilement courbée autour d'un axe parallèle à son plan. Il serait donc possible, comme le montre la figure 20 de vriller sur un quart de tour l'extrémité d'une bande 4 de façon que la crosse 5 tourne autour d'un axe vertical 50. On obtiendrait ainsi le même effet de blocage en donnant à la crosse une hauteur limitée à la largeur e de la bande 4. Une telle disposition pourrait être avantageuse pour réaliser des pièces particulièrement minces ou bien, par exemple, pour amincir les extrémités d'une dalle. En particulier, l'utilisation d'une bande plate 4 permet, en cas de besoin, de faire varier l'orientation de celle-ci, comme le montre la figure 20, par exemple, pour amincir certaines parties de la pièce.It should be noted, moreover, that the use of flat strips 4 to form the longitudinal reinforcing bars makes it possible to vary the orientation of the butt formed at the end of such a bar. Indeed, in general, the flat strip 4 can be easily bent around an axis parallel to its plane. It would therefore be possible, as shown in figure 20 twist a quarter turn the end of a strip 4 so that the butt 5 rotates about a vertical axis 50. This would give the same locking effect by giving the stock a height limited to the width e This arrangement could be advantageous for making particularly thin pieces or, for example, for thinning the ends of a slab. In particular, the use of a flat strip 4 allows, if necessary, to vary the orientation thereof, as shown in FIG. figure 20 for example, to thin some parts of the room.

D'autre part, comme on l'a déjà indiqué, il est avantageux de réaliser également les armatures comprimées 31' sous forme de bandes plates mais, par économie, on pourrait aussi utiliser des barres classiques.On the other hand, as already indicated, it is advantageous to also realize the compressed armatures 31 'in the form of flat strips but, for economy, one could also use conventional bars.

Il faut noter, cependant, que les avantages apportés par l'utilisation de barres plates compensent largement un surcoût éventuel sur les armatures.It should be noted, however, that the advantages provided by the use of flat bars largely offset any additional cost on the reinforcements.

A cet égard, il pourrait même être avantageux de réaliser des barres en acier inoxydable en raison, non seulement, de la résistance à la corrosion qui permettrait de diminuer l'épaisseur d'enrobage mais également d'un plus grande ductilité, ce qui augmente la résistance à la fatigue et la capacité d'absorption d'énergie. De tels avantages sont particulièrement intéressant pour la réalisation d'ouvrages d'art car ils améliorent la résistance aux tassements différentiels et, dans certains cas, aux secousses sismiques.In this respect, it could even be advantageous to produce stainless steel bars because of not only the corrosion resistance which would make it possible to reduce the thickness of the coating but also of greater ductility, which would increases fatigue resistance and energy absorption capacity. Such advantages are particularly advantageous for the construction of structures because they improve the resistance to differential settlements and, in some cases, to earthquakes.

Par ailleurs, pour simplifier les figures, celles-ci représentent des dalles ou poutres planes mais il faut remarquer que l'utilisation de bandes plates comme barres d'armatures présente de nombreux avantages pour la réalisation de pièces courbes ou mêmes gauches. En effet, une bande plate ayant un côté large parallèle à la face de parement de la pièce peut suivre facilement le profil incurvé de celle-ci.Furthermore, to simplify the figures, they represent slabs or flat beams but it should be noted that the use of flat strips as reinforcement bars has many advantages for producing curved or even left pieces. Indeed, a flat strip having a broad side parallel to the facing face of the workpiece can easily follow the curved profile thereof.

En particulier, il est ainsi possible de réaliser à plat une cage de ferraillage adaptée à une pièce incurvée, une telle cage pouvant ensuite prendre naturellement le profil du fond du moule lorsqu'elle est posée dans celui-ci.In particular, it is thus possible to form a flat reinforcement cage adapted to a curved piece, such a cage can then naturally take the profile of the bottom of the mold when it is placed therein.

Les bandes plates constituant les armatures longitudinales et transversales pourraient même être incurvées dans des sens opposés de façon à s'adapter à un profil gauche dans le sens transversal, tel qu'une surface réglée ayant des génératrices transversales non parallèles. C'est le cas, par exemple, du platelage d'un pont incliné latéralement d'un angle variable d'une extrémité à l'autre et dont le ferraillage est difficile à réaliser par les méthodes classiques.The flat strips constituting the longitudinal and transverse reinforcements could even be curved in opposite directions so as to adapt to a left profile in the transverse direction, such as a regulated surface having non parallel parallel generatrices. This is the case, for example, the decking of a laterally inclined bridge of variable angle from one end to the other and whose reinforcement is difficult to achieve by conventional methods.

D'autre part, comme elle permet de réaliser des pièces en béton particulièrement souples pouvant admettre une flèche assez importante, l'invention est spécialement adaptée à la réalisation d'ouvrages de franchissement enterrés sous un remblai et ayant un profil incurvé leur permettant de se déformer légèrement sous la charge appliquée pour prendre appui par leurs côtés sur les remblais latéraux.On the other hand, since it makes it possible to produce particularly flexible concrete parts that can accommodate a large enough spire, the invention is especially adapted to the realization of crossing structures buried under an embankment and having a curved profile allowing them to slightly deform under the load applied to support the side embankments by their sides.

En outre, comme indiqué plus haut, les zones de blocage entre lesquelles le béton est mis en compression peuvent être placées à des endroits, déterminés par le calcul, dans lesquelles le béton est soumis une contrainte de traction maximale et où le risque de fissuration est le plus grand. L'invention permet donc, à partir d'un modèle type, d'adapter le ferraillage de chaque pièce à la répartition prévisible des contraintes, compte tenu des charges appliquées.In addition, as indicated above, the blocking zones between which the concrete is placed in compression can be placed at locations, determined by calculation, in which the concrete is subjected to a tensile stress maximum and where the risk of cracking is greatest. The invention therefore makes it possible, from a standard model, to adapt the reinforcement of each part to the predictable distribution of the stresses, taking into account the loads applied.

Par exemple, on sait que l'on peut distinguer, dans une dalle ou poutre chargée verticalement de façon uniforme, une zone centrale dans laquelle l'effort de traction appliqué sur la face inférieure est maximal, deux zones latérales dans lesquelles la dalle est soumise à un effet de cisaillement, et deux extrémités d'appui. Cependant, comme indiqué précédemment, la disposition des zones de compression n'est pas nécessairement symétrique par rapport au plan médian de la pièce.For example, it is known that it is possible to distinguish, in a slab or beam loaded vertically in a uniform manner, a central zone in which the tensile force applied to the lower face is maximum, two lateral zones in which the slab is subjected to a shearing effect, and two support ends. However, as indicated above, the arrangement of the compression zones is not necessarily symmetrical with respect to the median plane of the part.

Grâce à l'invention il sera possible, sans complication du ferraillage d'adapter celui-ci, dans chaque partie de la pièce, aux efforts principaux à encaisser, en faisant judicieusement varier l'orientation des bandes plates constituant les armatures de façon à réaliser des zones de blocage dans les parties les plus tendues, afin de compenser cette tension par un effet de compression du béton.Thanks to the invention it will be possible, without complication of the reinforcement to adapt it, in each part of the room, the main efforts to cash, by judiciously vary the orientation of the flat strips constituting the frames so as to achieve blocking zones in the most tensioned parts, in order to compensate for this tension by a compression effect of the concrete.

De plus, comme indiqué plus haut, il est possible d'orienter verticalement les bandes tendues de la façon représentée sur la figure 8, pour augmenter la résistance à la flexion, ou bien d'incliner les bandes de la façon indiquée sur la figure 20, afin de mieux résister aux efforts de cisaillement, ou encore de réaliser des crosses horizontales comme le montre la figure 20, pour diminuer l'épaisseur de la pièce aux appuis, ces différentes variantes pouvant, d'ailleurs, être combinées.Moreover, as indicated above, it is possible to orient the stretched strips vertically as shown in FIG. figure 8 , to increase the flexural strength, or to tilt the bands as indicated on the figure 20 , in order to better withstand the shearing forces, or to make horizontal sticks as shown in FIG. figure 20 to reduce the thickness of the support part, these different variants can, moreover, be combined.

En outre, comme indiqué précédemment, la disposition des zones de compression n'est pas nécessairement symétrique par rapport au plan médian de la pièce.In addition, as indicated above, the arrangement of the compression zones is not necessarily symmetrical with respect to the median plane of the part.

Les dispositions selon l'invention permettent donc de faire varier la forme de la cage de ferraillage de façon à moduler l'action des armatures en fonction des sollicitations appliquées en service sur la pièce.The arrangements according to the invention therefore make it possible to vary the shape of the reinforcement cage so as to modulate the action of the reinforcements as a function of the stresses applied in use on the part.

Claims (19)

  1. A manufacturing method of a concrete piece (1) provided with a reinforcing cage (3) bedded in concrete (2) during the casting thereof, so that, when said piece is subjected to a load, it includes, under the effect thereof, two sections on both sides of a neutral axis, respectively a compressed section subjected to compressive stress absorbed mainly by the concrete (2) and a stretched section subjected to tensile stress absorbed mainly by at least one stretched longitudinal reinforcement (31) of the reinforcing cage (3) extending along a longitudinal direction of application of the tensile stress, at a short covering distance of a stretched longitudinal face (20) of the piece (1) and having a cross-section determined relative to the stresses induced by the load, method wherein said stretched longitudinal reinforcement (31) comprises at least one flat band (4) with a rectangular section, having a wide face (41) and a narrow face (41'), and including a central part (44) comprised between two parts (43,43') clamping in the concrete, each realised by twisting the band (4) over a certain length (L1), with a gradual rotation of the wide face (41) around the longitudinal axis (40) of the band (4), the two twisted parts (43,43') extending substantially in the same direction as the central part (44) of the flat band (4), parallel to the stretched longitudinal face (20) of the piece (1) and resting in the concrete by the wide face (41) of the flat band (4) in the opposite direction to the absorbed tensile stress while providing, inside the piece (1), two clamping zones (B, B') constituted by said twisted clamping parts (43, 43') between which extends a central sliding zone (C) wherein the central part (44) of the stretched band (4) is free to be elongated under the effect of the absorbed stresses, with a uniform distribution of tension over the whole length of said central part (44).
  2. A method according to claim 1, characterised by the fact that, from a certain threshold of stress, at least the central part (44) of the stretched band (4) comprised between the two clamping zones (B, B') is free to separate from the concrete with which it is covered, by sliding slightly relative thereto.
  3. A method according to any of the claims 1 and 2, characterised by the fact that the width (I) and the thickness (e) of the band (4) are determined relative to a maximum tensile stress to be absorbed, on the one hand in order to provide a sufficient cross-section for the absorption of said maximum stress while remaining in the resilient domain and, on the other hand, so that, in each clamping zone, the part of the concrete where the wide face (41) of the band (4) rests is subjected to a compressive stress not exceeding an admissible threshold.
  4. A method according to any of the previous claims, characterised by the fact that the central part (44) of the stretched band (4) which is comprised between two twisted parts (43,43') is oriented so that its wide face (41) is substantially parallel to the longitudinal stretched face (20) of the piece (1).
  5. A method according to claim 4, characterised by the fact that each twisted clamping part (43,43') of the band (4) is realised with a gradual rotation of its wide face (41) around its longitudinal axis (40) over at least one quarter of a turn.
  6. A method according to claim 5, characterised by the fact that the twisted part (43) of the band (4) is twisted by a complete turn around its longitudinal axis (40).
  7. A method according to any of the claims 1 to 6, characterised by the fact that each end of the flat band (4) is curved around a transversal axis (50) to form an anchoring crosshead (5) resting on the concrete by a wide face (41).
  8. A method according to any of the previous claims, wherein the reinforcing cage includes two longitudinal reinforcement sets, respectively (31) in the stretched section and (31') in the compressed section, characterised by the fact that the compressed longitudinal reinforcements (31') are also formed of flat bars.
  9. A method according to any of the previous claims, characterised by the fact that, in its twisted parts (43,43'), the band (4) forming the stretched reinforcement (31) is slit axially over a certain length and that both thus formed partitions (46,47) are spaced apart to form an opening (45') for the transversal insertion of at least one rigid bar section (48) able to rest on the concrete (2) in the opposite direction to the tensile stress applied to the band (4) constituting the stretched longitudinal reinforcement (31).
  10. Concrete piece (1) provided with a reinforcing cage (3), so that, when said piece (1) is subjected to a load, it includes, under the effect thereof, two parts on both sides of a neutral axis, respectively a compressed part (C) subjected to compression stresses absorbed mainly by the concrete (2) and a stretched part (T) subjected to tensile stresses absorbed mainly by at least one stretched longitudinal reinforcement (31) of said reinforcing cage (3) which extends, along a longitudinal direction of application of the tensile stresses, at a short covering distance of a stretched longitudinal face (20) of the piece (1) and exhibits a cross-section determined relative to the stresses induced by the load, said stretched longitudinal reinforcement (31) being formed by at least one flat band (4) with a rectangular section, with a wide face (41) and a narrow face (41'), and including a central part (44) comprised between two parts (43,43') clamping in the concrete, each realised by twisting the band (4) over a certain length (L1), with a gradual rotation of the wide face (41) around the longitudinal axis (40) of the band (4), the two twisted parts (43,43') extending substantially in the same direction as the central part (44) of the flat band (4), parallel to the stretched longitudinal face (20) of the piece (1) and resting in the concrete by a wide face (41) of the flat band (4) in the opposite direction to the absorbed tensile stress while providing, inside the piece (1), two clamping zones (B, B') constituted by said twisted clamping parts (43, 43') between which extends a central sliding zone (C) wherein the central part (44) of the stretched band (4) is free to be elongated under the effect of the absorbed stresses, with a uniform distribution of tension over the whole length of said central part (44).
  11. Concrete piece provided with a reinforcing cage according to claim 10, characterised by the fact that each twisted part (43) of the flat band (4) is twisted around its longitudinal axis (40) over at least one quarter of a turn.
  12. Concrete piece provided with a reinforcing cage according to claim 10, characterised by the fact that the twisted part (43) of the band (4) is twisted over a complete turn around its longitudinal axis (40).
  13. Concrete piece provided with a reinforcing cage according to any of claims 10,11,12, characterised by the fact that each end of the flat band (4) is curved around a transversal axis (50) so as to form at least one anchoring crosshead (5) resting on the concrete by a wide face (41)
  14. Concrete piece provided with a reinforcing cage according to any of claims 10 to 13, characterised by the fact that the central part (44) of the stretched band (4) which is comprised between two twisted parts (43,43') is oriented so that its wide face (41) is substantially parallel to the longitudinal stretched face (20) of the piece (1).
  15. Concrete piece provided with a reinforcing cage according to any of claims 10 to 14, comprising, in at least one sector, two longitudinal reinforcements, respectively stretched (31) and compressed (31'), characterised by the fact that the compressed reinforcements (31') are also formed of flat bars.
  16. Concrete piece provided with a reinforcing cage according to any of the claims 10 to 15, characterised in that at least the stretched longitudinal reinforcements (31) are made of stainless steel.
  17. Concrete piece provided with a reinforcing cage according to any of the Claims 10 to 16, characterised by the fact that each twisted part (43) of a stretched longitudinal reinforcement (31) having the form of a band (4), is slit axially over a certain length and that both thus formed partitions (46,47) are spaced apart to form an opening (45') for the transversal insertion of at least one rigid bar section (48) able to rest on the concrete (2) in the opposite direction to the tensile stress applied to the band (4) constituting the stretched longitudinal reinforcement (31).
  18. A manufacturing method of a concrete piece provided with a reinforcing cage according to any of the claims 10 to 17, characterised by the fact that the concrete piece is curved and obtained by casting concrete into a mould or casing with a curved bottom, after laying into the mould the reinforcing cage and that the reinforcing cage is manufactured down flat and exhibits, by reason of the use of flat bands, sufficient flexibility to adopt, by its own weight, the curved shape of the bottom of the mould after laying the cage (3) therein.
  19. A concrete piece (1) realised by the method according to any of the claims 1 to 9.
EP04805843A 2003-11-18 2004-11-18 Method for production of a block of concrete and a block of concrete Active EP1689951B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP09173849.2A EP2141300B1 (en) 2003-11-18 2004-11-18 Method for manufacturing a concrete part and reinforcement cage for a part manufactured according to this method

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0350857A FR2862323B1 (en) 2003-11-18 2003-11-18 METHOD FOR PRODUCING A CONCRETE PIECE AND PIECE PRODUCED THEREBY
PCT/FR2004/050600 WO2005049934A1 (en) 2003-11-18 2004-11-18 Method for production of a block of concrete and reinforcing cage for a block produced thus

Related Child Applications (1)

Application Number Title Priority Date Filing Date
EP09173849.2A Division EP2141300B1 (en) 2003-11-18 2004-11-18 Method for manufacturing a concrete part and reinforcement cage for a part manufactured according to this method

Publications (2)

Publication Number Publication Date
EP1689951A1 EP1689951A1 (en) 2006-08-16
EP1689951B1 true EP1689951B1 (en) 2009-12-16

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Application Number Title Priority Date Filing Date
EP09173849.2A Active EP2141300B1 (en) 2003-11-18 2004-11-18 Method for manufacturing a concrete part and reinforcement cage for a part manufactured according to this method
EP04805843A Active EP1689951B1 (en) 2003-11-18 2004-11-18 Method for production of a block of concrete and a block of concrete

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP09173849.2A Active EP2141300B1 (en) 2003-11-18 2004-11-18 Method for manufacturing a concrete part and reinforcement cage for a part manufactured according to this method

Country Status (13)

Country Link
EP (2) EP2141300B1 (en)
JP (1) JP4709767B2 (en)
KR (1) KR20060129218A (en)
AT (1) ATE452255T1 (en)
AU (1) AU2004291708B2 (en)
DE (1) DE602004024707D1 (en)
DK (1) DK1689951T3 (en)
ES (1) ES2338235T3 (en)
FR (1) FR2862323B1 (en)
MA (1) MA28165A1 (en)
PT (1) PT1689951E (en)
TN (1) TNSN06144A1 (en)
WO (1) WO2005049934A1 (en)

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US887863A (en) * 1907-07-26 1908-05-19 Edgar N Spaulding Steel girder-frame for reinforced-concrete girders.
GB410866A (en) * 1933-10-11 1934-05-31 Robert Hopewell Improvements in reinforced concrete
US2167029A (en) * 1936-11-19 1939-07-25 Joel E Mclafferty Reinforcing member for heterogeneous beams
US3825465A (en) * 1972-03-24 1974-07-23 R Stock Three dimensional reticulated structure
JPS5963127U (en) * 1982-10-21 1984-04-25 鹿島建設株式会社 Joint structure of major and minor beams
JPS5976348A (en) * 1982-10-21 1984-05-01 鹿島建設株式会社 Beam with wall of reinforced concrete structure
DE3541875A1 (en) * 1985-11-27 1987-06-04 Ostertag Werke Gmbh Security reinforcement means for a strongroom, safe, banking area or the like
FR2814480B1 (en) * 2000-09-26 2008-10-17 Soc Civ D Brevets Matiere REINFORCING CAGE FOR AN ARMED CONCRETE ELEMENT

Also Published As

Publication number Publication date
DE602004024707D1 (en) 2010-01-28
ATE452255T1 (en) 2010-01-15
AU2004291708A1 (en) 2005-06-02
EP1689951A1 (en) 2006-08-16
FR2862323B1 (en) 2006-03-10
TNSN06144A1 (en) 2007-11-15
EP2141300B1 (en) 2014-03-05
JP4709767B2 (en) 2011-06-22
EP2141300A2 (en) 2010-01-06
DK1689951T3 (en) 2010-04-26
AU2004291708B2 (en) 2010-05-27
KR20060129218A (en) 2006-12-15
MA28165A1 (en) 2006-09-01
PT1689951E (en) 2010-03-16
FR2862323A1 (en) 2005-05-20
WO2005049934A1 (en) 2005-06-02
EP2141300A3 (en) 2010-01-20
JP2007511689A (en) 2007-05-10
ES2338235T3 (en) 2010-05-05

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