Classifications

• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
  • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
  • E04C5/08—Members specially adapted to be used in prestressed constructions
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
  • E04B1/20—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons the supporting parts consisting of concrete, e.g. reinforced concrete, or other stonelike material
  • E04B1/22—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons the supporting parts consisting of concrete, e.g. reinforced concrete, or other stonelike material with parts being prestressed
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
  • E04C3/00—Structural elongated elements designed for load-supporting
  • E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
  • E04C3/20—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of concrete or other stone-like material, e.g. with reinforcements or tensioning members
  • E04C3/26—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of concrete or other stone-like material, e.g. with reinforcements or tensioning members prestressed
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
  • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
  • E04C5/08—Members specially adapted to be used in prestressed constructions
  • E04C5/085—Tensile members made of fiber reinforced plastics

Definitions

• the present invention relates generally to the manufacture of structural elements (such as beams and concrete slabs), in particular of concrete, reinforced concrete and prestressed concrete structural elements. , mixed material concrete-steel, composite material, or more generally any type of material used in the field of construction.
• It relates more particularly to a reinforcing bar for structural element.
• It also relates to a method of manufacturing a structural element incorporating such a reinforcing bar.
• the invention applies to any type of frame, for example to floors, poles, retaining walls, rafts or footings and more generally to any type of structural element (prefabricated or manufactured in situ).
• a well-known problem of concrete is that, although it resists compressive forces, it cracks quickly when subjected to tensile forces, even at low intensities.
• the idea is to make sure that the concrete always works in compression and never (or little) in traction. For this, we exercise a traction initially on the metal frame so that at rest, the concrete beam is compressed.
• the metal reinforcement used is generally formed of cables or bars of steel.
• the first method consists in applying a tension to the metal frame before the complete setting of the concrete.
• the reinforcement is then released, thus putting the concrete in compression by simple adhesion effect.
• the second method consists in arranging the cables through sheaths incorporated in the concrete. After the setting of the concrete, the cables are stretched by means of jacks so as to compress the beams.
• This technique relatively complex, is generally reserved for large structures since it requires the implementation of cumbersome tensioning machines.
• the present invention proposes a structural element in which internal forces are exerted, but which is either devoid of metal reinforcement or has few metal reinforcements.
• a reinforcement strip which comprises:
• a deformation means adapted to elastically deform said body
• a structural element comprising a frame (beam, slab, etc.) and at least one reinforcement strip as mentioned above, the body of which is fixed to said frame and whose anchoring means are accessible. from outside said frame.
• the reinforcement bar once attached to the frame while it is deformed (thanks to the deformation means), is then able to restore its prestressing to the frame after its means of deformation has been extracted from its body.
• the deformation means exerts a compressive force on the body
• the body exerts on the frame a tensile force.
• the reinforcing strip is placed on one side of the frame, it allows to generate a compression on the other side of this frame (relative to the neutral fiber of this frame).
• the reinforcing bar makes it possible to limit these compressive forces and to reduce, or even cancel, the tensile forces exerted on the other. side of the building.
• the deformation means may exert a tensile force on the body so that, as soon as the deformation means is extracted from the body, the body exerts on the frame a compressive force.
• the deformation means may also exert a bending or torsion force on the body so that, as soon as the deformation means is extracted from the body, the body exerts on the frame a bending or torsion force in the opposite direction.
• This reinforcement strip having a size smaller than that of the frame, it can also be judiciously installed in the only places of the frame with which will exert efforts of high intensities.
• said body has an elongated shape and is traversed longitudinally by a conduit for passing said deformation means;
• said deformation means is a rod or a metal cable slidably mounted through said passage duct;
• said passage duct is curved
• the deformation means is adapted to exert a compressive force and / or bending and / or torsion on said body to deform elastically;
• said body is formed of a single piece of concrete.
• it could be epoxy, mortar, or any other elastically deformable material.
• said frame further comprises a prestressed metal reinforcement, distinct from each reinforcing bar;
• said frame is formed of a single piece of concrete.
• the invention also provides a method of manufacturing a structural element comprising steps of:
• the step of fixing said body to said frame consists in molding said frame around said body.
• FIG. 1 is a schematic perspective exploded view of a reinforcing strip according to the invention
• FIG. 2 is a schematic perspective view of a structural element incorporating several reinforcing bars of the type of that represented in FIG. 1;
• FIG. 3 is a schematic side view of a beam embedded at its ends, subjected to a transverse force
• Figures 4 and 5 are schematic side and top views of the structural element of Figure 2;
• FIG. 6 is a detailed view of zone VI of FIG. 2;
• FIG. 7 is a schematic side view of an arched structure
• FIG. 8 is a schematic view of a cross section of an alternative embodiment of the structural element of Figure 2;
• FIG. 9 is a diagram of the forces exerted on the structural element of FIG. 8;
• FIG. 10 is a sectional view of a box incorporating a reinforcing strip of the type of that of Figure 1;
• FIG. 11 is a view of a section of a pipeline duct incorporating two reinforcing bars
• FIG. 12 is a sectional view of a buttress panel incorporating a reinforcing strip of the type of that of Figure 1;
• FIG. 13 is a sectional view of a box incorporating two reinforcing bars.
• a reinforcing bar 1 (or "bar internal forces") can be used on such a structural element.
• This reinforcement bar 1 may thus for example be used to reinforce a slab or, as will be detailed later in this presentation, to reinforce a beam.
• FIG 3 there is shown a beam 12 'of concrete (devoid of metal reinforcement), which is embedded at its ends, which is positioned horizontally, and which is subjected to its own weight P and a transverse force F transverse to its longitudinal axis.
• one or more reinforcing bars 1 are used which make it possible to exert on the beam forces which compensate for these traction forces.
• the number, shape and position of these reinforcing bars can be adjusted to best compensate for these tensile forces, depending on the shape of the beam, its position (vertical, horizontal or inclined) and its points of attachment to the rest of the structure of the structure (embedded at the ends, simple support in the center, ).
• the reinforcing bar 1 comprises (see FIG. 1):
• a deformation means 3 adapted to elastically deform said body 2
• anchoring means 4 of said deformation means 3 to said body 2 which are adapted to retain said deformation means 3 in the position of elastic deformation of said body 2 and which are removable so as to allow extraction of said deformation means 3 with respect to body audit 2.
• the deformation means 3 will be adapted to elastically deform said body 2 in compression and / or flexion.
• the body 2 here has a rectangular parallelepiped shape, elongated along a main axis A1.
• the body could have an irregular section, that is to say a section whose shape varies along its longitudinal axis.
• the body could have a section whose shape varies so that at its ends, the body has sections in the form of triangles identical, but positioned head to tail. It is understood in this example that the forces transmitted by the body to the structural element will have varying forces and directions along the body.
• the neutral fiber of the body 2 as the line passing through the center of gravity of its cross-sections.
• this neutral fiber is confused with the main axis A1.
• the upper fiber of the body 2 will be defined as the line located on the upper face 2A of the body 2 (see FIG. 1), and which extends equidistant from the two longitudinal edges of the upper face 2A of the body 2.
• the lower fiber will be defined as the line situated on the lower face 2B of the body 2, and which extends at equal distances two longitudinal edges of the lower face of the body 2.
• the body 2 is here made of high, very high or ultra high performance concrete. Alternatively, it may be formed in a different material, for example plastic, mortar, epoxy or composite material.
• This body 2 is here crossed longitudinally by a conduit passage
• This passage duct 5 here has a cylindrical shape of revolution about an axis parallel to the main axis A1.
• This axis is here coplanar with the upper and lower fibers of the body 2. It is preferably located parallel to and at a distance from the neutral fiber of the body 2, for a reason which will be explained in detail later in this discussion.
• the passage duct 5 is not straight, but curved. Its curvature can be provided in such a way that the axis of the passage duct 5 extends along its entire length at equal distance from the upper fiber of the body 2. It could alternatively be provided that it be otherwise, for example if it is desired that the deformation means 3 generates a torsional force on the body 2 .
• a sheath is provided inside this conduit 5, to facilitate the manufacture of the body 2 (the body 2 being cast in a mold around this sheath).
• the deformation means 3 of the body 2 is here intended to be engaged through this passage duct 5, so as to open at both ends of this passage duct 5.
• it could be provided that it is a carbon fiber cable.
• the wire rope 3 is threaded through the passage duct 5, so that it can slide in this passage duct 5.
• the anchoring means 4 are then provided at the ends of this metal cable 3.
• These anchoring means 4 may thus comprise washers for distributing efforts on a large part of the section of each end of the body 2.
• anchoring means 4 must also be dismountable without damaging the body 2, to release the wire rope 3. They could thus for example comprise unscrewable screwing means, or a breakable part using an ad hoc tool, or a fusible portion at high temperature.
• the body 2 may for example have the following dimensions:
• the wire rope 3 may have a diameter of 12 or 15 mm, so as to withstand a tensile force of the order of 50 kN and to be reusable.
• the reinforcement strip 1 will here be manufactured in the following manner. The manufacturer will first engage the sheath in the mold of the body 2. He will then pour concrete into the mold around the sheath and wait until the concrete is fully set to obtain the body 2. He will then thread the cable metal 3 through the sheath. Then, it will apply a voltage of 50 kN to the ends of the wire rope 3. It will then anchor the ends of the wire rope 3 to the ends of the body 2, so as to compress the body longitudinally 2. Thus the reinforcement bar 1 will be she is ready for use.
• the reinforcing bar 1 could be manufactured otherwise.
• the concrete could then be poured into the mold, around the wire rope 3.
• the wire rope 3 will be rotated about its axis, so that it does not adhere to the concrete and that it digs itself a passage conduit 5 in the body 2.
• the wire rope 3 will then be tensioned and anchored to the ends of the body 2.
• wire rope 3 It could alternatively be envisaged to apply a retarding device on the wire rope 3.
• the concrete could then be poured into the mold, around the wire rope 3.
• the wire rope will be rotated 3 around its axis, so that it does not adhere to the concrete and that it digs of itself a passage conduit 5 in the body 2.
• the wire rope 3 will then be tensioned and anchored at the ends of the body 2.
• the reinforcing bar 1 is thus ready to be used in combination with a beam 12 (or with another kind of frame, for example with a slab) to form therewith a structural element 10 for the construction of any work.
• This beam 12 will here be formed of a single piece of poured concrete. Alternatively, it could be a completely different material, for example a plastic material or wood. In the example considered, the beam 12 has a rectangular or square section. It could of course have a different section, for example T or I.
• the dimensions of the beam 12 are as follows:
• reinforcing bars 1 can be used to reinforce the beam 12.
• each reinforcing bar 1 must then be fixed to the beam 12 in such a way that the anchoring means 4 of each reinforcement bar 1 remain accessible to the user from outside the beam 12.
• the purpose is indeed to dismount these anchoring means 3 in order to release the compression of the body 2 of the reinforcing bar 1 (by extracting the wire rope 3), so as to release internal forces in the beam 12 (to generate a tensile force in the beam 12, in the area that surrounds each reinforcement bar 1).
• each reinforcing strip 1 inside the beam 12, for reasons of ease of use of the beam 12 and better transmission of the forces from the body 2 of each reinforcement strip 1 to the beam 12.
• the beam 12 will be cast around the reinforcing bars 1, so as to ensure good adhesion of the body 2 to the beam 12.
• the latter will be placed flush with the upper face or the lower face of the beam 12. In this way, one of the upper and lower faces of the body 2 of each reinforcement strip 1 will remain visible from outside the beam 12.
• the reinforcing bars could be placed in the beam such that they emerge in part from the upper face or the lower face of the beam.
• Two reinforcing bars 1 will thus be placed in the center of the upper face of the beam 12, on either side of the upper fiber of the beam 12, 25 mm from it.
• Two reinforcement bars 1 will also be placed at each end of the lower face of the beam 12, on either side of the lower fiber of the beam 12, 25 mm from it.
• cavities 14 will then be formed in the beam 12 at the ends of the body 2 of each reinforcing bar 1. These cavities 14 will preferably be formed at the moment of molding of the beam 12.
• the structural element 10 To manufacture the structural element 10, we first install the six reinforcing bars 1 in a form whose shape corresponds to the desired shape for the beam 12. At this stage, the reinforcing bars 1 are fixed in the form with their metallic cables 3 under tension. They are held in the formwork by their ends, by means of cores which will form said cavities 14.
• the structural element 10 formed of the beam and the six reinforcing bars 1 is ready for use.
• the metal cables 3 will be removed in such a way as to be able to reuse them, which will substantially reduce the cost of the structural element 10. Then, the element of structure 10 will be formed only of concrete. However, it will be prestressed for the following reasons.
• FIG. 3 On which a beam 12 'devoid of metal reinforcement and reinforcement bar is shown.
• This tensile force is maximum at the level of the middle of the body 2 and it gradually decreases towards the ends of the body 2. To ensure a good distribution of forces, it will then be preferred to use bodies 2 of large lengths (preferably greater than 1 meter) .
• the tensile force exerted in the beam 12, on one side of the neutral fiber of this beam 12, will then generate a compressive force on the other side of the neutral fiber of this beam 12. This compression force comes then compensate, at least partially or completely, the tensile force exerted in the zones Z1, Z2 of the beam 12.
• the reinforcement bars 1 also generate another effect: the effort of traction exerted by each reinforcement strip 1 will generate compressive forces in the extension of the ends of this bar.
• reinforcing bars 1 located on the lower face of the beam 12 at the ends thereof. These reinforcing bars 1 will generate compressive stresses not only at the ends of the upper face of the beam 12, but also in the middle of the lower face of the beam 12.
• the balance of efforts will be obtained by placement and judicious sizing of the reinforcing bars 1 in the beam 12 so that the cross sections of concrete remain (almost) fully compressed even under the effect of the weight P and maximum effort F.
• empty internal forces restored by the reinforcing bars 1 can create a counter-arrow, that is to say a deformation of the beam 12 upwards.
• the beam 12 will have no or less arrow.
• each reinforcing bar 1 extends along a distinct axis parallel to the main axis A1 of the body 2.
• the beam 12 ' also has an arrow, in that it has a curvature at its ends and its center.
• the reinforcing bars 1 may exert a force that goes against the curvatures of the beam 12. This effort will also make it possible to compensate for the tensile forces exerted in the beam 12.
• the reinforcing bars 1 situated on the top of the beam 12 will be oriented in such a way that their passage ducts 5 extend on the side of the upper fiber of their bodies 2, whereas the reinforcement bars 1 located on the underside of the beam 12 will be oriented in such a way that their passage ducts 5 extend on the side of the lower fiber of their bodies 2.
• reinforcing bars 1 Another advantage of the reinforcing bars 1 is that in case of cracking of the beam 12, these bars (which remain partially compressed after extraction of the metal cables 3) limit the propagation of the cracks and participate in the overall strength of the beam, to the way of a simple reinforcement.
• FIG. 7 in which the structure has an arch form formed of several vertical columns 20A, 20B, 20C and a horizontal structure element 21, it is possible to use the bars of FIG. reinforcement in various ways.
• the horizontal structure element 21 will be formed of a beam 23 and of reinforcement strips 1, 1 'to compensate for these internal tensile forces.
• reinforcement bars 1, Y will then be placed at each connection between the beam 23 and the vertical columns 20A, 20B, 20C, so as to reduce or even cancel the tensile forces exerted in the hatched areas.
• a reinforcing bar 1 of the type shown in FIG. This may be integrated in the beam 23 in such a way that its upper face extends flush with the upper face of the beam 23.
• the reinforcement bars 1 in a beam also equipped with a metal reinforcement (ie say in a beam of reinforced concrete or prestressed concrete).
• FIG. 8 thus shows a section of a beam 22 which, flush with its upper surface, has two parallel reinforcing bars 1 and, near its lower face, a prestressed metal reinforcement 14.
• pre-stressed metal reinforcement 14 may consist of parallel metallic cables powered.
• the reinforcing bars 1 and the prestressed metal reinforcement 14 are advantageously combined to generate on the beam 22 efforts which will prevent the beam from experiencing internal tensile forces.
• FIG. 9 it can be seen that at its center a beam of the type represented in FIG. 3 undergoes a first positive moment P1 due to its own weight P and a second positive moment F1 due to to the effort F exerted on it. These two positive moments add up and then generate tensile forces in the shaded area Z1 in FIG.
• a beam of the type shown in FIG. 2 undergoes, in addition to the first positive moment P1 and the second positive moment F1, a tensile force T1 due to the reinforcing bars 1 and a first negative moment M1 due to the position. reinforcing bars 1 in the center of the upper face of the beam 12.
• This first negative moment M1 therefore counteract the two positive moments P1, F1.
• reinforcing bars of the type shown in FIG. 1 can be used in a concrete slab, for example by distributing these reinforcement strips on the upper face of this concrete slab.
• reinforcing bars of the type of that shown in FIG. 1 it is possible to use reinforcing bars of the type of that shown in FIG. 1 to reduce the torsion of a beam, by placing this reinforcing strip not parallel to the average fiber of the beam, but in a manner that inclined with respect to this average fiber.
• the casing 30 extends over a large length, it will be possible to place several reinforcing bars 1 in the lower wall, in parallel with each other.
• This concrete pipe 40 may be subjected to different types of efforts. It may in particular be subjected to strong tensile stresses on certain portions of the pipeline route.
• reinforcing bars 1 in the wall of this pipe 40.
• these reinforcement strips 1 (here two in number) will then each extend in the wall of the pipe 40, in parallel with the axis of this pipe 40, on the opposite side of the pipe 40 where will exert strong tensile stresses.
• FIG 12 there is shown a cross section of the buttress panel 50, on each side of which appear any material (eg earth).
• the earth extends here to a greater height on one side than the other of the buttress panel 50.
• reinforcing bars 1 as walls of a box 60.
• this box 60 may form reinforcing bars, in that they each comprise a flat plate-shaped body pierced with a plurality of parallel conduits (in which initially will be placed metal cables 3) .
• the anchoring means (4) is fuse. In this way, it will be enough to heat it to release the corresponding end of the wire rope (so that the compression exerted by the latter on the body ceases).
• This detachable fastening means and fuse may be in the form of a hollow frustoconical sleeve, which is threaded on the wire rope and whose inner face is notched so as to be hooked to this cable in the manner of a jaw.
• the frustoconical sleeve will then be engaged by its top in the end of the sheath located in the passage (5).
• this cable will remain in tension thanks to the frustoconical sleeve which will be inserted a little in the passage so that it will close on the end of the cable.
• the cable will remain so stretched until an operator comes to heat the frustoconical sleeve to release the cable.
• the frustoconical sleeve is split longitudinally so that it can deform more easily to ensure better grip of the cable. It may also be provided that this frustoconical sleeve is made by molding a single piece of zinc, since the melting temperature of this material is quite low (about 350 ° C) to allow its melting on site by means of a blowtorch, and that its rigidity at ambient temperature is sufficient to ensure good grip of the wire rope.

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• 2014
  • 2014-03-10 FR FR1451963A patent/FR3018298B1/fr active Active
• 2015
  • 2015-03-06 EP EP15713990.8A patent/EP3117054A1/de not_active Withdrawn
  • 2015-03-06 WO PCT/FR2015/050559 patent/WO2015136194A1/fr active Application Filing

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