Classifications

• • 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
  • E04C3/22—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 built-up by elements jointed in line
• • 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

Definitions

• the present invention relates to a prestressed concrete beam and a method of connecting such beams.
• the first of these methods consists in introducing the concrete in a more or less liquid state into a mold or formwork in the form of the beam to be obtained and then allowing the concrete to harden before removing the formwork.
• This method allows the manufacture of beams having sections of various shapes. A large number of shapes are feasible as long as they allow the removal of the formwork once solidified concrete. This process, however, allows only low productivity.
• the second method is to pass the concrete in a die moving along a table serving as a support for the beam formed by the concrete out of the die and being solidified.
• This method allows a high productivity but is unsuitable for the manufacture of beams with parts overhang or cantilever. Such parts would indeed tend to collapse immediately after extrusion, the concrete being solidified not being supported by a mold once out of the die.
• the high-performance fiber concretes have thus made it possible to obtain beams having relatively thin sections while exhibiting high mechanical strength.
• the fire resistance of such beams is higher than that of standard metal beams.
• the techniques used in metallic frameworks, in particular the welding and the mechanically welded assembly, to realize a connection of the beams between them making it possible to ensure a transmission and a distribution of the forces and the constraints are not transposable to the connection concrete beams, while their simplicity has greatly contributed to the development of metal structures.
• the manufacture of beams having sections having relatively thin portions and / or overflow is also more difficult to achieve with concrete than with metal.
• An object of the invention is to provide a beam structure thanks to which it is possible to obtain, from manufacture, a beam of better performance and, at the moment of its use, a greater diversity of use than the beams in traditional concrete.
• an ultra-high performance fiber concrete beam which comprises a first spar comprising at least one core, one longitudinal edge of which is in the form of a flange and whose other edge forms a flange.
• longitudinal tongue for cooperating with at least one longitudinal groove of a second spar also having, opposite the groove, the shape of a bearing flange, at least one of the longitudinal members comprising a prestressing cable longitudinal embedded in the concrete parallel to the neutral longitudinal axis of the beam.
• the beams are made independently of one another before being nested one in the other.
• Each spar can thus be manufactured in the most convenient position, for example with the soleplate facing down to rest on the table, in the case of extrusion or with the sole upwards, in the case of molding in a formwork.
• the interlocking of the longitudinal members ensures a transmission of forces and a distribution of stresses between them such that the composite beam thus formed behaves like a beam in one piece. It is even possible, by this structure, to provide longitudinal members of compositions leading to different mechanical qualities and thus act on the load behavior of the beam.
• the longitudinal tongue has convergent flanks advantageously defining a vertex angle determined so that jamming can occur between this tongue and the groove which receives it and which also has diverging sides.
• the longitudinal members are thus firmly connected mechanically.
• the tongue has a connection fillet flanks to each other.
• a binder layer is interposed between the tongue and the groove, the binder being preferably a structural adhesive.
• the binder layer reinforces the connection of the longitudinal members.
• the beam of the invention may comprise regularly distributed pins passing through both the flanks of the groove of the groove spar and the tongue of the other spar. This provision is a keyway of the connection which constitutes a security, opposing the separation of the spars if this connection was to be ruined over time.
• the plugs may be replaced by bolts or the like.
• the tongue spar of the beam of the invention comprises several parallel webs coming from a common sole and defining a plurality of tongues while the groove spar comprises several parallel grooves, of the same spacing as that separating the aforesaid webs.
• the beam formed by the combination of these two longitudinal members is a hollow beam with several compartments that can be used as a component wall or floor.
• the internal spaces of this beam can be filled before assembly, a sound and / or thermally insulating material.
• the invention also relates to a method of abutting two beams in accordance with those described above, according to which is capped by a groove spar section ends placed end to end of two tongue members. These ends belong of course to beams whose remaining length is according to the invention formed of two associated beams. Two variants of this process are possible.
• the first consists in that said section is an axial extension of the groove spar belonging to one of the two beams while the other beam is devoid of groove spar a length substantially identical to that of said extension.
• each of the adjacent beams is devoid of groove spar near its end to abut the other beam, said section being a jumper placed overlapping on the exposed tongue portions of each beam.
• the method of the invention allows one abutting beams ensuring the continuity of the thrust force in the connection region in a simple and efficient manner.
• the method comprises the step of: engaging at least one peg transversely to the groove and the tongue that it overlaps, to the right of each beam; layer of binder between the tongue and the groove.
• FIG. 1 is a cross-sectional view of a simple beam according to the invention
• FIG. 2 illustrates a hollow composite beam according to the invention, capable of forming an element of floor or wall
• - Figures 3 and 4 are partial side views, each illustrating two abutment girders according to the invention
• FIG. 5 illustrates, in sectional view, a complementary end-to-end connection element of two beams according to the invention
• Figures 6 and 7 illustrate, respectively, a side view and a sectional view along line VII-VII of Figure 6, an alternative embodiment of the abutment means of two beams according to the invention.
• the beam shown in Figure 1 has an I-section.
• the beam, generally designated 1 comprises a first spar 2.1 and a second spar 2.2 extending parallel to each other.
• the first spar 2.1 comprises a core 3.1 bordered by a longitudinal support portion 4.1 shaped as a sole and whose other longitudinal edge forms a tongue 5.1.
• the support plate 4.1 extends here perpendicularly to the central portion of the core 3.1 and comprises portions extending on either side of the central portion of the core and projecting therefrom.
• the end of the web 5.1 forming tongue is delimited laterally by convergent sides 6 connected to each other by a substantially cylindrical fillet 7.
• the second spar 2.2 comprises a core 3.2 having a longitudinal bearing portion 4.2 shaped as a sole and, on the opposite side, a longitudinal portion with a groove 5.2 of shape complementary to that of the tongue 5.1.
• the sole plate 4.2 extends perpendicular to the core 3.2, is parallel to the support plate 4.1 and comprises parts extending on either side of the core 3.2 and projecting therefrom.
• the tongue 5.1 is nested in the groove 5.2.
• the flanks 6 are convergent at a given vertex angle, for example 5 °, just as the flanks of the groove are diverging at the same angle, to encourage a jamming of the tongue 5.1 in the groove 5.2.
• a layer of binder 8, here a structural adhesive extends between the tongue 5.1 and the groove 5.2 on all or part of their surfaces in contact.
• the glue is a rigid epoxy structural glue of class 2.
• the glue conforms to the French standard NFP 35 18.870 and has a compressive strength of at least 50 MPa and a flexural tensile strength of at least equal to at 15 MPa.
• the spars are made of high performance fiber concrete (UHPC).
• the fibers used are metal fibers possibly associated with fibers of plastic material such as propylene to increase the fire resistance.
• the mechanical tensile performance of the binder used is comparable to that of high performance fiber concrete.
• the beam 1 comprises a longitudinal prestressing cable 9 embedded in the concrete. In the case of Figure 1, this cable is embedded in the spar 2.1, under a longitudinal axis 10 of the beam.
• the cable is made of steel having a temperature withstand up to 35O 0 C.
• the cable is housed in the beam 2.2 of the beam. In this case, the beam is used so that its lower support on a support infrastructure (wall, pole, ...) is achieved by the sole 4.2.
• Figure 2 illustrates in cross section a beam 20 according to the invention in which the pattern of the single beam I of Figure 1 is repeated twice along two wide flanges.
• the tongue spar 21 has three webs 22, 23 and 24, erected on a common sole 25 while the grooved spar 26 has three grooved webs 27, 28 and 29 erected on a common sole 30.
• the resulting beam has two internal spaces 31 and 32 which can be filled with a sound-insulating material and / or thermally. These spaces may also constitute reserves for installing fluid or electrical lines.
• One of the ends of the tongue member 2.1.A projects axially beyond the second groove spar 2.2.
• the second spar 2.2. B is in axial projection of the first spar 2.I.B.
• the step of abutting the ends of the beam 1A and the beam 1B consists in fitting the exposed tongue 5.1.A of the beam 2.1.A of the beam 1A in the groove 5.2 . B of the spar 2.2. B of the beam 1B A binder layer is interposed between these nested parts.
• the method further comprises the additional step of engaging transverse pegs through the nested portions.
• These pins 11 reinforce the connection between the beam IA and the beam IB while working in shear.
• the pegs 11 may be pins or bolts. It will be noted that these dowels may also be present from place to place along each beam through the nested groove and tongue.
• Each beam end 1A and 1B is devoid of the associated channel spar so that a groove section 12 is straddling the butt contact zone of beams 1A and 1B. This section is also glued
• FIG. 5 a cross-sectional view shows the presence of a lower shoe 13 which comprises a base plate 14 and two wings 15 and 16, these elements being assembled, between themselves, by gluing and at the junction end to end of two beams IA and IB, by bonding the base plate 14 under the sole of these beams.
• the base plate 14 can be pre or post stressed by means of cables 17.
• This shoe is located under the section 12 of grooved spar.
• the means shown are a variant of those shown in Figure 5.
• the section of spar 12a has a sole 4.2a which is wider than the sole 4.2 previously described so as to carry three longitudinal portions , each with a groove 5.2, 5.2a, 5.2b capable of fitting the tongue 5.1 of the spar 2.1.A and the ends of the flanges 15a and 16a in the form of tongues 15b and 16b.
• These wings belong to the shoe 13a being in one piece with the base plate 14a of this shoe.
• the spar 2.1.A comprises two cables 9a and 9b of pre or post stress and that the base plate 14a is fixed to the sole 4.1 of the spar 2.1.A by pins (pins or bolts) 18.
• the beam may have a section different from that described and, for example, a section C, U, diabolo ...
• the beam may be longitudinally constrained by prestressing or post-stressing.
• the connection of the beams can be performed without binder or without ankle.
• the binder may be an epoxy type glue or the like, or even a mortar.
• the tongue spar may be different from the groove spar.

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Rod-Shaped Construction Members (AREA)

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Citations (5)

• 2008
  • 2008-02-08 FR FR0800663A patent/FR2927342B1/fr not_active Expired - Fee Related
• 2009
  • 2009-02-05 EP EP09717198A patent/EP2396482A2/fr not_active Withdrawn
  • 2009-02-05 CN CN200980104593.3A patent/CN101952522B/zh not_active Expired - Fee Related
  • 2009-02-05 WO PCT/FR2009/000130 patent/WO2009109726A2/fr active Application Filing
  • 2009-02-05 BR BRPI0908064-3A patent/BRPI0908064A2/pt not_active IP Right Cessation

Patent Citations (5)

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