FR2482168A1 - REINFORCING ELEMENT FOR THE TRANSMISSION OF CROSSFORCES IN PLATE-CARRIED ELEMENTS, FOR EXAMPLE, FLAT CEILINGS - Google Patents

Abstract

THE INVENTION CONCERNS A REINFORCEMENT ELEMENT FOR THE TRANSMISSION OF TRANSVERSAL FORCES IN CARRIER ELEMENTS IN THE FORM OF PLATES, FOR EXAMPLE, FLAT CEILINGS. THE FRAMEWORK OF THE INVENTION INCLUDES A LOWER MEMBER CONSTITUTED OF SEVERAL BARS 1 ARRANGED PARALLELLY SEPARATELY FROM ONE ANOTHER. BETWEEN TWO BARS 1 OF THE LOWER MEMBER, EACH TIME EXTEND VERTICAL BARS 2, THE LOWER ENDS OF WHICH FORM FEET SPRING DOWN. THESE VERTICAL BARS 2 ARE WELDED TO NEIGHBORING BARS 1 OF THE LOWER MEMBER. THE INVENTION IS USED FOR LAYING MARGINAL AREAS OF CONSTRUCTION-BEARING ELEMENTS, FOR EXAMPLE, FLAT CEILINGS.

Description

The present invention relates to an element of

  mature for the transmission of transverse forces in plate-shaped supporting elements, for example, flat ceilings, of reinforced concrete or prestressed concrete, this element having, within the thickness of a plate, bars d frame (bars

  vertical) with thickened heads, directed essentially

  perpendicularly to the surface of the ceiling and fixed firmly apart from one another on a lower chord and in the longitudinal direction thereof. Reinforcement elements of this type are known

  according to the patent of the Federal Republic of Germany

  In the known elements, the lower chord was formed by a flat steel strip having to engage, in the manner of an ankle, in the concrete supports around which the elements

  of reinforcement were arranged in the form of rays.

  The end of the flat steel profile constituting the lower chord> which was engaged in the concrete supports, was blunt without however having a particular shape. With such reinforcing elements, it was impossible to arm the corner areas and marginal areas of a flat ceiling so that, no doubt, the forces concentrated at these places could be introduced into these areas

angle and these marginal areas.

  As tests have shown, we can

  luer exactly the distribution of the forces if one considers the elements of reinforcement like lattice girders whose upper chord (chord of pressure) which, in itself, is lacking in the elements of reinforcement, is formed by the thickened heads vertical bars between which are interposed concrete parts. If we take this analogy

  with a lattice structure as a base for the in-

  concentrated forces in marginal areas

  the corner areas, we note that the mem-

  lower ridges consisting of flat steel sections and arranged in the concrete stretched zone are not sufficiently bonded to the latter and are also not able to anchor sufficiently in the

  immediate area of introduction of the charge, the di-

  Compressed gonales which one can admit the presence in the concrete. As a result, forces introduced into marginal areas or corner areas

  can not be so absorbed. Since this

  The deficiency comes mainly from the insufficient connection with the concrete.

  first of all is to realize the

  by simple and economical means so as to improve their bond with the concrete for all applications, that is to say, even when

  laying a flat ceiling on cylindrical supports

  or prismatic; this general problem also encompasses a particular partial problem

  to allow the reinforcing elements to anchor sufficiently

  the compressed diagonals formed in the concrete near the force introduction zone,

  so that the ceiling achieved is thus

  sure to absorb the concentrated forces even in the

  corner areas and marginal areas.

  According to the present invention, it is first of all solved the general problem posed by the improvement

  the connection with concrete because, in one

  In the above introduction, the bottom chord is formed of at least two bars (bars of the bottom chord) extending horizontally apart from each other.

  and parallel one beside the other on the

part of their length.

  Starting from bars extending in parallel

  away from each other, a mem-

  lower bridle more economical than an internal chord

  made of flat steel sections with comparable properties. As a result of the concrete coming

  ssengager between and around the bars, the re -

  Multiple bar partition provides a far better connection than a lower chord made of flat steel profiles. This remark is valid, particularly when using fluted bars which are commercially available

as rebar.

  Moreover, by using several bars

  In parallel with the spacing of one another, it is easy to achieve a support width for a safer implementation of reinforcing elements on a formwork. Finally, the use of several parallel bars of this type offers many possibilities of construction to suitably achieve the ends of the reinforcing element, even for the installation of the corner zones or the marginal zones of the reinforcement element. a plate-shaped carrier element, in particular,

a flat ceiling.

  The effect exerted by the lower chord bars extending parallel to the gap from each other corresponds to that of a relatively wide steel tie rod which, together with the vertical bars, forms a support for large area for compressed diagonals of concrete at the nodal points of the bottom chord of the lattice girder

  imaginary. An important advantage of the element of ar-

  Mature made according to the invention also

  in the fact that despite its wide

  total, the lower chord consisting of several

  The bars may be suitably encased in concrete both on the periphery and at the base. Since then,

  the conditions imposed with regard to the protection

  against corrosion and fire are perfectly

  filled for the bars of the lower chord

  by maintaining a normal concrete cover without the need for additional means. Finally, also without having to resort to

  additional means, the reinforcing elements

  according to the invention can be assembled to a formwork by resisting the traction and this, by means of screws or nails that are introduced between the

  different bars of the lower chord.

  Because the lower chord is

  stacked with several bars, the reinforcement element

  the invention also offers advantages when

  that it is placed on supports, since as well the frame of the supports constitutes less a hindrance

  implementation while, on the other hand, the introduction

  force generation is improved, in particular, to

  angles of the cross sections of the supports.

  In all cases, the bending stiffness of a lower chord subdivided into several

  bars is greater than that of a non-subframe

  divided of the same width. Similarly, by prolonging

  by a tie rod, a lower chord thus subdivided

  in several bars, these tie rods can be welded more easily than in the case of the extension

a flat strip.

  According to another embodiment of the invention, the outer ends of the bars

  vertices adapted to the lower chord

  tooth each time between two bars of this chord

  lower. In this way, the possibilities of

  vertical bars with the bars of the lower chord are simplified and, at the same time,

  time, the ends of the vertical bars that extend

  tooth between the bars of the lower chord, act as spacers for these bars of the lower chord. The lower ends of the vertical bars advantageously extend downward beyond the bars of the lower chord forming feet; in this way, the possibility of

  setting up the reinforcement element is improved.

  On the feet formed by the lower extremities

  vertical bars and emerging beyond the bar-

  of the lower chord, it is advantageous to

  made of hats, preferably made of

  synthetic material and protecting the aforementioned feet

  against rust or other type of corrosion.

  The lower ends of the vertical bars

  wedges are advantageously welded to the neighboring bars

  from the lower chord. This welding assembly is advantageously carried out by performing electric pressure welding. Instead or in addition

  welding, it is also possible to assemble

  mechanical tensile strengths, for example

  ple, by engagement below or in the bars

  of the lower chord. Thus, for example,

  ple, the vertical bars can engage from below the bars of the lower chord with

  thickening in the form of consoles, thickening

  ments on which are placed the bars of

  the lower chord. A pulling force acts

  in a vertical bar is transmitted to the bar-

  of the lower chord by geo-

  metric, so that only short weld seams should be made for the transmission of the horizontal force

acting in a vertical bar.

  The use of usual round steel bars both for the vertical bars and for the horizontal bars, which are thus cylindrical,

  significantly reduces manufacturing costs.

248 21 6 8

  cation; however, for particular applications

  It may be advantageous to make the bar-

  vertical bars and / or the bars of the lower chord

  in sharp-edged sections, for example, in

  $ square or rectangular cross-section profiles

  lar. As we know, for a bar of a volume

  given, the cylindrical surface is the smallest sur-

  face enclosing this volume so that, conversely,

  the surface enlarges in relation to the volume, improves

  thus bonding to the concrete if, instead of cylindrical bars, edge profiles are used

  bright. When the flat surfaces of vertical bars

  wedges with sharp edges come to apply on

  flat surfaces of the sharp-edged bars of the mem-

  lower breaking, the welding of the bars one to the

  it is also simplified. This goal can also

  be reached when cylindrical bars

  additionally, at their lower extremities,

  implemented in such a way that they improve the

  of the lower ends of the green bars

  ticals on the horizontal bars at o

  these bars must be welded to each other.

  In an embodiment having more than two lower chord bars extending apart from one another in a plurality of spaces formed between the bars of the lower chord,

  come to engage the lower ends of bar-

  vertical lines which are thus shifted-one beside the other in the transverse direction, either in a plane or vis-à-vis one another. By varying the number of juxtaposed vertical bars, as well as the spacing of their ends, the reinforcing element according to this embodiment of the invention can

  be best adapted to the strengths of the amounts of

  imaginary lily exercising during the setting up.

  If more than two horizontal bars are chosen, the

  vertical bars introduced into the ex-

  can be tilted outwards by

  compared to those introduced in

  and with respect to those introduced into the center space when four bars are used for the lower chord. Of sorts in spite of the thickened heads of the vertical bars, there may still be gaps wide enough to

  freely introduce from above a higher reinforcement

  plate between the vertical bars.

  quton uses reinforcing mesh for the usual top frame of a plate, the inclinations

  vertical bars can be chosen

  so that their thickened heads are spaced a distance corresponding to the width

mesh of the armature lattice.

  According to another embodiment of the invention

  vention, the bars of the lower chord

  at least one vertical bar length beyond the point of application

  vertical bars that is closest to the ex-

  tremity of the reinforcing element on the side of the

  Harbor. The projecting parts are advantageously curved away from each other outwardly and upwardly to the marginal bearing surfaces and they also comprise thickened heads instead of or in addition to which they can still be assembled to one another by welded crosspieces,

  Correspondingly, the ends of the element

  armatures located on the field side are appropriate for interrupting the transmission of traction forces from the adjacent field.

  thanks to the maintenance with 1t flexure-trac-

  existing situation in this case. The compressed diagonals forming in the concrete can be supported on the projecting portions of the horizontal bars. In

  subdividing the lower chord into several bars

  By removing the latter, a particularly advantageous characteristic for the transmission of forces is thus obtained, the thickened heads of the protruding portions of the bars and the struts welded thereto further improving the introduction of the forces. By folding the projecting portions upwards, the forces to be absorbed in the compressed diagonals can be reduced, since a portion of the transverse forces is absorbed by the folded portions projecting towards

  the top of the bars of the lower chord.

  Therefore, the invention also consists of

  use the reinforcing elements made in the way

  re described above for laying end zones

  of a plate-shaped carrier element, in particular

  tying, of a flat ceiling, as well as for the laying of

  corner areas of such bearing elements.

  The accompanying drawings illustrate examples of

  realization of reinforcing elements made according to

  the invention, as well as their use for

  laying marginal areas of a ceiling of a building

struction. In the accompanying drawings

  Figures 1-5 are sectional views of different

  various embodiments encased in concrete; Figure 6 is a section of a ceiling

  in a marginal area containing elements of ar-

  coated concrete and only one of which is visible, and FIG. 7 is a diagrammatic plan view

  of the structure shown in FIG.

  The reinforcement element represented by a sectional view in FIG. 1 comprises two lower chord bars 1 between which the vertical bars 2 arranged one behind the other are introduced.

  and only one of which is visible. The lower extremities

  of these vertical bars 2 extend towards the

  between the bars 1 of the lower chord,

  thus the feet of the armament element. On these

  feet, are placed 7 synthetic hats

  than. The bars 1 of the lower chord are joined to the vertical bars 2 by electric pressure welding as shown in the drawing by the flattened contact points. The reinforcing element is coated with concrete in a plate-shaped carrier element 8, for example, a flat ceiling; its height is calculated so that it can be placed inside the thickness of this flat ceiling. At their upper ends, the vertical bars 2

  are provided, in a manner known per se, with thick heads.

  4 which are delimited downwards by surfaces

  chamfered and which, therefore, allow

  air> to escape when introducing the

  concrete between the reinforcing elements laid on a

  frage, so that the concrete load

  quer on the underside of these thickened heads 4

without forming hollow spaces.

  The example illustrated in FIG. 2 differs from that shown in FIG. 1 only in that the vertical bars 2 are joined to the bars 1 of the lower chord by welding cords.

by merger 9.

  In the example illustrated in Figure 3, the mem-

  lower burr is subdivided into four bars 1.

  Between the central bars of this lower chord

  re, are welded vertical bars 2 extending perpendicular to the ceiling surface, while the bars 2 welded in the outer spaces are slightly inclined outwards. In this case, only the lower ends of these bars

  angled outwards are pointing downwards out-

  beyond the bars of the lower chord by forming

24821 68

  the feet of the reinforcing element, these feet being

  provided with caps of synthetic material 7.

  In the exemplary embodiment illustrated in FIGS. 4 and 5, the vertical bars 2 comprise, at their lower ends, thickenings in

  form of consoles 6 by which they come to

  ger below the bars 1 of the lower chord and on which they come to take support. On their upper face, the bars 1 of the lower chord are still welded to the vertical bars 2 by cords on leave. Before pouring the concrete of the carrier element 8, in this form of

  the lower surfaces of the thickeners

  consoles 6 build on the cost of

  by means of spacer elements (not shown

  conventional type of concrete or synthetic material

  than. Figures 6 and 7 illustrate an example of

  realization of a reinforcement element according to the invention.

  suitable for laying marginal areas of a plate-shaped carrier element, for example, a flat ceiling. In this case, four lower chord bars 1 extending parallel to each other are provided.

  away from each other and between which are

  three spaces in which the vertical bars

  2 engage in the manner previously described

  to be subsequently welded to the bars of the mem-

  lower burn. Near the end of the reinforcing element, a bar 2 is provided each time in each space; therefore, in this case, three bars

  vertical 2 are arranged in a vertical plane.

  A little further away from the end of the element

  of reinforcement, there is no longer, in each outer space,

  only one vertical bar 2 and further

  again, there is again only one vertical bar

  wedge 2 and, further still, there is only one vertical bar 2 in the central space, the fact that

  in all the examples described, the lower extremes

  vertical bars should always be

  at and between two adjacent bars of

  does not exclude that, for particularly important requests, it is also possible to

  to weld or otherwise fix vertical bars

  additional shims only on the outer face

  the lower chord bars, which are

  externally, that is to say, for example in FIG. 7, on either side of the row which is closest to the end of the reinforcing element and which consists of three bars vertical 2. In addition, the additional vertical bars can also be offset with respect to the bars

  neighboring verticals (seen in the transverse direction).

  In the exemplary embodiment illustrated in FIGS. 6 and 7, the ends of the bars A of the

  lower chord protrude beyond the point of

  plication of the vertical bars 2 which is closest to the end of the reinforcing element i these ends emerge over a corresponding distance

  at least at the height of the vertical bars. In 1tOC-

  currents, the protruding parts 3 of the central bars

  Traies 1 of the lower chord are longer than the protruding portions 3 'of the outer bars 1 of the lower chord. Reported to space

  central, all projecting parts are

  not only outward, but also

  up and, in fact, the 3 'parts are

  more sharply upwards than the longer parts 3 (see Figure 6). All protruding parts have, at their ends, heads

  thickened 4 corresponding to the heads 4 of the green bars

  these heads could also be replaced by welded or similar pins or by

24821 68

  short tongues. In this case, although they are also provided with heads 4, the longer projecting parts 3 are also connected by a cross member 5 which is welded thereto. In other cases of use, for example, when placing elements of reinforcement distributed in the form of spokes around an isolated support, one could also dispense with deviation and, at least, fold towards

  the top the projecting parts and one could

  keep these protruding parts in an essential position

  horizontally as shown in dashed lines.

tinus in Figures 6 and 7.

  In this case, the flat ceiling 8 is placed

  on a supporting element It of the construction in inter-

wedging a support plate 10.

Claims (16)

  1. Reinforcing element for the transmission of transverse forces in plate-shaped supporting elements, for example, flat ceilings, of reinforced concrete or prestressed concrete, this element comprising, within the thickness of a plate, rebars (vertical bars) having   thickened heads, directed essentially perpendicular   at the surface of the ceiling and fixed firmly apart from one another on a lower chord and in the longitudinal direction thereof> characterized in that the lower chord is formed of at least two bars (bars 1). of the lower chord) extending horizontally away from each other and parallel to each other on the major part of their length.   2. Reinforcement element according to claim 1, characterized in that the vertical bars (2) are each time to be placed, by their lower ends o they are assembled to the frame   lower, between two bars (1) of the latter.   3. Reinforcement element according to any one   than claims 1 and 2, characterized in that   the lower ends of the vertical bars (2) extend downwards beyond the bars (1) of the   lower chord forming feet.   4. Reinforcement element according to any one   than claims 1 to 3, characterized in that   hats of synthetic material (7) are applied   on the feet of the vertical bars (2) standing out   beyond the bars (1) of the lower chord.   5. Reinforcement element according to any one   claims 1 to 4, characterized in that   the lower ends of the vertical bars (2)   are welded to adjacent horizontal bars (1). 24821-68   Reinforcing element according to claim 1, characterized in that the welding connection is   realized by electric pressure welding.   7. Reinforcement element according to any one   Claims 1 to 4, characterized in that   the lower ends of the vertical bars (2) are assembled in tensile strength and in solidarity with the neighboring bars (1)   of the lower chord, in particular by coming   from below or in the latter.   8. Reinforcement element according to any one   than claims 1 to 7, characterized in that   the vertical bars and / or the bars of the lower chord (i or 2) are formed of sharp-edged sections, for example of square cross-section or   rectangular, or in that they are rods Lées.   9. Reinforcement element according to any one   that claims 1 and 2, having more than two   lower chord bars extending apart from each other, characterized in that in several   spaces formed between the bars (1) of the mem-   the lower extremity are introduced   vertical bars (2) which are thus   juxtaposed in the transverse direction.   10. Reinforcement element according to the claim   9, this element comprising four bars of   equidistant lower burr characterized in that   the vertical bars (2) introduced into the   outside walls are inclined outwards by   compared to those introduced in the central space.   11. Reinforcement element according to any one   claims 1 to 10, characterized in that   the bars (1) of the lower chord emerge from a distance at least equal to a length of one   vertical bar, beyond the last point of application   vertical bars (2) at the end of the elec- reinforcement.   12. Reinforcing element according to the claim   11, characterized in that the ends   (3) bars of the lower chord are folded apart from each other outwards and to the top.   13o Reinforcement element according to any one   than claims 11 and 12, characterized in that   the projecting ends (3) of the bars of the lower chord are joined to each other by welded tram-links (5) o   14o Reinforcement element according to any one   as in claims 1 to 13, characterized in that   the vertical bars (2) are provided in a larger number close to the ends of this element   than at a greater distance from these.   15. Reinforcement element according to any one   Claims 1 to 14, characterized in that,   just like vertical bars (2), bars (1)   of the lower chord have thick heads at their ends.   16. Reinforcing element according to any one   claims 1 to 15, characterized in that   close to their ends and on their upper face, the bars (1) of the lower chord   short sleepers which are preferably welded.   17. Use of reinforcement elements next   any of claims 11 to 13 for the   laying marginal areas of shaped bearing elements   plates, for example, flat ceilings.   18. Use of reinforcing elements according to claim 16 for laying the corner zones of plate-shaped bearing elements, for example flat ceilings.