EP0188395A2 - Lattice girder, in particular for constructing a bridge - Google Patents

Lattice girder, in particular for constructing a bridge Download PDF

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Publication number
EP0188395A2
EP0188395A2 EP86400051A EP86400051A EP0188395A2 EP 0188395 A2 EP0188395 A2 EP 0188395A2 EP 86400051 A EP86400051 A EP 86400051A EP 86400051 A EP86400051 A EP 86400051A EP 0188395 A2 EP0188395 A2 EP 0188395A2
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EP
European Patent Office
Prior art keywords
bars
elements
beam according
members
concrete
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP86400051A
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German (de)
French (fr)
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EP0188395A3 (en
Inventor
François Conversy
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Campenon Bernard SA
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Campenon Bernard SA
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Filing date
Publication date
Application filed by Campenon Bernard SA filed Critical Campenon Bernard SA
Publication of EP0188395A2 publication Critical patent/EP0188395A2/en
Publication of EP0188395A3 publication Critical patent/EP0188395A3/en
Ceased legal-status Critical Current

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    • 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
    • E04C3/205—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 with apertured web, e.g. frameworks, trusses
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D2/00—Bridges characterised by the cross-section of their bearing spanning structure
    • E01D2/02—Bridges characterised by the cross-section of their bearing spanning structure of the I-girder type
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D6/00—Truss-type bridges
    • 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
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D2101/00—Material constitution of bridges
    • E01D2101/20—Concrete, stone or stone-like material
    • E01D2101/24—Concrete
    • E01D2101/26—Concrete reinforced
    • E01D2101/28—Concrete reinforced prestressed

Definitions

  • the present invention relates to a prestressed truss beam, at least partially made up of prefabricated elements, in particular for the construction of a bridge.
  • This beam is intended to be in support at two or more points spaced so as to form one or more spans.
  • Lattice beams comprising, for each span, two series of beam elements arranged on either side of a point of the span where the shear forces under permanent load are substantially zero, these elements being assembled by tensioned reinforcements. , say prestressing reinforcements, each extending over more than one element.
  • Each element of this beam has an upper member and a lower member in concrete, extending in the longitudinal direction of the span. These elements are assembled end to end so that the upper and lower members of the different elements are in line with each other.
  • each element is connected at least by a group of three substantially coplanar bars forming an N.
  • the object of the present invention is to provide a lattice beam particularly well suited to construction from prefabricated elements and having improved resistance to shearing force.
  • this beam is characterized in that two bars of N connect the two members together and extend transversely to the longitudinal direction of the span, near the ends of these members and are anchored to the latter so as to resist essentially tensile forces, while the third bar of N extends between the two aforementioned bars, and in that for the first series of elements, when moving on the span of a support to the 'other, said third bars are rising, while for the second series of elements located beyond a point where the shear forces under permanent load are substantially zero, said third bars are descending, so that these third bars undergo essentially compression forces.
  • the beam according to the invention comprises at least one group of two bars located on either side of the ends situated in the extension of one another of two neighboring elements. These bars which are essentially subjected to tensile stresses are anchored to the concrete members so as to resist such stresses.
  • third bars the arrangement of the other bars known as "third bars” is such that they essentially undergo compression forces and have their opposite ends in abutment against the lower and upper members.
  • the lattice beam is in support at two points 1, 2, the part located between these two points constituting a span 3.
  • This span 3 comprises two series of beam elements 4a, 4b, 4c , ... and 5a, 5b, 5c, ... arranged on either side of a point M of the span 3 where the shear forces under permanent load are substantially zero.
  • the elements 4a, 4b, 4c, ... are arranged symmetrically with respect to the elements 5a, 5b, 5c, ... with respect to a plane passing through the point M and perpendicular to the longitudinal direction D of span 3.
  • Each element 4a, 4b, 4c, ...; 5a, 5b, 5c, ... includes an upper member 6a, 6b, 6c, ...; 7a, 7b, 7c, ... and a lower member 8a, 8b, 8c, ...; 9a, 9b, 9c, ... made of concrete which extend in the longitudinal direction D of span 3.
  • Elements 4a, 4b, 4c, ...; 5a, 5b, 5c, ... are assembled end to end so that their concrete members 6a, 6b, 6c, ...; 7a, 7b, 7c, ... and 8a, 8b, 8c, ...; 9a, 9b, 9c, ... are in line with each other.
  • the upper members 6a, ...; 7a, ... and lower Sa, ...; 9a, ... are connected to each other by a group of three bars 10a, 11a, 12a; 10b, 11b, 12b; ... 13a, 14a, 15a, ... arranged substantially in a plane and together forming an N.
  • the elements 4a, 4b, 4c, ... 5a, 5b, 5c are inscribed in a rectangle, their members being parallel to each other.
  • two bars 10a, 11a; 1 Ob, 11b; 13a, 14a of N connect the upper members 6a, 6b; 7a, 7b and lower 8a, 8b; 9a, 9b between them and extend transversely (in the example shown perpendicularly) to the longitudinal direction D of the span 3.
  • these two bars 10a, 11a; 10b, 11b; 13a, 14a are arranged near the ends such as 16a, 17a of the members.
  • These two bars 10a, 11a; 10b, 11b; 13a, 14a are anchored in the concrete members 6a, 8a; ... so as to resist essentially tensile forces, as will be explained in more detail later.
  • the other bars which will be called “third bars” of the N such as 12a, 12b, ... 15a, ... extend between the two bars 10a, 11a; 10b, 11b; ... 13a, 14a, their opposite ends being in abutment against parts such as 18a, 19a, forming a stop for the upper members 6a, 6b; ... and below Sa, 8b; ...
  • the elements 4a, 4b, 4c, ... 5a, 5b, 5c, ... are assembled to each other by prestressing cables 20, 2 1 , 22, extending in channels formed in the concrete members of these elements.
  • the cable 21 is anchored in a boss 25 formed on the upper member 6b of the element 4b.
  • the other end of this cable is anchored in a similar boss made on the neighboring span (located on the left of Figure 1).
  • the cable 22 is anchored in a boss 26 formed on the upper member of the element 5b.
  • This cable 22 is anchored in a similar boss formed on the neighboring span (located to the right of FIG. 1).
  • the ends in contact such as 16a. 17a upper and lower members of two neighboring elements such as 4a, 4b are located in planes perpendicular to the direction D of the span 3 and parallel to each other.
  • each bar such as 11 has adapted to resist essentially the tensile forces, is symmetrical with the bar such as 10b of the neighboring element with respect to the plane in which the ends in contact such as 16a, 17a, are located.
  • two neighboring elements 4a, 4b are located.
  • the third bars such as 12b (see FIGS. 2 and 3), which essentially undergo compression forces, extend along an axis A which intersects the axis B of each member such as 8b, in a point located at equal distances from axes a and b of bars 11 a and 10b.
  • FIGS. 2 and 3 it can also be seen that the abutment parts 18b and 19b molded in one piece with the upper and lower members have bearing surfaces 29, 30 which are perpendicular to the axis A of the third bar 12b.
  • the element 4 b is made entirely of concrete.
  • This Figure 3 shows that the lower members Sa, 8b of two neighboring elements 4 8 , 4b are in contact along a surface 17a perpendicular to the axis B of these members.
  • the bars 11a and 10b are arranged in parallel and on either side of this surface 17a.
  • the axis A of the third bar 12b of the element 4b intersects the axis B common to the lower members 8a and 8b at a point 17b located at equal distance from the axes a and b of the bars 11 a and 10b.
  • the vector F located on the axis A of the third bar 12b of the element 4b represents the compression force applied to this bar.
  • the force F decomposes into a force F, which biases in tension the vertical bar 10b and a force F 2 which is oriented towards the point of intersection between the axis of the vertical bar 11a of the neighboring element 4a and the axis B the frame 8a of this element.
  • this force F 2 decomposes into a force F, which biases the vertical bar 11a of the element 4a and a force F which compresses the frame 8a of this element.
  • the angle formed by the force F 2 and the axis B is the maximum angle which the total force which crosses the contact surface 17a can form with this axis, this total force being the sum of the force F 2 and the compressive force F 5 of the frame 8b which, for a suitably prestressed structure must always be positive.
  • these vertical bars 11a, 10b be anchored in the concrete of these members beyond the axis of these.
  • the boss such as 19b formed on the frame 8b can collect the compressive force F exerted by the third bar 12b.
  • FIG. 4 shows by way of example, a bar 10b made of concrete and capable of withstanding the tensile forces.
  • This bar 10b has a rectangular section and has at its two ends steel plates 31, 32 perpendicular to the axis of the bar and which project on either side of the concrete body of the bar.
  • the prestressing of the bar 10b is obtained by exerting before the pouring of the concrete equal and opposite forces on the steel plates 31, 32 in a direction which tends to move them away from each other in order to tension the son 33. These forces are maintained after the concrete has been poured until it has acquired sufficient strength.
  • the concrete of the members 6b and 8b is then poured onto the ends of the bar 10b so that the plates 31, 32 are embedded in the concrete of the members.
  • these rods 34, 35 are embedded in the concrete thereof and extend parallel to the axis of these members.
  • the holes 36, 37 formed near the opposite ends of the bar 10b, perpendicular to the axis of the bar and parallel to the steel rods 34, 35 are intended for the passage of prestressing cables such as cables 20, 21, 22 shown in Figure 1.
  • the beam member comprises upper and lower members 6b, 8b which are made of concrete, as in the case of the elements described above.
  • the bars 10 "b, 11" b, and 12'b are made of steel.
  • the vertical bars 10 "b and 11" b have their ends firmly anchored in the concrete of the frames 6b and 8b, while the bar 12'b undergoing essentially compressive forces is in abutment against the parts forming stops 18b and 19b of the frames .
  • This bar 10" b is a steel tube which, filled with concrete 50, has at its opposite ends a crown also made of steel 38, 39 projecting on either side of the tubular body of the bar.
  • These rings 38, 39 intended to be embedded in the concrete of the members 6b, 8b provide excellent anchoring of the bars 10 "b and 11" b and allow them to withstand the tensile forces.
  • the bar 10 "b is crossed by holes 40, 41 allowing the passage of prestressing cables.
  • the beam according to the invention instead of being constituted by a single row of elements 4a, 4b, 4c as indicated in FIG. 1, can comprise two or more parallel rows of elements.
  • Figure 8 shows in detail one 4 'of the two elements of the segment shown in Figure 7.
  • the element 4' is identical to the element 4b shown in Figure 2, except that the upper chord 6 'has a thickness weaker than the member 6b of the element 4b of FIG. 2.
  • the ends 10'b and 11'b of the vertical bars 10b and 11 protrude beyond the upper edge of the member 6 'so as to be embedded in the slab 42 which is poured between the two elements 4 'and 4 ".
  • Figure 9 shows a segment identical to that of Figure 7, except that the lower members are interconnected by two cross members 43, 44 of concrete arranged in a cross, which further improves the mechanical strength of the segment.
  • the segment is also identical to those of FIGS. 7 and 9, except that the lower members of the elements 4 'and 4 "are connected by a concrete slab 45 parallel to the upper slab 42.
  • the segment comprises an upper slab 46 and a lower slab 47 which connect the upper and lower chords of four elements 4A, 4B, 4C, 4D similar to those described above but which are arranged in oblique planes relative to the slabs 46 and 47.
  • the upper and central member 6BC is common to the two central elements 4B and 4C, the latter being connected by progressively deviating from the plane of symmetry of the segment with two lower members 8AB and 8CD which are common to the external elements 4A and 4D.
  • These checkers are each connected to a frame 6A and 6D forming part of the upper slab 46.
  • FIG. 12 represents a bridge resting on vertical piers 48, 49 produced by means of segments V ,, V b V 3 , V. comprising two parallel elements linked together by an upper slab and a lower slab, as in the case of FIG. 10, and of segments V ,, V 6 , V, also comprising two parallel elements connected together by an upper slab, but the lower members of which are connected by crosspieces arranged in a cross as in the case of the segment shown in the figure 9.
  • the segments V 1 , V 2 , V 3 , V 4 which have a stronger lower chord than that of the segments V 5 , V 6 , V 7 , are arranged near the stacks 48, 49.
  • the upper members are as previously arranged along a straight line parallel to the longitudinal direction of the span.
  • the lower members assembled end to end define an arc.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Rod-Shaped Construction Members (AREA)
  • Bridges Or Land Bridges (AREA)
  • Joining Of Building Structures In Genera (AREA)

Abstract

The prestressed lattice girder is supported at several points (1, 2) so as to form, for each span, two series of elements (4a, 4b, 4c, ... 5a). Each element comprises an upper boom (6a) and a lower boom (8a) made of concrete, connected to one another by bars (10a, 11a, 12a) forming an N. The vertical bars (10a, 11a) are arranged close to the ends of the booms and essentially resist the tensile forces. The third bar (12a) resists the compressive forces and is upward in the case of the first series of elements (4a, 4b, ...) and downward in the case of the second series of elements (5a, ...) situated beyond a point M at which the shearing forces under a permanent load are substantially nil. Used especially for constructing bridges. <IMAGE>

Description

La présente invention concerne une poutre précontrainte en treillis, constituée au moins partiellement d'éléments préfabriqués, notamment pour la réalisation d'un pont. Cette poutre est destinée à être en appui en deux ou plusieurs points espacés de façon à former une ou plusieurs travées.The present invention relates to a prestressed truss beam, at least partially made up of prefabricated elements, in particular for the construction of a bridge. This beam is intended to be in support at two or more points spaced so as to form one or more spans.

On connaît des poutres en treillis comprenant pour chaque travée deux séries d'éléments de poutre disposées de part et d'autre d'un point de la travée où les efforts tranchants sous charge permanente sont sensiblement nuls, ces éléments étant assemblés par des armatures tendues, dites armatures de précontrainte, s'étendant chacune sur plus d'un élément.Lattice beams are known comprising, for each span, two series of beam elements arranged on either side of a point of the span where the shear forces under permanent load are substantially zero, these elements being assembled by tensioned reinforcements. , say prestressing reinforcements, each extending over more than one element.

Chaque élément de cette poutre comporte une membrure supérieure et une membrure inférieure en béton, s'étendant dans la direction longitudinal de la travée. Ces éléments sont assemblés bout à bout de sorte que les membrures supérieure et inférieure des différents éléments sont dans le prolongement les unes des autres.Each element of this beam has an upper member and a lower member in concrete, extending in the longitudinal direction of the span. These elements are assembled end to end so that the upper and lower members of the different elements are in line with each other.

Les membrures supérieure et inférieure de chaque élément sont reliées au moins par un groupe de trois barres sensiblement coplanaires formant un N.The upper and lower members of each element are connected at least by a group of three substantially coplanar bars forming an N.

Lorsqu'une charge est appliquée sur cette poutre, cette dernière subit des efforts tranchants qui sont transmis par les barres qui relient les membrures supérieure et inférieure des éléments. Certaines barres subissent des efforts de traction et d'autres des efforts de compression.When a load is applied to this beam, the latter undergoes shearing forces which are transmitted by the bars which connect the upper and lower members of the elements. Some bars undergo tensile forces and others compressive forces.

En procédant à une analyse très poussée d'une part des forces qui s'appliquent aux barres disposées en N et d'autre part des forces qui traversent les surfaces de jonction des membrures, dans les éléments constituant les poutres en treillis connues, la demanderesse a constaté qu'il était possible d'optimiser la transmission de ces forces, de façon à accroître la résistance de la structure et éventuellement d'alléger celle-ci.By carrying out a very detailed analysis on the one hand of the forces which apply to the bars arranged in N and on the other hand of the forces which cross the junction surfaces of the members, in the elements constituting the known lattice girders, the applicant found that it was possible to optimize the transmission of these forces, so as to increase the resistance of the structure and possibly to lighten it.

Le but de la présente invention est de proposer une poutre en treillis particulièrement bien adaptée à une construction à partir d'éléments préfabriqués et présentant une résistance à l'effort tranchant améliorée.The object of the present invention is to provide a lattice beam particularly well suited to construction from prefabricated elements and having improved resistance to shearing force.

Suivant l'invention, cette poutre est caractérisée en ce que deux barres du N relient les deux membrures entre elles et s'étendent transversalement à la direction longitudinale de la travée, près des extrémités de ces membrures et sont ancrées à ces dernières de façon à résister essentiellement à des efforts de traction, tandis que la troisième barre du N s'étend entre les deux barres précitées, et en ce que pour la première série d'éléments, lorsqu'on se déplace sur la travée d'un appui à l'autre, lesdites troisièmes barres sont montantes, tandis que pour la seconde série d'éléments située au-delà d'un point où les efforts tranchants sous charge permanente sont sensiblement nuls, lesdites troisièmes barres sont descendantes, de façon que ces troisièmes barres subissent essentiellement des efforts de compression.According to the invention, this beam is characterized in that two bars of N connect the two members together and extend transversely to the longitudinal direction of the span, near the ends of these members and are anchored to the latter so as to resist essentially tensile forces, while the third bar of N extends between the two aforementioned bars, and in that for the first series of elements, when moving on the span of a support to the 'other, said third bars are rising, while for the second series of elements located beyond a point where the shear forces under permanent load are substantially zero, said third bars are descending, so that these third bars undergo essentially compression forces.

Ainsi, la poutre conforme à l'invention, comporte au moins un groupe de deux barres situées de part et d'autre des extrémités situées dans le prolongement l'une de l'autre de deux éléments voisins. Ces barres qui subissent essentiellement des efforts de traction sont ancrées aux membrures en béton de façon à résister à de tels efforts.Thus, the beam according to the invention comprises at least one group of two bars located on either side of the ends situated in the extension of one another of two neighboring elements. These bars which are essentially subjected to tensile stresses are anchored to the concrete members so as to resist such stresses.

Par contre, la disposition des autres barres dites "troisièmes barres" est telle qu'elles subissent essentiellement des efforts de compression et ont leurs extrémités opposées en appui contre les membrures inférieure et supérieure.On the other hand, the arrangement of the other bars known as "third bars" is such that they essentially undergo compression forces and have their opposite ends in abutment against the lower and upper members.

D'autres particularités et avantages de l'invention apparaîtront encore dans la description ci-après.Other features and advantages of the invention will appear in the description below.

Aux dessins annexés, donnés à titre d'exemples non limitatifs:

  • - la figure 1 est une vue en élévation d'une poutre en treillis conforme à l'invention,
  • - la figure 2 est une vue en perspective, à échelle agrandie d'un élément de cette poutre en treillis, qui est réalisé entièrement en béton,
  • - la figure 3 est une vue schématique en élévation montrant les membrures inférieures de deux éléments voisins représentés partiellement et les répartitions des forces dans ceux-ci,
  • - la figure 4 est une vue en perspective à échelle agrandie d'une barre adaptée à résister essentiellement à des efforts de traction,
  • - la figure 5 est une vue analogue à la figure 2, dans laquelle les barres sont en acier,
  • - la figure 6 est une vue en perspective, d'une barre en acier,
  • - la figure 7 est une vue en perspective de deux éléments parallèles reliés par une dalle et formant un voussoir,
  • - la figure 8 est une vue à échelle agrandie de l'un des éléments de la réalisation selon la figure 7,
  • - la figure 9 est une vue analogue à la figure 7, concernant une variante de réalisation,
  • - la figure 10 est une vue analogue aux figures 7 et 8, concernant une autre variante,
  • - la figure 11 est une vue en perspective d'un voussoir comprenant plusieurs éléments disposés obliquement les uns par rapport aux autres,
  • - la figure 12 est une vue en perspective avec arrachements d'un pont composé d'éléments conformes à l'invention.
In the appended drawings, given by way of nonlimiting examples:
  • FIG. 1 is an elevation view of a truss beam according to the invention,
  • FIG. 2 is a perspective view, on an enlarged scale, of an element of this trellis beam, which is made entirely of concrete,
  • FIG. 3 is a schematic elevation view showing the lower members of two neighboring elements partially represented and the distributions of the forces therein,
  • FIG. 4 is a perspective view on an enlarged scale of a bar adapted to resist essentially tensile forces,
  • FIG. 5 is a view similar to FIG. 2, in which the bars are made of steel,
  • FIG. 6 is a perspective view of a steel bar,
  • FIG. 7 is a perspective view of two parallel elements connected by a slab and forming a segment,
  • FIG. 8 is a view on an enlarged scale of one of the elements of the embodiment according to FIG. 7,
  • FIG. 9 is a view similar to FIG. 7, concerning an alternative embodiment,
  • FIG. 10 is a view similar to FIGS. 7 and 8, concerning another variant,
  • FIG. 11 is a perspective view of a segment comprising several elements arranged obliquely with respect to each other,
  • - Figure 12 is a perspective view with cutaway of a bridge composed of elements according to the invention.

Dans la réalisation de la figure 1, la poutre en treillis est en appui en deux points 1, 2, la partie située entre ces deux points constituant une travée 3. Cette travée 3 comprend deux séries d'éléments de poutres 4a, 4b, 4c, ... et 5a, 5b, 5c, ... disposées de part et d'autre d'un point M de la travée 3 où les efforts tranchants sous charge permanente sont sensiblement nuls.In the embodiment of Figure 1, the lattice beam is in support at two points 1, 2, the part located between these two points constituting a span 3. This span 3 comprises two series of beam elements 4a, 4b, 4c , ... and 5a, 5b, 5c, ... arranged on either side of a point M of the span 3 where the shear forces under permanent load are substantially zero.

Dans l'exemple de la figure 1, les éléments 4a, 4b, 4c, ... sont disposés symétriquement par rapport aux éléments 5a, 5b, 5c, ... par rapport à un plan passant par le point M et perpendiculaire à la direction longitudinale D de la travée 3.In the example of FIG. 1, the elements 4a, 4b, 4c, ... are arranged symmetrically with respect to the elements 5a, 5b, 5c, ... with respect to a plane passing through the point M and perpendicular to the longitudinal direction D of span 3.

Chaque élément 4a, 4b, 4c, ...; 5a, 5b, 5c, ... comprend une membrure supérieure 6a, 6b, 6c, ...; 7a, 7b, 7c, ... et une membrure inférieure 8a, 8b, 8c, ... ; 9a, 9b, 9c, ... en béton qui s'étendent dans la direction longitudinale D de la travée 3.Each element 4a, 4b, 4c, ...; 5a, 5b, 5c, ... includes an upper member 6a, 6b, 6c, ...; 7a, 7b, 7c, ... and a lower member 8a, 8b, 8c, ...; 9a, 9b, 9c, ... made of concrete which extend in the longitudinal direction D of span 3.

Les éléments 4a, 4b, 4c, ...; 5a, 5b, 5c, ... sont assemlés bout à bout de telle sorte que leurs membrures en béton 6a, 6b, 6c, ...; 7a, 7b, 7c, ... et 8a, 8b, 8c, ...; 9a, 9b, 9c, ... soient dans le prolongement les unes des autres.Elements 4a, 4b, 4c, ...; 5a, 5b, 5c, ... are assembled end to end so that their concrete members 6a, 6b, 6c, ...; 7a, 7b, 7c, ... and 8a, 8b, 8c, ...; 9a, 9b, 9c, ... are in line with each other.

Les membrures supérieures 6a, ...; 7a, ... et inférieures Sa, ...; 9a, ... sont reliées les unes aux autres par un groupe de trois barres 10a, 11 a, 12a ; 10b, 11 b, 12b ; ... 13a, 14a, 15a, ... disposées sensiblement dans un plan et formant ensemble un N.The upper members 6a, ...; 7a, ... and lower Sa, ...; 9a, ... are connected to each other by a group of three bars 10a, 11a, 12a; 10b, 11b, 12b; ... 13a, 14a, 15a, ... arranged substantially in a plane and together forming an N.

Dans l'exemple représenté, les éléments 4a, 4b, 4c, ... 5a, 5b, 5c sont inscrits dans un rectangle, leurs membrures étant parallèles entre elles.In the example shown, the elements 4a, 4b, 4c, ... 5a, 5b, 5c are inscribed in a rectangle, their members being parallel to each other.

Conformément à l'invention, pour chaque élément, deux barres 10a, 11 a ; 1 Ob, 11b; 13a, 14a du N relient les membrures supérieures 6a, 6b ; 7a, 7b et inférieures 8a, 8b ; 9a, 9b entre elles et s'étendent transversalement (dans l'exemple représenté perpendiculairement) à la direction longitudinale D de la travée 3.According to the invention, for each element, two bars 10a, 11a; 1 Ob, 11b; 13a, 14a of N connect the upper members 6a, 6b; 7a, 7b and lower 8a, 8b; 9a, 9b between them and extend transversely (in the example shown perpendicularly) to the longitudinal direction D of the span 3.

De plus, ces deux barres 10a, 11a ; 10b, 11b; 13a, 14a, sont disposées près des extrémités telles que 16a, 17a des membrures. Ces deux barres 10a, 11 a ; 10b, 11 b; 13a, 14a sont ancrées dans les membrures en béton 6a, 8a ; ... de façon à résister essentiellement à des efforts de traction, comme on l'expliquera plus en détail plus loin.In addition, these two bars 10a, 11a; 10b, 11b; 13a, 14a, are arranged near the ends such as 16a, 17a of the members. These two bars 10a, 11a; 10b, 11b; 13a, 14a are anchored in the concrete members 6a, 8a; ... so as to resist essentially tensile forces, as will be explained in more detail later.

Les autres barres que l'on appellera "troisièmes barres" du N, telles que 12a, 12b, ... 15a, ... s'étendent entre les deux barres 10a, 11a; 10b, 11b; ... 13a, 14a, leurs extrémités opposées étant en appui contre des parties telles que 18a, 19a, formant butée des membrures supérieures 6a, 6b; ... et inférieures Sa, 8b; ...The other bars which will be called "third bars" of the N, such as 12a, 12b, ... 15a, ... extend between the two bars 10a, 11a; 10b, 11b; ... 13a, 14a, their opposite ends being in abutment against parts such as 18a, 19a, forming a stop for the upper members 6a, 6b; ... and below Sa, 8b; ...

Par ailleurs, on voit que pour la première série d'éléments 4a, 4b, 4c, ... lorsqu'on se déplace sur la travée 3 dans la direction D, les troisièmes barres 12a, 12b, ... sont montantes, tandis que pour la seconde série d'éléments 5a, 5b, 5c, ... située au-delà du point M, les troisièmes barres 15a, ... sont descendantes.Furthermore, we see that for the first series of elements 4a, 4b, 4c, ... when moving on the span 3 in the direction D, the third bars 12a, 12b, ... are rising, while that for the second series of elements 5a, 5b, 5c, ... located beyond point M, the third bars 15a, ... are descending.

Ces troisièmes barres 12a, 12b, ... 15a, ... subissent essentiellement des efforts de compression, comme on va l'expliquer plus en détail plus loin.These third bars 12a, 12b, ... 15a, ... essentially undergo compression forces, as will be explained in more detail below.

Dans la réalisation représentée sur la figure 1, les éléments 4a, 4b, 4c, ... 5a, 5b, 5c, ... sont assemblés les uns aux autres par des câbles de précontrainte 20, 21, 22, s'étendant dans des canaux ménagés dans les membrures en béton de ces éléments.In the embodiment shown in Figure 1, the elements 4a, 4b, 4c, ... 5a, 5b, 5c, ... are assembled to each other by prestressing cables 20, 2 1 , 22, extending in channels formed in the concrete members of these elements.

Les extrémités opposées du câble 20 qui s'étend dans les membrures inférieures 8a, 8b, ... 9a, ... sont ancrées dans des bossages 23, 24 ménagés sur les deux membrures inférieures situées aux extrémités de la travée 3.The opposite ends of the cable 20 which extends in the lower members 8a, 8b, ... 9a, ... are anchored in bosses 23, 24 formed on the two lower members located at the ends of the span 3.

Le câble 21 est ancré dans un bossage 25 ménagé sur la membrure supérieure 6b de l'élément 4b. L'autre extrémité de ce câble est ancrée dans un bossage similaire ménagé sur la travée voisine (située à gauche de la figure 1 ).The cable 21 is anchored in a boss 25 formed on the upper member 6b of the element 4b. The other end of this cable is anchored in a similar boss made on the neighboring span (located on the left of Figure 1).

Le câble 22 est ancré dans un bossage 26 ménagé sur la membrure supérieure de l'élément 5b.The cable 22 is anchored in a boss 26 formed on the upper member of the element 5b.

L'autre extrémité de ce câble 22 est ancrée dans un bossage similaire ménagé sur la travée voisine (située à droite de la figure 1 ).The other end of this cable 22 is anchored in a similar boss formed on the neighboring span (located to the right of FIG. 1).

Dans l'exemple représenté sur la figure 1, les extrémités en contact, telles que 16a. 17a des membrures supérieure et inférieure de deux éléments voisins tels que 4a, 4b sont situées dans des plans perpendiculaires à la direction D de la travée 3 et parallèles entre eux.In the example shown in Figure 1, the ends in contact, such as 16a. 17a upper and lower members of two neighboring elements such as 4a, 4b are located in planes perpendicular to the direction D of the span 3 and parallel to each other.

Par ailleurs, chaque barre telle que 11 a adaptée à résister essentiellement aux efforts de traction, est symétrique de la barre telle que 10b de l'élément voisin par rapport au plan dans lequel sont situés les extrémités en contact telles que 16a, 17a, des deux éléments voisins 4a, 4b. Ainsi, il existe de part et d'autre des plans de contact entre les éléments deux barres perpendiculaires à la direction D.Furthermore, each bar such as 11 has adapted to resist essentially the tensile forces, is symmetrical with the bar such as 10b of the neighboring element with respect to the plane in which the ends in contact such as 16a, 17a, are located. two neighboring elements 4a, 4b. Thus, there are on both sides of the contact planes between the elements two bars perpendicular to the direction D.

D'autre part, les troisièmes barres, telles que 12b (voir figures 2 et 3), qui subissent essentiellement des efforts de compression, s'étendent suivant un axe A qui coupe l'axe B de chaque membrure telle que 8b, en un point situé à égales distances des axes a et b des barres 11 a et 10b.On the other hand, the third bars, such as 12b (see FIGS. 2 and 3), which essentially undergo compression forces, extend along an axis A which intersects the axis B of each member such as 8b, in a point located at equal distances from axes a and b of bars 11 a and 10b.

Sur la figure 2, on distingue les canaux 27 ménagés dans la membrure inférieure 8b pour le passage de câbles de précontrainte tels que 20 et les canaux 28 ménagés dans la membrure supérieure 6b pour le passage de câbles de précontrainte tels que 21.In FIG. 2, a distinction is made between channels 2 7 formed in the lower member 8b for the passage of prestressing cables such as 20 and the channels 28 formed in the upper member 6b for the passage of prestressing cables such as 21.

Sur les figures 2 et 3, on voit également que les parties formant butée 18b et 19b moulées d'une seule pièce avec les membrures supérieure et inférieure présentent des surfaces d'appui 29, 30 qui sont perpendiculaires à l'axe A de la troisième barre 12b.In FIGS. 2 and 3, it can also be seen that the abutment parts 18b and 19b molded in one piece with the upper and lower members have bearing surfaces 29, 30 which are perpendicular to the axis A of the third bar 12b.

Dans l'exemple représenté sur la figure 2, l'élément 4b est entièrement réalisé en béton.In the example shown in Figure 2, the element 4 b is made entirely of concrete.

On va maintenant expliquer en référence à la figure 3, les effets techniques de la poutre en treillis et des éléments qui la composent, que l'on vient de décrire.We will now explain with reference to Figure 3, the technical effects of the lattice beam and the elements that compose it, which we have just described.

Cette figure 3 montre que les membrures inférieures Sa, 8b de deux éléments voisins 48, 4b sont en contact suivant une surface 17a perpendiculaire à l'axe B de ces membrures. Les barres 11 a et 10b sont disposées parallèlement et de part et d'autre de cette surface 17a.This Figure 3 shows that the lower members Sa, 8b of two neighboring elements 4 8 , 4b are in contact along a surface 17a perpendicular to the axis B of these members. The bars 11a and 10b are arranged in parallel and on either side of this surface 17a.

L'axe A de la troisième barre 12b de l'élément 4b coupe l'axe B commun aux membrures inférieures 8a et 8b en un point 17b situé à égale distance des axes aet b des barres 11 a et 10b.The axis A of the third bar 12b of the element 4b intersects the axis B common to the lower members 8a and 8b at a point 17b located at equal distance from the axes a and b of the bars 11 a and 10b.

Le vecteur F situé sur l'axe A de la troisième barre 12b de l'élément 4b représente la force de compression appliquée sur cette barre. Au point où l'axe A rencontre l'axe b de la barre verticale 10b, la force F se décompose en une force F, qui sollicite en traction la barre verticale 10b et une force F2 qui est orientée vers le point d'intersection entre l'axe de la barre verticale 11 a de l'élément voisin 4a et l'axe B la membrure 8a de cet élément.The vector F located on the axis A of the third bar 12b of the element 4b represents the compression force applied to this bar. At the point where the axis A meets the axis b of the vertical bar 10b, the force F decomposes into a force F, which biases in tension the vertical bar 10b and a force F 2 which is oriented towards the point of intersection between the axis of the vertical bar 11a of the neighboring element 4a and the axis B the frame 8a of this element.

En ce point d'intersection, cette force F2 se décompose en une force F, qui sollicite en traction la barre verticale 11a de l'élément 4a et une force F qui comprime la membrure 8a de cet élément.At this point of intersection, this force F 2 decomposes into a force F, which biases the vertical bar 11a of the element 4a and a force F which compresses the frame 8a of this element.

Compte tenu des dispositions géométriques précitées, les forces F, et F, qui s'appliquent respectivement aux barres verticales 10b et 11 a sont égales et la force F2 qui traverse la surface de contact 17a comprime les membrures 8a et 8b l'une contre l'autre et forme avec l'axe B un angle α qui est relativement faible puisque sa tangente est la moitié de la tangente de l'angle des axes A et B.Taking into account the aforementioned geometrical arrangements, the forces F, and F, which apply respectively to the vertical bars 10b and 11a are equal and the force F 2 which crosses the contact surface 17a compresses the members 8a and 8b one against the other. the other and forms with the axis B an angle α which is relatively small since its tangent is half the tangent of the angle of the axes A and B.

L'angle formé par la force F2 et l'axe B est l'angle maximal que peut former avec cet axe la force totale qui traverse la surface de contact 17a, cette force totale étant la somme de la force F2 et de la force F5 de compression de la membrure 8b qui, pour un ouvrage convenablement précontraint doit toujours être positive.The angle formed by the force F 2 and the axis B is the maximum angle which the total force which crosses the contact surface 17a can form with this axis, this total force being the sum of the force F 2 and the compressive force F 5 of the frame 8b which, for a suitably prestressed structure must always be positive.

Pour que les barres verticales 11 a et 10b résistent aux efforts de traction F, et F3, celles-ci doivent être solidement ancrées dans le béton des membrures inférieures 8a, 8b et supérieures 6a, 6b.In order for the vertical bars 11a and 10b to resist the tensile forces F, and F 3 , these must be firmly anchored in the concrete of the lower members 8a, 8b and upper members 6a, 6b.

A cet effet, il est préférable que ces barres verticales 11a, 10b, soient ancrées dans le béton de ces membrures au-delà de l'axe de celles-ci.For this purpose, it is preferable that these vertical bars 11a, 10b, be anchored in the concrete of these members beyond the axis of these.

Le bossage tel que 19b ménagé sur la membrure 8b permet d'encaisser la force de compression F exercée par la troisième barre 12b.The boss such as 19b formed on the frame 8b can collect the compressive force F exerted by the third bar 12b.

La figure 4 représente à titre d'exemple, une barre 10b réalisée en béton et capable de résister aux efforts de traction. Cette barre 10b a une section rectangulaire et présente à ses deux extrémités des plaques d'acier 31, 32 perpendiculaires à l'axe de la barre et qui débordent de part et d'autre du corps en béton de la barre.FIG. 4 shows by way of example, a bar 10b made of concrete and capable of withstanding the tensile forces. This bar 10b has a rectangular section and has at its two ends steel plates 31, 32 perpendicular to the axis of the bar and which project on either side of the concrete body of the bar.

Ces plaques 31, 32 sont reliées entre elles par des fils d'acier 33 sous tension, noyés dans le béton et dont les extrémités comportent des renflements 33a en contact avec les plaques 31, 32.These plates 31, 32 are interconnected by steel wires 33 under tension, embedded in the concrete and the ends of which include bulges 33a in contact with the plates 31, 32.

La précontrainte de la barre 10b est obtenue en exerçant avant le coulage du béton des forces égales et opposées sur les plaques d'acier 31, 32 dans un sens qui tend à éloigner celles-ci l'une de l'autre afin de tendre les fils 33. Ces forces sont maintenues après le coulage du béton jusqu'à ce que celui-ci ait acquis une résistance suffisante.The prestressing of the bar 10b is obtained by exerting before the pouring of the concrete equal and opposite forces on the steel plates 31, 32 in a direction which tends to move them away from each other in order to tension the son 33. These forces are maintained after the concrete has been poured until it has acquired sufficient strength.

Le béton des membrures 6b et 8b est ensuite coulé sur les extrémités de la barre 10b de façon que les plaques 31, 32 soient noyées dans le béton des membrures.The concrete of the members 6b and 8b is then poured onto the ends of the bar 10b so that the plates 31, 32 are embedded in the concrete of the members.

Pour améliorer l'ancrage de la barre 10b dans le béton des membrures, il est préférable de munir les extrémités de cette barre 10b de tiges d'acier 34, 35 faisant saillie hors du béton perpendiculairement à l'axe de la barre, comme indiqué sur la figure 4.To improve the anchoring of the bar 10b in the concrete of the members, it is preferable to provide the ends of this bar 10b with steel rods 34, 35 projecting from the concrete perpendicular to the axis of the bar, as indicated in figure 4.

Après le coulage des membrures, ces tiges 34, 35 sont noyées dans le béton de celles-ci et s'étendent parallèlement à l'axe de ces membrures.After casting of the members, these rods 34, 35 are embedded in the concrete thereof and extend parallel to the axis of these members.

Les trous 36, 37 ménagés près des extrémités opposées de la barre 10b, perpendiculairement à l'axe de la barre et parallèlement aux tiges d'acier 34, 35 sont destinés au passage de câbles de précontrainte tels que les câbles 20, 21, 22 représentés sur la figure 1.The holes 36, 37 formed near the opposite ends of the bar 10b, perpendicular to the axis of the bar and parallel to the steel rods 34, 35 are intended for the passage of prestressing cables such as cables 20, 21, 22 shown in Figure 1.

Dans la réalisation de la figure 5, l'élément de poutre comprend des membrures supérieure et inférieure 6b, 8b qui sont réalisées en béton, comme dans le cas des éléments décrits précédemment. Par contre, les barres 10"b, 11"b, et 12'b sont réalisées en acier.In the embodiment of Figure 5, the beam member comprises upper and lower members 6b, 8b which are made of concrete, as in the case of the elements described above. On the other hand, the bars 10 "b, 11" b, and 12'b are made of steel.

Les barres verticales 10"b et 11"b ont leurs extrémités solidement ancrées dans le béton des membrures 6b et 8b, tandis que la barre 12'b subissant essentiellement des efforts de compression est en appui contre les parties formant butées 18b et 19b des membrures.The vertical bars 10 "b and 11" b have their ends firmly anchored in the concrete of the frames 6b and 8b, while the bar 12'b undergoing essentially compressive forces is in abutment against the parts forming stops 18b and 19b of the frames .

L'une 10"b des barres verticales est représentée en détail sur la figure 6. Cette barre 10"b est un tube en acier qui, rempli de béton 50, présente à ses extrémités opposées une couronne également en acier 38, 39 faisant saillie de part et d'autre du corps tubulaire de la barre. Ces couronnes 38, 39 destinées à être noyées dans le béton des membrures 6b, 8b assurent un excellent ancrage des barres 10"b et 11"b et permettent à celles-ci de résister aux efforts de traction.One 10 "b of the vertical bars is shown in detail in FIG. 6. This bar 10" b is a steel tube which, filled with concrete 50, has at its opposite ends a crown also made of steel 38, 39 projecting on either side of the tubular body of the bar. These rings 38, 39 intended to be embedded in the concrete of the members 6b, 8b provide excellent anchoring of the bars 10 "b and 11" b and allow them to withstand the tensile forces.

Par ailleurs, la barre 10"b est traversée par des trous 40, 41 permettant le passage de câbles de précontrainte.Furthermore, the bar 10 "b is crossed by holes 40, 41 allowing the passage of prestressing cables.

La poutre conforme à l'invention, au lieu d'être constituée par une seule rangée d'éléments 4a, 4b, 4c comme indiqué sur la figure 1, peut comprendre deux ou plusieurs rangées parallèles d'éléments.The beam according to the invention, instead of being constituted by a single row of elements 4a, 4b, 4c as indicated in FIG. 1, can comprise two or more parallel rows of elements.

Dans la réalisation de la figure 7, on a représenté deux éléments 4' et 4" parallèles et identiques dont la membrure inférieure est libre mais dont la membrure supérieure 6', 6" fait partie d'une dalle 42 s'étendant perpendiculairement aux éléments 4' et 4" en reliant ceux--ci et en débordant de part et d'autre de ces éléments.In the embodiment of Figure 7, there are shown two elements 4 'and 4 "parallel and identical whose lower chord is free but whose upper chord 6', 6" is part of a slab 42 extending perpendicular to the elements 4 'and 4 "by connecting these and overflowing on either side of these elements.

Cette réalisation forme un voussoir. A l'aide de plusieurs voussoirs de ce type, assemblés bout à bout dans le prolongement des membrures, on peut réaliser un pont.This achievement forms a segment. Using several segments of this type, assembled end to end in the extension of the members, a bridge can be made.

La figure 8 représente en détail l'un 4' des deux éléments du voussoir représenté sur la figure 7. L'élément 4' est identique à l'élément 4b représenté sur la figure 2, sauf que la membrure supérieure 6' a une épaisseur plus faible que la membrure 6b de l'élément 4b de la figure 2. De plus, les extrémités 10'b et 11'b des barres verticales 10b et 11 font saillie au-delà du bord supérieur de la membrure 6' de façon à être noyées dans la dalle 42 qui est coulée entre les deux éléments 4' et 4".Figure 8 shows in detail one 4 'of the two elements of the segment shown in Figure 7. The element 4' is identical to the element 4b shown in Figure 2, except that the upper chord 6 'has a thickness weaker than the member 6b of the element 4b of FIG. 2. In addition, the ends 10'b and 11'b of the vertical bars 10b and 11 protrude beyond the upper edge of the member 6 'so as to be embedded in the slab 42 which is poured between the two elements 4 'and 4 ".

La figure 9 représente un voussoir identique à celui de la figure 7, excepté que les membrures inférieures sont reliées entre elles par deux traverses 43, 44 en béton disposées en croix, ce qui améliore encore davantage la résistance mécanique du voussoir.Figure 9 shows a segment identical to that of Figure 7, except that the lower members are interconnected by two cross members 43, 44 of concrete arranged in a cross, which further improves the mechanical strength of the segment.

Dans la réalisation de la figure 10, le voussoir est également identique à ceux des figures 7 et 9, sauf que les membrures inférieures des éléments 4' et 4" sont reliées par une dalle en béton 45 parallèle à la dalle supérieure 42.In the embodiment of FIG. 10, the segment is also identical to those of FIGS. 7 and 9, except that the lower members of the elements 4 'and 4 "are connected by a concrete slab 45 parallel to the upper slab 42.

Dans la réalisation de la figure 11, le voussoir comprend une dalle supérieure 46 et une dalle inférieure 47 qui relient les membrures supérieure et inférieure de quatre éléments 4A, 4B, 4C, 4D semblables à ceux décrits précédemment mais qui sont disposés dans des plans obliques par rapport aux dalles 46 et 47. La membrure supérieure et centrale 6BC est commune aux deux éléments centraux 4B et 4C, ces derniers étant reliés en s'écartant progressivement du plan de symétrie du voussoir à deux membrures inférieures 8AB et 8CD qui sont communes aux éléments extérieurs 4A et 4D. Ces damiers sont reliés chacun à une membrure 6A et 6D faisant partie de la dalle supérieure 46.In the embodiment of FIG. 11, the segment comprises an upper slab 46 and a lower slab 47 which connect the upper and lower chords of four elements 4A, 4B, 4C, 4D similar to those described above but which are arranged in oblique planes relative to the slabs 46 and 47. The upper and central member 6BC is common to the two central elements 4B and 4C, the latter being connected by progressively deviating from the plane of symmetry of the segment with two lower members 8AB and 8CD which are common to the external elements 4A and 4D. These checkers are each connected to a frame 6A and 6D forming part of the upper slab 46.

La figure 12 représente un pont reposant sur des piles verticales 48, 49 réalisé au moyen de voussoirs V,, Vb V3, V. comprenant deux éléments parallèles reliés entre eux par une dalle supérieure et une dalle inférieure, comme dans le cas de la figure 10, et de voussoirs V,, V6, V, comprenant également deux éléments parallèles reliés entre eux par une dalle supérieure, mais dont les membrures inférieures sont reliées par des traverses disposées en croix comme dans le cas du voussoir représenté sur la figure 9.FIG. 12 represents a bridge resting on vertical piers 48, 49 produced by means of segments V ,, V b V 3 , V. comprising two parallel elements linked together by an upper slab and a lower slab, as in the case of FIG. 10, and of segments V ,, V 6 , V, also comprising two parallel elements connected together by an upper slab, but the lower members of which are connected by crosspieces arranged in a cross as in the case of the segment shown in the figure 9.

Les voussoirs V1, V2, V3, V4 qui ont une membrure inférieure plus résistante que celle des voussoirs V5, V6, V7, sont disposés près des piles 48, 49.The segments V 1 , V 2 , V 3 , V 4 which have a stronger lower chord than that of the segments V 5 , V 6 , V 7 , are arranged near the stacks 48, 49.

Dans le cas de la réalisation selon la figure 12, les membrures supérieures sont comme précédemment disposées suivant une droite parallèle à la direction longitudinale de la travée.In the case of the embodiment according to Figure 12, the upper members are as previously arranged along a straight line parallel to the longitudinal direction of the span.

Par contre, les membrures inférieures assemblées bout à bout définissent un arc.On the other hand, the lower members assembled end to end define an arc.

Dans un tel pont, les efforts sont répartis comme expliqué en référence à la figure 3, à savoir que les barres verticales des éléments subissent essentiellement des efforts de traction, tandis que les barres obliques (appelées troisièmes barres) dans la description précitée subissent essentiellement des efforts de compression.In such a bridge, the forces are distributed as explained with reference to FIG. 3, namely that the vertical bars of the elements essentially undergo tensile forces, while the oblique bars (called third bars) in the above description undergo essentially compression forces.

Bien entendu, l'invention n'est pas limitée aux exemples que l'on vient de décrire et on peut apporter à ceux-ci de nombreuses modifications sans sortir du cadre de l'invention.Of course, the invention is not limited to the examples which have just been described and numerous modifications can be made to them without departing from the scope of the invention.

Claims (15)

1. Poutre en treillis, notamment pour réaliser un pont. cette poutre étant en appui en plusieurs points (1, 2) espacés de façon à former une ou plusieurs travées (3) et comprenant, pour chaque travée, deux séries d'éléments de poutre (4a, 4b, ...5a) disposées de part et d'autre d'un point (M) de la travée où les efforts tranchants sous charge permanente sont sensiblement nuls, ces éléments étant assemblés par des armatures tendues, dites armatures de précontrainte, s'étendant chacune sur plus d'un élément, chaque élément (4a, 4b, ... 5a) comportant une membrure supérieure (6a, 6b, ... 7a) et une membrure inférieure (Sa, 8b, ... 9a) en béton, s'étendant dans la direction longitudinale (D) de la travée, les éléments étant assemblés de sorte que les membrures supérieure et inférieure soient dans le prolongement les unes des autres, les membrures supérieure et inférieure de chaque élément étant reliées l'une à l'autre par au moins un groupe de trois barres (10a, 11a, 12a ; 10b, 11b, 12b, ...) sensiblement coplanaires formant un N, caractérisée en ce que deux barres (10a, 11 a ; 10b, 11 b, ...) du N relient les deux membrures (6a, 8a ; 6b, 8b, ...) entre elles et s'étendent transversalement à la direction longitudinale (D) de la travée (3) près des extrémités de ces membrures, et sont ancrées à ces dernières de façon à résister essentiellement à des efforts de traction, tandis que la troisième barre (12a, 12b, ...) s'étend entre les deux barres précitées, et en ce que pour la première série d'éléments (4a, 4b, ...) lorsqu'on se déplace sur la travée d'un appui vers l'autre, lesdites troisièmes barres (12a, 12b, ...) sont montantes, tandis que pour la seconde série d'éléments (5a, ...) située au-delà dudit point (M), lesdites troisièmes barres (15a, ...) sont descendantes, de façon que ces troisièmes barres subissent essentiellement des efforts de compression. 1 . Lattice beam, in particular for making a bridge. this beam being supported at several points (1, 2) spaced so as to form one or more spans (3) and comprising, for each span, two series of beam elements (4a, 4b, ... 5a) arranged on either side of a point (M) of the span where the shear forces under permanent load are substantially zero, these elements being assembled by tensioned reinforcements, called prestressing reinforcements, s '' each extending over more than one element, each element (4a, 4b, ... 5a) comprising an upper chord (6a, 6b, ... 7a) and a lower chord (Sa, 8b, ... 9a) made of concrete, extending in the longitudinal direction (D) of the span, the elements being assembled so that the upper and lower members are in line with one another, the upper and lower members of each element being connected one to the other by at least one group of three bars (10a, 11a, 12a; 10b, 11b, 12b, ...) substantially coplanar forming an N, characterized in that two bars (10a, 11a; 10b, 11 b, ...) of N connect the two frames (6a, 8a; 6b, 8b, ...) between them and extend transversely to the longitudinal direction (D) d e the span (3) near the ends of these frames, and are anchored to the latter so as to essentially resist tensile forces, while the third bar (12a, 12b, ...) extends between the two said bars, and in that for the first series of elements (4a, 4b, ...) when moving on the span from one support to the other, said third bars (12a, 12b, .. .) are rising, while for the second series of elements (5a, ...) located beyond said point (M), said third bars (15a, ...) are descending, so that these third bars undergo essentially compressive forces. 2. Poutre conforme à la revendication 1, dans laquelle les barres, résistant essentiellement aux efforts de traction - (11a, 10b), situées de part et d'autre et au voisinage des extrémités (16a, 17a) au contact des membrures (6a, 6b; 8a, 8b), appartenant à deux éléments voisins (4a, 4b) sont sensiblement parallèles entre elles, et dans laquelle la troisième barre (12a, 12b, ...) de chaque élément qui résiste essentiellement à des efforts de compression et qui s'étend entre les deux barres de cet élément (10a, 11 a ; 10b, 11 b; ...) résistant essentiellement à des efforts de traction, a ses extrémités opposées en appui contre les membrures inférieure et supérieure de cet élément.2. Beam according to claim 1, in which the bars, essentially resistant to tensile forces - (11a, 10b), located on either side and in the vicinity of the ends (16a, 17a) in contact with the members (6a , 6b; 8a, 8b), belonging to two neighboring elements (4a, 4b) are substantially parallel to each other, and in which the third bar (12a, 12b, ...) of each element which essentially resists compressive forces and which extends between the two bars of this element (10a, 11 a; 10b, 11 b; ...) essentially resistant to tensile forces, at its opposite ends in abutment against the lower and upper members of this element . 3. Poutre conforme à l'une des revendications 1 ou 2, caractérisée en ce que l'axe de la troisième barre (12b) d'un élément (4b) coupe l'axe de la membrure inférieure (8b) de cet élément en un point situé à égale distance des axes des barres résistant essentiellement aux efforts de traction (10b et 11a) et coupe l'axe de la membrure supérieure (6b) en un point situé à égale distance des axes des barres résistant essentiellement aux efforts de traction - (11b et 10c).3. Beam according to one of claims 1 or 2, characterized in that the axis of the third bar (12b) of an element (4b) intersects the axis of the lower member (8b) of this element in a point located at equal distance from the axes of the bars essentially resistant to tensile forces (10b and 11a) and intersects the axis of the upper chord (6b) at a point located equidistant from the axes of the bars essentially resistant to tensile forces - (11b and 10c). 4. Poutre conforme à l'une des revendications 1 à 3, caractérisée en ce que les deux barres (10a, 11 a) d'un élément (4a) résistant aux efforts de traction sont ancrées dans le béton des membrures (6a, 8a) au-delà de l'axe de celles-ci.4. Beam according to one of claims 1 to 3, characterized in that the two bars (10a, 11a) of an element (4a) resistant to tensile forces are anchored in the concrete of the members (6a, 8a ) beyond the axis of these. 5. Poutre conforme à l'une des revendications 1 à 4, caractérisée en ce que les parties (18a, 19a) formant butées pour la troisième barre (12a) sont constituées par des bossages en béton moulés d'une seule pièce avec les membrures (6a, 8a), ces bossages comportant une face d'appui (30) perpendiculaire à l'axe de la troisième barre.5. Beam according to one of claims 1 to 4, characterized in that the parts (18a, 19a) forming stops for the third bar (12a) are constituted by concrete bosses molded in one piece with the members (6a, 8a), these bosses comprising a bearing face (30) perpendicular to the axis of the third bar. 6. Poutre conforme à l'une des revendications 1 à 5, caractérisée en ce que les barres (10a, 11a, 12a) sont réalisées en béton.6. Beam according to one of claims 1 to 5, characterized in that the bars (10a, 11a, 12a) are made of concrete. 7. Poutre conforme à l'une des revendications 1 à 5, caractérisée en ce que au moins une partie des barres sont des profilés ou des tubes en acier (10"b, 12'b).7. Beam according to one of claims 1 to 5, characterized in that at least a portion of the bars are sections or steel tubes (10 "b, 12'b). 8. Poutre conforme à la revendication 6, caractérisée en ce que les barres en béton (10b) résistant aux efforts de traction, comportent à leurs extrémités opposées, des plaques en acier (31, 32) sensiblement perpendiculaires à l'axe de la barre et débordant de part et d'autre de celle-ci, ces plaques étant reliées entre elles par des fils d'acier - (33) sous tension qui traversent le béton de la barre.8. Beam according to claim 6, characterized in that the concrete bars (10b) resistant to tensile forces, have at their opposite ends, steel plates (31, 32) substantially perpendicular to the axis of the bar and overflowing on either side thereof, these plates being interconnected by steel wires - (33) under tension which pass through the concrete of the bar. 9. Poutre conforme à la revendication 7, caractérisée en ce que les barres résistant aux efforts de traction, sont constituées par un tube en acier (10"b) présentant à ses extrémités une plaque en acier (38, 39) rempli de béton - (50), sensiblement perpendiculaire à l'axe du tube, débordant de part et d'autre de celui-ci et présentant un trou central.9. Beam according to claim 7, characterized in that the bars resistant to tensile forces, consist of a steel tube (10 "b) having at its ends a steel plate (38, 39) filled with concrete - (50), substantially perpendicular to the axis of the tube, projecting on either side of it and having a central hole. 10. Poutre conforme à l'une des revendications 6 à 9, caractérisée en ce que les barres (10b, 10"b) résistant aux efforts de traction, présentent près de leurs extrémités, des trous (36, 37 ; 40, 41) sensiblement perpendiculaires à leur axe, destinés au passage d'armatures de précontrainte.10. Beam according to one of claims 6 to 9, characterized in that the bars (10b, 10 "b) resistant to tensile forces, have near their ends, holes (36, 37; 40, 41) substantially perpendicular to their axis, intended for the passage of prestressing reinforcements. 11. Poutre conforme à la revendication 6, caractérisée en ce que les barres (12'b) subissant des efforts de compression, sont constituées par un profilé ou tube en acier présentant à ses extrémités une plaque en acier sensiblement perpendiculaire à l'axe du profilé ou du tube et débordant de part et d'autre de celui-ci, cette plaque prenant appui sur la partie (18b, 19b) formant butée de la membrure (6b, 8b).11. Beam according to claim 6, characterized in that the bars (12'b) undergoing compressive forces, consist of a steel section or tube having at its ends a steel plate substantially perpendicular to the axis of the profile or tube and projecting on either side thereof, this plate bearing on the part (18b, 19b) forming a stop for the frame (6b, 8b). 12. Poutre conforme à l'une des revendications 1 à 11, caractérisée en ce que les membrures (6a, 6b ; 8a, ...) sont traversées longitudinalement par des canaux destinés au passage d'armatures de précontrainte (20, 21, 22).12. Beam according to one of claims 1 to 11, characterized in that the members (6a, 6b; 8a, ...) are traversed longitudinally by channels intended for the passage of prestressing reinforcements (20, 21, 22). 13. Poutre conforme à l'une des revendications 1 à 12, comprenant au moins deux rangées parallèles d'éléments - (4', 4") assemblés bout à bout, caractérisée en ce que les membrures supérieure et/ou inférieure des éléments font partie d'une dalle (42) qui relie les deux éléments.13. Beam according to one of claims 1 to 12, comprising at least two parallel rows of elements - (4 ', 4 ") assembled end to end, characterized in that the upper and / or lower members of the elements make part of a slab (42) which connects the two elements. 14. Poutre conforme à la revendication 13, caractérisée en ce que les membrures inférieures sont reliées ensemble par des traverses en béton (43, 44).14. Beam according to claim 13, characterized in that the lower members are connected together by concrete sleepers (43, 44). 15. Poutre conforme à l'une des revendications 13 ou 14, caractérisée en ce que les éléments (4A, 4B, 4C, 4D) de chaque rangée sont situés dans des plans obliques par rapport à la dalle (46) ou (47).15. Beam according to one of claims 13 or 1 4 , characterized in that the elements (4A, 4B, 4C, 4D) of each row are located in oblique planes relative to the slab (46) or (47 ).
EP86400051A 1985-01-16 1986-01-10 Lattice girder, in particular for constructing a bridge Ceased EP0188395A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8500565 1985-01-16
FR8500565A FR2576053B1 (en) 1985-01-16 1985-01-16 LATTICE BEAM, PARTICULARLY FOR REALIZING A BRIDGE

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EP0188395A2 true EP0188395A2 (en) 1986-07-23
EP0188395A3 EP0188395A3 (en) 1987-08-26

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JP (1) JPS61225406A (en)
CA (1) CA1270355A (en)
DE (1) DE188395T1 (en)
FR (1) FR2576053B1 (en)

Cited By (9)

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Publication number Priority date Publication date Assignee Title
FR2612963A1 (en) * 1987-03-27 1988-09-30 Muller Jean BRIDGE CONSISTING OF AN APRON AND MEANS FOR SUPPORTING IT, ESPECIALLY A LONG-RANGE SHAFT BRIDGE AND METHOD OF CONSTRUCTION THEREOF
FR2629111A1 (en) * 1988-03-25 1989-09-29 Muller Jean APRON FOR BRIDGE OF LARGE LENGTH
GB2279387A (en) * 1993-06-23 1995-01-04 Malcolm Martin Strong Framework for a bridge or truss
GB2281572A (en) * 1991-05-31 1995-03-08 Alfred Alphonse Yee Truss for e.g. bridges
US6591567B2 (en) * 2000-12-09 2003-07-15 West Virginia University Lightweight fiber reinforced polymer composite modular panel
EP1802813A1 (en) * 2004-09-25 2007-07-04 Ajou University Industry Cooperation Foundation Hollow prestressed concrete (hpc) girder and spliced hollow prestressed concrete girder (s-hpc) bridge construction method
WO2007086720A1 (en) * 2006-01-30 2007-08-02 Javier Mentado Duran Concrete truss
US7275348B2 (en) * 2003-02-06 2007-10-02 Ericksen Roed & Associates Precast, prestressed concrete truss
DE102006056866A1 (en) * 2006-12-01 2008-07-17 Max Bögl Bauunternehmung GmbH & Co. KG Modular truss structure made of concrete and a method for its production and assembly

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JPH0765292B2 (en) * 1988-08-11 1995-07-19 日本鋼管株式会社 Aerodynamic vibration prevention structure for box girder bridge
JP2886364B2 (en) * 1991-07-01 1999-04-26 住友建設株式会社 PC composite truss beam and its construction method
JP3948809B2 (en) * 1998-02-05 2007-07-25 三井住友建設株式会社 Joining structure and joining method between concrete member and steel pipe member, and concrete / steel composite truss bridge
KR100423757B1 (en) * 2001-05-04 2004-03-22 원대연 Prestressed composite truss girder and construction method of the same
JP2011246979A (en) * 2010-05-27 2011-12-08 Ps Mitsubishi Construction Co Ltd Rigid slab girder bridge of high torsion

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FR885531A (en) * 1942-08-27 1943-09-17 Fixed or removable reinforced cement frames
FR917303A (en) * 1945-07-10 1947-01-03 Applic Des Procedes Enklay Cim New roof
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Cited By (15)

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Publication number Priority date Publication date Assignee Title
WO1988007604A1 (en) * 1987-03-27 1988-10-06 Jean Muller Bridge comprising a bridge floor and elements supporting said floor, particularly a long span cable-stayed bridge, and process of construction
EP0288350A1 (en) * 1987-03-27 1988-10-26 Societe Centrale D'etudes Et De Realisations Routieres- Scetauroute Bridge consisting of a deck and its supporting means, especially a large-span cable-stayed bridge, and its construction process
US4993094A (en) * 1987-03-27 1991-02-19 Scetauroute Bridge comprising a bridge floor and elements supporting said floor, particularly a long span cable-stayed bridge, and process of construction
FR2612963A1 (en) * 1987-03-27 1988-09-30 Muller Jean BRIDGE CONSISTING OF AN APRON AND MEANS FOR SUPPORTING IT, ESPECIALLY A LONG-RANGE SHAFT BRIDGE AND METHOD OF CONSTRUCTION THEREOF
FR2629111A1 (en) * 1988-03-25 1989-09-29 Muller Jean APRON FOR BRIDGE OF LARGE LENGTH
EP0340051A1 (en) * 1988-03-25 1989-11-02 Societe Centrale D'etudes Et De Realisations Routieres- Scetauroute Bridge floor for long span bridge
GB2281572A (en) * 1991-05-31 1995-03-08 Alfred Alphonse Yee Truss for e.g. bridges
GB2279387A (en) * 1993-06-23 1995-01-04 Malcolm Martin Strong Framework for a bridge or truss
GB2279387B (en) * 1993-06-23 1997-01-08 Malcolm Martin Strong Framework for a bridge or a truss
US6591567B2 (en) * 2000-12-09 2003-07-15 West Virginia University Lightweight fiber reinforced polymer composite modular panel
US7275348B2 (en) * 2003-02-06 2007-10-02 Ericksen Roed & Associates Precast, prestressed concrete truss
EP1802813A1 (en) * 2004-09-25 2007-07-04 Ajou University Industry Cooperation Foundation Hollow prestressed concrete (hpc) girder and spliced hollow prestressed concrete girder (s-hpc) bridge construction method
EP1802813A4 (en) * 2004-09-25 2013-03-20 Univ Ajou Ind Coop Foundation Hollow prestressed concrete (hpc) girder and spliced hollow prestressed concrete girder (s-hpc) bridge construction method
WO2007086720A1 (en) * 2006-01-30 2007-08-02 Javier Mentado Duran Concrete truss
DE102006056866A1 (en) * 2006-12-01 2008-07-17 Max Bögl Bauunternehmung GmbH & Co. KG Modular truss structure made of concrete and a method for its production and assembly

Also Published As

Publication number Publication date
CA1270355A (en) 1990-06-19
FR2576053B1 (en) 1988-04-15
FR2576053A1 (en) 1986-07-18
JPS61225406A (en) 1986-10-07
DE188395T1 (en) 1986-11-06
EP0188395A3 (en) 1987-08-26

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