Classifications

• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
  • E01D21/00—Methods or apparatus specially adapted for erecting or assembling bridges
  • E01D21/06—Methods or apparatus specially adapted for erecting or assembling bridges by translational movement of the bridge or bridge sections
  • E01D21/065—Incremental launching
• • 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
• • 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
  • E01D2101/30—Metal

Definitions

• the present invention relates to a method for making a bridge, in particular for producing the slab of a composite bridge, particularly when the slab is carried by the upper flanges of metal girders.
• These beams generally comprise connectors that allow to secure the slab to the beams, so that such a bridge operates in "mixed beam”.
• the invention also relates to a formwork system for implementing this method.
• the composite bridge slabs of the prior art have very serious problems of structural quality, particularly transverse cracking problems.
• the transverse cracking is more specifically due to the embodiments of these slabs, in particular to the mechanical actions resulting from the progressive loading of the metal beams, which causes deformations of the already poured slab concrete, and moreover, to the recesses of the concrete "At a young age", hampered by the metal beams to which the slab is connected.
• the mechanical actions are due to a setting in traction of the concrete slab, in some sections of slab already poured when the beams are deformed under the weight of the added sections.
• the consequences of these mechanical actions have been reduced, thanks to a first technique called “strumming”, which consists in phasing the realization of the slab by first making sections located in the middle of the span, thus to load the beams metal, and then end with keying sections, in the most tense areas, at the point of the beam supports.
• a second technique is to use prefabricated slabs, then placed side by side on the beams. These slabs include reservations for their sealing on the connectors. This technique nevertheless has disadvantages, in particular the presence of transverse joints between each slab, a discontinuous connection with the framework, at the right of each seal, and a risk of corrosion of the upper face of the sole vis-à-vis the underside of each slab, outside the reservations, duly completed.
• a third technique called pushed slabs, consists of prefabricating the slab in successive sections, generally of a length of 5 to 10 meters, on a formwork area, comprising a fixed formwork, then pushing the slab longitudinally on the frame, as and when prefabrication, and finally connect the slab to the frame, only when it has taken its final place.
• This third technique has the advantage of a delayed connection, thus eliminating the cracking due to the progressive loading of the frame and the annoying withdrawals.
• the connectors are generally welded to the frame after pushing, in reservations provided for this purpose and in particularly uncomfortable conditions. This third technique therefore has the disadvantage of a discontinuous connection, associated with the disadvantage of making welds on site, in poor working conditions.
• FR-A-2 698 111 It is moreover known from FR-A-2 698 111 to construct a bridge deck by prefabricating two concrete blocks separated by an interval traversed by transverse reinforcements which extend reinforcements internal to each block.
• a provisional bracing is placed on the edges of two adjacent concrete blocks.
• the temporary bracing does not prevent the relative movements of the concrete blocks parallel to the length of the deck, which has the effect of shear reinforcements that extend in the meantime, especially if one seeks to put in place the prefabricated element on a bridge beam by pushing it in its longitudinal direction.
• a first object of the invention is therefore to provide a method for making a bridge, including a composite bridge, which allows a substantially continuous connection of the slab on the frame and avoids soldering connectors on site.
• a second object of the invention is to provide a formwork device for making a bridge according to such a method.
• such a method for making a bridge comprising a reinforced concrete slab and at least one longitudinal beam provided to support the slab, the beam comprising an upper flange and connectors extending upwardly since the sole, comprises steps in which: a) - the slab is prefabricated on a formwork area in at least one section; b) - for each beam, a longitudinal reservation, open downward, is formed in the thickness of said slab, so that the slab is supported, on either side of the reservation, on the sole of the beam; c) - a connection is made and maintained between portions of slab each of a respective side of the beam, so that said connection allows the passage of connectors
• This method is characterized in that it comprises the steps of: d) - pushing longitudinally part of already prefabricated slab after completion of each section and before, if necessary, the realization of a section adjacent to said part of slab previously pushed; e) - for each beam, arrange the longitudinal reservation as a longitudinal tunnel formed in the thickness of said slab, so that said tunnel is open downwards and that the slab is supported on both sides of said tunnel on said sole of said beam and so that the tunnel forms a vault serving as a reinforced concrete connection over said connectors; f) - for each tunnel, forming at least one well through said vault, between an upper surface of said slab and said tunnel; g) - after the slab has taken its final place on said beam, implement self-placing concrete through said well in said tunnel, for sealing said slab on said beam.
• the vault serves as a rigid connection between the parts of the slab previously manufactured, which allows to exert the thrust force on the vault itself, without having to precisely control the distribution of forces between the two parts of the slab previously manufactured.
• the setting up of the slab by successive thrusts sections is therefore facilitated.
• the vault ensures the continuity of the upper surface of the bridge deck, which prevents the appearance of cracks along its length.
• it is not necessary for reinforcements to pass through the tunnel since the mechanical connection between the parts of the slab is made by and through the vault, so that the formwork device must not be provided with reservations for the passage of such frames. This facilitates and makes faster the formwork and formwork operations.
• Such a method is particularly applicable for the realization of a mixed bridge, that is to say particularly in a case where the at least one longitudinal beam is metallic.
• the slab may comprise several wells distributed over the length of each tunnel.
• the walls of the tunnel tunnel may advantageously comprise reliefs for a longitudinal grip of the precast concrete of the slab with the sealing concrete. These reliefs may be grooves extending substantially perpendicular to the sole.
• common reinforcing cages for sealing concrete may advantageously be arranged on each beam, prior to pressing, so that said cages do not interfere with said stuffing, and that connectors extend inside said cages.
• these frames can be arranged before pushing the slab, under particularly favorable implementation conditions.
• Reinforcements for sealing concrete may be placed in the wells after the slab has taken its final place.
• a formwork system for implementing the method in its particular embodiment, is characterized in that it comprises two shoes leaving between them a space, actuating means for the transverse displacement of said shoes between a formwork position, in which said shoes are spaced from each other and a retracted position, wherein said shoes are close to one another, and a plate bearing longitudinally on each said slats, said tray being provided for shuttering a part of the connection above said space, so that in the retracted position, the tray escapes their longitudinal support, and can be retracted, vertically downwards, it comprises a fixed spacer extending longitudinally and that the actuating means comprise two inflatable tubes arranged longitudinally on either side of the hold, a first hose being disposed between an inner wall of the wedge and a wall of the shoe vis-à-vis the inner wall, the second pipe being disposed between an outer wall of the wedge and a wall of the shoe vis-à-vis the wall external.
• the maneuvering of the shoes in spacing / approximation is obtained by means of the inflatable tubes which are arranged longitudinally on either side of the fixed block, which leaves free the center of the space arranged between these two hooves.
• Such a formwork system is compatible with the passage of a rail along which is moved the slab or section of slab, for its introduction by longitudinal thrust.
• such a formwork system may incorporate the features of one or more of claims 9 and following.
• FIG. 1 is a cross section and schematic of a dual-girder composite bridge according to a first preferred mode of implementation of a method according to the invention, before sealing the slab on the beams, the left half-cut illustrating a running half-section of the slab, and the right half-section illustrating a half section of the slab at the location of a concreting well;
• FIG. 2 illustrates detail II of the left half-section of FIG. 1,
• FIG. 3 illustrates detail III of the right half-section of FIG.
• Figure 4 is a figure similar to Figure 2, further illustrating the reinforcement
• Figure 5 is a figure similar to Figure 3, further illustrating the reinforcement
• FIG. 6 shows two half-sections of a formwork system for implementing a method according to the invention; the upper half-section illustrating the formwork position and the lower half-section illustrating a retracted position; and
• FIG. 7 is a partial perspective view of a prefabrication area for deck slab sections which comprises two formwork systems such as that of FIG. 6.
• the examples illustrated in the figures relate to the realization of a composite bridge 1 mainly consisting of two metal beams 2 supporting a slab 3 of reinforced concrete.
• a method according to the invention provides for the prefabrication of the slab 3, in one or more sections, on a prefabrication area and then pushing the slab, from the prefabrication area to the beams 2, before sealing the slab on the beams.
• Prefabrication and pushing of the slab can be carried out by known or new techniques.
• Figures 1 to 5 illustrate the slab in place on the beams 2 after stuffing and before sealing.
• the slab 3 comprises a central portion 4 formed between the beams and corbels 5 formed on either side of the central portion, beyond the beams.
• the beams have an I-shaped cross-section, comprising two substantially horizontal flanges 6,7 and interconnected by a substantially vertical core 8. As particularly illustrated in FIG. 1, the slab 3 rests on the upper flanges 6 of the beams 2 .
• the bridge 1 is a bi-beam that has no slope. It is substantially symmetrical with respect to a longitudinal plane P.
• Figure 1 is a composite illustration. It is formed on the one hand, in its left part, of a current half-section of which a detail II is illustrated in figure 2, and on the other hand in its right part, of a singular half-section of which one detail III is illustrated in figure 3.
• each beam 2 comprises connectors 9 welded to the upper flange 6.
• the connectors are in the form of studs which extend upwards, substantially vertically, from the flange 6. They are arranged in several longitudinal rows. In this example, the rows are four in number.
• the slab 3 is formed so as to achieve, in the thickness of the slab, a longitudinal tunnel-shaped reservation 10.
• the tunnel has a substantially trapezoidal cross section. It is open downwards. It is designed to form a vault over the connectors, this vault forming a mechanical link 11, made of reinforced concrete, between the two parts 4,5 of the slab adjacent to the beam.
• side walls 12 of the tunnel 10 each bear on a respective edge 14 of the sole 6.
• At least one well 16 is formed through the connection 11, from the surface 18 of the slab 3 to the tunnel 10.
• several wells 16 are provided, substantially regularly spaced along each tunnel. These wells are designed to allow sealing concrete to be introduced into the tunnel 10, from the surface 18 of the slab 3.
• a self-placing sealing concrete is preferably used, which makes it possible to ensure the correct filling of the tunnel 10 between two wells 16 neighbors.
• a seal 15 is provided on each side 14 between the upper flange 6 and the underside of the slab 3. This seal makes it possible to avoid flow of laitance during the application of the grouting concrete.
• Embossments 20 are formed in the lateral faces 12 of the tunnel 10. In the illustrated example, these reliefs are vertical grooves 20. These grooves allow the precast concrete of the slab 3 and the sealing concrete to come into mutual engagement, ensuring thus a reinforced transmission of the longitudinal forces between these two concretes.
• FIGS. 4 and 5 illustrate possible arrangements for the reinforcement respectively corresponding to the current and singular zones of FIGS. 2 and 3.
• common reinforcement cages comprise transverse frames 22 and pins 24, supporting 26.
• the connectors 9 extend through the current frames.
• the current zone further comprises two superposed beds of connecting reinforcements 28 extending transversely and horizontally in the thickness of the connection 11, and beyond, in the adjacent parts 4.5 of the slab 3.
• the connecting armatures 28 are arranged in the thickness of the roof 11, they do not exceed in the interior volume of the tunnel 10, so that the formwork used to make this tunnel must not be pierced with reservations for the passage of these frames . This facilitates both the construction of this formwork and its implementation: the cost and time of formwork / stripping are thus reduced.
• the current reinforcing cages 22, 24, 26 are substantially continuous and pass through each singular zone of a well.
• the link 11 being interrupted by the well 16, the singular zone does not comprise binding armature.
• Well frames are constituted by pins 30 so the lower part of the loop is substantially level with the lower part of the frames 22, and whose ends 32 are folded substantially horizontally, close to the surface 34 (shown in phantom ) sealing concrete.
• each tunnel 10 The standard reinforcement cages 22,24,26 are provided to be put in place on each beam 2 before pushing the prefabricated slab 3.
• the transverse dimensions of each tunnel 10 are provided so that the thrust of the slab 3 is not hindered by the current reinforcement cages and a distance is maintained around the reinforcements for their sufficient coating by the sealing concrete .
• the well reinforcement 30 are put in place after pushing the prefabricated slab 3 to its final place and before implementation of the concrete seal.
• FIG. 8 represents two superimposed half-cross sections, each schematically representing the left half of the formwork device. 100.
• the system 100 In the upper half-cut, the system 100 is in its formwork position, that is to say in the position provided during the pouring of concrete slab.
• the system 100 In the lower half-section, the system 100 is a retracted position, allowing the slab 3 to be pushed.
• the formwork device 100 In its formwork position, the formwork device 100 is symmetrical with respect to a symmetry plane S of the tunnel 10. following only the visible elements on each half-cut. Each of these elements has its symmetrical relative to the plane S.
• the system 100 has a substantially identical section for the entire length of the tunnel, including the singular areas, in which specific formwork means are used for the wells. This device is intended to be used on the prefabrication area of the sections of the slab shown in FIG. 7. Typically, for each tunnel, the shuttering system 100 has substantially the length of a section of slab to be cast.
• the system 100 comprises a base 101, substantially flat. In the example shown, the base is substantially horizontal.
• the base 101 also serves as a formwork base for the underside of the slab, on either side of the tunnel.
• the device 100 comprises a longitudinal shim 102 fixed on the base 101, a lateral shoe 103 and a plate 104, as well as actuating means 106, 107 for the shoe 103.
• the shim extends parallel to the plane S and is of substantially rectangular section. It has two 108,109 longitudinal and vertical faces. A face 108, the closest to the plane S, is said to be internal, the other face 109 being said to be external.
• Each shoe 103 is placed in abutment on the base 101, away from the plane S, that is to say that a space 110 exists transversely between the two shoes of the system.
• the plate 104 is in longitudinal support on each of the shoes, so that it allows the formwork on the underside of the link 11, above the space 110.
• the shoe comprises a top formwork face 112 having a draft angle A112, with respect to a horizontal direction ⁇ i and perpendicular to the plane S, for its transverse formwork.
• This draft angle ⁇ 112 has a value of between 5 ° and 20 °, preferably of the order of 10 °.
• the upper formwork face 112 is provided for the formwork on the underside of the link 11, beyond, transversely, the plate 104.
• Each longitudinal edge of the plate forms a longitudinal bearing heel 113, extending downwards. beyond the underside 114 of the plateau.
• a counter-support 116 is formed in a corresponding bank, proximal to the plane S, of the shoe 103. This counter-support extends upwards relative to the upper formwork face 112.
• the bearing heel 113 and counter support 116 together form a form band 118 whose clearance angle A118 is larger than the clearance angle A112 of the upper formwork face 112.
• the value of the angle A118 is between 20 ° and 60 ° preferably from the order of 40 °.
• the shoe comprises a distal and substantially vertical formwork face, the furthest away from the plane S.
• This formwork face forms counter flutes 120, for the formwork of the flutes 20 of the slab 3.
• the depth D120 of the counter flutes corresponds to the groove depth 20.
• the shoe 103 forms an arch 122 extending longitudinally.
• the arch forms an arch above the hold 102 and bears on the base 101, on either side of the hold, so that an inner face 124 of the arch is vis-à- screw with the inner face 108 of the wedge 102, and an outer face 126 of the arch is vis-à-vis the outer face 109 of the arch.
• V122 denotes the volume of the arch 122 defined between the surfaces 124 and 126 and in which the shim 102 is received.
• the formwork of the tunnel is provided by transverse displacement, in translation in the direction A 1 , of the shoe 103 of a DC value, in the direction of the plane S.
• the shoe passes from its formwork position to the retracted position
• the value of the displacement DC is greater than that of the depth D120 of the counter splines 120, so that during longitudinal thrusting of the slab 3, the splines 20 and counter-grooves 120 do not come into contact.
• a non-zero clearance J120 is thus provided, equal to the difference between the displacement DC and the depth D120.
• the actuating means 106, 107 are preferably locking means which enable the displacement of the formwork shoe 103 to be moved. These means 106, 107 are in engagement with both the shim and the shoe. In the illustrated example, these braking means comprise two pipes 106, 107. These pipes are preferably chosen to be flexible, but not substantially elastically deformable. They are advantageously chosen from those used by firefighters.
• a formwork pipe 106 is disposed longitudinally in the volume V122, between the outer face 109 of the shim 102 and the outer face 126 of the arch 122.
• a formwork pipe 107 is arranged longitudinally in the volume V122, between the inner face 108 of the wedge 102 and the inner face 124 of the arch 122.
• the pipes are inflated, that is to say put under pressure with a fluid that can be air or water.
• the pipes work together like a double acting cylinder.
• the pressurizing of the shuttering pipe 106, and the venting of the stripping pipe 107 inflates the shuttering pipe 106.
• This causes both the separation of the respective external faces 109, 126 of the shim and of the the arch and crushing of the formwork pipe 107 between their inner faces 108,124.
• the shoe is brought or held in the formwork position, preferably in abutment, symbolized by the reference 128.
• the pressurizing of the stripping pipe 107, and the venting of the shuttering pipe 106 causes the stripping pipe 107 to inflate.
• This causes both the separation of the respective internal faces 108, 124 of the wedge and arch and crushing of the formwork pipe 106 between their outer faces 109,126.
• the shoe is brought or maintained in the retracted position. Just make sure that the tray is down, to push the prefabricated slab and release the system 100 for the formwork of a possible next section of the slab 3.
• V122 defined within each shoe 103, these elements do not encumber the space 1 10 delimited between the shoes 103 and under the plate 104. This allows to accommodate in this space a guide rail 200 of a thrust system 300 which makes it possible to move a section of slab, or a slab, prefabricated (e) by exerting on it or it a thrust force represented by the arrows Ei in Figure 7.
• a superstructure structure 400 is shown partially, this support structure being intended to be fixed to the end of two longitudinal beams 2 provided for supporting a bridge slab.
• this structure 400 are mounted two shuttering systems 100 according to the invention, the shuttering system 100 visible in the upper part of this FIG. 7 being in a configuration where its shoes are spaced apart from one another, which corresponds to to the representation of the upper part of Figure 6.
• the formwork system 100 shown in the lower part of Figure 7 is in a configuration where its shoes are close to each other, as shown in the lower part of the FIG. 6 shows a slab formwork area A or slab sections in the vicinity of the beams 2 of point 1.
• a rail 200 extends longitudinally in the central space 110 of each formwork system 100 and supports a thrust system 300 which comprises two jacks 301 and a thrust plate 302 for exerting, on a section of slab that is not shown for the sake of clarity, the effort Ei. It is noted that the force E 1 is exerted by the thrust plates 302 below the shuttering systems 100, that is to say at the vaults 1 1 of the slab 3 which rigidly connect the central portion 4 and the corbels 5 made on both sides of the formwork systems 100.
• each rail 200 is a rack rail, which allows incremental positioning of the thrust devices 300 along this rail.
• the formwork system of the invention is therefore particularly simple to use, especially since it does not include reservations for the passage of reinforcements that would cross the space 110. Formwork and formwork operations carried out thanks to this system are therefore fast and, as a result, economic.
• the bridge may have a cant and a curvature.
• the bridge may comprise only one beam, or more than two beams.
• the number of rows of connectors and the spacing of the connectors, as well as their nature, may vary, in particular according to the efforts to be transmitted between the slab and the corresponding beam.
• Seals may also be provided on the edges of the soles also for the first and second embodiments.
• grooves can be replaced by a lost formwork, for example by a metal lattice type "Nerlat”, the company Metal Expanded.

Landscapes

• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Bridges Or Land Bridges (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=40332886

Family Applications (1)

Country Status (3)

Families Citing this family (7)

Family Cites Families (7)

• 2008
  • 2008-07-08 FR FR0854637A patent/FR2933718B1/fr active Active
• 2009
  • 2009-07-08 EP EP09794034A patent/EP2321463A1/de not_active Withdrawn
  • 2009-07-08 WO PCT/FR2009/051350 patent/WO2010004210A1/fr active Application Filing

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events