Pedestrian walkway structure, in particular for a railway station

Abstract

A pedestrian walkway (4) structure (10), in particular for a railway station, comprising longitudinal beams (14, 16) and a contributing decking board (12) stiffened by transverse beams (20), the decking board (12) extending in the thickness of the structure (10), defined by the height (X1) of the longitudinal beams (14, 16).

Description

[0001] Description

[0002] Title: Pedestrian bridge structure, particularly for a railway station

[0003] Technical field

[0004] The invention relates to the field of bridge-type engineering structures, in particular for pedestrians.

[0005] The invention is of particular interest in the railway sector, for crossing railway lines.

[0006] State of the prior art

[0007] In the railway sector, different types of pedestrian bridges are implemented.

[0008] According to a first type of footbridge, the deck comprises a concrete slab serving as a decking, supported by metal profiles. Such a structure is generally used for footbridges with a useful width between 1.8 m and 3.0 m.

[0009] The use of a concrete slab requires significant quantities of construction materials, affecting the cost of the structure, its carbon footprint, and the mass and thickness of the deck. The installation of such a structure requires expensive lifting equipment. In addition, the total height of such a structure, including the deck, supporting sections, and catenary protection screens, is typically around 1.7 m, creating significant wind-resistant surfaces and generating significant forces at the base of the column that affect the foundations. Such a structure may therefore require semi-deep foundations such as micropiles, which are expensive and irreversible.

[0010] According to a second type of footbridge, the deck comprises a metal deck supported by steel beams. Such a deck makes it possible to reduce the mass of the structure compared to a concrete slab, but typically limits the useful width to a width of between 1.8 m and 2.5 m. Description of the invention

[0011] The invention aims to overcome all or part of the aforementioned drawbacks, in particular by providing a footbridge structure capable of reducing the mass of the structure.

[0012] The invention also aims to provide a footbridge structure making it possible to reduce the economic and / or ecological cost and / or to improve the replicability and / or maintainability and / or durability of the structure.

[0013] Another aim of the invention is to provide a footbridge structure making it possible to improve the durability of its waterproofing and / or its non-slip coating and consequently to reduce the maintenance and immobilization costs of the structure.

[0014] Yet another object of the invention is to provide a footbridge structure making it possible to reduce the crossing height for the user and consequently the length of the stairs.

[0015] The invention also aims to facilitate the installation of the structure in its environment.

[0016] The invention also aims to provide a solution for establishing a gateway standard in the railway sector, particularly on a national scale.

[0017] To this end, the invention relates to a structure for a crossing structure, in particular a railway crossing footbridge, comprising a decking element, two main beams and secondary beams connected to the main beams and supporting the decking element.

[0018] Main beams are also called "longitudinal beams" or "edge beams." Secondary beams are also called "cross beams" or "braces."

[0019] The decking element comprises an upper surface contained in a space delimited: in a first direction, on the one hand by a lateral surface of one of the main beams and, on the other hand, by a lateral surface of the other main beam, in a second direction, on the one hand by a first fictitious plane passing through a lower surface of the main beams and, on the other hand, by a second fictitious plane passing through an upper surface of the main beams.

[0020] In other words, considering that the main beams form a reinforcement whose thickness is defined by their height, the upper surface of the decking element extends into the thickness of this reinforcement.

[0021] Such positioning of the decking element relative to the main beams allows the decking element, particularly its top surface, to be brought closer to the neutral axis of the main beams, thereby reducing or eliminating the longitudinal bending component in the decking element when the structure is loaded.

[0022] This makes it possible, in particular, to reduce the thickness of the decking element and consequently to reduce the dimensions and mass of the structure, as well as its cost.

[0023] Secondary beams allow, on the one hand, the positioning of the decking element in relation to the main beams. On the other hand, they allow a stiffening function of the decking element, reducing transverse deformations, transferring the loads from the decking element to the main beams, and improving the mechanical resistance of the structure.

[0024] The decking element thus has orthotropic mechanical behavior. The invention makes it possible to reduce longitudinal bending stresses in the decking element, which can absorb almost exclusively transverse bending stresses.

[0025] This also reduces the dependence of the decking element dimensioning on the span of the deck and the structure.

[0026] In one embodiment, said upper surface of the decking element is positioned, in said second direction, at a distance from the lower surface of the main beams of between 10% and 40%, more preferably between 20% and 30%, even more preferably between 24% and 26%, of a height of these main beams. Such positioning makes it possible to optimize the orthotropic behavior of the decking element, or the dissociation of the forces between the decking element and the reinforcement.

[0027] The decking element preferably comprises a plate, or sheet.

[0028] In this document, the terms "plate" and "sheet" generally designate an element having a relatively small thickness compared to its surface area, in this case compared to the dimensions of said upper surface formed by the decking plate or sheet.

[0029] As an indication, the decking plate can have a thickness between 5 mm and 20 mm, more preferably between 7 mm and 12 mm, for example equal to 8 mm.

[0030] In one embodiment, the decking member is metallic.

[0031] In one embodiment, the decking element is connected to the main beams by weld beads.

[0032] Such welding seams help to improve the tightness of the structure.

[0033] In one embodiment, the structure comprises a waterproofing coating extending over said upper surface of the decking element and, preferably, over said lateral surface of the main beams.

[0034] This coating, of the complex waterproofing type, makes it possible in particular to prevent corrosion of steel parts of the structure and to ensure the sanitation of the work.

[0035] The coating may also have other properties, including non-slip properties.

[0036] For information purposes, this coating may have a thickness of between 1 mm and 10 mm, preferably between 3 mm and 7 mm, for example equal to 5 mm.

[0037] In one embodiment, each of the secondary beams comprises a web and a flange.

[0038] The web of the secondary beams preferably provides a bearing surface for the decking element. In one embodiment, the web of the secondary beams extends between their flange and the decking element.

[0039] In other words, said wing of the secondary beams can form a lower wing and the decking element can form an upper wing of the secondary beams.

[0040] For each of the secondary beams, the flange may extend along said first direction over a central portion of the web.

[0041] Preferably, the ends of the web of the secondary beams can thus be without flanges.

[0042] This makes it easier to assemble the structure, by providing access to create welding beads, for example.

[0043] In one embodiment, each of the main beams comprises a web.

[0044] For each of the main beams, said lateral surface can be formed by this web.

[0045] It is preferred that each of the main beams also comprise two flanges, each of which may form a respective one of said lower and upper surfaces.

[0046] In one embodiment, the web of each of the main beams extends obliquely relative to said second direction.

[0047] Such an inclination of the web of the main beams makes it possible to increase the useful crossing width and to limit the span of the secondary beams.

[0048] In one embodiment, said upper surface of the decking element comprises one or more slopes extending obliquely relative to said fictitious planes.

[0049] This or these slopes, which can be transverse and / or longitudinal, allow water to flow away, particularly rainwater.

[0050] The invention also relates to a crossing structure comprising such a structure. The structure may be a footbridge, in particular a footbridge crossing a railway line and / or another type of track.

[0051] Without limitation, the footbridge may include catenary protection canopies, which are preferably carried by the main beams.

[0052] The structure may be intended for pedestrians to cross roads.

[0053] In other, non-limiting variants, the structure may be of the road bridge type, a motorway wildlife crossing, or even a tram, train or tram and train crossing.

[0054] The invention also relates to a railway station installation comprising such a footbridge.

[0055] Among other advantages of the invention, it makes it possible to constitute a mainly light and flat metallic structure, the thickness of which is defined by the distance between the underside of the main beams and the decking element.

[0056] It has been estimated in particular that, compared to conventional footbridges, the invention makes it possible to reduce the quantity of steel by approximately 35% as well as the quantity of concrete in the structure, to reduce the carbon footprint, to reduce the crossing height and the length of the stairs by approximately 6% to 8% and therefore the user journey, to increase the permissible useful width of the footbridge, in particular compared to conventional footbridges with metal decking, to obtain a significant lifespan for the structure, to facilitate the implementation of the structure given the lightness of the structure, to reduce the manufacturing and installation cost, and to satisfy criteria of replicability and industrialization.

[0057] The invention also makes it possible to establish a gateway standard, particularly in the railway sector.

[0058] Other advantages and characteristics of the invention will appear on reading the detailed, non-limiting description which follows.

[0059] Brief description of the drawings

[0060] The following detailed description refers to the appended drawings in which: Figure 1 is a schematic perspective view of a railway station comprising a footbridge according to the invention; Figure 2 is a schematic cross-sectional view of a footbridge according to the invention, this footbridge comprising on the one hand a structure formed by two main edge beams and a deck which comprises secondary beams and a decking plate and, on the other hand, lateral catenary protection canopies; Figure 3 is a schematic perspective view of the structure of the footbridge of Figure 2, showing the main beams and the decking plate; Figure 4 is a schematic top view of the structure of the footbridge of Figure 2, showing the main beams and the secondary beams; Figure 5 is a schematic perspective view of part of the footbridge of Figure 2.

[0061] Detailed description of embodiments

[0062] Figure 1 schematically shows part of a railway station comprising two platforms 1 and 2 which extend on either side of a double railway track 3, as well as an installation allowing users to cross the railway track 3.

[0063] As is known per se, this installation comprises a footbridge 4 forming an overhead passage, as well as staircases 5 and 6 and elevators 7 and 8 connecting footbridge 4 to platforms 1 and 2.

[0064] Footbridge 4 in Figure 1 is intended to allow pedestrian users to cross railway line 3.

[0065] In this document, the term "pedestrian" includes in particular people on foot and people with reduced mobility, for example, using a wheelchair.

[0066] The footbridge 4 of Figure 1 may comprise a structure 10 as described below with reference to Figures 2 to 5, which illustrate a non-limiting embodiment of the invention. The figures indicate a relative orientation of the structure 10 - and therefore of the footbridge 4 - using a reference system defining a transverse direction D1, a vertical direction D2 and a longitudinal direction D3, the directions D1, D2 and D3 being orthogonal.

[0067] Referring to Figures 2 to 4, the structure 10 comprises a decking element 12, main beams 14 and 16, stiffeners 18 and secondary beams 20.

[0068] The decking element 12 comprises in this example a metal plate forming a solid and continuous decking.

[0069] The decking plate 12 extends transversely between the main beams 14 and 16 (see figure 2) and, in the direction D3, substantially over the entire length of the main beams 14 and 16 (see figure 3).

[0070] Referring to Figure 2, the decking plate 12 comprises a lower surface 22 and an upper surface 24 defining the thickness of this plate 12, in this example a thickness of 8 mm.

[0071] In order to ensure in particular the flow of rainwater, the decking plate 12 has one or more bulges defining transverse slopes.

[0072] More specifically, the plate 12 comprises a first transverse section extending along the direction D3 from a median coordinate 26 to a first transverse end 27 of the plate 12 and a second transverse section extending along the direction D3 from said median coordinate 26 to a second transverse end 28 of the plate 12. On each of these transverse sections, the upper surface 24 has a respective transverse slope which is here of the order of 1.1%.

[0073] The upper surface 24 of the decking plate 12 thus has surface portions which are oblique relative to a reference plane D1-D3.

[0074] Concerning the main beams 14 and 16 of the structure 10, these extend along the longitudinal direction D3, that is to say in the direction of the span of the structure 10. The beams 14 and 16, also called “edge beams”, are spaced from each other in the transverse direction DI and, in this example, are symmetrical with respect to a reference plane D2-D3 passing through said median coordinate 26 of the decking plate 12.

[0075] Beams 14 and 16 are here metal load-bearing profiles, of the welded reconstituted profile type.

[0076] With reference to figures 2 and 5, the beam 16 comprises in a manner known per se a web 32, a lower flange 34 and an upper flange 36.

[0077] The wings 34 and 36 of the beam 16 respectively form a lower surface 40 and an upper surface 42 of the beam 16 which are spaced from each other in the direction D2 so as to define a height XI of the beam 16 (see figure 2).

[0078] As a guide, the height XI can be between 400 mm and 800 mm, for example equal to 500 mm.

[0079] In this example, the wings 34 and 36 of the beam 16, and more specifically the surfaces 40 and 42 which they form, extend substantially parallel to the reference plane D1-D3.

[0080] The web 32 of the beam 16 extends obliquely relative to the reference plane D2-D3 and therefore relative to the vertical direction D2, so that the height XI of the beam 16, considered along D2, is less than the length of the web 32, considered in the oblique direction along which it extends.

[0081] Such an inclination of the beam 16 thus makes it possible to reduce the distance between the wings 34 of the main beams 14 and 16, defining the functional width of the structure, and the dimensioning of the secondary beams 20.

[0082] The web 32 of the beam 16 further comprises lateral surfaces 44 and 46, the surface 44 forming an internal surface extending opposite the beam 14 and the decking element 12, the surface 46 forming an external surface extending towards the outside of the structure 10. In FIG. 2, the lateral surface 44 of the beams 14 and 16 is respectively numbered 44A and 44B.

[0083] With reference to Figures 3 and 5, several stiffeners 18 are fixed to the beam 16 in order to improve its mechanical resistance.

[0084] The stiffeners 18 are here formed from metal plates arranged along the external surface 46 of the web 32, between the flanges 34 and 36 of the beam 16.

[0085] In this example, the stiffeners 18 are regularly spaced along the direction D3 and are distributed over the entire length of the beam 16 (see figure 3).

[0086] In a non-limiting manner, the beam 16 in this example has a length X2 of 12.40 m and the stiffeners 18 are longitudinally spaced, two by two, by a distance X3 of 1.2 m.

[0087] In this embodiment, beam 14 is symmetrical to beam 16 and is also equipped with stiffeners 18, one of which is visible in Figure 2. The preceding description, relating to beam 16, applies by analogy to beam 14.

[0088] Now concerning the secondary beams 20, also called “spacers”, these each extend along the transverse direction DI and are spaced from each other in the longitudinal direction D3.

[0089] With reference to Figure 4, the beams 20 are regularly spaced along the direction D3, over the entire length X2 of the structure 10.

[0090] In this non-limiting example, the beams 20 are longitudinally spaced, two by two, by a distance X4 of 600 mm, so that one beam 20 out of two is longitudinally aligned with a respective stiffener 18 secured to the main beam 14 and a respective stiffener 18 secured to the main beam 16.

[0091] The secondary beams 20 are here metallic and each comprise a web 52 and a flange 54, visible in figure 4. For each of the beams 20, the web 52 extends transversely so as to be fixed by a first end to the main beam 14 and by a second end to the main beam 16 (see figure 2).

[0092] For each of the beams 20, the flange 54 extends over a central part of this beam, in this case over a distance X5 less than the length of the web 52 and consequently less than the average distance X6 along DI between the main beams 14 and 16 (see figure 4).

[0093] For information, the distances X5 and X6 are in this example equal to 2.2 m and 3.2 m, respectively.

[0094] In this example, the ends of the wing 54 of each of the beams 20 have a tail-shaped geometry, intended to gradually dissipate the mechanical stresses present at the ends of the wing 54 towards the web 52.

[0095] Thus, the secondary beams 20, which are here welded reconstituted profiles, are devoid of flanges at their ends which are formed solely by the web 52. This makes it easier to fix by welding the secondary beams 20 and the decking element 12 with the main beams 14 and 16.

[0096] In this embodiment, the secondary beams 20 are welded to the main beams 14 and 16, in particular by welding the ends of the web 52 of the beams 20 with the internal surface 44A / 44B of the web 32 of the main beams 14 and 16. The web 52 of the beams 20 is also welded to the lower flanges 34 of the main beams 14 and 16.

[0097] The secondary beams 20 support the decking plate 12, the lower surface 22 of which is, on the one hand, arranged on the web 52 of each of the beams 20 and, on the other hand, welded to them.

[0098] For each of the beams 20, the web 52 therefore extends vertically between the flange 54 and the decking element 12.

[0099] The secondary beams 20 thus constitute stiffeners of the decking element 12 and make it possible to transmit loading forces from the decking element 12 to the main beams 14 and 16. In this example, the secondary beams 20 have a geometry allowing them to fit the decking plate 12 taking into account its bulge.

[0100] Referring to Figure 2, the decking plate 12 thus supported by the secondary beams 20 is also connected to the main beams 14 and 16 by weld beads. The weld beads are in this example made at the transverse ends 27 and 28 of the plate 12 in order to connect these transverse ends 27 and 28 to the internal surface 44A / 44B of the web 32 of the main beams 14 and 16, respectively.

[0101] Such weld beads are essentially intended to improve the sealing of the structure 10, for example with regard to rainwater likely to flow onto the decking plate 12. They also contribute to the rigidity of the structure, in particular of the frame formed by the main beams 14 and 16 and by the overall bracing of this structure - secondary beams 20 and decking element 12.

[0102] Figure 2 shows a first fictitious plane PI passing through the lower surface 40 of the main beams 14 and 16, as well as a second fictitious plane P2 passing through the upper surface 42 of the main beams 14 and 16, the planes PI and P2 being parallel to the reference plane D1-D3.

[0103] The fictitious planes PI and P2 make it possible to define a space El which is delimited in the direction D2 by these fictitious planes PI and P2 and which is delimited in the direction DI by the main beams 14 and 16.

[0104] In this embodiment, the secondary beams 20 as well as the decking element 12, which constitute a deck of the structure 10, are entirely contained in the space E1.

[0105] In other words, the decking element 12 and in particular its upper surface 24 are positioned in the thickness of a reinforcement of the structure 10, reinforcement constituted by the main beams 14 and 16.

[0106] The deck of the structure 10 is therefore circulated between the main beams 14 and 16. The invention thus makes it possible to reduce the thickness of the structure 10, that is to say its vertical dimension, while reducing its mass which can typically, in this example, be around 5 tonnes.

[0107] With reference to Figure 2, the upper surface 24 of the decking plate 12 is positioned at a distance X7 of approximately 130 mm from the fictitious plane PI, transversely at the level of said median coordinate 26 of the decking plate 12.

[0108] The decking plate 12 is thus spaced from the lower 34 and upper 36 ends of the main beams 14 and 16, and consequently from the zones of maximum elongation stresses of these beams 14 and 16 during their bending under the action of the dead weight of the footbridge 4 and the operating loads.

[0109] In other words, the decking plate 12 is here brought closer to the neutral axis of the main beams 14 and 16.

[0110] The beams 20 and the decking plate 12 thus behave like an orthotropic structure configured to take up transverse bending stresses while remaining little subject to longitudinal bending stresses which are exerted on the main beams 14 and 16.

[0111] Tests have indeed made it possible to observe a differentiated behavior between the main beams 14 and 16 and the decking plate 12, in the embodiment described above. In particular, mid-span stress values ​​were observed that were significantly higher at the level of the main beams 14 and 16 than at the level of the decking plate 12, in this case of the order of four to five times higher.

[0112] In this example, the structure 10 comprises a coating in the form of a sealing complex (not shown) continuously covering the upper surface 24 of the decking element 12 and a portion of the main beams 14 and 16, in particular so as to cover the weld beads made at the transverse ends 27 and 28 of the decking element 12.

[0113] To reduce the risks of water infiltration, the coating can be raised on the main beams 14 and 16 so as to cover both a part of the internal surface 44A / 44B of the core 32 and a part of the upper flange 36. This arrangement makes it possible to have the entire end linear of the sealing complex in the direction D3 protected from the water line, rain and ultraviolet radiation.

[0114] As a guide, this coating can be 5 mm thick.

[0115] The positioning of the decking element 12 relative to the main beams 14 and 16 makes it possible to create a casing with optimal sealing.

[0116] In this example, the waterproofing coating also has anti-slip properties.

[0117] The structure 10 of the footbridge 4, including the covering, can be fully assembled and welded in the workshop.

[0118] With reference to figures 2 and 5, the footbridge 4 comprises in this example catenary protection canopies 60 which are supported by the main beams 14 and 16 of the structure 10.

[0119] In the example of Figure 5, the canopies 60 comprise, in a manner known per se, metal uprights 62 and mesh walls 64 which are connected to the uprights 62 by metal frames 66.

[0120] The uprights 62 are each fixed to the upper flange 36 of one of the main beams 14 and 16, in the continuity of a respective stiffener 18.

[0121] For information, the 60 canopies have a height X8, according to D2, of approximately 1.50 m (see figure 2).

[0122] Of course, many variations can be made to the structure 10 and more generally to the walkway 4 described above, in particular in geometric and / or dimensional terms. For example, the decking element 12 may comprise or support a non-metallic material and / or have a thickness different from that indicated above, in particular depending on the geometry and dimensions of the other parts of the walkway 4.

[0123] In alternative embodiments, the position of the decking element 12 may be different from that illustrated in Figures 2 and 5. For example, the decking element 12 may be configured so that its upper surface 24 is located equidistant along D2 from the flanges 34 and 36 of the main beams 14 and 16.

[0124] In alternative embodiments, the upper surface 24 of the decking element 12 may have no transverse slope or comprise a single transverse slope, and / or comprise a longitudinal slope. When the upper surface 24 of the decking element 12 comprises one or more slopes, each of these slopes may have a value different from that indicated above, for example a value between 0.5% and 3%.

[0125] In one embodiment, not shown, the walkway 4 may also include roofing elements.

[0126] More generally, the structure 10 of the invention, according to the embodiment of Figures 2 to 5 or according to any variants, may constitute an installation different from that illustrated in Figure 1, for example a bridge-type installation for crossing an element other than a railway, for example a road, a watercourse or even a ravine. Several structures in accordance with the invention may also be associated with each other to together constitute a single installation. For example, two structures 10 such as that described above may be arranged end to end in order to increase the number of spans of a footbridge that they constitute together, for example in order to allow the crossing of several railways and the service of several platforms.

Claims

Claims 1. Structure (10) of a crossing structure, in particular a footbridge (4) for crossing a railway line (3), comprising a decking element (12), two main beams (14, 16) and secondary beams (20) connected to the main beams (14, 16) and supporting the decking element (12), the decking element (12) comprising an upper surface (24) contained in a space (El) delimited: in a first direction (Dl), on the one hand by a lateral surface (44A) of one (14) of the main beams and, on the other hand, by a lateral surface (44B) of the other main beam (16), in a second direction (D2), on the one hand by a first fictitious plane (PI) passing through a lower surface (40) of the main beams (14, 16) and, on the other hand, by a second fictitious plane (P2) passing through an upper surface (42) of the main beams (14, 16).

2. Structure (10) according to claim 1, wherein said upper surface (24) of the decking element (12) is positioned, in said second direction (D2), at a distance from the lower surface (40) of the main beams (14, 16) of between 10% and 40%, more preferably between 20% and 30%, even more preferably between 24% and 26%, of a height of these main beams.

3. Structure (10) according to claim 1 or 2, in which the decking element (12) comprises a plate, preferably having a thickness of between 5 mm and 20 mm, more preferably of between 7 mm and 12 mm, for example equal to 8 mm.

4. Structure (10) according to any one of claims 1 to 3, in which the decking element (12) is connected to the main beams (14, 16) by weld beads (27, 28).

5. Structure (10) according to any one of claims 1 to 4, comprising a sealing coating extending over said upper surface (24) of the decking element (12) and over said lateral surface (44A, 44B) of the main beams (14, 16).

6. Structure (10) according to any one of claims 1 to 5, wherein each of the secondary beams (20) comprises a web (52) and a flange (54), the flange (54) preferably extending along said first direction (D1) on a central portion of the web (52).

7. Structure (10) according to any one of claims 1 to 6, wherein each of the main beams (14, 16) comprises a web (32) which extends obliquely with respect to said second direction (D2).

8. Structure (10) according to any one of claims 1 to 7, wherein said upper surface (24) of the decking element (12) comprises one or more slopes extending obliquely relative to said fictitious planes (P1, P2), in order to allow water flow.

9. Footbridge (4) comprising a structure (10) according to any one of claims 1 to 8.

10. Railway station installation comprising a footbridge (4) according to claim 9.

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