EP0021873B1 - Block for railways limited in height, especially for ballastless railways - Google Patents

Abstract

The construction of steel-concrete railroad ties onto which rails are fixed is disclosed. The ties are composed of a metal saddle for fastening to the rail, comprising a tie-plate extending over a part of the upper surface of the tie and forming the zone for attachment and support of the rail. The tie-plate further extends into the tie through ribs sealed in the concrete of the tie and constitutes at least part of its reinforcement.

Description

The present invention relates to a construction of a concrete-steel railroad blocker where the rails bear on blocks of reinforced concrete, called blocks, optionally connected two by two in a crosspiece by a metal frame with ends sealed in said blocks.

This type of block is used mainly in so-called ballast-free tracks, where the blocks rest on plates of vibration damping material, in direct support on a concrete screed, in which they are generally embedded. These tracks are in particular in rail transport networks in tunnels, where the absence of ballast makes it possible to significantly reduce the height of the tunnel.

By cons, and despite the use of reinforced concrete reducing the need for reinforcement, the reinforced concrete structure oblique blocks to give them a certain dimensional mass to acquire the strength and rigidity required. Account must be taken of the significant concentrated pressures on the center of the block vertical to the rail during the passage of trains, tending to make the latter work in bending on repeated central support which is undesirable for concrete parts. This therefore results, in order to resist these flexions, necessarily fairly massive blocks, in particular in height, which go against the desired objective of a track assembly as low as possible.

US-A-1788913 describes a low railroad block of the type reinforced concrete with a metal saddle of general shape in inverted U; the base or sole of the rectangular saddle receives the support and the fixing of the rail and is extended downward by ribs sealed in the concrete of the block, forming a frame.

The patents BE-A-421 322 and CH-A-97 008 also present blocks of the analogous type made of reinforced concrete by a saddle or a framework.

The structures of the preceding blocks do not allow, although they are not excessively massive, a uniform distribution of pressure on the concrete of these blocks.

The present invention relates to a block structure according to the preamble of claim 1 which does not have the above drawbacks, while retaining sufficient strength and being of simple and economical construction. It is characterized in that the sole of the saddle covers most of the upper surface of the block by being stiffened by a network of solid ribs crisscrossing its lower volume and in that the ribs have a decreasing height from their support area of the rail towards the ends of the saddle, giving it a beam shape of equal flexural strength.

It follows from this structural combination of a metal frame in the form of a saddle covering the concrete block in which it is sealed by its wings that most of the bending forces exerted by the concentrated pressure of the rail will be supported by the metal structure. in a very rigid U of the saddle, under which the concrete of the wall will work mainly in compression. The height of the block can therefore be reduced as much as possible. In practice, it will only have to be slightly higher than the wings of the saddle, enough to ensure their correct sealing, and transmit the pressure exerted by the saddle uniformly to the damping plate on which the block rests.

The saddle can be made of molded metal such as cast iron, the support sole of the rail then being stiffened by a network of ribs obtained by molding, these ribs crisscrossing for example the lower surface of the sole.

This sole will advantageously be bordered by a peripheral rib comprising external ribs at the connection points with the internal grid ribs, on the longitudinal edge of the sole, to increase the anchoring of the reinforcement.

According to another type of construction according to claim 4, the saddle will be a steel plate cut out and folded into a U-shaped profile.

The two wings of this U-shaped section can be fitted by wedging in the external frame of a reinforcement frame in a flat grid formed of round concrete iron.

The support stops and the fixing holes of the rail fasteners will be fitted in the sole of the saddle and produced, depending on the type of construction, either directly by foundry, or by cutting, embedding and / or welding of added elements.

• -La figure 1 représente en coupe longitudinale axiale 1-1 un blochet selon l'invention dans sa version préférée avec une selle en matériau coulé en fonderie.
• -La figure 2 représente le même blochet en vue de dessus.
• -La figure 3 représente le même blochet en coupe transversale III-II1.
• -La figure 4 représente un blochet selon l'invention dont la selle est réalisée à partir d'une plaque d'acier découpée et pliée en U, en coupe longitudinale IV-IV.
• -La figure 5 représente, en vue de dessus, la disposition de la même selle dans le même blochet.
• -La figure 6 représente, en coupe VI-VI, les sections transversales de la selle et du blochet.

Examples of embodiments of the invention will be described below, with reference to the accompanying drawings, in which:

• - Figure 1 shows in axial longitudinal section 1-1 a block according to the invention in its preferred version with a saddle of material cast in foundry.
• FIG. 2 represents the same block in top view.
• FIG. 3 represents the same block in cross section III-II1.
• FIG. 4 represents a block according to the invention, the saddle of which is produced from a steel plate cut and folded in a U, in longitudinal section IV-IV.
• - Figure 5 shows, in top view, the arrangement of the same saddle in the same block.
• - Figure 6 shows, in section VI-VI, the cross sections of the saddle and the block.

In FIG. 1, a rail 1, fixed in the usual way by fasteners 2 rests on a sole 3 forming the upper plate of a saddle 4 made of cast material such as cast iron. Said sole extends vertically downwards by a network of ribs 5, sealed in the concrete of a block 6. The sole 3 and its network of ribs 5 give the saddle 4 a very resistant and rigid ribbed beam structure in flexion .

The sole 3 has reliefs 7 forming the support stops for the rail fixing system and orifices 8 for passage and for fixing the bolt heads of the rail fasteners 2.

Two different types of fasteners are shown on either side of the rail in Figures 1 and 2, to illustrate the adaptability of this type of block to different fastening systems.

These Figures 1 and 2 show a network of ribs 5 crisscrossing the bottom surface of the sole 3 and slightly protruding at 9, their junction with a peripheral rib of the sole 3, which increases the anchoring of the sole in the concrete block 6 and avoids any other conventional auxiliary frame. The block 6 is shown equipped with a liner 10 and a sole 11 of the type used for damping vibrations in tracks without ballast.

According to another embodiment of the invention, when this technique turns out to be more advantageous according to the industrial means available, the saddle 4 can be made of thick sheet metal cut and folded into a U as shown in FIGS. 4, 5 and 6 where , for the sake of simplification of the drawings, the rail fastening systems 1 have not been shown, but will be fitted out with suitable holes in the sole 3 and stops which can either be wedged in such holes, cut directly, or made up of metal studs welded to this sole according to the types of fastening used.

The inherent limitations of this embodiment limit the ribs 5 to two longitudinal ribs giving the saddle the shape of a U-beam. These longitudinal wings have, as in the previous case, a decreasing height from the middle to the ends in a shape d equal conventional resistance for such beams working in bending. This limitation to the two longitudinal ribs is compensated for by a reinforcing reinforcement in conventional round concrete iron, but presenting itself, as indicated in FIGS. 4 and 6, like a flat grid 12 which can be wedged, by its external frame 13, and other ribs 5, taking advantage of their residual folding inclination. This wedging at 14 allows the reinforcement 13 to be held in place during the pouring and setting of the concrete.

It can be seen that in the two embodiments described, the concrete block 6 has a height reduced to the strict minimum for coating the lower part of the saddle 4 and that its role is limited to transmitting by simple compression, a constraint for which this material is well suited, the concentrated pressures of the rail 1, received through the saddle 4, to the damping plate 11, in the form of a uniformly distributed pressure.

Claims (4)

1. A tie-beam, for a surbased railway, made of concrete reinforced by a metallic saddle (4) having the general shape of an inverted U the base or sole (3) whereof, which receives the support and the attachment of the rail (1) is constituted by a plain, substantially rectangular plate extended downwardly by ribs or branches (5) embedded in the concrete of the tie-beam (6) and constituting a reinforcing structure, characterized in that:

-the sole (3) covers the major portion of the upper surface of the tie-beam (6);

-the sole (3) is stiffened by a net of solid ribs (5) cross-ruling its lower volume;

-the ribs (5) have a height decreasing from their rail (1) supporting zone towards the ends of the sole (4) so as to confer on them the shape of a beam having an equal flexional strength.

2. A tie-beam according to claim 1, characterized in that the sole (4) is made of moulded metal, while said net of ribs (5) cross-rules the lower volume of said sole (3) by means of a peripheral rib and internal ribs.

3. A tie-beam according to claim 2, characterized in that the peripheral rib of the sole (3) comprises external ribs (9) at the points of connection with the internal cross-ruling ribs, on the longitudinal border of the sole.

4. A tie-beam according to the generic part of claim 1, characterized in that:

-the sole (4) is constituted by a steel plate which is cut and plied so as to form a profile having the shape of a "U" the two flanges (5) of which are embedded by wedging (14) in the external frame (13) of a supplementary reinforcing structure in the form of a flat grid (12) made of concrete reinforcing iron bars having a circular cross section;

-the base or sole (3) covers the major portion of the upper surface of said tie-beam (6);

-the flanges have a height decreasing from their resting zone of the rail (1) toward the ends of the sole (4), so as to confer on them the shape of a beam having an equal flexional strength.

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