DK2697430T3

DK2697430T3 - Banesvelle

Info

Publication number: DK2697430T3
Application number: DK12714922.7T
Authority: DK
Inventors: Roger Höfle; Harald Loy; Arnold Flatz; Andreas Augustin
Original assignee: Getzner Werkstoffe Holding Gmbh
Priority date: 2011-04-15
Filing date: 2012-03-13
Publication date: 2015-08-24
Also published as: AT510835A4; EP2697430A1; ES2546434T3; AT510835B1; WO2012139142A1; EP2697430B1; PL2697430T3

Description

The invention relates to a railway sleeper which has a concrete body with a sleeper sole which is attached thereto, wherein a connecting layer is provided for connecting the sleeper sole to the concrete body in a manner resistant to shearing forces, which layer is connected on one hand to the sleeper sole and on the other hand to the concrete body and in so doing is partially embedded in the concrete of the concrete body.

Under-sleeper pads which consist of elastic plastics material, e.g. foamed polyurethane, for railway sleepers are used in the case of concrete sleepers in particular to protect against vibration and to preserve ballast. Not only vertical but also horizontal forces, in particular in the transverse direction to the rails, act on such under-sleeper pads, such horizontal forces occurring for example when a train passes over them when cornering or due to temperature-induced expansion. In order for sufficient resistance to lateral displacement to be maintained, the transverse forces which occur must be able to be absorbed. In order to achieve a connection of the concrete body of the railway sleeper to the ballast which is resistant to shearing forces, with the mediation of the sleeper sole which lies on the ballast, a connection between the concrete body and the sleeper sole which is resistant to shearing forces thus has to be provided.

In order to form a connection which is resistant to shearing forces between the concrete body of the railway sleeper and the sleeper sole, it is known to form the sleeper sole with elevations and undercut faces. Such a design is disclosed for example in FR 2 753 998 A1. Railway sleepers in which geotextile layers are applied to the underside of the sleeper sole which is remote from the concrete body in order to protect the sleeper sole against the penetration of ballast points are known from DE 43 15 215 A and EP 609 729 A.

For ballastless tracks, sleepers which are partially surrounded by elastic profiles (what are called "booted" sleepers) are known. Such booted sleepers do not lie on ballast, and the demands existing and problems occurring in the case of ballastless tracks differ from those for tracks with sleepers laid on ballast. A railway sleeper of the type referred to first hereinbefore is disclosed in EP 1 298 252 A2. The sleeper sole is connected to the concrete body of the railway sleeper via a connecting layer which is formed by a layer of randomly oriented fibres, in particular a non-woven layer. Fibres of the layer of randomly oriented fibres in this case are on one hand embedded in the concrete of the concrete body in the underside region thereof which is close to the surface, and on the other hand are embedded in the material of the sleeper sole or bonded thereto.

Furthermore, a railway sleeper is known through prior use in which a three-dimensional, thermally bonded entangled mesh having a relatively great thickness of the fibres (= "plastic wires") of the entangled mesh is used as a connecting layer between the sleeper sole and the concrete body, this entangled mesh again being embedded on one hand in the concrete body and on the other hand in the material of the sleeper sole.

Fikewise, concrete sleepers for railway tracks which have a sleeper sole on their undersides are disclosed by EP 1 445 378 A2 and WO 2009/108972 Al. In order to produce an improved bond between the concrete body of the sleeper and the sleeper sole, a fibre layer is arranged which is integrated both in the concrete and in the plastics layer of the sole.

Owing to the three-dimensional structure of these already-known connecting layers which is partially embedded in the concrete, the permanent connection between the concrete body of the railway sleeper and the sleeper sole which is tear-resistant and resistant to shearing forces is improved. The already-known connecting layers, which are formed by layers of randomly oriented fibres, in particular needled non-woven layers or entangled meshes, however have disadvantages in various respects. For example, the three-dimensional form of non-wovens is restricted, which leads to problems in particular when a distinct layer of cement slurries (= laitance) which is formed of cement, water and fines is present at the boundary layer of the concrete body. A layer of this type is capable of transmitting only relatively low forces, which is why subsequently the forces between the connecting layer and the concrete body are also limited. In contrast, a three-dimensional entangled mesh has the advantage that it can also be embedded in deeper-lying regions of the concrete body, as a result of which the transmission of force can in principle be increased. What is disadvantageous in this case, however, is that such entangled meshes are relatively heterogeneous, with typical forms being holes, lump-like accumulations of fibres, variations with regard to thickness, etc. The transmission of force which is achieved via the connecting layer is thus subject to a certain spread.

The object of the invention is to provide a soled concrete sleeper which is improved over this. This is achieved according to the invention by a railway sleeper having the features of Claim 1.

In a railway sleeper according to the invention, the sleeper sole is connected to the concrete body via a connecting layer which is formed by a knitted spacer fabric. A fabric of this type comprises two knitted layers (these are also referred to as fabric faces) which are held spaced apart from each other by connecting threads. The first of these layers in this case is embedded in the concrete of the concrete body.

The second layer, in one advantageous embodiment of the invention, is embedded in the material of the sleeper sole. In another possible embodiment of the invention, the second layer is not embedded in the material of the sleeper sole, but connected to the outer surface of the sleeper sole in a substance-to-substance bond. Such a substance-to-substance connection may for example be formed in that the second layer is pressed against the surface of the reaction mixture, which once set forms the sleeper sole. When the reaction mixture sets, the substance-to-substance connection is then brought about. Another possible way is for the second layer to be glued or thermally bonded to the sleeper sole once it has set.

The two knitted layers may have pattemings which differ from each other and/or be formed by threads of different configurations. The connection of the first layer to the concrete body and the connection of the second layer to the sleeper sole can thereby be optimised.

The term "thread" is used in this specification generally for monofilament threads, yams and plied yams. Yams are practically endless filamentary formations which may consist of finite fibres (= spun yam) or of a plurality of practically endless filaments. Plied yams are special forms of yams with two or more plied individual yams.

Further advantages and details of the invention will be explained below with reference to the appended drawings. Therein:

Fig. 1 is a schematic representation of a railway sleeper according to the invention;

Fig. 2 is a schematic three-dimensional representation of a portion of a connecting layer according to one embodiment of the invention;

Fig. 3 is a side view of the connecting layer of Fig. 2, viewed in the direction A.

Fig. 1 is a schematic representation of a railway sleeper 1 in the form of a concrete sleeper which comprises a concrete body 2 and a sleeper sole 3 attached to the underside thereof. With the sleeper sole 3, the railway sleeper 1 lies on ballast 4 indicated in Fig. 1.

The railway sleepers 1 which are laid spaced apart from each other on the ballast bear a track, one rail 5 of which is indicated in broken lines in Fig. 1. The fastening of the rail 5 to the railway sleeper 1 is not shown in this case. A layer of an elastic material may be arranged between the rail 5 and the railway sleeper 1.

The concrete body 2 is formed from reinforced concrete. This may be a "late stripper", for which the mould stripping takes place once the concrete is set, or an "early stripper", which can be stripped even before the concrete has set. For example, the concrete body 2 may be in the form of prestressed concrete.

The sleeper sole 3 consists of an elastic plastics material. It is preferably formed from foamed polyurethane. It is conceivable and possible to form it from other, in particular foamed, elastomers or thermoplastic elastomers.

The sleeper sole 3 preferably covers only the underside of the concrete body 2.

The sleeper sole 3 is connected to the concrete body 2 via a connecting layer 6. The connecting layer 6 in this case is embedded in the concrete of the concrete body 2 over a part of its thickness d. Over another part of its thickness d, the connecting layer 6 is embedded in the material of the sleeper sole 3.

It is indicated in Fig. 1 that the amount of embedding of the connecting layer 6 in the concrete body 2 and in the sleeper sole 3 equates in total to the overall thickness d of the connecting layer 6. There is therefore, in a region lying within the extent of the connecting layer 6, an interface between the concrete of the concrete body 2 and the material of the sleeper sole 3.

Instead of this, it might also be possible for a layer of the connecting layer 6 which is embedded neither in the concrete body 2 nor in the sleeper sole 3 to remain between the concrete body 2 and the sleeper sole 3. This would then lie between the material of the concrete body 2 and the material of the sleeper sole 3, and the material of the concrete body 2 and the material of the sleeper sole 3 would not directly adjoin each other (would not form a mutual interface).

The embedding of the connecting layer 6 in the concrete body 2 takes place during the production of the concrete body 2 before the concrete of the concrete body 2 has set. When the concrete sets, the non-positive connection to the concrete body 2 takes place. In so doing, positive connections between the connecting layer 6 and the concrete body 2 are produced in relation to the transverse direction 7 of the railway sleeper 1. Furthermore, the connecting layer 6 possesses undercut faces behind which the concrete of the concrete body 2 penetrates upon embedding the connecting layer 6 in the concrete body 2, as a result of which positive connections in the direction of tearing-out (= direction of extraction) 8 which lies at right-angles to the underside of the concrete body 2 or at right-angles to the transverse direction 7 are formed.

If the connecting layer 6 is embedded in the concrete body 2 once the concrete body 2 has been cast, and before it has set, said layer is preferably already connected to the sleeper sole 3. The sleeper sole 3, with the connecting layer 6 which is fixed thereto, and which points in the direction of the concrete of the concrete body 2, is laid on the cast concrete body 2 in the mould and preferably is vibrated into the concrete of the concrete body 2. Instead of this, the sleeper sole 3 with the connecting layer 6 which is directed into the mould cavity could also be laid in the mould cavity or laid against it even before the sleeper is cast, so that the mould cavity is limited by the sleeper sole with the connecting layer 6 which is attached thereto, whereupon the concrete is poured in.

The connecting layer 6 is embedded in the material of the sleeper sole 3 before the plastics material of the sleeper sole 3 has set. For this purpose, the connecting layer 6 is pressed correspondingly far into the reaction mixture, which forms the sleeper sole 3 once set.

Instead of embedding the connecting layer 6 in the material of the sleeper sole 3, the connecting layer 6 could also be attached to the surface of the sleeper sole 3 in a substance-to-substance bond, e.g. by gluing and/or thermal welding. A substance-to-substance connection of this type can take place once the material of the sleeper sole 3 has already set. A substance-to-substance connection can also be achieved by laying the connecting layer 6 against the surface of the sleeper sole 3 before the material thereof has set, with the substance-to-substance connection occurring upon the material of the sleeper sole 3 setting. In the case of the substance-to-substance connection to the surface of the sleeper sole 3, it is possible, if desired, to embed the connecting layer 6 in the material of the concrete body 2 over its entire thickness d, so that, apart from its surface portions by which it is connected to the sleeper sole 3 in a substance-to-substance bond, it is embedded completely in the material of the concrete body 2, i.e. apart from these surfaces it is completely surrounded by the material of the concrete body 2.

It would also be conceivable and possible in principle, but less preferable, initially to integrate the connecting layer 6 in the material of the concrete body 2, and only after that to form the connection to the sleeper sole 3.

The bond between the concrete body 2 and the sleeper sole 3 is advantageously effected already at the factory, so that no work is necessary in relation to this on the site.

The design of the connecting layer 6 is illustrated schematically in Fig. 2 and 3. The connecting layer 6 is formed by a knitted spacer fabric. This comprises first and second knitted layers 9, 10 which are held at a mutual distance by connecting threads 11.

The first and second layers 9,10 are also referred to as fabric faces in the case of such knitted spacer fabrics.

In one advantageous embodiment of the invention, the connecting threads 11 and the threads from which the first and second layers 9, 10 are knitted are each separate, i.e. different, threads. The connecting threads 11 are then referred to as "pile threads".

The pattemings of the first and second knitted layer are indicated schematically by hexagons in Fig. 2 and 3. This indicates holes which the first and second layers 9, 10 may have .

Different pattemings of the first layer 9 or second layer 10 are possible, but advantageously at least the first layer 9 which is embedded in the concrete of the concrete body 2 has holes, preferably with internal widths of at least 3 mm, in order to facilitate the embedding in the concrete of the concrete body 2.

If the second layer 10 is embedded in the material of the sleeper sole 3, the latter advantageously likewise has holes, preferably with internal widths of at least 3 mm, in order to facilitate the embedding in the material of the sleeper sole 3. If the second layer 10 is attached to the outer surface of the sleeper sole 3, the second layer 10 may also be knitted to be relatively narrow, without distinct holes.

The first layer 9 lies in a first plane 12 and the second layer 10 lies in a second plane 13, the two planes 12, 13 lying parallel to each other and being spaced apart from each other.

The pattemings of the first layer 9 and of the second layer 10 may differ in order to adapt the layers to the respective requirements. The threads of which the first layer 9 and the second layer 10 consist may be identical or, in order to adapt them to the respective requirements, may be formed differently.

The number and arrangement of the connecting threads 11 can also be adapted to the specific requirements.

One possible embodiment of the connecting threads 11 provides for them to consist of a monofilament thread. However, it is also conceivable and possible to form them from a yam.

The threads of the first layer 9 or second layer 10 may be formed of monofilament threads and/or yams, for example also in the form of plied yams.

The connecting threads 11 and/or the threads of the first layer and/or the threads of the second layer may for example consist of polyamide, polypropylene, PVC, polyethylene or combinations thereof, optionally also in conjunction with further materials.

The production of a knitted spacer fabric usually takes place in a single production step. For example a twill, tricot or plain weave can be used for the warp-knit first layer or for the warp-knit second layer.

The thickness of the knitted spacer fabric is defined by the distance of the two needle bars from each other. The thickness d of the knitted spacer fabric beneficially lies in the range from 1.5 mm to 40 mm, with a thickness in the range from 2 mm to 20 mm being preferred.

Upon connecting (= laminating) the connecting layer 6 to the reaction mixture of the sleeper sole 3, the second layer 10 which is directed towards the reaction mixture is pressed into the reaction mixture. Part of the connecting threads 11 and also the first layer 9 in this case at any rate still protmde out of the reaction mixture. The pressing into the reaction mixture is preferably done to a predetermined depth, with a layer of reaction mixture still being present beneath the pressed-in second layer 10. It is however also conceivable and possible to press the second layer 10 into the reaction mixture over the entire depth thereof. On the other hand, provision may also be made to press the second layer 10 merely on to the reaction mixture of the sleeper sole 3, whereupon a substance-to-substance bond occurs upon setting of the reaction mixture of the sleeper sole 3.

In one further possible embodiment, the second layer 10 may be glued to the sleeper sole 3 once the reaction mixture has set.

As has already been mentioned, the embedding of the first layer 9 in the concrete of the concrete body 2 beneficially takes place once the second layer 10 has already been connected to the sleeper sole 3.

The connecting threads 11 may run at different angles to the first and second layers 9, 10. In order to ensure good resistance to displacement of the first and second layers 9, 10 relative to each other and to prevent tilting of the structure under pressure, it is known for example in the case of knitted spacer fabrics to lay the connecting threads 11 in a cross-shape between the first and second layers, preferably with intersection angles of approximately 45°. Such a formation may for example be used.

Furthermore, also knitted spacer fabrics are known in which threads which are used to form the first and/or second layer 9, 10, are also used to form the connecting threads 11. Thus no separate pile threads are present. Such a formation of the knitted spacer fabric may also be used.

The thickness of the sleeper sole 3 preferably lies in the range from 4 mm to 20 mm.

Legend for the reference numerals: 1 railway sleeper 2 concrete body 3 sleeper sole 4 ballast 5 rail 6 connecting layer 7 transverse direction 8 direction of tearing-out 9 first layer 10 second layer 11 connecting thread 12 first plane 13 second plane

Claims

A web sleeper having a concrete element (2) with a sleeper base (3) arranged thereon, wherein for the purpose of a gravity-fixed connection of the sleeper base (3) to the concrete element (2) a connecting layer (6) is provided, which is partly connected to the swell bottom (3) and partly connected to the concrete element (2) and is thereby partially embedded in the concrete of the concrete element (2), characterized in that the connecting layer (6) is formed by a spacer material comprising a first and a second layer (9,10), which are kept at a distance from each other by means of connecting wires (11), and of which the first layer (9) is embedded in the concrete (2) of the concrete element.

A web sleeper according to claim 1, characterized in that the second layer (10) is embedded in the material of the sleeper bottom (3).

Web sleeper according to Claim 1, characterized in that the second layer (10) is connected in a material-like manner to the outer surface of the sleeper base (3).

Track sleeper according to one of Claims 1 to 3, characterized in that the thickness of the spacer fabric is in the range from 1.5 mm to 40 mm.

A web sleeper according to claim 4, characterized in that the thickness of the spacer fabric ranges from 2 mm to 20 mm.

Web sleeper according to one of Claims 1 to 5, characterized in that the connecting wires (11) are formed by pole wires which are present in addition to the wires from which the first and second layers (9, 10) are made.

Web sleeper according to one of Claims 1 to 6, characterized in that the connecting wires (11) are formed by monofilament wires.