NL2004642C2 - METHOD FOR INSTALLING A DIRECTLY SAND BODY-BASED CONSIDER. - Google Patents

Description

Method for constructing a level crossing based directly on a sand body.

This invention relates to a method for constructing a level crossing / railroad crossing directly based on a sand body.

Known is a level crossing / railway crossing that is directly based on a sand body and is built up in the work of two or more prefabricated, reinforced concrete slabs (each max. 6 or 9 meters long) with two grooves for receiving the rails. The concrete slabs are each lifted and positioned separately with a crane in place directly on the sand body in the railroad, after which the rails are placed in the grooves and fixed therein and embedded in cast material. To set, each concrete slab is equipped with four leveling feet, one at each corner, that come to rest directly on the sand body. Each adjusting foot comprises a membrane-like body protruding from the bottom side of the concrete slab which during filling is filled with grout or concrete and after hardening supports the concrete slab in a stable manner.

With a view to shortening the decommissioning time of the track, NL1030958 (Voestalpine Railpro bv) proposes to manufacture a level crossing of a prefabricated concrete slab cast with the above-mentioned leveling feet and to remove this concrete slab prior to installation. rest with the stated and embedded rails. This has turned out to be an unrealistic development.

US 6,016,968 A discloses the foundation of concrete slabs on sleepers, thus a different foundation technique than directly foundation on a sand body. Incidentally, it is known per se from this document to manufacture a concrete slab with molded-in grooves for the rails by pouring concrete into a longitudinal section into separate molded parts separated from one another by temporary upright partition walls and after curing concrete remove the upright partition walls of the concrete and press the obtained individual slab parts together, still in the mold, by tensioning tension cables running through the slab parts, common to all slab parts, after which the assembled concrete slab is taken out of the mold . DE 1.930.541A does not discuss the foundation technology. US 4,911,360A discloses the foundation of concrete slabs on a sand body by bottom grouting (column 3, lines 54-60). DE 29.48.526A discloses the foundation of only the ends of the concrete slabs directly on embankment bodies.

NL 276.179A discloses a level crossing that is built up in the work from two or more separate concrete slabs with grooves for receiving rails. After the concrete slabs have been placed in line with each other on a sand body 10, the rails are placed in the aligned grooves.

Vertical drillings in the concrete slab serve to inject sand under the concrete slab. After laying the concrete slab, these vertical bores are filled to prevent watering in. We speak of a large support surface and therefore a low soil load. It is also referred to as a reinforced substrate and that through the vertical drilling presses of sand under the concrete slab can be lifted by means of compressed air. Further details are not provided to make it clear to the person skilled in the art how the concrete slabs are founded.

It is known from practice that a level crossing directly based on a sand body is always installed with the application of the three steps of applying a temporary foundation for the level crossing, the setting of the level crossing and the bottom of the level crossing. These are time-consuming activities.

The object of the invention is, when installing a level crossing directly on a sand body, to avoid one or more of the three steps of applying a temporary foundation for the level crossing, the setting of the level crossing and the lowering of the level crossing and thereby shortening the decommissioning time of the track as much as possible.

It is therefore proposed a method according to the appended claim 1, which is delimited from the known from NL1030958 as the closest prior art.

The invention is based on the unexpected insight that the modular structure of the single concrete slab, by assembling it from two or more prefabricated concrete slab parts, offers the unique possibility of completing the usual three steps during the direct installation on the foundation. forming sand body, namely the use of a temporary foundation for the level crossing, the setting of the level crossing and the lowering of the level crossing, all three can be avoided by laying the concrete slab at its final destination in the railway on a flattened sand bed forming the foundation. Leveling feet on the concrete slab can therefore be omitted. The time-consuming use of a temporary foundation for the level crossing, the setting of the level crossing and the bottom of the level crossing can be avoided, thereby saving time.

The invention offers additional advantages in that, due to the modular construction of the single concrete slab, by assembling it from two or more prefabricated concrete slab parts, with a limited number of casting molds for the concrete slab parts, crossings of different lengths can be prefabricated in the factory, e.g. 12, 15, 18, 21 and 25 meters in length. This is favorable for the cost price and, moreover, concrete slab parts in a limited size, so cheaply, can be kept in stock, which is favorable for the delivery time.

It is known per se from the old FR.2.284.708, published in 1976, single concrete slabs equipped with rail slots for a railroad track in a motorway, one by one in a contiguous row with their bottom to be laid on a flat sand layer. The rails are then placed in the rail slots and fixed with rubber elements. A convex strip is placed in the middle of the mold to make uneven support of the concrete slabs impossible. The field to which this document focuses is away from the field of contemplation. And this document focuses on the rubber elements of the rails in the rail slots for rapid construction of the rail and rapid replacement of the rails. It is therefore unlikely that the person skilled in the art will consult this old document when looking for a solution for the purpose set. And even when it is considered likely that the person skilled in the art will consult this document 4, the combination of the insight from this document with the starting point, NL1030958, does not lead to the subject of claim 1. Therefore, the subject of claim 1 is indeed novelty and inventiveness.

By ensuring that the underside of the concrete slab, such as leveling feet, remains free from the flatness of the concrete slab, full flatness of the underside is well guaranteed, whereby foundation on a flattened sand bed is further simplified.

By producing upside down in a mold, according to the preferred embodiment of claim 3, the concrete slab parts automatically obtain the desired flat underside.

Through the measures of claim 4, an advantageous single concrete slab can be obtained with which the object of the invention is advantageously achieved.

A further explanation of the invention now follows:

The railway crossing is prefabricated in the factory from prefabricated concrete slab, during which one or more of the following steps are followed: in a factory two or more concrete slabs with the same or different length and with the same width and thickness are made separately in a mold by placing a reinforcement in each mold and pouring concrete in such a way that each time a concrete slab with one or more of the following properties is formed: a reinforcement embedded in the concrete of the concrete slab of prestressed reinforcement elements, such as steel, running parallel to the rails. rods or wires, if necessary. in bundles; in the top of the concrete slab in operation of the railway crossing, two parallel grooves for containing the two rails; a point of contact for a hoisting device near each corner point; two, three, four or more longitudinally and near the bottom of the concrete slab during operation of the railway crossing, preferably mutually at the same level and with mutual spacing, hollow channels running and embedded in the concrete thereof and terminating on both ends ; on one or both end faces at a location at a distance from the top surface and the bottom surface, preferably at a distance above the hollow channels, a surface profiling, preferably in such a position and / or size, that of two in use condition with the end faces concrete slabs placed against each other the surface profiling coincides with each other, for example the surface profiling formed by one or more recesses and / or protrusions spaced above and / or next to each other, such as two or more interposed spaced-apart sections, spread in the width direction of the concrete slab protrusions of concrete protruding in the direction of the length of the 10 rails over a distance of at least 2 or 5 or 10 centimeters and on the other end face at a location corresponding to the protrusions, possibly in the width direction of the concrete slab, with subdivided recess corresponding to the subdivision of the protrusions having a shape that comple is mentary to that of the protrusions and with a depth such that with two concrete slabs placed in line with each other where the protrusions of one concrete slab are inserted to a maximum depth in the recess of the other concrete slab, a joint between the concrete slabs with a width at 20 preferably between about 10 or 20 millimeters and 30 or 50 millimeters, which protrusions are preferably made of concrete and integrated into the plate; wherein furthermore during the method one or more of the following actions are performed: in the mold at the ends of the concrete slab steel profiles 25 are placed in width direction which protrude approximately halfway the thickness of the concrete slab with their ends sideways from the concrete slab around the engagement points to shape; after which at least two different concrete qualities are successively poured in layers above each other in the mold to obtain a highly wear-resistant top layer; after curing, the concrete slabs are removed from the molds and inverted and placed in line with each other, with the possible protrusions on the end face of one concrete slab in the recess on the end face of the other concrete slab but not to the maximum insertion depth, so that a joint remains between the concrete slabs which is preferably at least 5 millimeters and for example at most 15 millimeters wider (overdimensioning) than the width of that joint in the finished product, so that the assembly of these concrete slabs has a length equal to the length of the finished product, apart from the excess length determined by the overdimensioning of the joint or joints, while ensuring that the grooves for the rails on the one hand and the hollow channels on the other are aligned with each other and that the channels / sleeves preferably make flexible clamping elements strung that protrude beyond the ends of the concrete slab assembly and which are inserted into the head case without tension; shrink-free pouring mortar 10 is poured from above into the joints between the concrete slabs so that the joints, including any surface profiles, are completely filled with pouring mortar; while the pouring mortar is still sufficiently fluid, the tensioning elements are activated to keep the concrete slabs pressed against each other permanently, squeezing pouring mortar out of the joints, whereby any protrusions located at the end face are pressed deeper into the recesses, so that the joint width decreases with substantially the over-dimensioning while the tensioning elements are brought to their final tension; the pouring mortar is allowed to cure; At the top of the concrete slab in operation of the railway crossing, the cured pouring mortar in the joint is covered with a permanently flexible, initially form-free, hardening material, such as cork rubber, adhering to the concrete and the pouring mortar, for permanently waterproofing the joints ; a one-piece rail is laid in each groove 25 so that it protrudes at both ends of the assembly of concrete slabs preferably sufficiently far, for example over a minimum of 1 or 2 m, e.g. approx. 4 m, to facilitate connecting to the further rail , which rails are set and embedded; the prefabricated assembly of concrete slabs placed in line with each other with pre-tensioning elements placed thereon and rails placed, placed and embedded in both grooves is hoisted on a truck and transported to its destination in the track and hoisted in the track.

Furthermore, one or more of the following is preferably used: the hollow channels open at one end side to a level above the underside of the plate that is at least 1, 7, 2 or 3 centimeters higher than the level at which the hollow channels debouch on the other end face, wherein preferably the end face with the higher level of the hollow channels is intended to be turned away from the other concrete slab in the assembly; The hollow channels follow a path through the concrete slab that is horizontal, is continuously rising or consists of alternating horizontal and continuously rising parts; the hollow channels are filled over their entire length with shrink-free pouring mortar, so that the tensioning elements in the hollow channels are embedded along their entire length in shrink-free pouring mortar; the surface profiling on the front side consists exclusively of depressions made in the flat surface; the surface profiling comprises one or more grooves parallel to each other; the rails placed in the grooves do not protrude, or hardly so, above the top of the plate, the top of the plate possibly being formed by a top layer which is subsequently applied to the top of the plate to form the road surface for cars and the like .

Preferably one or more of the following aspects are applied: provisions are made for making leveling feet under the concrete slabs, for example one at each corner point of a concrete slab; sufficient attention during making in the mold to ensure the required minimum galvanic resistance between the rails; in the track, the product 25 is placed on a temporary foundation in order to, based on that foundation, fill the support feet with grout via pipes integrated in the concrete slabs; the rails are connected to the rails on either side of the level crossing; use of a concrete slab resp. mold of a first length, for example 6 meters 30 and a concrete slab of a second length resp. mold, for example 9 meters; exclusively use of one or more concrete slabs resp. mold of a first length and one or more concrete slabs resp. mold of a second length; use of at most two or three concrete slabs for making a prefabricated assembly. It has been found that it is advantageous for the tensioning cables to be brought to the permanent final tension before the filling of the joint hardens or the filling is only at the early stage of hardening and has not yet been tied off. It has also been found that it is advantageous if the joint is first completely filled with casting compound and then, before the casting compound hardens or settles, the joint is permanently squeezed, for example over a minimum of 5 mm and optionally a maximum of 15 mm so that part of the filling is made of the joint is pressed. It has been found that only tension cables at the bottom of the product will suffice. Bottom bolting is not necessary, which saves a considerable amount of time during installation.

By applying the prestressing wires running through the tubes, the level crossing can be lifted as a whole at a limited number of points of application and there is no risk that the level crossing will become hollow or convex after installation.

A non-limiting example is as follows: Two concrete slabs 15 with a length of 6 resp. 9 meters are manufactured in a factory in a shed by a 6 resp. 9 meters long mold reinforcement and pouring concrete. During the curing process, e.g. vibrators sufficiently compacted the concrete. The substantially flat bottom of the mold is equipped with profiles that save the grooves 20 for the rails in the concrete surface. In the mold, concrete of at least two qualities is deposited on top of each other in layers; first concrete is poured which provides a very durable surface. Also, before or during the making of the concrete slab, provisions are placed in the mold for integrating the support feet and the connected grout pipes into the concrete slab. Steel profiles, for example pieces of rail, with a length greater than the width of the concrete slab are also placed in the mold at the ends of the concrete slab. These profiles will protrude approximately halfway through the thickness of the concrete slab with their ends to the side from the concrete slab and form lifting points. And hollow tubes are placed in the longitudinal direction of the mold at a small distance, for example 25 centimeters, below the filling height of the mold.

It is ensured that two integral, identical protrusions are formed on an end face of the concrete slabs 35, which, viewed from the side of the concrete slab, are frusto-conical, with the truncated top of the concrete slab facing away and viewed one behind the other in the same view. Viewed from the top view of the concrete slab, each protrusion extends over about 1/3 of the width of the concrete slab, keeping a distance to the side edge of the concrete slab and keeping a wider distance with the other protrusion. On the other end face, each concrete slab has a recess into which the protrusion fits tightly, while maintaining a joint between the facing ends of the concrete slabs. With protrusions of the other concrete slabs inserted into the recess of one concrete slab to a maximum depth, the concrete slabs only support via the protuberance or protrusion. the recess against each other and the joint width is 20 millimeters.

After sufficient hardening, the concrete slab is removed from the mold and vice versa, so that the side facing downwards in the mold with the two grooves is facing upwards.

The two concrete slabs are placed end to end so that the grooves at the top and the hollow pipes at the bottom are in line with each other. Clamping cables are inserted into the hollow tubes, the ends of which extend beyond the concrete slabs. On those ends 20 there is thread on which one tightens tensioning screws, without tensioning the tensioning cables. A formwork is applied along the bottom and both sides of the joint between the concrete slabs, after which the joint is filled from above with mortar that is as fluid as water. Immediately afterwards the tensioning screws are tightened, whereby they press directly or indirectly against the end faces of the concrete slabs while tensioning the tensioning cables. As a result, the concrete slabs are pressed towards each other, as a result of which the joint width decreases, mortar is pressed out of the joint and the concrete slabs eventually come to rest against each other via the protrusions projecting into the recesses. As soon as the desired tension has been built up in the tensioning cables, the tensioning nuts are secured, after which the mortar is allowed to cure in the joint. After the mortar has hardened, the joint on the top of the product is scratched open to a certain depth, after which the released space is filled with an adhesive, hardening, flexible paste or sealant so that the joint is watertight from above.

The rails are then placed in the grooves, whereafter the remaining space in the groove is filled with an initially form-free embedding and bonding material. The rails are eight meters longer than the two concrete slabs together and protrude about the same end beyond the respective end of the two concrete slabs together on either side. After the embedding material has hardened sufficiently, the product is placed on a truck and transported to the destination.

At the place of destination, the product is attached at its four corners and elsewhere along its length by the laterally protruding pieces of rail to the lifting hook of a crane and hoisted at its final destination. From this stage during the installation, the following two alternative ways can be continued: FIRST WAY, not belonging to the invention stated in the claims 15: The product is supported on a temporary foundation, after which the support feet are filled with grout. After the grout has hardened sufficiently, the temporary foundation is removed and the specified concrete product rests on its support feet.

SECOND WAY, though belonging to the invention indicated in the claims: the level crossing is placed directly from the transport vehicle on a flattened sand bed at its final destination, wherein use of a temporary foundation, adjustment of the product and filling of the support feet 25 (which level crossing) will be canceled.

The accompanying drawing shows in Fig. 1 a perspective view of a part of a concrete slab according to an embodiment of the invention and Fig. 2 shows in a side view in section along the line II-II in Fig. 1 a part of two in Concrete slabs of Fig. 1 placed in line with each other for making a level crossing according to the invention.

Shown are the concrete slabs 1, the grooves 2 for the rails 3, the lifting points 4, the surface profiling 5 in the ends, the hollow sleeves 6 and the joint 7.

In Fig. 1 the rails 3 are missing and in both figures the tension wires are missing in the sleeves 6. The sleeves 6 open below the profiling 5 and are located next to each other and run from 11 the joint 7 obliquely upwards to the other end face ( this applies to both the plate 1 on one side and the other side of the joint 7). The profiling 5 consists of three grooves running horizontally one above the other. The rails 3 protrude outside the concrete plates 5 (Fig. 2).

Other embodiments also belong to the invention. For example, where the protrusions and optionally also the matching recesses on the end face of each plate are missing, or wherein each end face of each plate contains both recesses and matching protrusions, or each end face of each plate contains only recesses. The concrete slabs could further be provided on their end faces on two or more levels with protrusions and / or matching recesses. It is to be understood that protrusions 15 on the end face of one plate are intended to fit into recesses on the end face of an adjacent plate.

The product can have, apart from the rails, a length that is created by assembling one, two or more pieces of 6 or 9 meters, so that a length of 6 meters is created 20 plus 3 meters or a multiple of 3 meters, for example 18 or 27 meters.

Claims (14)

A method for constructing a level, foundation-based, sand-based, straight-through, ie without the intervention of a foundation body, such as a (transverse) beam, the level crossing comprising a prefabricated assembly consisting of a coherent, dimensionally stable and load-bearing, single concrete slab with a length equal to the level crossing and of a minimum of ten meters, and rails placed, set and embedded in rail grooves in the single concrete slab 10 with a length longer than that of the single concrete slab, so that the rails protrude beyond the concrete slab for a length on both sides of at least 1 meter, which level crossing is transported in its entirety from a factory on a transport vehicle to its final destination 15 and then is lifted in its entirety from the transport vehicle and is laid in the railroad on a foundation after which the protruding rails are connected to the rail on either side of the level crossing to be part and of the track, so that the weld connecting the rails is at a distance of at least 1 meter from the concrete slab of the level crossing, characterized in that in the factory: - individual concrete slab parts are produced with completely flat underside, with rail grooves for the rails and with a width and thickness equal to the single concrete slab; 25. two or more of these prefabricated concrete slab parts each with a length of at least five meters are laid one behind the other while aligning the rail grooves and are joined together to form said single concrete slab so that a coherent, dimensionally stable and load-bearing assembly with a completely flat underside is created; then, after placing, adjusting and embedding the rails in the factory and transporting them to the final destination on a transport vehicle; - the level crossing as a whole is placed directly from the transport vehicle 35 on a flattened sand bed forming the foundation at its final destination in the railway, excluding the use of a temporary foundation for the level crossing at the final destination, setting the level crossing and lowering the level crossing. Method according to claim 1, wherein during the method 5 it is ensured that the underside of the single concrete slab remains free of any protrusion affecting the flatness, such as an adjusting foot. 3. Method according to claim 1 or 2, wherein the concrete slab parts are produced upside down in the casting mold. 4. Method as claimed in claim 1, 2 or 3, wherein the concrete slab parts are made with internal, hollow channels (6) running through at the same level near the underside, which run along the entire length thereof in the single concrete slab and in which at the assembling the single concrete slab until tensioning elements running at both ends of the single concrete slab are placed which are then brought to the desired final bias by pulling at their ends and then fixing, so that the concrete slab parts are pressed together with their end faces pressed together, while the Joints (7) between the concrete slab parts are filled with an initially form-free adhesive material. 5. Method as claimed in any of the claims 1-4, wherein the concrete slab parts are coupled to each other so that a concrete slab is created with a strength and rigidity equal to a monolithic concrete slab of the same size. Method according to claim 5, wherein the concrete slab parts are coupled to each other with separate coupling means. 7. Method according to claim 6, wherein the coupling means comprise separate rod-shaped members, each of which protrudes into its own opening (6) in a concrete slab part (1) A method according to any of claims 1-7, wherein each concrete slab part is produced by placing reinforcement for each one and pouring concrete for each. 9. Method as claimed in any of the claims 1-8, wherein at least two parallel hollow tubes (6) are placed in the casting mold and concrete is subsequently poured, so that each concrete slab part has the following properties by hardening in the mold: near the bottom used in use the hollow tubes (6) run side by side on a mutually equal level in the longitudinal direction of the level crossing and 10 in the top in use run two parallel grooves (2) for receiving the rails (3) sunk therein, the two or more cured concrete slab parts (1) are arranged in line with each other in such a way that the rail grooves (2) and sleeves (6) are mutually aligned while maintaining a joint (7) between two adjoining concrete slab parts and in each tube (6) one or more tensioning elements are provided so that each tensioning element extends through all concrete slab parts over substantially the entire length of the level crossing. 20 10. Method as claimed in claim 9, wherein the tensioning elements are brought to the desired final bias by pulling at their ends and then fixing, and the thus prefabricated level crossing with the tensioning elements brought to final bias and set, set and embedded rails in both grooves. the factory is transported to its final destination 11. Method as claimed in claim 9 or 10, wherein during compilation of the level crossing from the uncovered concrete slab parts, the tubes (6) are filled over the entire length with initially form-free filling material so that the clamping elements in the tubes are embedded over their entire length in hardened filling material. A method according to any one of claims 1-11, wherein the one or more joints (7) are filled with an initially form-free filler. A method according to claim 12, wherein after curing of the filler, the concrete slab parts are permanently fixed to each other. 5 A method according to any one of claims 1-13, wherein it is ensured that the concrete slab parts during molding in the mold on one or both end faces at a location at a distance from the top surface and the bottom surface, preferably at a distance above the hollow channels, 10 have a surface profiling (5), preferably consisting exclusively of depressions made in the flat surface, such as one or more grooves parallel to each other, which profiling (5) is of placement and size such that of two in use condition with the end face concrete slab parts placed against each other on one side the surface profiling coincides with each other, and which surface profiling forms part of the joint (7) when assembling the level crossing from the concrete casing parts and when filling the joint with filler, it is also completely filled with filler.