CROSSINGS, ESPECIALLY HOME DRIVEWAY CROSSINGS

The invention relates to crossings, especially home driveway crossings.

At numerous settlements, both on the outskirts and within the confines of settlements, the rainwater drainage ditches along the roads are generally constructed as open ditches with a solid surface or without any surfacing at all, and these ditches need to be spanned by driveways providing a connection between the gates of the individual properties and the road. Presently, according to the general practice at such places, the ditches are filled with earth up to the height of the roadway, and the continuity of rainwater flow in the ditch is ensured by culverts made of reinforced concrete pipes with a diameter of at least 30 cm embedded in the filling.

The surfaces of driveways made of refilled soil facing the ditch are exposed to erosion, consequently they need to be protected. In the past - in some cases even today - only slopes were formed in order to stabilise driveways, but these slopes could be washed away by water, for example in the case of heavy downpours, they could be grown over by weed, and the culvert mouths opening to the slopes were susceptible to getting blocked.

Presently at points where the open ditch joins the culvert and where the culvert joins the open ditch again, which points occur very frequently within a settlement (at every 20.0 metres on average) generally culvert end-walls

are used, but up until recently these were constructed as individual structures out of monolithic concrete or bricks, and they were self-made. Their disadvantage is that these culvert end-walls constructed in a better or worse quality both from aesthetic and technical aspects spoil the overall picture of the village on the one part, and on the other hand - often due to unprofessional construction - they also represent a risk to safety to a certain extent. It also needs to be pointed out that although culverts may be laid down by unskilled workers, skilled workers are needed for building the monolithic concrete or brick end-walls that also require foundations, which obviously makes the construction of the structure more expensive. Already built driveways are difficult to extend, move or lengthen.

The solution described in Hungarian utility model no. 2439 is aimed at overcoming these disadvantages, as it relates to a special end-wall unit. It is based on the idea that it is constructed as a prefabricated reinforced concrete unit with a wall plate containing the opening and a base distributing the load transmitted from the end-wall unit on the subsoil, favourably extending along the complete length of the lower end-part of the wall plate, with its upper surface situated below the opening. Although with the help of this solution the problems occurring at the points where the open ditch joins the culvert and where the culvert joins the open ditch can be solved - at relatively high costs -, it remains a fact that the culvert significantly reduces the speed of the water flowing in the ditch along the road having a significantly larger open section and a usually

trapezoid cross-section due to significant contraction in the great majority of the cases, it significantly delays the drainage of rainwater falling onto the settlement, and in the case of extreme intensity of rainfalls and/or neglected ditches and partly blocked culverts there may be such a great extent of backwater at the driveways, that the water overflowing from the ditch may flood the road and the properties, which may result in traffic hold-ups or even serious damage caused by inland waters.

The task to be solved with the invention is to provide a driveway, first of all home driveway, which perfectly fills its load-bearing function making it possible for vehicles to pass on it, does not reduce the water passing ability of the culvert running below it and falling into the continuation of the drainage ditch generally running along a public road, preventing by this the risk of backwater caused by contraction deriving from built-in culverts interrupting the continuity of the ditches; on all sections of the surfaced ditch it must be made possible to build a new crossing or extend, remove or terminate the old crossings, with a minimum investment of work and costs.

The invention is based on the recognition that if the crossing is constructed as a combination of a prefabricated reinforced concrete ditch surfacing unit with a cross-section suiting the cross-section of the section size of the ditch joining it on two sides and a prefabricated reinforced concrete cover plate (plates) fitting the said ditch surfacing unit, which ditch surfacing unit and cover plate statically interact with each other and are able to adopt the stresses exerted

onto the crossing deriving from the load of vehicles, contraction and the risk of backwater can be eliminated, and at the same time a perfect engineering structure can be provided from the aspect of transport and transport safety.

On the basis of the above recognition the set task was solved with the help of a crossing, especially home driveway, which has a structure spanning the ditch, enabling vehicle transport and enabling the flowing of water in the ditch, and which crossing is characterised by that the structure is formed by one or more prefabricated reinforced concrete ditch surfacing unit or units open at the ends and at the top, and one or more prefabricated reinforced concrete cover plate or plates fitting onto it/them at the top, which ditch surfacing unit(s) and cover plate(s) are dimensioned and constructed to be suitable for adopting stresses deriving from the load of vehicles by statically interacting with each other. Practically the ditch surfacing unit has a cross-section widening from the bottom towards the top, favourably it has a section approaching the hydraulically most favourable parabola section, provided with reinforcing ribs extending outwards from its sidewalls transverse with respect to the longitudinal direction of the sidewalls, favourably perpendicular to this longitudinal direction. Favourably the ditch surfacing units contain end- ribs situated in the range around the ends of their sidewalls; and one or more intermediate ribs between said end-ribs.

According to an embodiment, at one end of the ditch surfacing element there is a groove, while on its other end

there is α tongue suiting the shape and size of the groove. Favourably the tongue protrudes to the same extent as the depth of the groove. Generally the shape of the ribs follows the curve of the sloping sidewalls, or when built in the ribs have a vertical side plate and a flat, horizontal base plate.

According to another feature of the invention, the shape of the tongue and the groove looking from the flow direction is the same as the shape of the sidewall viewed in a section perpendicular to this flow direction.

According to another favourable embodiment the cover plate along its longitudinal external edge looking in the flow direction contains a flush groove running out onto the edge at the bottom, fitting onto the upper longitudinal faceplate of the ditch surfacing unit.

Another embodiment of the invention is characterised by that the ditch surfacing unit has a lower trapezoidal section part bordered at the bottom by a horizontal bottom plate and on the two sides by the lower sloping wall-sections of the sidewalls extending outwards and upwards, from the upper ends of which vertical or nearly vertical wall-sections start, on the upper plate of which one or more cover plates are resting.

According to a further feature of the invention the sidewall of the ditch surfacing unit has a curved cross- section or a nearly curved polygonal cross-section. In this case favourably the sidewall should have a parabolic or oval cross-section, or a nearly parabolic or nearly oval polygonal cross-section.

Below the invention is described in detail on the basis of the attached drawings containing favourable embodiments of the crossing. In the drawings

Fig. 1 shows a home driveway according to the invention, in top view;

Fig. 2 shows a possible construction of the prefabricated reinforced concrete ditch surfacing unit used for constructing a driveway as in figure 1 and the prefabricated reinforced concrete cover plate fitting onto it, in perspective view;

Fig. 3 shows a further embodiment of the prefabricated reinforced concrete unit used for constructing a driveway according to the invention and the cover plates forming the driveway together with said unit, in perspective view.

Figure 1 shows a driveway 4 in a settlement in top view, which driveway 4 spans an open surfaced water drainage ditch 1 running along a public road in front of the gates of a property. The connecting road section from the public road is marked with reference number 2, while the connecting road section leading from the driveway 4 to the gates of the property - situated at least partly on the pedestrian pavement - is marked with reference number 3. Figure 1 also shows that the ditch 1 is constructed with ditch surfacing elements 5, which - as described in detail below -

are external ribbed prefabricated reinforced concrete units, and several - generally 2 or 3 - ditch surfacing units 5a form a part of the driveway 4 itself, which also includes the prefabricated reinforced concrete cover plates 6 and 7 fitting onto the ditch surfacing units 5a from the top and falling in the continuation of the units 5 used for surfacing the open section of the ditch 1 ; generally 4-6 cover plates are used for a driveway.

Figure 2 shows a ditch surfacing unit 5a on a larger scale, which - apart from its ditch surfacing function - forms a part of the driveway 4 together with the cover plates 6, 7, and it is different from the ditch surfacing units 5 built in the open sections of the ditch 1 in that it is dimensioned to be able to adopt stresses deriving from the load of vehicles by statically interacting with the cover plates 6, 7 fitting onto it and having an appropriate load-bearing capacity, forming one single crossing engineering structure with them, like a box girder. As it can be seen in figure 2, the prefabricated reinforced concrete ditch surfacing unit 5a - a trough unit open at the top, at the front and at the back - has a regular trapezoidal section in the lower half of the unit, and above the two sides of the said trapezoidal section going upwards and outwards there is a section part with a horizontal rectangular cross-section; the main dimensions of the ditch surfacing unit 5a can be determined taking into consideration the current width and depth of the ditch; for example the length h should be practically about 2.0 m, the width s should be between 30 and 100 cm, the bottom width Sj should be between 20-60 cm, and the height m of the

section should be between 30-80 cm. Within these ranges of dimensions the weight of the units is between 350-1 ,300 kg. In accordance with the above each one of the two sidewalls 8 of the ditch surfacing unit 5a has a nearly vertical upper wall-part 8a slightly slanting outwards and a slanting lower wall-part 8b starting from the lower end of the upper wall- part 8a, and the lower ends of the lower wall-parts 8b are connected by a horizontal bottom plate 9 with an si width. (As described below, instead of the above ditch surfacing unit section it is also possible to choose a curved, favourably nearly parabolic section shape.) The width of the cover plates 6, 7 suits the width of the currently used ditch surfacing unit, their thickness - depending on the span and the vehicle load - may be between 8-14 cm, their length, i.e. their size in the longitudinal direction of the ditch, may be for example 50-100 cm.

The sidewalls 8 of the ditch surfacing unit 5a have end- ribs 10, 1 1 extending outwards at both ends and between the end-ribs 10, 1 1 they also have two intermediate ribs 12, 13 also extending outwards; practically the e distances between said ribs - edge-ribs - should be the same, beside the above dimensions this distance may be for example about 60 cm. The end-ribs 10, 1 1 and the intermediate ribs 12, 13 follow the broken-line or curved - favourably parabolic - section of the unit, and the size of their cross- section is the same along their whole length. The ditch surfacing unit 5a rests on the base (not shown here) constructed for the driveway 4 with its bottom plate 9 and with the sole of the ribs extending to this side, and the base

should be constructed in α way known in itself, depending on the current soil features and the expectable loading (e.g.: gravel layer, lean concrete base, maybe a reinforced plate, etc.). The thickness of the sidewalls 8 depends on the currently calculated loading, generally it should be 6-15 cm, and the thickness of the bottom plate 9 may vary between 7-20 cm.

As it has been pointed out above, the ditch surfacing units 5a must have a load bearing capacity to be able to adopt the stresses deriving from the load of vehicles safely with the mediation of the prefabricated reinforced concrete cover plates 6, 7 fitting onto them. The reinforcement of the ditch surfacing units 5a must be planned and the units must be dimensioned in accordance with this, in a way already known in itself. In this respect it needs to be pointed out that it may be sufficient to provide the strengthening ribs transverse with respect to the longitudinal direction of the trough unit with appropriate reinforcement, as they themselves can ensure the required stability of the sidewalls 8 built together with them, but obviously the sidewalls themselves may also contain reinforcement, and it may be favourable to add reinforcement to the bottom plate 9 too. It may be sufficient to reinforce only the ribs of the ditch surfacing units 5 used on the open section of the ditch 1 , or - depending on the dimensions - even this may not be absolutely necessary in every case.

At one end of the ditch surfacing unit 5a there is a groove 14, while at the other end there is a tongue 15; their shape and size suit each other, and the ditch surfacing units

5 contain the same type of grooves and tongues joining the ditch surfacing unit 5a of the driveway 4 (figure 1 ) 5a on two sides, as they are built into the continuous open ditch 1. In this way the tongue 15 can fit into the groove 14 of the neighbouring ditch surfacing unit 5a, while the tongue 15 of a ditch surfacing unit 5 may be fitted into the groove of the ditch surfacing unit 5a. In the case of the example as in figure 2, the tongue 15 is formed by the parts of the sidewalls 8 extending over the end-ribs 10, along their whole length, while the groove 14 has a notch suiting the size of the extension in the end-parts of the sidewalls 8 containing the end-rib 1 1 , also along their whole length.

The cover plates 6, 7 - as also shown in figure 2 - have an s _. 2 width exceeding the upper s width of the ditch surfacing unit 5a measured inside by the total wall width of the sidewalls 8, and their hi length is practically half of the h length of the ditch surfacing unit 5a, that is hi ~ h, that is for example about 1 .0 m, and along their external edges running along the longitudinal direction of the ditch 1 at the bottom there is a groove 16 or notch. Due to these grooves 16 the cover plates 6, 7 - practically set at a depth of about 10-30 mm - rest on the upper end surface of the sidewalls 8 in a fixed position, and they fit each other closely along the line 17. The tilt-free resting of the cover plates 6, 7 may be ensured by mortar spread onto the unit edges, or by other suitable, for example plastic-based tapes or other artificial materials. As it has been pointed out above, the cover plates 6, 7 are also prefabricated reinforced concrete units, and in the course of determining their dimensions the

requirement must be taken into consideration that on the one part they must be able to bear the load of vehicles, and on the other part they must interact statically with the ditch surfacing unit 5a, as together they form the crossing engineering structure according to the model, in this case the driveway 4 according to figure 1 ; on the third part - if necessary - it must be made possible to guide surface waters into the ditch from the top, through openings constructed to suit this purpose.

Figure 3 shows a prefabricated reinforced concrete ditch surfacing unit 17 for constructing a crossing according to the model, which unit is basically different from the ditch surfacing unit 5a as in figure 2 in respect of its section shape on the one part, and the construction of the lateral external ribs on the other part. In this case the wall 18 of the unit has a parabolic shape, so the ditch surfacing unit 17 has no wide base plate to rest upon the base, but the end-ribs 19, 20 and the intermediate rib 21 extend over the upper edge of the unit outwards in accordance with their initial b thickness of about 6-8 cm, but here they do not follow the section shape of the unit, but they have a vertical side plate 25 and a horizontal base plate 24, and the two latter plates together can provide an appropriate resting surface on the base for the ditch surfacing unit 17, as if providing flat foundation; the base plates 24 are situated at a c distance, e.g.: 6-8 cm below the lowest point of the wall 18. In this case too at one end of the ditch surfacing unit 17 there is a tongue 23, while on the other end there is a groove 22 dimensioned and shaped to be suitable for accommodating the tongue 23;

the tongue and the groove extend from or are built into the parabolic wall 18, they run along the whole length of the wall, and the a depth of about 6-8 cm of the groove 23 is the same as the size of the extension of the tongue 23. Therefore, when the ditch surfacing unit 17 used for constructing a driveway 4 (Fig. 1 ) needs to be connected to another ditch surfacing unit (not shown here) of the same construction but having an obviously lower load bearing capacity, it can be solved easily by fitting the grooves and tongues of the neighbouring ditch surfacing units into each other. Obviously in this case too the ditch surfacing unit 17 built into the crossing must be covered with prefabricated reinforced concrete cover plates 6, 7, similarly to the solution shown in figure 2, and the unit dimensions (length, height, width, wall and rib thicknesses) should also be determined in accordance with the dimensions shown in figure 2. The cover plates 6 and 7 may be the same as shown in figure 3, and they fit onto the upper edges of the ditch surfacing units 17 with grooves 16, in the same way as they fit onto the ditch surfacing units 5a shown in figure 2.

The ditch surfacing units 5a, 17 may join the open ditch units connected to them with tongue and groove joints as above in a way known in itself, with gaps the width of which is accepted in the profession, and which gaps are filled up with watertight cement mortar or with mortar modified with plastic, if water-tightness is required.

As it has been mentioned above, the ditch surfacing units 5a, 17 and the cover plates 6, 7 fitting onto them interact with each other statically, together they form a

loαd-beαring structure, the destruction test of both part-units must be performed so that the cover plate rests on the ditch surfacing unit and the compression piece is placed in the centre of the cover plate, that is both the lower trough unit and the cover plate must be tested in a state when they are built together with each other.

The invention has the following advantages: In the water drainage ditch the continuous flow of the rainwater can be ensured without any contraction or backwater, independently from the density of the home driveways. In the case of covered ditches the driveways can be constructed by placing in the same ditch surfacing units as the ones built in open ditch sections; the ditch surfacing unit used for driveways needs to be different from "standard" ditch units only from the aspect of load bearing. As compared to traditional driveways with culverts it makes construction work significantly easier and quicker; even after such crossings have been constructed it is easy to move or extend them or to build new crossings, so obviously all this work can be performed more economically than in the case of traditional structures.

Obviously the invention is not restricted to the constructions described in detail above on the basis of the drawings, but it can be realised in several different ways within the scope of protection determined in the claims. For example the crossing according to the model can be built in ditches without surfacing, especially if their section is at least approximately similar to the section of the ditch surfacing unit used for the crossing structure. Differences from the

features shown are allowed for example in the number of edge ribs, in the construction of the tongue/groove connection and in other features too, without going beyond the scope of protection.