Patent Description:
Culverts are known civil engineering structures. A culvert usually has a tubular construction and lies beneath a road or in a waterway crossing. The culvert is often configured to mutually connect bodies of water and is made of concrete.

An example of a known concrete culvert is shown in <FIG>. Concrete culvert <NUM> comprises a plurality of mutually coupled middle segments <NUM>, these together forming a tubular structure which is closed on either side by an end element <NUM>. End element <NUM> comprises here obliques side walls <NUM> and a lower wall <NUM>. The height of side walls <NUM> decreases in a direction toward the end of culvert <NUM>.

Culvert <NUM> is placed on a ground surface <NUM>. Soil will here be deposited onto culvert <NUM>. It is however also possible for culvert <NUM> to be placed directly in a dam or similar structure.

For a culvert, end element <NUM> is also referred to as culvert embankment. The length of such an element, measured in the longitudinal direction of the culvert, generally varies between <NUM> and <NUM>. The width and height of the element generally vary between <NUM> and <NUM>.

It is particularly the length of the element that poses limitations for the manner in which such an element can be manufactured. More particularly, it is very difficult in practice to manufacture end element <NUM> integrally in a single pouring run. This is because, if end element <NUM> is formed in the position shown in <FIG>, it becomes very difficult or even impossible to remove the element from the mould after curing of the concrete. If the element is manufactured in upright position, i.e. with the opening oriented vertically, the length of the element, which can be up to <NUM>, poses a problem. A hoisting device is needed to displace the element. At a length of <NUM>, this would mean that the height of the hall in which the element is made would have to be considerable.

A known method for realizing end element <NUM> will be elucidated hereinbelow with reference to <FIG> and <FIG>. It is noted here that end element <NUM> in <FIG> and <FIG> is not identical to the element shown in <FIG>. The same manufacturing method can however be followed for both elements.

<FIG> shows that side walls <NUM> are made separately in a mould <NUM>, wherein side walls <NUM> are formed flat on the bottom of mould <NUM>. Side walls <NUM> are provided with lift anchors <NUM> so that side walls <NUM> can be removed from mould <NUM> after pouring and curing of the concrete. Also visible is reinforcement <NUM>, which is placed before concrete is poured into mould <NUM> and which protrudes from the concrete. After sufficient curing of the concrete, side walls <NUM> are placed upright. This is shown in both <FIG> and <FIG>.

As shown in <FIG>, end element <NUM> comprises a part <NUM> which is provided with a central opening <NUM> which, when placed in culvert <NUM>, will connect to the central openings of middle segments <NUM>. <FIG> shows that part <NUM> is likewise provided with reinforcement <NUM> extending toward side walls <NUM>. Reinforcement <NUM> in side walls <NUM> protrudes here toward further part <NUM>.

Part <NUM> is manufactured in a separate mould, likewise flat on the bottom of the mould. The mould comprises here an inner mould and an outer mould. The walls of the inner mould and/or outer mould are hydraulically adjustable so that the part can be easily removed from the mould after curing of the concrete.

As shown in <FIG>, two different side walls <NUM> are manufactured. These differ in respect of the direction along which reinforcement <NUM> protrudes on the underside. <FIG> shows that the different side walls <NUM> are placed so that reinforcement <NUM> of the one side wall <NUM> extends to the other side wall <NUM>.

As subsequent step in the manufacture of end element <NUM> formwork is placed around side walls <NUM> and further part <NUM>. The lower wall of end element <NUM> will subsequently be poured as indicated by arrow A in <FIG>. After sufficient curing, the connection between side walls <NUM> and part <NUM> will subsequently further be made by additional pouring at the position of reinforcement <NUM>, as indicated by arrow B in <FIG>. It is noted here that side wall <NUM> comprises a part 4A which prevents the liquid concrete from finding its way into an inner space of end part <NUM> during the second pouring run.

The above shows that the manufacture of an end element for a known culvert is a relatively labour-intensive process which can generally take up to <NUM> days. Different moulds and/or mould parts must further be used for the different components of the end element to be formed.

<CIT> discloses a precast safety end for use with culverts on highway, driveway, and road drainage crossings.

An object of the present invention is to provide an end element wherein the above stated problem does not occur, or hardly so.

According to an aspect, the present invention provides a mould assembly for forming an end element of a concrete tubular structure such as a culvert or sewage pipe as defined in claim <NUM>. This mould assembly comprises a first mould and a second mould for forming respectively the first part and the second part of the end element. The first mould and the second mould each comprise an outer mould, an inner mould placed in the outer mould and a mould part placed in a space between the inner mould and an inner wall of the outer mould. The mould part comprises mould walls which extend obliquely relative to a bottom of the outer mould and which extend between the inner wall of the outer mould and an outer wall of the inner mould for the purpose of forming the side walls of the first part or the side walls of the second part.

The outer mould of the first mould usually has a receptacle-like construction with a bottom and side walls. The side walls are here usually adjustable for the purpose of removing the poured first part after curing of the concrete. The outer mould of the second mould can be formed partially by the outer mould of the first mould. In the manufacture of a concrete tubular structure use is likewise made of an outer mould and an inner mould for the manufacture of the middle segments. It is the case here that the outer mould of the first mould and the outer mould of the second mould can be formed at least partially by such an outer mould. It is the case for all moulds that the inner mould is preferably placed on a bottom of the outer mould.

The mould part comprises an elevated part which is placed on the bottom of the outer mould, and wherein the obliquely extending mould walls extend from the elevated part.

The mould part of the first mould can comprise a transverse part which extends substantially perpendicularly relative to the obliquely extending mould walls, wherein the mould walls extend between the elevated part or the bottom of the outer mould and the transverse part.

The mould part can also comprise chamfering parts which lie against the transverse part and/or the obliquely extending mould walls for the purpose of forming the chamfering or rounding of the first part or second part of an end element as described above.

The mould assembly can comprise a reinforcement placed in a space between the outer mould and the inner mould of the first mould. Reinforcement can also be placed in a space between the outer mould and the inner mould of the second mould.

The outer mould of the second mould preferably surrounds the inner mould of the second mould on three sides. The outer mould of the first mould however preferably surrounds the inner mould of the first mould on four sides. This difference is caused by the fact that, in contrast to the second part, the first part has an upper wall.

The first mould can further comprise filler parts which extend perpendicularly relative to the bottom of the outer mould or elevated part of the first mould and which are configured to form continuous openings during the pouring of concrete for the purpose of throughfeed of post-tension cables. The filler parts, which are usually formed as tubular elements, prevent the space taken up by the filler parts from being filled up with concrete. This creates continuous openings in the first part, in which post-tension cables can be arranged later. These filler parts are preferably arranged on the obliquely extending mould walls, the elevated part and/or the transverse part.

For the first mould and/or the second mould a height over which the elevated part extends and/or an angle formed by the obliquely extending mould walls with the bottom of the outer mould or the elevated part and/or a position where the obliquely extending mould walls engage on the bottom of the outer mould or the elevated part is adjustable. Such an adjustability can for instance be realized by means of hydraulics. The parts of the first mould and/or second mould can for instance be realized with metal such as steel, wherein hydraulic cylinders are used to change or set the relative position and/or orientation of the parts of the first and second mould.

The first mould can have first protruding edges for forming first recesses in end surfaces of the side walls of the first part which are directed toward the second part, and the second mould can have second protruding edges for forming second recesses in end surfaces of the side walls of the second part which are directed toward the first part.

According to a further aspect, the present invention provides a method for manufacturing an end element as defined in claim <NUM>.

The method comprises the steps of providing the mould assembly as described above and of pouring concrete into the first mould in a first pouring run for the purpose of forming the first part of the end element.

The method can further comprise of pouring concrete into the second mould in a second pouring run for the purpose of forming the second part of the end element. The method can also comprise the step of placing the filler parts on the oblique mould wall, the elevated part, the bottom of the outer mould and/or the transverse part of the first mould prior to concrete being poured into the first mould for the purpose of forming continuous openings in the first part. Reinforcement can be placed in a space between the inner mould and outer mould of the first mould and/or second mould.

According to an even further aspect, the present invention provides a method for manufacturing a concrete tubular structure such as a culvert or sewage pipe as defined in claim <NUM>. This method comprises the above described method for forming at least one end element, placing one or more concrete middle segments to form a middle part of the concrete tubular structure, placing the first part in the vicinity of a middle segment at an end of the middle part, and coupling this middle segment to the first part.

The middle segments and the first part can each have continuous openings. In this case the continuous openings of the middle segments can be aligned. Said coupling can further comprise of passing post-tension cables through the continuous openings of the middle part and continuous openings of the first part and tensioning them. The concrete tubular structure preferably comprises an end part on either side of the structure.

The method can further comprise the step of placing the second part in the vicinity of the first part. The second part can here be separate, i.e. not coupled, relative to the first part. If the first and second part are provided with the above described first and second recesses, the method can comprise the step of arranging sealing elements in the openings formed by the first and second recesses.

The present invention will be discussed in more detail hereinbelow with reference to the accompanying figures, in which:.

End element <NUM> comprises a first part <NUM> and a second part <NUM>. First part <NUM> comprises a lower wall <NUM>, a pair of side walls <NUM> and an upper wall <NUM>. Lower wall <NUM> and side walls <NUM> extend beyond upper wall <NUM> in the direction toward second part <NUM>. The height of side walls <NUM> further decreases in a first direction D1 away from upper wall <NUM>.

Walls <NUM>, <NUM>, <NUM> surround a central opening <NUM>. First part <NUM> further comprises a chamfering <NUM> which is formed at the corners between side walls <NUM> and upper wall <NUM> and at the corners between side walls <NUM> and lower wall <NUM>. As stated above, <FIG> shows a model. In a final first part <NUM> walls <NUM>, <NUM>, <NUM> and chamfering <NUM> form a concrete element moulded integrally in a single pouring run.

Second part <NUM> comprises a lower wall <NUM> and a pair of side walls <NUM>. Second part <NUM> further comprises a chamfering <NUM> which is formed at the corners between side walls <NUM> and lower wall <NUM>. In a final second part <NUM> walls <NUM>, <NUM> and chamfering <NUM> form a concrete element moulded integrally in a single pouring run and the height of side walls <NUM> decreases in the first direction D1.

During pouring of concrete, recesses can be realized in first part <NUM> second part <NUM> at the locations indicated by arrow C in <FIG>. In end element <NUM> the thus formed recesses co-act to form an opening. A sealing element, such as a plastic slat, can be introduced into this opening. Such an element prevents sand from entering through and/or eroding the opening between first part <NUM> and second part <NUM>. A more detailed example of the formation of this recess is shown in <FIG>.

<FIG> shows that side walls <NUM> of first part <NUM> are each provided with a first recess <NUM> in an end surface V6 thereof which is directed toward the second part <NUM>. Side walls <NUM> of second part <NUM> are each provided with a second recess <NUM> in an end surface V5 thereof which is directed toward the first part <NUM>. End element <NUM> comprises a sealing element <NUM> which is placed in an opening formed by the first recess <NUM> and second recess <NUM>.

A continuous opening <NUM> can also be provided in surface V6. The middle segments of the final tubular structure can likewise be provided with such continuous openings. After first part <NUM> has been placed in line with these middle segments, the continuous openings form a single continuous opening. A post-tension cable can be passed through this opening in order to pull the middle segments and first part <NUM> against each other. It is noted here that a tubular structure usually has an end element at both outer ends. It is further noted that second part <NUM> is usually not provided with such continuous openings. Second part <NUM> is usually placed separately in front of first part <NUM>.

<FIG> shows two views of a first mould <NUM> for the manufacture of first part <NUM> of end element <NUM> of <FIG>. The first mould shown in <FIG> is a model and demonstrates merely the functionality of first mould <NUM>. Components of first mould <NUM> are preferably made of metal parts, such as steel parts. It is also noted that first mould <NUM> comprises an outer mould (not shown) which is formed by a beam in which the components shown in <FIG> are placed.

Visible in the part-figure of <FIG> on the right are an inner mould <NUM> and a mould part <NUM>. Inner mould <NUM> is here preferably a hollow structure with chamfered edges for forming chamfering <NUM>.

Mould part <NUM>, which extends in the space between the outer mould (not shown) and inner mould <NUM>, comprises an elevated part <NUM>, oblique walls <NUM> and a transverse part <NUM>. Elevated part <NUM> comprises a platform <NUM> from which oblique walls <NUM> extend to transverse part <NUM>. Platform <NUM> is supported by legs <NUM> and transverse part <NUM> by legs <NUM>.

In an embodiment elevated part <NUM>, oblique walls <NUM> and transverse part <NUM> are fixed, non-adjustable elements. Different types of this element can in this case be used for the manufacture of different end elements <NUM>. In other embodiments the angle of oblique walls <NUM> relative to elevated part <NUM> is adjustable, for instance by means of hydraulic cylinders. The position of walls <NUM> relative to elevated part <NUM>, indicated by arrows P1, could likewise be adjustable. Such an adjustability is also possible for adjusting the height positioning of platform <NUM>. Transverse part <NUM> is also adjustable to different heights by making use of legs <NUM> with different lengths.

In order to realize a first part <NUM> of an end element <NUM> concrete is poured into the space between inner mould <NUM> and the outer mould from above. It runs up against mould part <NUM> here. Transverse part <NUM> defines here the position where upper wall <NUM> stops, platform <NUM> defines the end of first part <NUM>, and oblique walls <NUM> define side walls <NUM>. Prior to the pouring, filler parts (not shown) can be placed on platform <NUM>, transverse part <NUM> and/or oblique walls <NUM> for the purpose of realizing continuous openings <NUM> in which post-tension cables are later arranged. Edge parts can also be placed on platform <NUM>, or on the bottom of the outer mould if platform <NUM> is not used, for the purpose of forming recesses <NUM>. Such an edge can however also form an integral part of platform <NUM>.

Also visible in the figure on the right are filler parts <NUM> which, as shown in <FIG>, prevent chamfering <NUM> from running beyond upper wall <NUM> at the position of upper wall <NUM>. The figure on the left in <FIG> shows an example of a side view of a first part <NUM> formed with first mould <NUM>. Side wall <NUM> of first part <NUM> is visible here.

<FIG> shows a view of a second mould <NUM> for the manufacture of second part <NUM> of end element <NUM> of <FIG>. The second mould shown in <FIG> is a model and demonstrates merely the functionality of second mould <NUM>. Components of second mould <NUM> are preferably made of metal parts, such as steel parts. It is also noted that second mould <NUM> comprises an outer mould (not shown) which is formed by a number of walls which define a space in which the components shown in <FIG> are placed.

Second mould <NUM> comprises an inner mould <NUM> with rounded corners for forming chamfering <NUM>. Second mould <NUM> further comprises a mould part <NUM> which is placed in a space between inner mould <NUM> and the outer mould. Mould part <NUM> comprises here an elevated part <NUM> which comprises a platform <NUM> supported by legs <NUM>. The height positioning of platform <NUM> determines the length of second part <NUM>. Mould part <NUM> also comprises side walls <NUM>.

In <FIG> the angle of side walls <NUM> can be adjusted by placing support <NUM> in a different position. Such a function can be implemented by a steel wall which can be pivoted relative to the outer mould by means of a hydraulic cylinder. Such a function can also be implemented as shown in <FIG>. Side wall <NUM> comprises here a number of recesses <NUM> which are arranged in side wall <NUM> at several positions. It is noted here that <FIG> shows only a single recess <NUM>. Support <NUM> engages on a single recess and rests on a step of stair part <NUM>. Side wall <NUM> can now be adjusted by selecting a different recess <NUM> and a different step of stair part <NUM>.

The angle formed by side walls <NUM> must correspond with the angle formed by oblique walls <NUM>. The position of side walls <NUM> relative to platform <NUM>, indicated by arrows P2, can further be varied.

At the position indicated by arrows D edge-shaping elements can be pressed into the concrete immediately after it is poured for the purpose of forming recesses <NUM>.

Reinforcement can be placed in both first mould <NUM> and second mould <NUM>. Lift anchors, with which the concrete first part <NUM> and second part <NUM> can be removed from the respective moulds after sufficient curing, can also be cast in.

End element <NUM> can be coupled to known middle segments <NUM>. First part <NUM> is here placed against a middle segment <NUM> which is arranged at the end of the row of middle segments <NUM>. Opening <NUM> is here aligned with the openings of middle segments <NUM>. First part <NUM> is then coupled to the adjacent middle segment <NUM>. Use can be made here of a socket-spigot joint, wherein a socket is formed in or at middle segment <NUM> or end element <NUM> and a spigot is formed in or at end element <NUM> or middle segment <NUM>.

In other embodiments middle segments <NUM> are provided with continuous openings, which are likewise present in first part <NUM>. Post-tension cables can be arranged through these openings. Use can be made here of cone-shaped parts which are arranged at the end of the openings in first part <NUM> during pouring. The tensioned post-tension cables can be anchored in these parts.

If necessary, for instance if end element <NUM> has a great length, second part <NUM> can be placed adjacently of first part <NUM>. Lower walls <NUM>, <NUM> and side walls <NUM>, <NUM> are here aligned so that it seems as if first part <NUM> and second part <NUM> form an integral part. It is preferred here for upper surfaces V1, V2 shown in <FIG> to lie in the same plane. The same applies to upper surfaces V3, V4 and lower walls <NUM>, <NUM>.

The above described outer moulds and inner moulds can be embodied by means of metal walls, such as steel walls, which are hydraulically adjustable. Adjustment enables first part <NUM> or second part <NUM> to be easily removed from the mould after sufficient curing. Mould part <NUM> can here be placeable as a single element. Filler parts <NUM> can optionally be placed separately from the rest of mould part <NUM>. Mould part <NUM> can similarly be placeable as a single element.

Claim 1:
Mould assembly for forming an end element (<NUM>) of a concrete tubular structure such as a culvert (<NUM>) or sewage pipe, comprising a first mould (<NUM>) and a second mould (<NUM>) for forming respectively a first part (<NUM>) and a second part (<NUM>) of the end element (<NUM>), wherein the first mould (<NUM>) and the second mould (<NUM>) each comprise:
an outer mould;
an inner mould (<NUM>; <NUM>) placed in the outer mould;
a mould part (<NUM>; <NUM>) placed in a space between the inner mould (<NUM>; <NUM>) and an inner wall of the outer mould, wherein the mould part (<NUM>; <NUM>) comprises mould walls (<NUM>; <NUM>) which extend obliquely relative to a bottom of the outer mould and which extend between the inner wall of the outer mould and an outer wall of the inner mould (<NUM>; <NUM>) for the purpose of forming the side walls (<NUM>) of the first part (<NUM>) or the side walls (<NUM>) of the second part (<NUM>);
wherein the mould part (<NUM>; <NUM>) comprises an elevated part (<NUM>; <NUM>) which is placed on the bottom of the outer mould, and wherein the obliquely extending mould walls (<NUM>; <NUM>) extend from the elevated part (<NUM>; <NUM>);
wherein, for the first mould (<NUM>) and/or the second mould (<NUM>), a height over which the elevated part (<NUM>; <NUM>) extends and/or an angle formed by the obliquely extending mould walls (<NUM>; <NUM>) with the bottom of the outer mould or the elevated part (<NUM>; <NUM>) and/or a position where the obliquely extending mould walls (<NUM>; <NUM>) engage on the bottom of the outer mould or the elevated part (<NUM>; <NUM>) is adjustable.