PREFABRICATED MOVEMENT JOINT SYSTEM FOR CONCRETE FLOORS

The invention relates to prefabricated movement joint system as defined in the preamble of independent claim 1.

This invention relates to the forming of concrete floor slabs, particularly to the forming of the edges of the slabs or arris's, also to providing protection of said edges, and improved means for load transfer between adjacent slabs.

It is well known that concrete floor slabs are cast inside a formwork, commonly constructed of either timber or steel. This formwork provides an edge and defines a space in which to cast the concrete, some types of formwork are removed once the concrete sets, and some are designed to remain in place for the life of the floor.

Once cast, concrete slabs are prone to shrinkage during curing which causes the edges of the slabs to separate, and expose the upper edge or arris of each individual slab to damage from loads, such as lorries or fork trucks passing across the joint.

Individual slabs often support heavy loads passing from one slab to another and therefore require a method of load transfer between adjacent slabs, in order to prevent breakdown of the joint between adjacent slabs, caused by stresses induced by such loads Typically round, square or plate dowels and sleeves are embedded in the concrete to extend at 90° across the formed joint, and connect the slabs together in order to facilitate the transfer of a load from one slab across the joint to another.

Most available prefabricated joints are anchored into the concrete slabs by a plurality of Shear Studs which have been welded on either side of the top rails along their length, said welded studs present a potential consequential risk of failure at the weld, and can cause severe problems if they break off after the slab has been cast, making re-welding in situ extremely difficult.

Many existing prefabricated joint manufacturers also produce a dowel and sleeve of their own specific design, and often manufacture their joint to be able to accommodate only their style of dowel or similar, other standard dowels may not fit the aperture provided in the divider plate.

It is therefore an object of this invention to provide an improved prefabricated joint system which provides maximum protection to the newly formed joint edge in two planes as opposed to just one.

The prefabricated movement joint system of the invention is characterized by the definitions of independent claim 1.

Preferred embodiments of the prefabricated movement joint system are defined in the dependent claims.

In an embodiment of the prefabricated movement joint system, height adjustment is achieved by a customized jack arrangement which affixes to the prefabricated joint system by means of a threaded spigot on the jack which passes through a pre-punched aperture in the edge rails and is secured there by means of a nut on the other side said jack arrangement is the subject of a separate patent.

In one aspect, the invention provides a prefabricated movement joint system for forming the edge of the concrete slab, the system comprising a divider plate that may be reinforced by a plurality of embossed ridges, which may be of any shape or design to suit. Said divider plate may be formed with a plurality of apertures, which may be of any shape or design required to accept most known dowel types and sizes, thereby permitting the use of a wide range of load transfer mechanisms. The dowels and sleeves shown as may be used in this system are the subject of a separate patent.

The divider plate, because of its possible clamp fixing between the two top edge rails, can provide in use a degree of height adjustment to accommodate for different thickness slabs. Said divider plate will preferably be formed from metal sheet, but other materials may be used, and is intended to be left in place between concrete floor slabs cast on each side thereof.

The prefabricated joint system may further comprise top edge rails which are preferably supportable by the divider plate, to provide protection in two planes to the edge of the concrete floor cast slabs. The top edge rails may further comprise a plurality of integrated anchors, which are formed from the parent metal of the top edge rails, and which become embedded in the concrete during curing and which fix the top edge rails in position.

The top edge rails of adjoining concrete floor slabs are preferably attached together with yieldable fixings wherein, as shrinking occurs during the curing process and the top edge rails of adjacent slabs are drawn apart, the fixings yield to allow for the movement. The yieldable fixing may comprise low tensile bolts, studs or rivets, for example formed from nylon or similar plastics, which will shear or part under the shrinkage forces. The fixings for the top edge rails are preferably located in first apertures formed through the top edge rails and comprise a close tolerance fit to the fixing, in order to ensure that adjacent top edge rails are accurately placed in position.

When the top edge rails are fixed together back to back, because of a possible radii created by the forming of the angles, a curved depression is evident. Said depression may hold detritus and possibly cause hard wheeled traffic traversing the joint to jar or bump. This potential problem may be removed by the use of a formed nylon or similar plastic extrusion, shaped in cross section to exactly fit the curved depression, Said extrusion may also include a suitable lip or tag at the bottom of the section which can be captured and clamped in position by the top edge rails.

The invention relates to a prefabricated movement joint system 2 such as an expansion joint system and/or a contraction joint system for a concrete floor slab arrangement.

The prefabricated movement joint system is configured to be arranged in a joint (not marked with a reference numeral) to be formed between a first concrete floor slab 1a and a second concrete floor slab 1b when forming the first concrete floor slab 1a and the second concrete floor slab 1b by casting.

The prefabricated movement joint system 2 comprises a first top edge rail 3a of metal or other material for providing edge protection in two planes for a first upper edge 15a of the first concrete floor slab 1a in the joint to be formed between the first concrete floor slab 1a and the second concrete floor slab 1b in the concrete floor slab arrangement.

The prefabricated movement joint system 2 comprises a second top edge rail 3b of metal or other material for providing edge protection in two planes for a second upper edge 15b of the second concrete floor slab 1b in the joint to be formed between the first concrete floor slab 1a and the second concrete floor slab 1b in the concrete floor slab arrangement.

The prefabricated movement joint system 2 comprises a divider plate 4 of metal or other material to be arranged in the joint to be formed at least partly between the first concrete floor slab 1a and the second concrete floor slab 1b in the concrete floor slab arrangement and at least partly between the first two top edge rail 3a and the second top edge rail 3a.

The divider plate 4 of metal or other material may be formed with a plurality of first apertures 12 and second apertures 13 and embossed strengthening ridges 9. The divider plate 4 may be in the form of a height adjustable divider plate, which is lockable into several positions between the first top edge rail 3a and the second top edge rail 3b so as to adjust the height of the divider plate 4 for example in accordance with the thickness of the first concrete floor slab 1a and the second concrete floor slab 1b.

According to the invention as previously described above and shown in FIGS. 1 to 10, the prefabricated movement joint system 2 may be manufactured in discrete lengths to suit or as required, and by virtue of the overlap shown, a plurality of the joints may be connected together in order to form the total desired length of joint.

The drawings show a prefabricated movement joint system 2, suitable for use in forming concrete floor slabs 1a, 1b as shown in FIG. 1. The prefabricated movement joint system 2 as shown in FIG. 8 comprises a first top edge rail 3a possible provided with formed first anchors 6a, a second top edge rail 3b possible provided with formed second anchors 6b, a divider plate 4 as shown in FIG. 8 possible provided with a plurality of yieldable fixings 5.

The first top edge rail 3a and the second top edge rail 3b are preferably, as shown in the figures, elongate and can be provided in lengths and joined together and cut as required, comprising possible of a formed unequal angle, with the narrow plane facing uppermost to the top, and the other to the vertical, this angle being designed to provide armored protection to the edge of the first concrete floor slab 1a, or correspondingly, to the second concrete floor slab 1b.

In the prefabricated movement joint system 2 one of the first top edge rail 3a and the second top edge rail 3b of the prefabricated movement joint system 2 may be formed into an angle to provide edge protection to a part of the top face (not marked with a reference numeral) and to a part of the joint face (not marked with a reference numeral) of the first concrete floor slab 1a in the joint to be formed between a first concrete floor slab 1a and a second concrete floor slab 1b.

In the prefabricated movement joint system 2 one of the first top edge rail 3a and the second top edge rail 3b of the prefabricated movement joint system 2 may be formed into an angle to provide edge protection to a part of the top face and to a part of the joint face of the second concrete floor slab in the joint to be formed between a first concrete floor slab 1a and a second concrete floor slab 1b.

In an embodiment of the prefabricated movement joint system 2 the first top edge rail 3a of the movement joint system 2 may have has a plurality of first anchors 6a to embed and position the first top edge rail 3a in the first concrete floor slab 1a so that at by at least one first anchor 6a of said plurality of first anchors 6a has been formed from the parent metal of a vertical plane of the first top edge rail 3a, as opposed to being welded on or affixed by some other method.

In an embodiment of the prefabricated movement joint system 2 the second top edge rail 3b of the prefabricated movement joint system 2 may have has a plurality of second anchors 6b to embed and position the second top edge rail 3b in the second concrete floor slab 1a so that at by at least one second anchor 6b of said plurality of anchors 6 has been formed from the parent metal of a vertical plane of the second top edge rail 3b, as opposed to being welded on or affixed by some other method.

In an embodiment of the prefabricated movement joint system 2 the first top edge rail 3a of the prefabricated movement joint system 2 comprise a first rail portion 16a and a second rail portion 17a. The first rail portion 16a of the first top edge rail 3a is to be arranged essentially parallel with a top face of the first concrete floor slab 1a. The second rail portion 17a of the first top edge rail 3a is to be arranged essentially parallel with a joint face (not marked with a reference numeral) facing the joint to be formed between the first concrete floor slab 1a and the second concrete floor slab 1b. In this embodiment of the prefabricated movement joint system 2 the first rail portion 16a is provided in an essentially right angle in relation to the second rail portion 17a so that the first top edge rail 3a has an essentially L-shaped cross section form. In this embodiment of the prefabricated movement joint system 2 the first top edge rail 3a may have a plurality of first anchors 6a to be cast into concrete of the first concrete floor slab 1a to anchor the first top edge rail 3a in the first concrete floor slab 1a so that at least one first anchor 6a of said plurality of first anchors 6a has been formed by cutting and plastically deforming the material forming the second rail portion 17a of the first top edge rail 3a so that said at least one first anchor 6a is an integral part of the second rail portion 17a of the first top edge rail 3a and consist of material that has been used forming the second rail portion 17a of the first top edge rail 3a.

In an embodiment of the prefabricated movement joint system 2 the second top edge rail 3b of the prefabricated movement joint system 2 comprise a first rail portion 16b and a second rail portion 17b. The first rail portion 16b of the second top edge rail 3b is to be arranged essentially parallel with a top face of the second concrete floor slab 1b. The second rail portion 16b of the second top edge rail 3b is to be arranged essentially parallel with a joint face facing the joint to be formed between the first concrete floor slab 1a and the second concrete floor slab 1b. The first rail portion 16b is provided in an essentially right angle in relation to the second rail portion 17b so that the second top edge rail 3b has an essentially L-shaped cross section form. In this embodiment of the prefabricated movement joint system 2 the second top edge rail 3b may have a plurality of second anchors 6b to be cast into concrete of the second concrete floor slab 1b and to anchor the second top edge rail 3b in the second concrete floor slab 1b, and at least one second anchor 6b of said plurality of second anchors 6b has been formed by cutting and plastically deforming the material forming the second rail portion 17b of the second top edge rail 3b so that said at least one second anchor 6b is an integral part of the second rail portion 17b of the second top edge rail 3b and consist of material that has been used forming the second rail portion 17b of the second top edge rail 3b. In an embodiment of the prefabricated movement joint system, the first rail portion 16a of the first top edge rail 3a is in the form of an elongated flat sheet member having uniform thickness and the second rail portion 17a of the first top edge rail 3a is in the form of an elongated flat sheet member having uniform thickness so that the thickness of the first rail portion 16a of the first top edge rail 3a corresponds to the thickness of the second rail portion 17a of the first top edge rail 3a. In this embodiment, the first top edge rail 3a have a plurality of first anchors 6a to be cast into concrete of the first concrete floor slab 1a to anchor the first top edge rail 3a in the first concrete floor slab 1a, so that by at least one first anchor 6a of said plurality of first anchors 6a has been formed by cutting and plastically deforming material forming the second rail portion 17a of the first top edge rail 3a so that said at least one first anchor 6a is an integral part of the second rail portion 17a of the first top edge rail 3a and consist of material that has been used forming the second rail portion 17a of the first top edge rail 3a, and so that the second rail portion 17a of the first top edge rail 3a has a first opening 18a through the second rail portion 17a of the first top edge rail 3a at the location said at least one first anchor 6a has been formed of material forming the second rail portion 17a of the first top edge rail 3a. The first opening 18a increases the strength of the connection between the first top edge rail 3a and the first concrete floor slab 1a and increases the sheer strength of the movement joint system. The dimensions and the shape of the first opening 18a the in second rail portion 17a of the first top edge rail 3a may correspond at least partly to the dimensions and the shape of said at least one first anchor 6a. Alternatively, the dimensions and the shape of the first opening 18a the in second rail portion 17a of the first top edge rail 3a may correspond essentially to the dimensions and the shape of said at least one first anchor 6a. In this embodiment, said at least one first anchor 6a may have an elongated form, and said at least one first anchor 6a may have a thickness corresponding to the thickness of the second rail portion 17a of the first top edge rail 3a. In this embodiment, said at least one first anchor 6a may have an at least partly teethed side edge such as an at least partly saw-toothed side edge. In this embodiment, the first rail portion 16a of the first top edge rail 3a may be connected with the second rail portion 17a of the first top edge rail 3a by means of a first curved portion 19a of the first top edge rail 3a, wherein the thickness of the first curved portion 19a of the first top edge rail 3a corresponds to the thickness of the first rail portion 16a of the first top edge rail 3a and to the thickness of the second rail portion 17a of the first top edge rail 3a. Provision of a first curved portion 19a between the first rail portion 16a of the first top edge rail 3a and the second rail portion 17a of the first top edge rail 3a reduces impact damage for example to small fork truck wheels as opposed to sharp formed edges.

In an embodiment of the prefabricated movement joint system, the first rail portion 16b of the second top edge rail 3b is in the form of an elongated flat sheet member having uniform thickness, and the second rail portion 17b of the second top edge rail 3b is in the form of an elongated flat sheet member having uniform thickness, so that the thickness of the first rail portion 16b of the second top edge rail 3b corresponding to the thickness of the second rail portion 17b of the second top edge rail 3b. In this embodiment the second top edge rail 3b have a plurality of second anchors 6b to be cast into concrete of the second concrete floor slab 1b to anchor the second top edge rail 3b in the second concrete floor slab 1b, so that at least one second anchor 6b of said plurality of second anchors 6b has been formed by cutting and plastically deforming material forming the second rail portion 17a of the second top edge rail 3b so that said at least one second anchor 6b is an integral part of the second rail portion 17b of the second top edge rail 3b and consist of material that has been used forming the second rail portion 17b of the second top edge rail 3b, and so that the second rail portion 17b of the second top edge rail 3b has a second opening 18b through the second rail portion 17b of the second top edge rail 3b at the location said at least one second anchor 6b has been formed of material forming the second rail portion 17a of the second top edge rail 3b. The second opening 18b increases the strength of the connection between the first top edge rail 3a and the first concrete floor slab 1a and increases the sheer strength of the movement joint system. The dimensions and the shape of the second opening 18b the in second rail portion 17a of the second top edge rail 3b may correspond at least partly to the dimensions and the shape of said at least one second anchor 6b. Alternatively the dimensions and the shape of the second opening 18b the in second rail portion 17b of the second top edge rail 3b may correspond essentially to the dimensions and the shape of said at least one second anchor 6b. In this embodiment, said at least one second anchor 6b may have an elongated form, and said at least one second anchor 6b may have a thickness corresponding to the thickness of the second rail portion 17b of the second top edge rail 3b. In this embodiment said at least one second anchor 6b may have an at least partly teethed side edge such as an at least partly saw-toothed side edge. In this embodiment the first rail portion 16b of the second top edge rail 3b may be connected with the second rail portion 17b of the second top edge rail 3b by means of a second curved portion 19b of the second top edge rail 3b, wherein the thickness of the second curved portion 19b of the second top edge rail 3b corresponds to the thickness of the first rail portion 16b of the second top edge rail 3b and to the thickness of the second rail portion 17b of the second top edge rail 3b. Provision of a second curved portion 19a between the first rail portion 16b of the second top edge rail 3b and the second rail portion 17b of the second top edge rail 3b reduces impact damage for example to small fork truck wheels as opposed to sharp formed edges.

At least one of the first top edge rail 3a and the second top edge rail 3b may be provided with a plurality of first apertures 12 for receiving the yieldable fixings 5 and/or with another plurality of second apertures 13 for receiving the height adjusting jack 11 as shown in FIG. 10.

The first top edge rail 3a and the second top edge rail 3b of the prefabricated movement joint system 2 may be fixable back to back with the yieldable fixings 5 thereby clamping into position the divider plate 4 and an optional extrusion 7 of plastic such as nylon or other material, as shown in FIG. 7. The extrusion 7 serves two functions, firstly to keep out detritus from the curved depression and secondly to assist in smooth wheeled transition of the prefabricated movement joint system 2 once in situ.

A plurality of shaped openings 8 may be provided along the length of the divider plate 4. The shaped openings 8 are of a generally squat and wide shape in order to permit dowels 14 such as circular, square, or plate dowels to extend there through, thereby permitting the use of a wide variety of dowels and load transfer mechanisms.

Another optional feature of the divider plate 4 is a plurality of slots 15 uppermost along the top edge, these slots are there to permit the passage of yieldable fixings 5 and height adjustment jacks 11 through the first top edge rail 3a and the second top edge rail 3b when the prefabricated movement joint system 2 is assembled for use.

In order to strengthen the divider plate 4 to resist the flow of concrete being poured against it a plurality of embossed straightening ridges 9 as shown in FIG. 6 are formed, said embossed straightening ridges 9 may be of any suitable shape or design as required.

A view of the complete prefabricated movement joint system 2 or assembly ready for use, including plate dowels and sleeves 10 also a height adjusting jack 11 can be viewed in FIG. 10. The aforementioned plate dowels and jack are the subject of separate patents and do not form a part of this application.

Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance, it should be understood that the applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.