WO2013076500A1

WO2013076500A1 - Apparatus forming an edge of a concrete floor

Info

Publication number: WO2013076500A1
Application number: PCT/GB2012/052904
Authority: WO
Inventors: Shaun Spurrell
Original assignee: Shaun Spurrell
Priority date: 2011-11-24
Filing date: 2012-11-23
Publication date: 2013-05-30
Also published as: EP2785918A1; GB201120321D0

Abstract

Apparatus for forming an edge of a concrete floor slab panel as part of a contraction joint, the apparatus comprising: a non-deformable divider plate (1), and a base component (2), wherein the base component (2) comprises a socket (3) and the divider plate (1) is insertable into the socket (3) to variable depth.

Description

APPARATUS FORMING AN EDGE OF A CONCRETE FLOOR SLAB

Field of the invention

The present invention relates to an apparatus for forming the edge of a concrete floor slab panel, a base component for use in the apparatus, a concrete floor slab panel comprising the apparatus, a concrete floor comprising the apparatus, a method of manufacturing a concrete floor slab panel and a method of manufacturing a concrete floor.

Background to the invention

Concrete floor slabs are generally cast as adjoining slab panels and each slab panel is cast inside a formwork; this formwork defines a space in which to cast the concrete. The formwork may be constructed from timber, steel, aluminium, plastic or the like. The formwork may be removable, which means it is removed after the concrete has cured.

Alternatively, it may be leave-in-place formwork, which forms part of the resulting concrete structure, for example by providing at least part of an edge of a resulting concrete slab panel. The formwork generally comprises one or more upright elongate divider plates, which the concrete is cast against. The divider plates ensure that the concrete is contained within the desired space. When a number of floor slab panels are cast next to one another to form a concrete floor or slab, the divider plates generally sit in between adjacent slab panels, and dowels or dowel plates, attached to the divider plates, are used to connect the slab panels together in order to transfer loads across the joint.

During the casting of a concrete floor slab panel comprising leave-in-place formwork, the formwork should be positioned in such a way that the upper edges of the formwork coincide with the finished floor level (FFL), i.e. the level of the upper surface of the finished concrete floor slab. The slab and formwork rest on a subbase. If the subbase level (SBL) varies, the formwork will rest on the subbase's highest point. Because of this, it is common practice in casting concrete floors to allow around 15 - 25 mm for clearance. Concrete floor slab thicknesses are usually in the range of 150 to 200 mm. Formwork can be manufactured to desired thickness specifications, which is commonly done in 5 mm increments. If it is desired to cast a concrete slab with a thickness of 180 mm, formwork with a depth of 155 - 165 mm is normally used. In order to achieve the desired finished floor level (FFL), a divider plate can be suspended at the desired FFL using suspension means. Such suspension means can, for example, be a jack, or pins may be placed on both sides of the divider plate and studs, which are commonly present in an apparatus for forming the edge of a concrete floor slab, may be welded to these pins, thus suspending the divider plate at the desired FFL. In addition, wedges, adjustable feet and the like can be used to position the formwork in the desired manner against the subbase and hold it in place whilst the concrete is cast. However, in these known systems, when concrete is cast into a formwork comprising a divider plate in an elevated position, there will be a gap between the subbase and the divider plate, and some of the concrete will flow through the gap. This can negatively affect the structural soundness of the joint between neighbouring concrete slab panels, and can require rework to remove excessive spillage.

After casting, concrete slabs display normal drying shrinkage. This shrinkage may be exacerbated when the temperature of the concrete is reduced, for example in the case of floor slabs for freezer stores. The shrinkage of concrete floor slabs is a slow process: it can take up to two years for a concrete slab to stop shrinking. The shrinkage of concrete slab panels generally results in the opening of the joints between the slab panels, due to each concrete slab panel shrinking away from the joint in a direction generally perpendicular to the longitudinal axis of the joint. The type of joint which is adapted to accommodate such shrinking, or contraction, of a concrete slab panel on one or each side of the joint is known as a "contraction joint". This is as opposed to an "expansion joint", which is adapted to accommodate expansion of a concrete slab panel on one or each side of the joint where the slab panels are cast with a preset gap between them, to allow thermal expansion of the slab panel, after contraction of the slab panel due to curing has taken place.

EP-A-1985759 describes an apparatus for forming the edge of a concrete floor slab panel, the apparatus comprising a divider plate with a plurality of apertures, dowels for engaging through the apertures and sleeves for applying to the dowels, in which the divider plate or dowel or top strip is provided with means to adjust the height thereof above the subbase. These height adjustment means take the form of a supporting leg together with means for attaching the leg to the divider plate or dowel or top strip at a selected height. The leg is positioned alongside the divider plate or dowel or top strip, and is attached to the divider plate or dowel or top strip either via a separate lock means, which is passed through a vertical slot formed in the leg or the divider plate or top strip, or via a dowel plate. The effect of this set-up is to allow vertical movement of the divider plate parallel to the leg, which therefore adjusts the height of the divider plate relative to the subbase. However, when the divider plate in this apparatus is moved upwards relative to the leg, a gap is created between the subbase and the divider plate. Therefore, when concrete is cast into a formwork comprising the apparatus in its elevated position, some of the concrete will flow through the gap, which can negatively affect the structural soundness of the joint between neighbouring concrete slab panels and can require rework to remove excessive spillage. Furthermore, the lower part of the divider plate is not secured to the subbase at any point. The divider plate is only restricted in horizontal movement perpendicular to the thrust of the concrete against the divider plate where the height adjustment leg is fitted.

It is an aim of the present invention to provide an apparatus for forming the edge of a concrete floor slab panel, embodiments of which can enhance the ease with which formwork can be assembled, and hence with which concrete floor slabs can be produced, and which can also enhance the performance characteristics of the resulting concrete floor slabs and maintain the correct and essential FFL.

Statements of the invention According to a first aspect of the present invention there is provided an apparatus for forming an edge of a concrete floor slab panel as part of a contraction joint, the apparatus comprising: a non-deformable divider plate, and a base component, wherein the base component comprises a socket and the divider plate is insertable into the socket to variable depth . The term "insertable to variable depth" means that the divider plate may be inserted to two or more different depths in the socket.

In use, the base component can be moved up and down relative to the divider plate, which allows the height of the apparatus above the subbase level to be adjusted. The apparatus therefore allows a range of different contraction joint formwork heights to be achieved, which can be continuously variable, by using a single size of divider plate, instead of requiring a large number of different sizes of divider plates; the different formwork heights are achieved simply by adjusting the extent to which the divider plate is inserted into the socket in the base component. The apparatus of the invention can therefore allow much greater flexibility than known types of formwork and can allow distributors to stock a much smaller number of divider plate variants. The production methodology can be changed from 'make to order' to 'make to stock' which allows a quicker response time to customers. As mentioned above, it is known to suspend a divider plate at the desired finished floor level (FFL) using suspension means such as, for example, a jack. However, in these known systems, a gap is created between the subbase and the divider plate and therefore concrete can flow through the gap, which can negatively affect the structural soundness of the joint between neighbouring concrete slab panels. In the present invention, during pouring of concrete the base component would normally rest on the subbase. The apparatus of the invention therefore achieves a range of different formwork heights, which can be continuously variable, while avoiding a gap between the subbase and the divider plate which concrete can flow through.

In addition to this, the apparatus according to the first aspect of the invention can be easier to operate than existing apparatus in this field . The position of the divider plate relative to the base component can, for example, be adjusted simply by tapping the divider plate into the socket to a desired depth. In addition, if the apparatus has been supported at the desired FFL using support means (which can include suspension means such as e.g. a jack), the position of the base component relative to the divider plate can, for example, be adjusted simply by tapping the base component down to the subbase level.

Therefore the apparatus can enhance the ease with which concrete floor slab panels can be produced, can enhance the performance characteristics of the resulting concrete floor slabs, and can eliminate the need to trim off concrete spillage, which can save time and reduce waste management costs on site.

The base component is an essential element of the present invention. In addition, the base component is obviously suitable for putting the invention into effect.

In an embodiment, the base component is elongate. In an embodiment, the socket extends longitudinally. This means that the lower edge of the divider plate can slide into the socket along its length .

During pouring of concrete, the base component would normally rest on the subbase. The apparatus according to the first aspect of the invention allows the height of the formwork relative to the subbase to be adjusted without resulting in concrete flowing underneath the formwork. In an embodiment, the depth to which the divider plate is inserted in the socket can be adjusted in a stepwise manner. The steps can, for example, be arranged to be set at known intervals which can help in aligning different sections of formwork without the need to take measurements.

In an embodiment, the depth to which the divider plate is inserted in the socket can be adjusted in a continuous manner. This allows the height of the formwork relative to the subbase to be adjusted to any desired height, within the range to which the divider plate is insertable into the socket.

In an embodiment, the base component is arranged to be securable to the subbase. In an embodiment, the base component comprises one or more holes arranged to receive fastening means such as, for example, metal pins which, in use, secure the base component to the subbase. This arrangement makes the apparatus easier to operate, since it allows the concrete to be cast without the risk of the apparatus shifting in position (in a substantially horizontal direction) in the process under the influence of the concrete thrust. This can enhance the ease with which concrete floor slabs can be produced.

In an embodiment, at least one of the divider plate and the socket comprises members adapted to engage with the other, to hold the divider plate in position within the socket. This can prevent the divider plate and base component from slipping relative to each other. In an embodiment, the divider plate comprises members adapted to engage with the socket. In an embodiment, the socket comprises members adapted to engage with the divider plate. The divider plate can, for example, be held in position by friction. In an embodiment, the divider plate and the socket comprise interengaging members arranged to hold the divider plate in position within the socket.

In an embodiment, the divider plate and/or the socket comprise surface profiling arranged to hold the divider plate in position within the socket.

In an embodiment, the divider plate and/or the socket comprise serrations arranged to hold the divider plate in position within the socket.

In an embodiment, the divider plate is arranged to be held in position in the socket by means of a nut and bolt.

In an embodiment, the range of depths to which the divider plate is insertable into the socket is a range of about 50 mm. In use, this movement would generally be in a substantially vertical direction. Since the height of a concrete floor slab is usually in the range of 150 to 200 mm, the range of movement of about 50 mm can allow the full range of common floor slab heights to be achieved with a single size of divider plate.

In an embodiment, the base component is substantially L-shaped, for example in the form of an elongate component with an L-shaped cross-section. In an embodiment, the L-shaped component comprises an upright section with an elongate socket and a base section which can, for example, include one or more holes for securing the base component to the subbase.

In an embodiment, the base component is substantially U-shaped, for example in the form of an elongate component with a U-shaped cross-section.

In an embodiment, the base component comprises a base and two side walls defining the socket between them. In an embodiment, the side walls function as biasing means which hold the divider plate in place relative to the base component.

In an embodiment, at least one of the two side walls comprises one or more apertures.

In an embodiment, one of the side walls of the base component sits parallel and adjacent to the divider plate. In an embodiment, the cross-sectional shape of the base component (perpendicular to the elongate direction) is asymmetrical about the divider plate.

In an embodiment, the base of the base component resides substantially on one side of the divider plate.

In an embodiment, the load-bearing part of the base component resides substantially on one side of the divider plate.

In an embodiment, one of the side walls of the base component sits parallel and adjacent to the divider plate, and the base of the base component does not extend beyond this side wall on that side of the divider plate. This means that if, in use, two concrete slab panels are cast on either side of the apparatus, as they shrink the side of the apparatus where the side wall of the base component sits parallel to and adjacent to the divider plate is predisposed to readily separate from the concrete, while the other side is predisposed to stay attached to the concrete. In an embodiment, the base component extends no more than 20 mm beyond the divider plate on one side of the divider plate. In an embodiment, this is no more than 15 mm, or 10 mm, or 5 mm.

The divider plate is non-deformable. This means that the material from which the divider plate is made is not compressible by the concrete once the concrete has been cast on one or both sides of the divider plate. In an embodiment, the divider plate is formed from a metal such as, for example, steel. This can result in a divider plate of high mechanical strength.

The divider plate can be conventional in construction, for example as in EP-A-1985759 or similar. In an embodiment, the divider plate is an elongate flat section of material which can slide up and down within the socket.

In an embodiment, the base component is formed from a metal such as, for example, steel or from plastic. In an embodiment, the base component is formed from plastic.

In an embodiment, the base component is formed as an elongate extrusion. In an embodiment, the elongate extrusion has a substantially constant cross-section along its length.

A number of individual base components can be arranged at intervals along the bottom edge of the divider plate.

In an embodiment, the divider plate comprises a means of restricting its bottom section from being withdrawn from the base component. Such restricting means can include a fold at the lower end of the divider plate, such as for example a longitudinal L-fold, a longitudinal V-fold or a Dutch fold (where the divider plate is completely folded back on itself). Such a fold can strengthen the divider plate as well as being able to stop the divider plate from being accidentally pulled out of the base component. Other means of restricting the bottom section of the divider plate from being withdrawn from the base component can, for example, include pips or similar profiling on the divider plate or socket.

In an embodiment, the divider plate comprises one or more apertures. In an embodiment, the apparatus further comprises one or more dowels or dowel plates for engaging through the one or more apertures. These act to connect the resulting concrete slab panels together and to provide a method of load transfer between adjacent slab panels. In an embodiment, the apparatus further comprises edge rails supported by the divider plate. In an embodiment, the apparatus comprises two such edge rails adjacent to each other. Once cast, concrete slab panels are prone to shrinkage during curing which causes the edges of the slab panels to separate. This exposes the upper edge or arris of each individual slab panel to damage from loads such as from vehicles, including for example lorries or forklift trucks, passing across the joint. The edge rails can provide protection to the arris of the cast slab panels and improve the longevity of the slab at the joints.

In an embodiment, the edge rails further comprise anchor means for embedding in the concrete. The anchor means become embedded in the concrete during curing and fix the edge rails in position.

In an embodiment, the edge rails are attached together with yieldable fixings. These fixings fail under tension as shrinking occurs during the curing process and the edge rails of adjacent slabs are drawn apart.

In an embodiment, the yieldable fixings comprise low tensile bolts. .Examples of such low tensile bolts are bolts formed from nylon, the threads of which will become stripped under shrinkage forces, or the shanks of which will fail under tension .

The apparatus according to the first aspect of the invention can be used to form, for example, prefabricated four-way intersections, three-way "T" intersections, corner units and loading dock corners. According to a second aspect of the present invention there is provided a base component for use in the apparatus according to the first aspect of the present invention, the base component having a socket adapted to receive a divider plate to variable depth.

According to a third aspect of the present invention there is provided a concrete floor slab panel comprising the apparatus according to the first aspect of the present invention. According to a fourth aspect of the present invention there is provided a concrete floor comprising the apparatus according to the first aspect of the present invention.

According to a fifth aspect of the present invention there is provided a method of manufacturing a concrete floor slab panel, comprising the steps of (i) setting up the apparatus according to the first aspect of the present invention to form at least part of an edge of a space for casting concrete; and (ii) casting concrete in the space. In an embodiment, step (i) comprises supporting the apparatus using support means. In an embodiment, the support means comprise suspension means, such as e.g. a jack.

According to a sixth aspect of the present invention there is provided a method of manufacturing a concrete floor, comprising the steps of (i) setting up the apparatus according to the first aspect of the present invention to form at least part of an edge of a space for casting concrete; and (ii) casting concrete in the space; wherein steps (i) and (ii) are performed more than once.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", mean "including but not limited to", and do not exclude other moieties, additives, components, integers or steps. Moreover the singular encompasses the plural unless the context otherwise requires: in particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. Preferred features of each aspect of the invention may be as described in connection with any of the other aspects. Other features of the invention will become apparent from the following examples. Generally speaking the invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims and drawings). Thus features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. Moreover unless stated otherwise, any feature disclosed herein may be replaced by an alternative feature serving the same or a similar purpose. Where upper and lower limits are quoted for a property, then a range of values defined by a combination of any of the upper limits with any of the lower limits may also be implied.

Specific description

Embodiments of the present invention will now be further described with reference to the accompanying figures, of which: Figure 1 shows a perspective view of a first embodiment of the apparatus of the invention, with the divider plate inserted into the socket to the maximum depth.

Figure 2 shows a perspective view of the first embodiment of the apparatus of the invention, with the divider plate inserted into the socket to less than the maximum depth. Figure 3 shows a cross-sectional view of the first embodiment of the apparatus of the invention perpendicular to its length, with the divider plate inserted into the socket to the maximum depth.

Figure 4 shows a cross-sectional view of the first embodiment of the apparatus of the invention perpendicular to its length, with the divider plate inserted into the socket to less than the maximum depth.

Figure 5 shows a perspective view of a second embodiment of the apparatus of the invention, with the divider plate inserted into the socket to less than the maximum depth.

Figure 6 shows a perspective view of a third embodiment of the apparatus of the invention, with the divider plate inserted into the socket to less than the maximum depth. As shown in Figures 1 to 6, divider plate 1 can be inserted into elongate socket 3 in base component 2. Divider plate 1 is an elongate flat section of material which can slide up and down within socket 3.

In the first embodiment shown in Figures 1 to 4, the base component 2 is elongate and substantially L-shaped in cross-section. It comprises a base 4 and two side walls 5a, 5b, which together define the elongate socket 3. Side walls 5a, 5b sit parallel and adjacent to divider plate 1. Base component 2 has a substantially constant cross-section along its length.

In the second embodiment shown in Figure 5, the base component 2 is elongate and substantially triangular in cross-section. It comprises a base 4 and two side walls 5a, 5b, which together define the elongate socket 3. Side wall 5a sits parallel and adjacent to divider plate 1. Base component 2 has a substantially constant cross-section along its length. Side wall 5b contains apertures 13.

In the third embodiment shown in Figure 6, the base component 2 is elongate and substantially rectangular in cross-section. It comprises a base 4 and two side walls 5a, 5b, which together define the elongate socket 3. Side wall 5a sits parallel and adjacent to divider plate 1. Base component 2 has a substantially constant cross-section along its length. Side wall 5b contains apertures 13. At its lower end, the divider plate 1 has a Dutch fold 14. Fold 14 strengthens divider plate 1 and stops the divider plate 1 from being accidentally pulled out of the base component 2. In the embodiments shown in Figures 1 to 6, the depth to which the divider plate 1 is inserted in the socket 3 can be adjusted in a continuous manner. The base component 2 is arranged to hold the divider plate 1 in position within the socket 3 by friction.

Divider plate 1 further comprises apertures 6 along its length at regular intervals. The apertures 6 are adapted to receive dowel plates 7. On one side of the divider plate 1, the dowel plates 7 are encased in dowel sleeves 8, which, in use, allows movement of the concrete as it sets and shrinks.

The apparatus further comprises edge rails 9 supported by the upper flange 10 on divider plate 1. Anchor means 11 extend out from the edge rails 9 in the general direction where, in use, the concrete would be poured. As can be seen from Figures 1 and 2, in the first embodiment base 4 of base component 2 comprises holes 12. In use, these holes 12 can receive metal pins to secure the base component 2 to the subbase.

In use, the apparatus can be supported at the desired FFL using support means, which can include suspension means such as e.g. a jack. At this stage, the apparatus can be in the form where the divider plate 1 is inserted into the socket 3 to the maximum depth. The base component 2 can then be adjusted down relative to the divider plate 1 by a desired amount, usually until it is in contact with the subbase. The base component 2 can optionally be secured to the subbase with metal pins through holes 12.

In use, the apparatus will form at least part of an edge of a space for casting concrete. The entire edge may be formed by the apparatus, and the remaining edges may also be formed by further units of the apparatus. Once the space for casting concrete has been defined by the edges, i.e. the formwork has been set up, concrete is poured into the space. The concrete is then allowed to cure. The apparatus of the invention will form at least part of an edge of the resulting concrete floor slab panel. The apparatus of the invention can alleviate the need to manufacture, transport and stock a large number of different sizes of divider plates to suit all customer needs. Instead, a desired formwork height can be achieved by using a single size of divider plate; the height of the apparatus of the invention can be adjusted to the desired height on site in an easy and convenient manner.

Claims

1. Apparatus for forming an edge of a concrete floor slab panel as part of a contraction joint, the apparatus comprising:

a non-deformable divider plate, and

a base component,

wherein the base component comprises a socket and the divider plate is insertable into the socket to variable depth.

2. The apparatus of claim 1, wherein the base component is elongate.

3. The apparatus of claim 2, wherein the socket extends longitudinally.

4. The apparatus of any one of the preceding claims, wherein the depth to which the divider plate is inserted in the socket can be adjusted in a continuous manner.

5. The apparatus of any one of the preceding claims, wherein the base component is arranged to be securable to the subbase.

6. The apparatus of any one of the preceding claims, wherein at least one of the divider plate and the socket comprises members adapted to engage with the other, to hold the divider plate in position within the socket.

7. The apparatus of any one of the preceding claims, wherein the base component is substantially L-shaped.

8. The apparatus of any one of the preceding claims, wherein the base component comprises a base and two side walls defining the socket between them.

9. The apparatus of claim 8, wherein the side walls function as biasing means which hold the divider plate in place relative to the base component.

10. The apparatus of claim 8 or 9, wherein at least one of the two side walls comprises one or more apertures.

11. The apparatus of any one of the preceding claims, wherein the divider plate is formed from a metal.

12. A base component for use in the apparatus according to any one of claims

1-11, the base component having a socket adapted to receive a divider plate to variable depth .

13. A concrete floor slab panel comprising the apparatus according to any one of claims 1-11.

14. A concrete floor comprising the apparatus according to any one of

claims 1-11.

15. A method of manufacturing a concrete floor slab panel, comprising the steps of (i) setting up the apparatus according to any one of claims 1-11 to form at least part of an edge of a space for casting concrete; and

(ii) casting concrete in the space.

16. The method of claim 15, wherein step (i) comprises supporting the apparatus using support means.