AU729210B2 - Construction joint - Google Patents

Description

1

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT TERRY JOHN TRAPNELL .0 0 0 0 000.

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0 0*00 0 0* *0 00~* 0* 0 9 0* 00 0 *0 0e 0 *0 *0 Name of Applicant(s): Actual Inventor(s): JKi- TERRY JOHN TRAPNELL Address for Service: Invention Title: CULLEN CO., Patent Trade Mark Attorneys, 240 Queen Street, Brisbane, Qld. 4000, Australia.

CONSTRUCTION JOINT Details of Associated Provisional Applications: Nos. PO 6976 filed 23 May 1997 The following statement is a full description of this invention, including the best method of performing it known to me BACKGROUND OF THE INVENTION This invention relates to construction joint formation in concrete slabs and is particularly concerned with preformed inserts for this purpose.

Construction joints comprise elongate regions in a concrete slab which are devoid of concrete so as to enable expansion and/or contraction of the slab and thereby minimize the potential for cracking under varying ambient conditions or due to the natural curing of the slab which occurs over the lifetime of the slab. Such cracking can lead to weakening of the slab, destabilization of the building supported by it, and an entry point for termites into the building.

Construction joints can be formed in slabs 15 either while they are being poured or after they have set.

This invention is concerned with joint formation during pouring of the concrete. Such joints are typically formed with a simple space occupying member such as a strip of wood or the like. This normally means that for large concrete slabs, a continuous pour is not possible due to the need to be able to remove the jointing strips between e adjacent areas before the adjacent area can be poured.

The joints thus formed must subsequently be in-filled with a filler such as silicone to close off the gap.

OBJECTS OF THE INVENTION It is therefore an object of the invention to provide a new form of construction joint which permits continuous pours of large concrete slab areas to be made.

It is also an object of the invention to provide a construction joint having aN insert which can move in concert with the expansion or contraction of the concrete slab, while still retaining its integrity to prevent the ingress of termites.

These and other objects of the invention will become apparent from the subsequent description and statements of invention.

SUMMARY OF THE INVENTION According to one aspect of the present invention there is provided a construction joint for a concrete slab which is designed for placement prior to the pouring of the slab, said construction joint comprising an inverted channel member having flanges projecting outwardly from each edge, wherein an inwardly projecting extension is formed on at least one of the flanges and acts as a barrier to termites entering the construction joint channel from below.

DETAILED DESCRIPTION OF THE INVENTION The inwardly projecting extension on one or both 0 eo of the flanges is or are designed to move with the .15 movement of the walls of the channel member as the walls 0 .are compressed or expanded upon contraction or expansion of the concrete slab, whilst still maintaining a viable barrier to termites.

The or each extension can be in the form of a flat elongate strip which projects in an opposing direction to the flanges formed on the outer edges of the channel member. In the case of a single extension, this is typically designed to extend beneath the opposing S. flange of the channel member, with a snug face-to-face 25 contact therewith. A recess can be formed in the opposing flange to facilitate accommodation and movement.

Where there are two extensions, one extending from one edge of the channel member and the other extending from the other edge of the channel member, these will suitably be offset from one another so that one can slide over the other in face-to-face contact during expansion or contraction of the concrete slab. The two extensions will be of differing widths to enable this to occur.

The flanges suitably extend substantially at right angles to the open edges of the channel member and the, or each, extension formed in the same region of the channel member, extends in a directly opposing direction to the flange.

Preferably, the flanges have substantially flat rectangular configurations and incorporate upstanding longitudinally extending rims along their outer edges.

These rims are to assist placement and retention in the concrete slab during its formation, as described below.

Preferably, the channel section has a substantially U-shaped configuration. The apex of the channel can incorporate a longitudinally extending planar ridge to provide support for a capping element or an edge against which a groove trowelling tool can be run to form a groove above the channel section before the concrete has set. Such an element can be of a resiliently deformable construction and act as an infill for the top of the slab above the construction joint. Should an open groove be required above the construction joint, the capping element can be removed by peeling it away from the channel member.

*.The construction joint can be fabricated from a wide range of materials, including sheet aluminium iron and copper, and construction grade plastics materials.

The construction joint can be supported in situ prior to the pouring of the concrete by means of brackets which in turn are located on ground-engaging pins. Such brackets constitute another aspect of the invention.

25 According to this other aspect, the invention comprises a bracket for supporting the aforementioned construction joint, said bracket comprising a substantially U-shaped support with resiliently flexible arms and a pin accommodating hub projecting in the opposing direction to the support The hub is suitably in the form of a tubular section which is dimensioned to snugly fit over a peg extending into the ground beneath the slab. Preferably, the pegs are steel rods which are driven into the ground in a line to a uniform depth so as to support a plurality of brackets. A single construction joint is then fitted to the brackets by flexing open the resiliently deformable arms and letting the arms close about the edges of the construction joint.

Preferably, a lug is formed on the end of each bracket arm to prevent the construction joint from being displaced by the concrete when it is being poured about the joint.

The bracket can be fabricated from a range of different materials but plastics is preferred; in particular high density polyethylene or polyvinylchloride.

If desirable or necessary, a construction joint cap can be included in the assembly. This constitutes a third aspect of the invention.

According to the third aspect of the invention there is provided a resiliently deformable construction joint cap in the form of a longitudinally extending strip of material having a substantially planar upper facing surface and a lower facing surface incorporating a groove and a profile which conforms substantially to the outer facing top surface of the channel member.

The construction cap is suitably formed from polyvinylchloride or the like plastics material.

DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention will now be described with reference to the accompanying drawings, in which:- Figure 1 is a cross-sectional view of a bracket support according to one aspect of the invention; Figure 2 is a partial perspective view of a construction joint according to a second aspect of the invention; Figure 3 is a partial perspective view of a construction joint cap according to a third aspect of the invention, and Figure 4 is a cross-sectional view of a construction joint and support bracket in situ.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In all of the drawings, like reference numerals refer to like parts.

Referring firstly to Figure 2, the construction joint 10 comprises an inverted channel member 11 having flanges 12, 13 extending in a coplanar manner on each side thereof. Each flange has an upturned longitudinally extending rim 14, 15 which projects at substantially right angles to the plane of the flange.

Flange 13 has a longitudinal recess 16 formed at its intersection with the channel member 11. This recess is to accommodate movement of an extension 17 which projects inwardly of the channel member 11, away from S* flange 12, at the intersection of the channel member and flange.

A ridge 18 extends along the top of the channel member to provide support for the joint cap described below, or an edge against which a groove can be trowelled prior to the concrete in the slab setting.

The construction joint is fabricated from termite resistant PVC and is sufficiently resiliently deformable such that when in situ, as the concrete surrounding the channel member expands or contracts, the walls of the channel come together or extend outwardly and the extension 17 slides in the recess 16 in tight contact 25 with the recess walls so as to provide a barrier to termite ingress.

Figure 1 illustrates a bracket 22 which can be used to support the construction joint 10. The bracket is required in order to locate the construction joint at the correct location in the slab to be poured and (b) provide firm support for the construction joint when the concrete is being poured.

The bracket 22 consists of a generally U-shaped member having opposed clasping arms 23, 24 on one side and an axially located hub 25 on the other. Each arm 23, 24 has a lug 26, 27 formed on its end for retaining the upstanding longitudinal rims 14, 15 on the construction joint flanges and to prevent the construction joint from being dislodged during the concrete pour. This can be seen particularly clearly in Figure 4.

The axially located hub 25 on the bracket consists of a cylindrical tubular portion so that it can be snugly fitted over a stake as shown in Figure 4, and firmly retained thereon.

The bracket 22 is suitably formed by injection moulding polyvinylchloride.

A plurality of such brackets is required for each construction joint.

Referring to Figure 3, there is illustrated a resiliently deformable construction joint cap fabricated from polyvinylchloride. The cap includes a slot 31 and is designed to fit over the ridge 18 of the channel member 11.

The combination of the construction joint 10 of Figure 2 and the support bracket 22 of Figure 1 is shown in situ in Figure 4 to which reference is now made. This drawing illustrates a cured concrete slab 40 formed atop a ground surface 41. Mesh reinforcing 42, 43 is positioned *on each side of an expansion joint 44.

The construction joint 10 is supported atop a ".:plurality of brackets 22 (only one is seen in the cross- 25 section as the others are directly behind it) which in turn are respectively supported by a plurality of steel stakes 45 which penetrate into the ground 41. A construction joint cap 30 extends along the top of the construction joint.

The expansion joint thus formed meets the objectives of the invention and provides the public with a useful system of joint formation.

Whilst the above has been given by way of illustrative example of the invention, many modifications and variation may be made thereto by persons skilled in the art without departing from the broad scope and ambit of the invention as herein set forth.

Claims (11)

1. A construction joint for a concrete slab which is designed for placement prior to the pouring of the slab, side construction joint comprising an inverted channel member having flanges projecting outwardly from each edge, wherein an inwardly projecting extension is formed on at least one of the flanges and acts as a barrier to termites entering the construction joint channel from below.

2. A construction joint as claimed in claim 1, wherein there is an extension formed on one flange only, which extension is in the form of a substantially flat elongated strip.

3. A construction joint as claimed in claim 2, *wherein the extension extends beneath the opposing flange on the channel member.

4. A construction joint as claimed in claim 2 or claim 3, wherein the extension extends into a recessed region formed in a longitudinal edge of the opposing flange.

A construction joint as claimed in claim 1, wherein there is an extension formed on both flanges, which extensions are in the form of substantially flat elongated strips, one of which strips being offset from the other so as to enable the strips to slide relative to one another during expansion or contraction of the concrete slab.

6. A construction joint as claimed in any one of the preceding claims, wherein the flanges have longitudinally extending lips formed on their outer edges.

A construction joint as claimed in any one of the preceding claims, wherein the inverted channel has a substantially U-shaped cross-sectional configuration.

8. A construction joint as claimed in any one of the preceding claims, wherein the flanges extend substantially at right angles to the open edges of the channel member.

9. A construction joint as claimed in any one of claims 2-5, wherein the or each extension is formed at the open edge or edges of the channel member.

A construction joint as claimed in any one of the preceding claims, wherein a longitudinally extending planar ridges formed along the outer surface of the channel member.

11. A construction joint for a concrete slab substantially as herein described with reference to Figure 2 of the accompanying drawings. o e DATED this 22 n day of November 2000 TERRY JOHN TRAPNELL 25 By his Patent Attorneys ::*CULLEN CO. o •go* *go *oo* oooo. oooo.