GB2432373A

GB2432373A - Foundation support mechanism

Info

Publication number: GB2432373A
Application number: GB0523664A
Authority: GB
Inventors: Richard John Withers; Robert Douglas Withers
Original assignee: WITHERS HOLDINGS Ltd R
Current assignee: WITHERS HOLDINGS Ltd R
Priority date: 2005-11-21
Filing date: 2005-11-21
Publication date: 2007-05-23
Anticipated expiration: 2025-11-21
Also published as: GB0523664D0; GB2432373B

Abstract

This invention relates to the formation of foundations of buildings and specifically to a support for use in such. The support for use in the formation of buildings' foundations comprises an elongated structure(2) capable of supporting an imposed load and being changeable between an assembled position and a collapsed position. The structure(2) is comprised of three side elements(4,6,8) arranged such that in the assembled position the structure(2) has an effectively triangular configuration and wherein one side element(4,6,8) of the structure(2) is removable so as to cause the structure(2) to change from the assembled position to the collapsed position. A method of forming a void beneath a concrete foundation slab is also claimed. A decking layer is supported on at least one such support in the assembled position and the concrete foundation slab formed above the decking layer.

Description

1 243237 Foundation Support MemafliS This invention relates to the

formation of foundations of buildings and specifically to a support for use in such.

On laying foundations on ground liable to movement due to, for example clay heave, it is well known to provide a void between the ground and the foundation slab on which the building is constructed. The void accommodates any ground movement and thus prevents or reduces the effect of the movement on the building.

standard practices for providing voids in building foundations involve using spacers such as paper or polystyrene based products, which may be left within the void after construction. The use of such spacers is expensive and not nvjronmentally friendly due to their single use application.

Paper based spacers are designed to collapse once wet. Therefore they are not suitable for use in wet conditions, and furthermore, gases will be released on degradation of the spacers, necessitating a path to allow gas to be vented from the void.

Removable spacers can also be used in foundation void forming. However, shrinkage of concrete on setting can cause the spacers to become jammed in the void, therefore making removal of the spacers from the confined space of the void difficult. This is a particular problem in the creation of low voids, such as those of the standard 225mm. -2

collapsible structures for void forming can suffer from the same problem of jamming. Such structures could also be unsteady and liable to premature collapse.

A collapsible support is known from European Patent Application number EP1281815 (Abbey Pynford Holdings plc). The support disclosed in this application comprises a platform to support a decking layer on which a concrete slab will be formed, a base member connected to the platform, and a strut to maintain separation between the base member and the platform in the open' configuration.

A breakable barrier is provided to prevent the strut from slipping prematurely. Collapse of the structure is effected by removal of the strut by pulling in a longitudinal direction away from the support. The support collapses in the direction of pull of the supporting strut, therefore any irregularities on the underneath of the decking layer (above the void) in the direction of pull, for example caused by shrinkage/leakage of concrete, will cause an obstruction which could prevent the support from collapsing. Further, as the platform is in contact with the decking layer, the force required for removal of the strut must be sufficient to overcome the friction caused by the contact between the platform and the decking layer/raft, and also sufficient to break the barrier.

There is a need for a collapsible, removable and reusable structure for supporting decking layers for the creation of voids during foundation forming, which is sufficiently strong and stable to support a raft and yet which can be easily collapsed and removed from the void after use. n 3

Accordingly, the present invention provides a support for use in the formation of buildings' foundations comprising an elongated structure capable of supporting an imposed load and being changeable between an assembled position and a collapsed position1 wherein the structure is comprised of three side elements arranged such that in the assembled position the structure has an effectively triangular configuration and wherein one side element of the structure is removable so as to cause the structure to change from the assembled position to the collapsed position.

An advantage of the support is that the configuration provides it with strength in compression is when in the assembled position, whilst the simple removal of a side section enables easy collapse and removal of the support from the void after use.

When the support is in the form of a framework the weight of the support is minimised thus increasing ease of transportation.

Collapse of the support occurs in a lateral direction i.e. a direction perpendicular to the direction of pull of the side section to be removed. This results in the contact between the support and the decking layer ceasing as soon as collapse begins. Therefore any irregularities on the underneath of the decking layer (above the void) will not cause obstructions to prevent the structure from collapsing and being removed from the void. Furthermore, as contact between the support and the decking layer is minimised, the force required to effect collapse and removal of the support is less than that required for known structures for void forming.

The support can be reused, thus making it a less expensive and more environmentally friendly means for void forming than single use spacers.

Reference will now be made by way of example only to the accompanying drawings which illustrate a preferred embodiment of the present invention, and in which: Figure 1 shows a pair of supports according to the invention in the assembled position.

Figure 2 is a partial view of a support of Figure 1 in its assembled position.

Figure 3 is the support of Figure 1 in its collapsed position.

As illustrated in Figures 1 and 2, each of the pair of supports comprises an elongated framework 2 having three side elements being formed of two strengthened side sections 4 and 6, and skeleton base section 8. In the assembled position, side sections 4 and 6 are hingedly linked to one another at their upper edges, and linked by base section 8 at their lower edges such that the support forms a triangular configuration, i.e. the support as a whole has a triangular cross section in plane Y-Z.

Base section 8 comprises a U-shaped member having arms 10 and 10' and link 12. A cord 16 is attached to link 12. Arms 10 and 10' are insertable into hollow members 14 and 14' provided on side sections 4 and 6 respectively. -5

In the assembled position, arms 10 and 10' are inserted into members 14 and 14', preferably with the aid of a lubricant such as grease.

One or more supports may be placed at suitable positions across a blinding layer such as concrete provided over the ground. A decking layer or other shuttering (not shown) may be placed on top of the support, and a concrete slab formed on top of the decking io layer using a conventional method.

The interaction of arms 10 and 10' with members 14 and 14' maintains the framework in a triangular configuration by preventing lower edges of side sections 4 and 6 from sliding outwardly, i.e. prevents the lower edge of side section 4 from sliding in the direction of arrow Z, and the lower edge of side section 6 from sliding in the direction of arrow Z'.

Once the concrete slab has been formed, the support may be removed. This is effected by pulling cord 16 in the direction of arrow X so as to cause arms 10 and 10' to be removed from members 14 and 14'. This will cause the lower edges of side sections 4 and 6 to slide outwardly, i.e. in the directions of arrows Z and Z' respectively, under their own weight, to collapse the support. Once in the collapsed position, the support may then by removed from the void which has been formed between the decking layer and the blinding layer by pulling cord 18 which may be attached to either or both side sections.

Should a support become jammed due to irregularities in the underneath of the decking layer, the pulling motion on cord 18 will assist the collapse, especially if performed on an angle in direction X. Base section 8 could be formed of a plurality of U-shaped members, each being linked for example by an extension of cord 16, or each being removable separately by separate cords.

Other embodiments could be used to maintain the io triangular configuration of the support in the assembled position, such as pins provided on the base section insertable into lugs provided on the side sections.

However, in practice it has been found that the embodiment described herein provides the necessary strength in compression when the support is in the assembled position, whilst enabling easy removal of the base section to allow for collapse of the support.

Although the preferred embodiment describes the removal of the base section, in an alternative embodiment, the collapse of the support could equally be effected by removal of one of the side sections by providing suitable apertures and arms on the sections.

Whilst the support illustrated fl the preferred embodiment has a simple triangular shape when in the assembled position, an effectively triangular configuration, for example wherein one or more side elements are slightly curved, could be used in

Claims

Cia ima 1. A support for use in the formation of buildings' foundations

comprising an elongated structure capable of supporting an imposed load and being changeable between an assembled position and a collapsed position, wherein the structure is comprised of three side elements arranged such that in the assembled position the structure has an effectively triangular configuration and wherein one side element of the structure is removable so as to cause the structure to change from the assembled position to the collapsed position.

2. A support as claimed in claim 1 wherein two of the sides elements are substantially similar.

3. A support as claimed in claims 1 or 2 wherein two of the side elements are arranged to pivot one in relation to another.

4. A support as claimed in any one of the preceding claims wherein the removable side element is a U-shaped member insertable into apertures provided on the other two side elements.

5. A support as claimed in any one of the preceding claims wherein one or more of the side elements comprises a framework.

6. A support as claimed in claim i substantially as described herein. -8

7. A support substantiallY as herein described with reference to and as illustrated by the accompanying drawings.

8. A method of forming a void beneath a concrete foundation slab for a building comprising steps of supporting a decking layer above and on at least one support according to any one of the preceding claims in the assembled position, and forming the concrete foundation slab above the decking layer.

9. A method as claimed in claim 8 comprising subsequent additional steps of changing the or each support from the assembled position to the collapsed position and removing from the support from the void.

10. A method substantially as herein described with reference to the accompanying drawings.