AU2008241350B2

AU2008241350B2 - Permanent formwork system

Info

Publication number: AU2008241350B2
Application number: AU2008241350A
Authority: AU
Inventors: Alister Bennett
Original assignee: CSR Building Products Ltd
Current assignee: CSR Building Products Ltd
Priority date: 2007-04-23
Filing date: 2008-04-01
Publication date: 2013-03-14
Anticipated expiration: 2028-04-01
Also published as: WO2008128275A1; NZ580649A; AU2008241350A1

Abstract

A stud system for use in a formwork. The stud system has two spaced apart outer wall sheets and comprises at least one elongate stud member and one or more elongate reinforcing members. The stud member has a longitudinally extending web portion and first and a second longitudinally extending side wall portions. The longitudinally extending web portion has two opposite side edges and each of the side wall portions have a first side edge and an opposite second side edge. Each side wall portion has a first and a second longitudinally extending flange portion. Each flange portion has a first side edge and an opposite second side edge. Each of the reinforcing members have opposite ends and the stud system is adapted for the opposite ends to be secured in relation to the second edges of the flange portions to reinforce the stud member.

Description

WO 2008/128275 PCT/AU2008/000461 1 PERMANENT FORMWORK SYSTEM TECHNICAL FIELD The present invention relates to building panels and building systems for 5 forming building panels. Particularly, the present invention relates to a permanent formwork system for the construction of walls where concrete is placed within the formwork along with reinforcing steel and the outer skin remains in place and forms the finished wall surface. 10 BACKGROUND ART Building systems involving prefabricated formwork systems having outer skins that define a cavity which is then filled in with concrete are well known. The outer skins are usually fibre cement panels and remain in place to form the finished wall surface. Concrete is placed within the formwork, along with 15 reinforcing steel. In order to allow concrete to be poured into the cavity and to fit the reinforcing steel, there is a need for large openings within and between the studs. A significant cost element in these prefabricated formwork systems is the studwork, which is bonded to the outer skins. The studs both support and hold 20 the outer skins as well as keeping the opposing outer skins separated, to define the cavity. These studs must be capable of resisting the static head or force of the concrete during the pouring operation. US 6161361 (Ehrenkrantz) discloses a composite structural member comprising parallel flanges and a plurality of thermally insulative web 25 connectors intermittently disposed between the web connectors. This document describes the spreading apart and the subsequent springing back of the walls of the flanges. However, the planar finish to abutting surfaces of the flanges and ends would not be adequate for use in concrete pouring into the panel. This is because of the considerable pressure that is generated by the 30 flow of wet concrete pouring into the panel and if a web connector released a WO 2008/128275 PCT/AU2008/000461 2 flange, the panel would bow resulting in distortion of the outer wall. This patent is directed towards drywall construction where the loading and strength requirements are not as high as in concrete filled wall production. US 5609006 (Boyle) discloses a wall stud comprising C-shaped frame 5 members and core elements. The core elements may be located at the top and bottom of the stud and are adapted to accept nails and screws. Additional core elements may be slidably mounted between the top and bottom. The core elements are retained within the frame members by keepers that extend inwards from the frame members. The sliding core members must be secured 10 by punching through side walls of the frame members. The core elements must be slid along the length of the frame members, and in relation to the intermediate core elements, are not self retaining and must be punched into position. This patent is also directed only to drywall construction. One problem with known wall systems is that the studs deform or deflect 15 under the static force of the wet concrete when it is poured into the cavity formed by the opposed outer skins. This can result in distortion of the outer wall and a loss in the overall strength and integrity of the wall. The present invention relates to a permanent formwork system for the construction of walls, where concrete is placed within the formwork along with 20 reinforcing steel and the outer skin remains in place and forms the finished wall surface. Therefore it would be advantageous to provide an improved permanent formwork system. This would overcome at least some of the disadvantages of previously known approaches in this field, or would provide a useful 25 alternative. DISCLOSURE OF INVENTION According to a first aspect of the present invention there is provided a stud system for use in a formwork. The stud system has two spaced apart outer wall sheets and comprises at least one elongate stud member and one 30 or more elongate reinforcing members.

WO 2008/128275 PCT/AU2008/000461 3 The stud member has a longitudinally extending web portion and first and a second longitudinally extending side wall portions. The longitudinally extending web portion has two opposite side edges and each of the side wall portions have a first side edge and an opposite second side edge. The first side 5 edges of the side wall portions are joined to the respective side edges of the web portion, such that the side wall portions extend substantially perpendicularly to the web portion. Each side wall portion has an outer wall surface and an inner wall surface, with the inner wall surfaces of the two side wall portions facing each other; and a first and a second longitudinally 10 extending flange portion. Each flange portion has a first side edge and an opposite second side edge. The first side edge of the first flange portion is joined to the second side edge of the first side wall portion and the first side edge of the second flange portion is joined to the second side edge of the second side wall portion. In 15 this way, the flange portions extend from the side wall portions towards each other substantially parallel to the web portion, with the second side edges of the flange portions being spaced from each other. The stud member is adapted for the outer surface of each side wall portion to be joined face-to-face to a respective the outer sheet, such that the 20 web portion spans the distance between the outer wall sheets; and The reinforcing members have opposite ends and the stud system is adapted for the opposite ends to be secured in relation to the second edges of the flange portions to reinforce the stud member. Preferably, the stud system comprises a first and a second inner wall 25 portion, each inner wall portion having a first side edge and an opposite second side edge, the first side edge of the first inner wall portion being joined to the second side edge of the first flange portion and the first side edge of the second inner wall portion being joined to the second side edge of the second flange portion, such that the inner wall portions extend from the flange 30 portions towards the web portion substantially parallel to the side wall portions, with the second side edges of the inner wall portions being spaced from the web portion.

WO 2008/128275 PCT/AU2008/000461 4 Preferably the stud system comprises a first and a second lip portion, joined to, and extending from, the second side edges of the first inner wall portion and second inner wall portion, respectively, towards the first side wall portion and second side wall portion, respectively. 5 Preferably, each of the reinforcing members comprises an elongate central portion having two opposite ends and a hooked formation at each of the ends, the hooked formations being adapted to hook onto the first and second lip portions thereby to secure the lip portions to each other. Preferably, the stud member and reinforcing members are separate from 10 each other, although in a second embodiment of the present invention, the stud member and reinforcing members are formed integrally with each other. Preferably, the stud member includes extruded metal and most preferably includes roll formed galvanised steel and each of the reinforcing members is made by an injection moulding process. The stud member and the 15 reinforcing members are made from metal. Preferably there are a plurality of the reinforcing members. In one preferred embodiment, each of the side wall portions has a plurality of apertures therein to facilitate adhesion between the side wall portions and the outer wall sheets. 20 The web portion preferably has at least one aperture therein to allow concrete to flow therethrough. According to a second aspect of the present invention there is provided a formwork comprising two spaced apart outer wall sheets and at least one stud system. The outer surfaces of the side wall portions are joined, face-to-face 25 with the respective outer wall sheets such that the web portion spans the distance between the outer wall sheets. The outer surfaces of the side wall portions are preferably joined with the outer wall sheets by a polyurethane adhesive.

WO 2008/128275 PCT/AU2008/000461 5 BRIEF DESCRIPTION OF DRAWINGS Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: 5 FIG 1 shows a perspective view of the permanent formwork system according to a first embodiment of the present invention; FIG 2 shows an enlarged perspective view of an elongate stud member of the permanent formwork system shown in FIG 1; and FIG 3 shows an enlarged perspective view of an elongate reinforcing 10 member of the permanent formwork system shown in FIG 1. BEST MODE FOR CARRYING OUT THE INVENTION FIG 1 shows a permanent formwork system 1 in accordance with a first embodiment of the present invention. The permanent formwork system 1 15 includes two spaced apart outer wall sheets 2a, 2b, at least one elongate stud member 4 and one or more reinforcing members 10. The outer wall sheets 2a, 2b are preferably fibre cement panels, although any suitable building panels may be used. The elongate stud members 4 and the reinforcing members are coated with an acrylic finish to improve their corrosion resistance and increase 20 the longevity of their effective use in the insulated permanent formwork system 1. The elongate stud members 4 include voids 3 therein to allow concrete to flow through the voids to fill the spaces on both sides of the stud members when concrete is poured into the cavity defined by the two outer wall sheets 25 2a, 2b. The distance between the outer wall sheets 2a, 2b is approximately 100-150mm and the distance between each of the stud members is approximately 100mm, although any suitable distances may be used.

WO 2008/128275 PCT/AU2008/000461 6 The wall sheets 2a, 2b are adhered to the stud members 4. The stud members 4 also include a plurality of apertures 15 therein. These apertures 15 improve the adhesion performance between the stud members 4 and the wall sheets 2a, 2b. The apertures 15 are formed by punching holes into the stud 5 members 4. Where adjacent sections of the wall sheets 2a, 2b need to be joined in order to create a wall surface that is larger than a single wall sheet, a rigid cementitious jointing is utilised. This rigid cementitious jointing is created by using a conventional adhesive product, manufactured and sold by Ardex GmbH 10 in conjunction with fibreglass reinforcing tape. This rigid cementitious jointing provides improved resistance to joint distortion due to thermal cycling and movement of the wall sheets 2a, 2b. The jointing also provides a smooth surface, which is suitable for a variety of coatings and wall treatments to be applied over the wall sheets 2a, 2b. 15 FIG 2 shows a stud member 4 according to the present invention. The stud member 4 includes a longitudinally extending web portion 5 with two opposite side edges 6a, 6b. The web portion 5 also includes first and second longitudinally extending side wall portions 7a, 7b. Each of the side wall portions 7a, 7b have a first side edge 8a and an opposite second side edge 8b. 20 The first side edge 8a of the side wall portions 7a, 7b is joined to the respective side edges 6a, 6b of the web portion 5. In this way, the side wall portions 7a, 7b are substantially perpendicular to the web portion 5. Each side wall portion 7a, 7b has an outer wall surface and an inner wall surface. The inner wall surfaces of the two side wall portions 7a, 7b face each 25 other. Each of the side wall portions 7a, 7b also have a longitudinally extending flange portion 9. The flange portion 9 has a first side edge 16a and an opposite second side edge 16b. The first side edge 16a of one of the flange portions 9 is joined to the second side edge 8b of the first wall portion 7a. The first side edge 16a 30 of the other flange portion 9 is joined to the second side portion 8b of the second wall portion 7b. In this way, the two flanges 9 extend from the side wall portions 7a, 7b, towards each other and are substantially parallel to the WO 2008/128275 PCT/AU2008/000461 7 web portion 5. The second side edges 16b of the flange portions 9 are spaced apart from each other. The outer surface of each of the side wall portion 7a, 7b of the stud members 4 are adapted to be joined face-to-face to respective outer wall 5 sheets 2a, 2b. In this way, the web portion 5 spans the distance between the two outer wall sheets 2a, 2b, such that the wall sheets 2a, 2b are supported and held in place by the stud members 4. This engagement is shown in FIG 1. The stud members 4 have first and second inner wall portions 18a, 18b. Each of the inner wall portions 18a, 18b have a first side edge and an opposite 10 second side edge. The first side edge of the first inner wall portion 18a, is joined to the second side edge 16b of the first flange portion 9. The first side edge of the second inner wall portion 18b, is joined to the second side edge 16b of the second flange portion 9. In this way, the inner wall portions 18a, 18b extend from the flange portions 9 towards the web portion 5, although the 15 second side edges of the inner wall portions 18a, 18b are spaced apart from the web portion 5. Each of the stud members 4 also includes a first and second lip portion 11, which is joined to, and extends from, the respective second side edges of the first and second inner wall portions 18a, 18b. The first and second lip 20 portions 11 extend towards the respective first side wall portion 7a and the second side wall portion 7b. As shown in FIG 3 the reinforcing members comprise an elongate central portion 12 having two opposite ends 13a, 13b. Located at each of the opposite ends 13a, 13b is a hooked formation 14. The hook formation is adapted to 25 hook onto the first and second lip portions 11 of the stud members 4, thereby securing the opposed lip portions 11 of each stud member to each other. The stud members 4 and the restraining members 10 are separate from each other. The stud members 4 include extruded aluminium and the reinforcing members 10 are made by an injection moulding process. Both the 30 stud members 4 and the reinforcing members 10 are made from roll formed WO 2008/128275 PCT/AU2008/000461 8 galvanised steel. In other embodiments not shown in the drawings, the stud members 4 and reinforcing members 10 can be integrally formed. Each stud member 4 has a number of restraining means 10 connected thereto. In the embodiment shown in FIG 1, three restraining means 10 are 5 connected to each of the stud members 4, whilst in the embodiment shown in FIG 2, two restraining means 10 are connected to the stud member 4. It should be understood that any number of restraining means 10 can be connected to each of the studs 4. In certain applications, only a single restraining means 10 may be used on each of the stud members 4. 10 Whilst the preferred embodiment show the restraining means 10 being substantially strip-like, in other embodiments, that are not shown in the drawings, the restraining means 10 can be any other suitable shape, have any suitable width or may be webbed or perforated to assist in the flow of concrete between spaces adjacent to the stud members 4. Also, the connection 15 between the restraining means 10 and the studs 4 may be altered within the scope of this invention to include other connection facilitations. Whilst in the preferred embodiment, the stud members 4 and restraining means 10 are manufactured from metal and most preferably galvanised steel, in other embodiments not shown in the drawings other suitable types of 20 material may also be used, such as polymers, plastics, timber and the like. INDUSTRIAL APPLICABILITY The invention can be utilised in building panels and building systems for forming building panels. Particularly, the present invention can be utilised in a 25 permanent formwork system for the construction of walls where concrete is placed within the formwork along with reinforcing steel and the outer skin remains in place and forms the finished wall surfaces. The word "comprising", or similar words, is generally intended to be interpreted in an inclusive sense, rather than exclusively, unless specifically WO 2008/128275 PCT/AU2008/000461 9 indicted otherwise, and would normally allow other examples or features to be included. It will be apparent that obvious variations or modifications may be made in accordance with the spirit of the invention that are intended to be part of 5 the invention, and any such obvious variations or modification are therefore within the scope of the invention.

Claims

1. A stud system for use in a formwork having two spaced apart outer wall sheets, the stud system comprising: at least one elongate stud member; and one or more elongate reinforcing members, wherein the stud member has a longitudinally extending web portion with two opposite side edges, a first and a second longitudinally extending side wall portion, each of the side wall portions having a first side edge and an opposite second side edge, the first side edges of the side wall portions being joined to the respective side edges of the web portion, such that the side wall portions extend substantially perpendicularly to the web portion; each side wall portion having an outer wall surface and an inner wall surface, with the inner wall surfaces of the two side wall portions facing each other; and each side wall portion having a longitudinally extending flange portion, wherein said flange portion has a first side edge and an opposite second side edge, the first side edge of the first flange portion being joined to the second side edge of the first side wall portion and the first side edge of the second flange portion being joined to the second side edge of the second side wall portion, such that the flange portions extend from the side wall portions towards each other substantially parallel to the web portion, with the second side edges of the flange portions being spaced from each other; wherein the outer surface of each side wall portion of the stud member is adapted to be joined face-to-face to a respective said outer sheet, such that the web portion spans the distance between the outer wall sheets; 11 wherein the reinforcing members have opposite ends, the stud system being adapted for said opposite ends to be secured in relation to the second edges of the flange portions to reinforce the stud member; wherein the stud system comprises a first and a second inner wall portion, each inner wall portion having a first side edge and an opposite second side edge, the first side edge of the first inner wall portion being joined to the second side edge of the first flange portion and the first side edge of the second inner wall portion being joined to the second side edge of the second flange portion, such that the inner wall portions extend from the flange portions towards the web portion substantially parallel to the side wall portions, with the second side edges of the inner wall portions being spaced from the web portion; and wherein a first and a second lip portion is joined to, and extending from, the second side edges of the first inner wall portion and second inner wall portion, respectively, towards the first side wall portion and second side wall portion, respectively.

2. The stud system of claim 1 wherein each of said reinforcing members comprises an elongate central portion having two opposite ends and a hooked formation at each of said ends, the hooked formations being adapted to hook onto the first and second lip portions thereby to secure the lip portions to each other.

3. The stud system of claim 1 wherein said stud member and reinforcing members are separate from each other.

4. The stud system of claim 1 wherein said stud member and reinforcing members are formed integrally with each other.

5. The stud system of claim 1 wherein said stud member includes roll formed galvanised steel. 12

6. The stud system of claim 1 wherein each of said reinforcing members is made by an injection moulding process.

7. The stud system of claim 1 wherein said stud member and said reinforcing members are made from metal.

8. The stud system of claim 1 comprising a plurality of said reinforcing members.

9. The stud system of claim 1 wherein each of the side wall portions has a plurality of apertures therein to facilitate adhesion between the side wall portions and the outer wall sheets.

10.The stud system of claim 1 wherein said web portion has at least one aperture therein to allow concrete to flow therethrough.

11.A formwork comprising two spaced apart outer wall sheets and at least one stud system as defined in claim 1, wherein the outer surfaces of the side wall portions are joined, face-to-face with the respective outer wall sheets such that the web portion spans the distance between the outer wall sheets.

12.The formwork of claim 11 wherein the outer surfaces of the side wall portions are joined with the outer wall sheets by a polyurethane adhesive.