AU2005201936B2

AU2005201936B2 - Reinforcement mesh for concrete elements

Info

Publication number: AU2005201936B2
Application number: AU2005201936A
Authority: AU
Inventors: James Francis O'grady
Original assignee: Australian Steel Company Operations Pty Ltd
Current assignee: Australian Steel Company Operations Pty Ltd
Priority date: 2004-05-07
Filing date: 2005-05-06
Publication date: 2010-04-01
Anticipated expiration: 2025-05-06
Also published as: AU2005201936A1

Description

P/00/01Il Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Reinforcement mesh for concrete elements The following statement is a full description of this invention, including the best method of performing it known to us: 2 REINFORCEMENT MESH FOR CONCRETE ELEMENTS Field of the invention The present invention relates to reinforcement mesh for use in concrete elements. Such elements include but are not limited to concrete slabs and 5 concrete panels. Background of the invention It is known to reinforce precast concrete slabs and panels with mesh. Typically, the reinforcement mesh is formed from a plurality of parallel longitudinal wires, generally referred to as "line wires", that are drawn out during manufacture. 10 A plurality of parallel wires, generally referred to as "cross wires", are then laid out transverse to the line wires and are welded together at the intersections of the wires. The line wires are typically of 6 to 12 mm in diameter and spaced at 100 to 200 mm, measured from centre to centre. The mesh is categorised by a 2-digit code: "62 mesh" means a 6 mm wire at 200 mm spacing, while "81 mesh" is 15 8 mm wire at 100 mm spacing. The concrete slabs or panels with the reinforcement mesh are produced either at the building site or at another location remote from the building site, from where they are transported, generally by truck, to the building site. In partially constructed buildings, edge regions of the slabs or panels are often exposed and 20 thereby susceptible to damage from cranes, trucks etc. The edge regions are also exposed during transportation of the concrete slabs and panels from where they are produced to the building site. Common practice is to strengthen the edge regions in situ with additional wires. This is accomplished by manually placing on top of the already laid out 25 mesh, additional wires of a larger diameter, in between the current smaller diameter wires in the respective edge region. This process occurs during the production of the concrete slabs or panels, not during the production of the mesh itself. The process of placing the additional larger diameter wires adds a level of 3 complexity to preparation for casting each slab or panel, and requires additional equipment, man-power and time. Summary of the invention It has been realised that significant benefits can be gained in the process of 5 concrete elements, such as slabs or panels, having one or more strengthened edge regions, by manufacturing reinforcement mesh specially adapted to the application. According to a first aspect of the present invention, there is provided a reinforcement mesh for use in concrete elements, having: 10 a first set of parallel wires at a first uniform spacing; and a second set of parallel spaced wires transverse to the wires of the first set, the wires being welded together at the intersections of the wires; wherein the wires of the first set have a first uniform diameter except in each of one or more edge regions adjacent the periphery of the mesh, where one 15 or more wire(s) of the first set nearest the periphery are of a second diameter larger than the first uniform diameter. According to a second aspect of the present invention, there is provided a concrete element, including a reinforcement mesh, the reinforcement mesh having: 20 a first set of parallel wires; and a second set of parallel wires transverse to the wires of the first set, the wires being welded together at the intersections of the wires; wherein the wires of the first set have a first uniform diameter except in each of one or more edge regions adjacent the periphery of the mesh and of the 4 slab, where one or more wire(s) of the first set nearest the periphery are of a second diameter larger than the first uniform diameter; and wherein said one or more wire(s) of the first set of wires of a larger second diameter are disposed within an edge region of the concrete element to reinforce 5 the edge region and thereby reduce the incidences of cracking and of fragments being dislodged. Advantageously, the first and second sets of wires are at right angles to each other so as to form a rectangular array. Preferably, one of the first and second sets of wires comprises line wires, 10 and the other cross wires. The wires of the larger second diameter advantageously comprise line wires. Preferably, both the line wires and cross wires are at uniform spacings typically different but optionally the same. Advantageously, the cross wires are of a diameter the same as the first 15 uniform diameter of the line wires. Typically, the first uniform diameter is in the range 5 to 12 mm. The second diameter is advantageously in the range 10 to 16 mm. Preferably, the first uniform spacing is in the range 50 to 300 mm most preferably in the range 100 to 200 mm, measured from centre to centre. 20 Conveniently, the wires are steel wires. The concrete element may be a concrete slab or panel. Preferably, the slab or panel is a precast concrete element.

5 Brief description of the drawings The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a fragmentary perspective view of a reinforcement mesh 5 according to an embodiment of the first aspect of the invention, in which, for illustrative purposes, the wires are of exaggerated diameters relative to their spacings; Figure 2 is a cross-sectional view through the line A-A of the reinforcement mesh of Figure 1; and 10 Figure 3 is a partially cut-away perspective view of a concrete element in the form of a concrete slab according to an embodiment of the second aspect of the invention. Description of preferred embodiments The reinforcement mesh 10 illustrated in Figures 1 and 2, is formed by 15 drawing out a plurality of parallel line wires 12. A plurality of parallel cross wires 14 are then laid on top of and transverse to line wires 12 at a uniform spacing. Line wires 12 and cross wires 14 are welded together at the intersections 16 of the wires 12,14. Line wires 12 comprise a first set 11 of wires, generally of a uniform 20 diameter in the range 5 to 12 mm and uniformly spaced between 100 to 200 mm, measured centre to centre. Cross wires 14 comprise a second set 13 of spaced parallel wires. At edge region 18 adjacent periphery 20 of reinforcement mesh 10, the two line wires 22 nearest periphery 20 are of a larger diameter than the other line wires 12 of set 11. The diameter of line wires 22 is generally in the range 10 25 tol6 mm. The spacing between line wires 22 and the outermost of line wires 12 is maintained at the same uniform spacing, i.e. generally between 100 to 200 mm measured centre to centre, as that between smaller diameter line wires 12.

6 Figure 3 is a fragmentary view of a concrete element 24, in this case a precast concrete slab containing the reinforcement mesh 10 of Figures 1 and 2. It will be appreciated that the concrete element 24 may be any appropriate concrete element, such as a slab or panel, and may or may not be precast. The slab 24 is 5 formed in the conventional manner. Line wires 22 provide additional strength to edge region 25 of slab 24, which is prone to damage during transportation, when on the building site, and once installed in a partially erected building. This additional reinforcement of the edge region 25 reduces the incidences of serious cracking of the edge region and of fragments being dislodged: these can occur 10 through the edge region being struck by building site equipment or by other components of the building as it is erected. Mesh 10 can be produced entirely conventionally by simply substituting large diameter wires 22 for the selected outer line wires 12, a more economical approach than the conventional practice of placing additional wires at the casting 15 site. It will of course be appreciated that cross wires 14 may additionally or alternatively include wires of larger diameter than the other cross wires, in one or more further edge regions of the slab 24. It will also be understood that the invention disclosed and defined in this 20 specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

Claims

1. A reinforcement mesh for use in concrete elements, having: a first set of parallel wires at a first uniform spacing; and a second set of parallel spaced wires transverse to the wires of the 5 first set, the wires being welded together at the intersections of the wires; wherein the wires of the first set have a first uniform diameter except in each of one or more edge regions adjacent the periphery of the mesh, where one or more wire(s) of the first set nearest the 10 periphery are of a second diameter larger than the first uniform diameter.

2. A reinforcement mesh according to claim 1, wherein the first and second sets of wires are at right angles to each other so as to form a rectangular array. 15

3. A reinforcement mesh according to claim 1 or 2, wherein one of the first and second sets of wires comprises line wires and the other cross wires.

4. A reinforcement mesh according to claim 3, wherein the cross wires are of a diameter the same as the first uniform diameter of the line wires.

5. A reinforcement mesh according to claim 1, 2, 3 or 4, wherein the wires of 20 the larger second diameter comprise line wires.

6. A reinforcement mesh according to any one of claims 1 to 5, wherein the spacing of the second set of wires is the same as the first uniform spacing.

7. A reinforcement mesh according to any one of claims 1 to 5, wherein the spacing of the second set of wires is different to the first uniform spacing. 8

8. A reinforcing mesh according to any one of the preceding claims, wherein the first uniform diameter is in the range 5 to 12 mm.

9. A reinforcing mesh according to any one of the preceding claims, wherein the second diameter is in the range 10 to 16 mm. 5

10. A reinforcing mesh according to any one of the preceding claims, wherein the first uniform spacing is in the range 50 to 300 mm.

11. A concrete element, including a reinforcement mesh, the reinforcement mesh having: a first set of parallel wires; and 10 a second set of parallel wires transverse to the wires of the first set, the wires being welded together at the intersections of the wires; wherein the wires of the first set have a first uniform diameter except in each of one or more edge regions adjacent the periphery of the mesh and of the slab, where one or more wire(s) of the first set 15 nearest the periphery are of a second diameter larger than the first uniform diameter; and wherein said one or more wire(s) of the first set of wires of a larger second diameter are disposed within an edge region of the concrete element to reinforce the edge region and thereby reduce the 20 incidences of cracking and of fragments being dislodged.

12. A concrete element according to claim 11, wherein the first and second sets of wires are at right angles to each other so as to form a rectangular array.

13. A concrete element according to claim 11 or 12, wherein one of the first and second sets of wires comprises line wires and the other cross wires. 9

14. A concrete element according to claim 13, wherein the cross wires are of a diameter the same as the first uniform diameter of the line wires.

15. A concrete element according to any one of claims 11 to 14, wherein the wires of the larger second diameter comprise line wires. 5

16. A concrete element according to any one of claims 11 to 15, wherein the spacing of the second set of wires is the same as the first uniform spacing.

17. A concrete element according to any one of claims 11 to 15, wherein the spacing of the second set of wires is different to the first uniform spacing.

18. A concrete element according to any one of claims 11 to 17, wherein the 10 first uniform diameter is in the range 5 to 12 mm.

19. A concrete element according to any one of claims 11 to 18, wherein the second diameter is in the range 10 to 16 mm.

20. A concrete element according to any one of claims 11 to 19, wherein the first uniform spacing is in the range 50 to 300 mm.