Plastic panel and structures using the same

1. A hollow plastic wall panel, the panel having a length greater than a width, a thickness less than the width, a front wall, an opposite back wall and opposed first and second long edge regions, wherein the panel comprises a first end and a longitudinally opposite second end, wherein the first long edge region defines at least one first recessed portion to longitudinally receive and mate with a first longitudinal support beam and wherein the second long edge region defines at least one second recessed portion to longitudinally receive and mate with a second longitudinal support beam, wherein the at least one first recessed portion is arranged, in use, to partially surround the first longitudinal support beam and the at least one second recessed portion is arranged, in use, to partially surround the second longitudinal support beam, whereby the panel can be held in place by the first and second longitudinal support beams, wherein the first end has at least one end recessed portion arranged, in use, to accommodate a coupling structure disposed about or adjacent to one or both of the first and second longitudinal support beams, wherein the at least one end recessed portion comprises first opposed end recessed portions formed in the back wall at or adjacent respective top and bottom edges of the first end; and wherein the length of the panel is between about 2 m and about 4 m.

2. The panel of claim 1 , wherein the front wall is formed to have a substantially continuous convex curvature across a front face of the front wall from adjacent the first long edge region to adjacent the second long edge region.

3. The panel of claim 2 , wherein a maximum distance of the front wall from the first and second long edge regions in the thickness direction due to the convex curvature is between about 10 mm and about 30 mm.

4. The panel of claim 1 , wherein at least one of:

the thickness of the panel is between about 15 cm and about 25 cm; and

the width of the panel is between about 30 cm and about 100 cm.

5. The panel of claim 1 , wherein the panel has a substantially hollow shell structure defined at least in part by the front and back walls.

6. The panel of claim 5 , wherein the shell structure comprises joining portions at the first and second ends and the long edge regions and wherein the shell structure is substantially free of joining portions that extend between the front and back walls other than at the first and second ends and the long edge regions.

7. The panel of claim 5 , wherein the shell structure is formed of at least one polyolefin material suitable for rotational moulding.

8. The panel of claim 1 , wherein the front wall has a substantially consistent thickness.

9. The panel of claim 1 , wherein at least one of:

the first and second recessed portions of the panel are generally longitudinally extending and approximately u-shaped in cross-section; and

the first and second recessed portions are defined by the panel to have a depth and a width, wherein the depth is about half of the width.

10. The panel of claim 1 , wherein a first distance in the thickness direction of the first and second recessed portions from the front wall is not equal to a second distance in the thickness direction of the first and second recessed portions from the back wall.

11. The panel of claim 1 , wherein the panel is free of non-moulded longitudinal reinforcing structure.

12. The panel of claim 1 , wherein the panel defines at least one locating recess to allow positioning of the panel in one or more specific positions in relation to cooperating structure on the first or second support beam.

13. The panel of claim 1 , wherein the panel is configured to accommodate movement due to thermal expansion or contraction in the length direction or the width direction relative to the first and second support beam.

14. The panel of claim 1 , wherein attenuation of sound through the panel is at least about 25 decibels at frequencies between 250 Hz and 5000 Hz.

15. The panel of claim 1 , wherein at least the front and back walls are formed by rotational moulding.

16. The panel of claim 1 , further comprising a second end recessed portion extending inwardly from a face of the first end to at least partially coincide with the first opposed end recessed portions, the second end recessed portion shaped to reduce the width of the panel at the first end.

17. The panel of claim 16 , further comprising a third end recessed portion, the third end recessed portion formed as an extension of the first and second recessed portions of the first and second long edge regions, the third end recessed portion preventing the first end of the panel interfering with a sliding movement of the panel relative to the first and second longitudinal support beams.

18. A barrier comprising:

at least one panel according to claim 1 ;

a vertically extending support structure that is fixed relative to the ground;

wherein the first and second longitudinal support beams are coupled to the vertically extending support structure; and

wherein the first and second longitudinal support beams are respectively received in the at least one first recessed portion and the at least one second recessed portion so that the at least one panel is supported by the first and second longitudinal support beams.

19. The barrier of claim 18 , wherein the first longitudinal support beam is fixedly connected to the vertically extending support structure at a lowest beam position and the second longitudinal support beam is clamped to the vertically extending support structure at a position vertically spaced above the lowest beam position to secure at least one panel between the first longitudinal support beam and the second longitudinal support beam.

20. The barrier of claim 19 , wherein two of the panels are positioned end-to end in a line between the first longitudinal support beam and the second longitudinal support beam.

21. A method of erecting a barrier, comprising:

erecting a vertically extending support structure that is fixed relative to the ground;

coupling at least two vertically spaced, horizontally extending longitudinal support beams to the vertically extending support structure; and

positioning at least one panel according to claim 1 between two of the at least two horizontally extending longitudinal support beams.