Barrier

1. An elongate barrier that comprises:

(a) a shell that defines a cavity, the shell comprising a base wall, opposed side walls and opposed end walls that define the cavity, wherein:

the base wall and the side walls of the shell comprise two components with each component comprising a sheet of steel strip/plate folded along the length of the sheet forming one side wall and one-half section of the base wall, and

each one-half section of the base wall are connected together at a central seam to form the base wall; and

(b) a block of a ballast material in the cavity, the block filling the cavity in a lower section of the barrier and occupying only the lower section of the barrier.

2. The barrier defined in claim 1 wherein the cavity comprises a single cavity that extends the length of the barrier.

3. The barrier defined in claim 1 , wherein the barrier comprises a plurality of cavities spaced apart along the length of the barrier and the barrier comprises at least two blocks of the ballast material in the cavities along the length of the barrier.

4. The barrier defined in claim 1 wherein the end walls of the shell are separate components connected to the base wall and side walls of the shell.

5. The barrier defined in claim 1 comprises an upper hollow box beam section structural element comprising one or more lifting points for the barrier extending along the length of the barrier.

6. The barrier defined in claim 5 wherein the upper hollow box beam section comprises a sheet of steel strip/plate folded along the length of the sheet forming the upper hollow box beam section with a required transverse cross-section.

7. The barrier defined in claim 1 wherein the ballast material is concrete having a compressive strength of at least 20 MPa.

8. The barrier defined in claim 1 wherein the height of the block is less than 50% of a total height of the barrier.

9. The barrier defined in claim 1 wherein the weight of the block is up to 85% of the total weight of the barrier.

10. The barrier defined in claim 1 wherein the weight of the barrier is less than 450 kg/m of length of the barrier.

11. The barrier defined in claim 1 comprises complementary connectors at the ends of the barrier to allow a plurality of the barrier to be connected together in end-to-end relationship.

12. A barrier assembly comprising a plurality of the barrier defined in- claim 1 connected together in an end-to-end relationship forming a line of the barriers.

13. A method of manufacturing an elongate barrier, the method comprising:

(a) forming a shell that defines a cavity, the shell comprising a base wall, opposed side walls and opposed end walls that define the cavity, wherein forming the shell comprises:

forming two separate mirror-image components and connecting the components together to form the base wall and the opposed side walls, wherein each of the two separate mirror-image components of the base wall and side walls are formed by folding a sheet of steel strip/plate along the length of the sheet to form one half of the base wall and one of the side walls, and

forming the end walls of the shell as separate components, and connecting the end walls to opposite ends of the base wall and the opposed side walls to form the shell, and

(b) pouring a pourable, settable ballast material into the cavity and allowing the ballast material to set and form a block of the ballast material in the cavity, the block filling the cavity in a lower section of the barrier and occupying only the lower section of the barrier.

14. The method defined in claim 13 wherein step (a) further comprises forming an upper hollow box beam section structural element of the barrier by folding a sheet of steel strip/plate along the length of the sheet to form a box beam section with a required transverse cross-section.