GB2159190A

GB2159190A - Concrete block

Info

Publication number: GB2159190A
Application number: GB08413062A
Authority: GB
Inventors: Anthony Walter Bell
Original assignee: VECTIS STONE GROUP PLC
Current assignee: VECTIS STONE GROUP PLC
Priority date: 1984-05-22
Filing date: 1984-05-22
Publication date: 1985-11-27
Also published as: GB2159190B; GB8413062D0

Abstract

A concrete block is substantially in the shape of a polygonal ring one face of which is plain and from the other face of which legs (2) project perpendicularly thereto. A respective leg (2) is provided at each vertex of the polygonal ring. Structures are built from assembling a plurality of the blocks together. <IMAGE>

Description

SPECIFICATION Concrete block This invention relates to interlocking concrete blocks and structures made up of such blocks.

In coastal engineering a wide variety of different structures are provided for different purposes.

These are typically made in situ and are consequently expensive.

One exception to construction in situ is the use of what are known as "tetrapods" to protect a sea wall or similar structure. The tetrapods are four legged structures shaped like caltrops (but much larger) and are simply placed at random along the shore in front of the sea wall. A disadvantage of the tetrapods is that they are liable to "walk" out to sea as a result of erosion under the seaward legs.

According to the invention there is provided a concrete block substantially in the shape of a polygonal ring one face of which is plain and from the other face of which legs project perpendicular thereto, a respective leg being provided at each vertex of the polygonal ring.

Blocks of this kind can readily be interlocked by inserting legs of one block into a ring of another block. When interlocked the blocks cannot shift independently of one another.

Preferably the polygonal ring is rectangular and most advantageously square. In the preferred embodiment of the invention the width of a side of the ring is half the interior width and interior length of the ring and the legs are of square crosssection, the square having sides of the same length as the width of a side of the ring. With such an arrangement the interior of the ring is able to accommodate a leg from each of four other blocks and the ring is filled by the four legs.

The width of a side of the ring is preferably at least 100 mm. A block of this size is sufficiently heavy to stay where it is placed in most contiditions of use.

The depth of the ring is preferably the same as the width of a side of the ring.

The legs preferably project from the ring by a distance equal to the depth of the ring. In this case when legs are inserted into the interior of a ring, they terminate flush with the plain face of the ring so that a smooth surface can be provided.

There is no need for the concrete blocks to be reinforced and indeed steel reinforcement is undesirable in certain respects; for example, if the concrete is eroded, rusty steel reinforcement may be left projecting from the block; nonetheless in certain applications steel reinforcement may be required. The blocks may include fibre reinforcement, if desired.

Preferably the block tapers from the plain face towards the distal ends of the legs. A half angle of taper of not more than 1 or 2 degrees is sufficient so that the block remains substantially in the shape defined above.

According to another aspect of the invention there is provided a structure comprising a multiplicity of blocks as defined above, a first plurality of the blocks being disposed adjacent to one another to define a first layer and a second plurality of blocks being disposed adjacent to one another to define a second layer lying adjacent the first, the legs of blocks in one of the layers projecting into the rings of blocks in the other of the layers.

A structure of this kind is very easy to assemble in situ, simply by placing the blocks individually in their desired positions. If the blocks are of the preferred form then the structure also has a degree of flexibility to accommodate a curved support base or to define a curved vertical boundary.

In a first form of structure the legs of the blocks in the first layer project into the rings of the blocks in the second layer and the legs of the blocks in the second layer project into the rings of the blocks in the first layer. If the blocks are of the preferred form, this arrangement provides a self-draining structure with a smooth surface to the top and bottom of the structure. Such a structure may be used to provide a jetty or a pathway across a sandy beach or other surface.

In a second form of structure the legs of the blocks in the first layer project into the rings of the blocks in the second layer and the legs of the blocks in the second layer project away from the first layer. In a structure of this form additional interlocking layers may be added at will and towers may be built. The legs of the blocks may project upwards; a marine application for a structure of this kind it to provide "dragon's teeth" along a shoreline. The structure may also be used with the legs pointing downwards.

A hybrid structure may also be formed including the first form of structure defined above and either or both alternatives of the second form of structure defined above.

The structure may simply be laid in position and the interlocking of the blocks together with their weight relied upon to keep them in position or some of the blocks may be anchored, for example by a pin pile in one or more interior corners of each anchored block.

By way of example embodiments of the invention will now be described with reference to the accompanying drawings, of which: Figure 1 is a perspective view of a concrete block embodying the invention; Figure 2 is a side view of the block of Figure 1; Figure 3 is a schematic plan view of a first form of structure made up of the blocks of Figures 1 and 2; Figure 4 is a sectional view along the lines IV-IV of Figure 3; Figure 5 is a schematic plan view of a second form of structure made up of the blocks of Figures 1 and 2; and Figure 6 is a sectional view along the lines VI-VI of Figures 5.

The block shown in Figures 1 and 2 is made of concrete and is substantially in the shape of a square ring 1 one face of which (the bottom face in Figures 1 and 2) is plain and from the other face of which four legs 2 project perpendicular thereto, a respective leg being provided at each corner.

It will be appreciated from Figure 1 that the block has 90 degree rotational symmetry and Figure 2 could therefore be a view of any side of the block.

Taking the width ws of a side of the ring 1 as one unit of length and ignoring for the moment effects of tapering, the interior width wi and interior length li of the ring are each 2 units and the exterior width we and exterior length le are each 4 units. The depth d of the ring is 1 unit and the legs 2 are cubes having edges of length 1 unit.

As can be seen in Figure 2 the block actually tapers progressively from its plain face towards the distal ends of the legs 2. The half angle d of this taper is of the order of one degree. Thus some of the dimensions quoted above are not exactly as stated and are reduced by the effect of the taper.

The shape of the blocks are such that they can be interlocked in a variety of ways. Figures 3 and 4 show schematially one way of interlocking the blocks. The taper on the blocks is not shown in these figures. The structure shown in Figures 3 and 4 comprises a lower layer of six blocks 4 laid with their plain face on the bottom and the legs 2 projecting upwards and an upper layer of six blocks 5 laid with their plain face on the top and the legs 2 projecting downwards. The legs of the blocks in one layer terminate flush with the plain face of the blocks in the other layer and therefore the structure has an even upper (and lower) surface.

As a result of the tapering of the blocks there is an element of play between the blocks so that they are able to follow a slightly curved path if desired.

Furthermore the curve may be that obtained by pivoting a block about an axis passing perpendicularly through the square ring 1 or about an axis perpendicular to that axis so that the structure may be laid on a surface of varying slope and/or may follow a curved or straight path over that surface.

Another result of the tapering of the blocks is that drainage paths through the structure are provided between the interlocking blocks.

A structure of the kind shown in Figures 3 and 4 may for example be used to provide a jetty or a concrete pathway across a sandy beach.

Figures 5 and 6 show schematically another way of interlocking the blocks. In this case, the structure comprises a bottom layer of six blocks 6 laid with their plain face on the bottom and the legs 2 projecting upwards, a second layer of six blocks 7 laid on top of the blocks 6 also with their plain face on the bottom and the legs 2 projecting upwards, and a third layer, which for the purposes of illustration is shown as comprising a single block 8 only, laid on top of the blocks 7 again with its plain face on the bottom and the legs 2 projecting upwards. For the sake of clarity the legs of the blocks 6, 7 and 8 are shown shaded in Figure 5 a different shading being used for each layer.

As with the structure of Figures 3 and 4, the ta pering of the blocks provides natural drainage and allows the structure to curve. it will be appreciated that the structure of Figures 3 and 4 may be built upwards (and also of course outwards) indefinitely so that towers or piers may be formed. Furthermore it will be seen that right hand end of the structure of Figures 3 and 4 could be interlocked with the left hand end of the structure of Figures 5 and 6. It is also possible to use the structure of Figures 5 and 6 the other way up and this kind of structure can be interlocked with the left hand end of the structure of Figures 3 and 4.

A structure of the kind shown in Figures 5 and 6 may be used to provide dragon's teeth on a shoreiine, or to construct a sea wall or a pier.

The structures of Figures 3 to 6 are very simple to assemble. It is merely necessary to transport precast concrete blocks (which are themselves a simple shape) to the site and lay them in the desired configuration. Because the blocks interlock they cannot move once laid; while the blocks can be laid on a wide variety of surfaces, a particularly advantageous surface is provided by a geotextiie material. If desired additional anchorage for the blocks can be provided by driving pin piles into the corners of one or more blocks.

While for most purposes it will be desirable for each layer of blocks to be complete it is possible to omit odd blocks from a given layer without affecting the interlocking nature of the structure.

As will be clear from a study of Figures 3 to 6 the boundary edges of the structure may run parallel to the sides of the square rings of the blocks or at 45" thereto.

The size of the blocks is a matter of choice but for most purposes the unit of length referred to above with reference to Figures 1 and 2 will be between about 100 mm and 1,000 mm.

Claims

1. A concrete block substantially in the shape of a polygonal ring one face of which is plain and from the other face of which legs project perpendicular thereto, a respective leg being provided at each vertex of the polygonal ring.

2. A block according to claim 1 in which the polygonal ring is rectangular.

3. A block according to claim 2 in which the polygonal ring is square.

4. A block according to claim 3 in which the width of a side of the ring is half the interior width and interior length of the ring.

5. A block according to claim 4 in which the width of a side of the ring is at least 100 mm.

6. A block according to claim 5 in which the legs are of square cross-section, the square having sides of the same length as the width of a side of the ring.

7. A block according to any of claims 3 to 6 in which the depth of the ring is the same as the width of a side of the ring.

8. A block according to any preceding claim in which the legs project from the ring by a distance equal to the depth of the ring.

9. A block according to any preceding claim wherein no reinforcement is provided.

10. A block according to any of claims 1 to 8 in which fibre reinforcement is provided.

11. A block according to any preceding claim in which the block tapers from said one face to the distal end of the legs.

12. A concrete block substantially as herein described with reference to and as illustrated by Figures 1 and 2 of the accompanying drawings.

13. A structure comprising a multiplicity of blocks as claimed in any preceding claim, a first plurality of the blocks being disposed adjacent to one another to define a first layer and a second plurality of blocks being disposed adjacent to one another to define a second layer lying adjacent the first, the legs of blocks in one of the layers projecting into the rings of blocks in the other of the layers.

14. A structure according to claim 13 in which the legs of the blocks in the first layer project into the rings of the blocks in the second layer and the legs of the blocks in the second layer project into the rings of the blocks in the first layer.

15. A structure according to claim 13 in which the legs of the blocks in the first layer project into the rings of the blocks in the second layer and the legs of the blocks in the second layer project away from the first layer.

16. A structure according to claim 15 in which the legs of the blocks project upwards.

17. A structure according to claim 15 in which the legs of the blocks project downwards.

18. A structure according to claim 13 including a structure according to claim 14 and a structure according to any of claims 15 to 17 interlocked together.

19. A structure comprising a multiplicity of interlocking concrete blocks, the structure being substantially as herein described with reference to and as illustrated by Figures 3 and 4 or by Figures 5 and 6 of the accompanying drawings.