Concrete retaining walls

Abstract

A concrete retaining wall section 10 comprises projecting elements 40 and recesses 24A, 24B. The projecting elements are threadingly engaged with the wall section. The projecting elements and recesses

Description

The present invention relates to concrete retaining wall sections (i.e. retaining wall sections formed predominantly of concrete) and to concrete retaining walls constructed from such sections. Concrete retaining walls can be used to store bulk materials, such as waste materials, aggregates and grain. Concrete retaining walls are typically constructed from plural wall sections which are arranged side-by-side. GB2377949A and GB2477296A disclose concrete retaining walls in which the sections are joined to one another using metallic securing straps on the faces of the wall. However, the straps require a large number of bolts and therefore can be inconvenient and time-consuming to install. GB2388569A and GB2475899A disclose concrete wall sections that are aligned relative to one another using corresponding precast concrete tongue and groove features. However, the concrete tongue features have a tendency to become damaged upon impact or when adjacent sections are laterally shifted relative to one another, for example upon contact by plant machinery. GB2475904A discloses concrete retaining walls in which the sections are joined to one another by filling vertical cavities located on the sides of the sections with concrete. The joint is made even stronger by using reinforcing rods which pass through horizontal cavities in adjacent sections. The horizontal cavities are then filled with concrete to hold the rods in place. However, the assembled concrete retaining walls cannot be reconfigured once the concrete is set. 0? 12 24 It is desired to provide improvements relating to concrete retaining wall sections and to concrete retaining walls constructed from such sections. According to an aspect of the present invention there is provided a concrete retaining wall section, the wall section comprising first and second 5 substantially vertical sides, wherein the first vertical side has one or more projecting elements and the second vertical side has one or more recesses which correspond to the one or more projecting elements, the correspondence being such that, when two such walls sections are located adjacent one another to form a concrete retaining wall, one or more projecting elements of one of the wall 10 sections is removably engageable with one or more recesses of the other of the wall sections, wherein the one or more projecting elements are threadingly engaged with the first vertical side of the wall section, wherein the one or more projecting elements each comprise a tapered portion, and wherein the one or more projecting elements each have a shape which is substantially conical, 15 substantially pyramidal or substantially a frustum. It will be appreciated that embodiments of the present invention can be used to construct concrete retaining walls in a manner which is convenient, reconfigurable, and robust. In particular, the ability to removably engage one or more projecting elements of the wall section with one or more recesses of another 20 similar or identical wall section means that a retaining wall can be rapidly constructed and reconfigured. Furthermore, the one or more projecting elements may be unscrewed from the wall section to provide a neat finish at the end of the retaining wall, if desired. Moreover, since the one or more projecting elements are threadingly engaged with the wall section, the projecting elements can be 0? 12 24 formed of a material other than concrete, e.g. a material with greater shear strength than concrete, and this can provide a more robust joint. In embodiments, the one or more projecting elements may be formed of a material other than concrete. The one or more projecting elements may each be 5 formed of a metallic material, such as steel. The one or more projecting elements may each comprise a threaded shaft which is received in a threaded bore provided in (e.g. cast into) the first vertical side of the wall section. These embodiments can provide a substantially flush surface by unscrewing the projecting element from the first vertical side if desired. The threaded shaft may, 10 for example, be provided by a bolt which is inserted through the projecting element. The projecting element may accordingly have an aperture therethrough for receiving the bolt. The aperture may have a shoulder against which the head of the bolt may bear. In embodiments, the tapered portion may taper outwardly (i.e. in a 15 direction away from the first vertical surface) from a wider span (e.g. diameter) to a narrower span (e.g. diameter). As discussed above, the one or more projecting elements each have a shape which is substantially conical, substantially pyramidal or substantially a frustum, e.g. frustoconical. Similarly, the one or more recesses may each be tapered inwardly from a wider span (e.g. width or height) 20 to a narrower span (e.g. width or height). The one or more recesses may each define a void, which may be substantially conical, substantially pyramidal or substantially a frustum, e.g. frustoconical. These embodiments can facilitate engagement of adjacent wall sections by guiding the projecting element into the 0? 12 24 recess. The one or more recesses may each comprise an opening into the second vertical side. In embodiments, the one or more recesses may each be elongate in the vertical direction. These embodiments can further facilitate engagement of 5 adjacent wall sections. For example, one of the wall sections may be located adjacent another wall section with a vertical offset, e.g. using a crane or forklift truck, and then lowered into position. These embodiments can also help to accommodate minor vertical offsets between adjacent wall sections due to uneven ground. 10 In embodiments, the one or more projecting elements may each have a span (e.g. diameter) in the range 25mm-100mm. The one or more projecting elements may each have a smallest span (e.g. diameter) in the range 25mm-50mm. The one or more projecting elements may each have a greatest span (e.g. diameter) in the range 50mm-100mm. The one or more projecting elements (e.g. 15 the tapered portion) may each have a projecting length in the range 50mm-100mm. Similarly, the one or more recesses may each have a span (e.g. width or length) in the range 25mm-100mm. The one or more recesses may each have a smallest span (e.g. width) in the range 50mm-100mm. The one or more recesses may each have a greatest span (e.g. height) in the range 100mm-20 250mm. The one or more recesses may each have an inward depth in the range 50mm-100mm. Overall, the dimensions of the one or more projecting elements (e.g. the tapered portion) may be smaller than the corresponding dimensions of the one or more recesses so that the one or more projecting elements may be wholly received within the one or more recesses. 0? 12 24 ln embodiments, the one or more projecting elements may comprise plural projecting elements. Similarly, the one or more recesses may comprise plural recesses. These embodiments can help to provide a more robust joint between adjacent wall sections by providing multiple points of engagement. The plural 5 projecting elements may be vertically aligned with one another. Similarly, the plural recesses may be vertically aligned with one another. These embodiments can allow a thinner, and hence lighter, wall section to be provided. In embodiments, the wall section may be free-standing in use. The wall section may have a front wall face for retaining bulk material and / or a rear wall 10 face for retaining bulk material. The front wall face and rear wall face may be substantially non-parallel to one another. The wall section may have a substantially uniform cross-section in planes parallel to the first and / or second vertical side. The wall section may be substantially triangular in cross-section in planes parallel to the first and / or second vertical side. The wall section may have 15 a base on which it can be stood in use. The base may be substantially planar and / or horizontal in use. Notwithstanding this, the base may be raised slightly towards a central region. This can help to accommodate uneven ground. The wall section may have a top edge. The top edge may be substantially planar and / or horizontal in use. The top edge of the wall section may comprise one or more 20 lifting elements, such as one or more threaded bores and / or (threaded) lifting hooks or loops, to allow lifting of the wall section by a crane. In embodiments, the wall section may taper from being thicker at its base to being thinner at its top edge. The wall section may have one or more (e.g. plural) wall portions which taper substantially linearly. The wall section may 0? 12 24 comprise a lower wall portion having a shallower gradient and an upper wall portion having a steeper gradient (i.e. relative to the shallower gradient). The wall section may comprise an intermediate wall portion between the lower and upper wall portions, the intermediate wall portion having an intermediate gradient 5 relative to the lower and upper wall portions. These embodiments can provide greater strength by providing a wider base region, which is under greatest pressure in use, whilst increasing the overall height and reducing the overall weight of the wall section. In embodiments, the wall section may have a height (e.g. in a vertical 10 direction from the base to the top) in the range 2000-4000mm, for example in the range 2500mm-3500mm. The wall section (e.g. the base) may have a greatest thickness (e.g. in a horizontal direction from the front face to the rear face) in the range 400-2000mm, for example in the range 800-1600mm, for example in the range 1000-1400mm. The wall section (e.g. the top) may have a smallest 15 thickness (e.g. in a horizontal direction from the front face to the rear face) in the range 50-150mm, for example in the range 75-125mm. The wall section (e.g. the front face and / or rear face) may have a width (e.g. in a horizontal direction from the first side to the second side) in the range 400-2000mm, for example in the range 800-1600mm, for example in the range 1000-1400mm. It has been found 20 that these dimensions are generally suitable for most concrete retaining wall applications. In embodiments, the wall section may comprise a substantially hollow portion extending therethrough. The hollow portion may extend from the first vertical side to the second vertical side. The hollow portion may have a 0? 12 24 substantially uniform cross-section in planes parallel to the first and / or second vertical side. The hollow portion may be substantially triangular in cross-section in planes parallel to the first and / or second vertical side. The hollow portion can help to reduce the overall weight of the wall section without compromising 5 significantly on strength. The hollow portion may also be used as a lifting point for a forklift truck. A (e.g. metallic) cover plate may be situated over one or each opening to the hollow portion, e.g. prior to locating the wall sections adjacent one another. The opening to the hollow portion may comprise a chamfer or step to at least partially accommodate the cover plate. The cover plate can help to prevent 10 vermin from entering the hollow portion. In embodiments, the wall section may have one or more fixing cavities therethrough which extend from the base into the hollow portion. The one or more fixing cavities may allow the wall section to be secured to fixing points on the ground with one or more mechanical fixings (e.g. bolts). In this regard, the 15 Applicants have identified that alignment of fixing cavities and fixing points on the ground can be difficult. Also, drilling out precisely located fixing cavities in situ through concrete can be problematic. To address this issue, in embodiments, the wall section may further comprise one or more (e.g. metallic) fixing plates which are located in the hollow portion over the one or more fixing cavities. The one or 20 more fixing plates can again help to prevent vermin from entering the hollow portion. The one or more fixing plates may comprise one or more fixing openings, which may either be pre-formed or easily formed in situ (e.g. by drilling or punching). The mechanical fixings may then be readily inserted through the fixing openings in the fixing plates, through the fixing cavities, and into the fixing points 0? 12 24 on the ground (adjusting the positions of the one or more fixing plates if necessary) thereby effectively clamping the wall section to the ground in a convenient manner. According to another aspect of the present invention, there is provided a 5 method of manufacturing a concrete retaining wall section, the method comprising forming (e.g. by moulding) a wall section as described herein in any aspect or embodiment. In embodiments, the method may comprise threadingly attaching one or more projecting elements to the first side of the wall section. The method may 10 also or instead comprise situating a cover plate over an or each opening to the hollow portion. The method may also or instead comprise locating one or more fixing plates in a hollow portion of the wall section over one or more fixing cavities of the wall section. According to another aspect of the present invention there is provided a 15 concrete retaining wall kit comprising a plurality of wall sections as described herein in any aspect or embodiment. According to another aspect of the present invention there is provided a concrete retaining wall comprising a plurality of wall sections as described herein in any aspect or embodiment. 20 According to another aspect of the present invention, there is provided a method of constructing a concrete retaining wall from plural wall sections as described herein in any aspect or embodiment, the method comprising locating the wall sections adjacent one another. 0? 12 24 ln embodiments, the method may comprise locating the wall sections adjacent one another such that one or more projecting elements of one of the wall sections are removably engaged with the one or more recesses of the other of the wall sections to form the concrete retaining wall. The method may comprise 5 threadingly attaching or removing one or more projecting elements to or from the first side of one of the wall sections. The method may also or instead comprise locating one or more fixing plates in a hollow portion of the wall section over one or more fixing cavities of the wall section. The method may comprise forming (e.g. drilling or punching) one or more fixing openings in the one or more fixing plates. 10 The method may comprise inserting one or more mechanical fixings through the one or more fixing openings, through the one or more fixing cavities, and into one or more fixing points on the ground. By way of example only, embodiments of the invention will now be described in detail with reference being made to the accompanying drawings in 15 which: Figure 1 is a front view of a concrete retaining wall section according to an embodiment of the present invention; Figure 2 is a first side view of the wall section as seen from line 1-1 in Figure 1; 20 Figure 3 is a second side view of the wall section as seen from line 2-2 in Figure 1; Figure 4 is a vertical cross-sectional view of the wall section as seen from line X-X in Figure 1; 0? 12 24 Figure 5 is a horizontal cross-sectional view of the wall section as seen from line Y-Y in Figure 1; Figures 6A, 6B and 6C show a projecting element for use with the wall section of Figure 1, with Figure 6A being a side view, Figure 6B being a first end 5 view, and Figure 6C being a second end view; Figures 7A and 7B show more detailed views of the upper recess of the wall section of Figure 1, with Figure 7A being a close up view and Figure 7B being a cross-sectional view as seen from line A1-A1 in Figure 7A; Figures 8A and 8B show more detailed views of the lower recess of the 10 wall section of Figure 1, with Figure 8A being a close up view and Figure 8B being a cross-sectional view as seen from line B1-B1 in Figure 8A; and Figure 9 is a front view of a retaining wall constructed from three wall sections as shown in Figure 1. Figures 1,2, 3, 4 and 5 illustrate a free-standing concrete wall section 10 15 for retaining bulk material according to an embodiment of the present invention. The dimensions provided in these Figures are in millimetres and are merely examples of suitable dimensions. As is shown, the wall section 10 has a front wall face 11 and a rear wall face 12 for retaining bulk material. The wall section 10 further comprises a first vertical side 14 and a second vertical side 16. The first 20 vertical side 14 has two vertically aligned threaded bores 22A, 22B for receiving respective threaded projecting elements. The threaded bores 22A, 22B are metallic parts cast into the wall section 10. The second vertical side 18 has two vertically aligned recesses 24A, 24B which are, respectively, horizontally aligned with the threaded bores 22A, 22B. The purpose of the threaded bores 22A, 22B 0? 12 24 and recesses 24A, 24B will be discussed in more detail below. The wall section 10 further comprises a base 18 on which the wall section 10 is stood in use. The base 18 is substantially planar and horizontal, but is raised slightly towards a central region to help to accommodate uneven ground. The wall section 10 further 5 comprises a planar and horizontal top edge 20. The top edge 20 comprises a pair of lifting elements in the form of threaded bores 30 configured to receive threaded lifting hooks (not shown). The threaded bores 30 are again cast into the wall section 10. The lifting elements can, for example, allow lifting of the wall section 10 by a crane. 10 As can be seen from Figures 2, 3 and 4, the wall section 10 tapers from being thicker at its base 18 to being thinner at its top edge 20. In this embodiment, the wall section 10 has three portions which taper linearly, with a lower wall portion 32 having a shallower gradient, an intermediate wall portion 34 having an intermediate gradient, and an upper wall portion 36 having a steeper gradient. 15 Referring again to all of Figures 1,2, 3, 4 and 5, the wall section 10 further comprises a hollow portion 26 extending from the first vertical side 14 to the second vertical side 16. In this embodiment, the hollow portion 26 is substantially triangular in cross-section in planes parallel to the first vertical side 14 and second vertical side 16. The wall section 10 further comprises two fixing cavities 28 which 20 extend from the base 18 into the hollow portion 26. The purpose of the fixing cavities 28 will be discussed in more detail below. Figures 6A, 6B and 6C illustrate a projecting element 40 for use with the threaded bores 22A, 22b of the wall section 10. The projecting element 40 comprises a frustoconical tapered portion 42 formed of steel. In this embodiment, 0? 12 24 the projecting element 40 has a smallest diameter ‘d’ of around 40mm, a greatest diameter ‘D’ of around 75mm and a projecting length ‘L’ of around 80mm. The tapered portion 42 has an aperture 44 therethrough for receiving a hex bolt 46. The head of the hex bolt 46 bears against a shoulder in the aperture 44, and the 5 threaded shaft 48 of the hex bolt 46 extends from the tapered portion 42 and is received in one of the threaded bores 22A, 22B of the wall section 10, thereby securing the projecting element 40 to the first vertical side 14. Figures 7A and 7B illustrate the upper recess 24A in more detail and Figures 8A and 8B illustrate the lower recess 24B in more detail. The dimensions 10 provided in these Figures again are in millimetres and are merely illustrative of suitable dimensions for receiving the projecting element 40 of Figures 6A, 6B and 6C. As is shown, the recesses 24A, 24B are tapered inwardly so as to become narrower and are elongate in the vertical direction to facilitate vertically offset engagement of the projecting elements 40 with the recesses 24A, 24B. 15 Figure 9 illustrates a retaining wall 50 comprising three side-by-side wall sections 10 as described above. As is shown in Figure 9, the correspondence between the projecting elements 40 and recesses 24A, 24B is such that, when two walls sections 10 are located adjacent one another to form the retaining wall 50, the two projecting elements 40 of one of the wall sections 10 are respectively 20 removably engageable with the two recesses 24A, 24B of the other of the wall sections 10. Construction of the retaining wall 50 includes positioning a first wall section 10 (e.g. the right-most wall section 10 shown) at a desired location, bringing a second wall section 10 (e.g. the central wall section 10 shown) into vertically offset engagement with the first wall section 10 and then lowering the second wall section 10 into place, bringing a third wall section 10 (e.g. the leftmost wall section 10 shown) into vertically offset engagement with the second wall section 10 and then lowering the third wall section 10 into place, and so on as desired. Construction of the retaining wall 50 also includes, prior to locating 5 the wall sections 10 adjacent one another, situating a metallic cover plate 52 over the openings to the hollow portions 26. Although not illustrated, the openings may comprise a chamfer or step to accommodate the cover plate 52. Construction of the retaining wall 50 also includes, whilst the hollow portion 26 is still accessible, locating a metallic fixing plate 54 in the hollow portion 26 over the fixing cavities 10 28. The fixing plate 54 comprises fixing openings through which mechanical fixings 56 are inserted. The mechanical fixings 56 extend into fixing points on the CM ground 60, thereby clamping the wall section 10 to the ground 60. i— CM 0? 12 24

Claims

1. A concrete retaining wall section, the wall section comprising first and second substantially vertical sides, wherein the first vertical side has one or more projecting elements and the second vertical side has one or more recesses which5 correspond to the one or more projecting elements, the correspondence being such that, when two such walls sections are located adjacent one another to form a concrete retaining wall, one or more projecting elements of one of the wall sections are removably engageable with one or more recesses of the other of the wall sections, wherein the one or more projecting elements are threadingly10 engaged with the first vertical side of the wall section, wherein the one or more projecting elements each comprise a tapered portion, and wherein the one or more projecting elements each have a shape which is substantially conical, substantially pyramidal or substantially a frustum.

2. A wall section as claimed in claim 1, wherein the one or more projecting15 elements are formed of a material other than concrete.

3. A wall section as claimed in claim 1 or 2, wherein the one or more projecting elements are formed of a metallic material.

4. A wall section as claimed in claim 1, 2 or 3, wherein the one or more projecting elements each comprise a threaded shaft which is received in a20 threaded bore provided in the first vertical side.

5. A wall section as claimed in claim 4, wherein the threaded shaft is provided by a bolt which is inserted through the projecting element.

6. A wall section as claimed in any one of the preceding claims, wherein the one or more recesses each taper inwardly from a wider span to a narrower span.0? 12 247. A wall section as claimed in any one of the preceding claims, wherein the one or more recesses each define a void which is substantially conical, substantially pyramidal or substantially a frustum.

8. A wall section as claimed in any one of the preceding claims, wherein the 5 one or more recesses are elongate in the vertical direction.

9. A wall section as claimed in any one of the preceding claims, wherein the dimensions of the one or more projecting elements are smaller than the corresponding dimensions of the one or more recesses so that the one or more projecting elements are wholly receivable within the one or more recesses.10 10. A wall section as claimed in any one of the preceding claims, wherein theone or more projecting elements comprises plural projecting elements and / or wherein the one or more recesses comprises plural recesses.

11. A wall section as claimed in any one of the preceding claims, wherein the wall section tapers from being thicker at its base to being thinner at its top edge.15 12. A wall section as claimed in any one of the preceding claims, wherein thewall section has one or more wall portions which taper substantially linearly.

13. A wall section as claimed in any one of the preceding claims, wherein the wall section comprises a lower wall portion having a shallower gradient and an upper wall portion having a steeper gradient.20 14. A wall section as claimed in claim 13, wherein the wall section comprisesan intermediate wall portion between the lower and upper wall portions, the intermediate wall portion having an intermediate gradient relative to the lower and upper wall portions.0? 12 2415. A wall section as claimed in any one of the preceding claims, wherein the wall section comprises a substantially hollow portion extending therethrough.

16. A wall section as claimed in claim 15, wherein the wall section further comprises a cover plate situated over an opening to the hollow portion.5 17. A wall section as claimed in claim 15 or 16, further comprising one or morecavities extending from a base of the wall section into the hollow portion, the wall section further comprising one or more fixing plates which are located in the hollow portion over the one or more fixing cavities, the one or more fixing plates comprising one or more fixing openings, wherein mechanical fixings are 10 insertable through the fixing openings in the fixing plates, through the fixing cavities, and into fixing points on the ground.

18. A method of manufacturing a concrete retaining wall section, the method comprising forming a wall section as claimed in any one of claims 1 to 17.

19. A concrete retaining wall kit comprising a plurality of wall sections as 15 claimed in any one of claims 1 to 17.

20. A concrete retaining wall comprising a plurality of wall sections as claimed in any one of claims 1 to 17.

21. A method of constructing a concrete retaining wall from plural wall sections as claimed in any one of claims 1 to 17, the method comprising locating the wall 20 sections adjacent one another.

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