GB2546446A

GB2546446A - Security barrier comprising gabions

Info

Publication number: GB2546446A
Application number: GB1706731.5A
Authority: GB
Inventors: Towers Simon; Binks David
Original assignee: Hesco Bastion Ltd; CRH Fencing and Security Group UK Ltd
Current assignee: Hesco Bastion Ltd; CRH Fencing and Security Group UK Ltd
Priority date: 2013-03-26
Filing date: 2013-03-26
Publication date: 2017-07-19
Anticipated expiration: 2033-03-26
Also published as: GB2512336A; GB2546446B; GB201706731D0; GB2512336B; GB201305537D0

Abstract

A security barrier 1 having a length L1, a height (figure 25, H2), and a breadth dimension D2. Where the barrier features a plurality of gabions 2 arranged on a ground surface, each gabion including a container 2 and at least a first fill material 13 contained in the container. A tensile element 30 extends in the length dimension of the barrier and a pair of load spreading elements 16 spaced apart in the length dimension of the barrier are provided. Each load spreading element extends in the height and breadth dimensions of the barrier. The tensile element is connected in tension between the load spreading elements, such that the load spreading elements react the tension in compression against the first fill material between the load spreading elements. In an alternative embodiment, there is provided a method of constructing a security barrier with containers instead of gabions. Optionally, the tensile element can be a steel cable and the first fill material is a loose fill material.

Description

Security barrier comprising gabions

This invention relates to security barriers made from gabions.

In this specification, a gabion is an assembly comprising a container and a fill material contained in the container so that the mass of the fill material maintains the container in a fixed, stable position.

Security barriers are often required to be deployed rapidly in hostile conditions and/or with minimal on-site preparation. Gabions are particularly suitable for this purpose since the containers (typically comprising wire mesh panels) can be prefabricated, transported in a compact (e.g. folded) condition and then reconfigured and deployed, optionally from a moving vehicle, before being filled on-site with any conveniently available fill material.

The mass and volume of the fill material greatly exceeds that of the containers so that by using a locally available fill material, a substantial barrier can be formed much more quickly and conveniently, for example, than equivalent barriers made from precast concrete blocks which must be transported individually to the site, or barriers supported by posts which must be concreted into the ground. WO2012107745 for example discloses a crowd control security barrier comprising wire mesh compartments containing a fill material, in which the front panels form an anti-climb wall, while W00040810 discloses a wall for defending against missile attack comprising wire mesh panels which are fixed together in situ to form a row of re-usable gabions.

Security barriers for use in hostile conditions such as war zones are often required to resist a variety of threats. It is the object of the present invention to provide a security barrier comprising gabions which is better able to resist attack by hostile vehicles.

In accordance with its various aspects the present invention provides a security barrier and a method as defined in the claims.

The dimensions of the gabions are selected to contain sufficient fill material to provide a hostile vehicle mitigation (HVM) barrier for resisting deliberate vehicle impact, preferably to the standard defined by the British Standards Institution PAS 68:2010 impact test specification for vehicle security barriers. The gabions are placed in compression by a post-tensioned element which effectively binds them together so that localised impact forces are transmitted through a larger mass of the fill material.

Optionally, by supporting panels on posts and connecting the posts with the gabions so that the gabions support the posts, a readily deployable barrier may be provided which combines HVM protection at a lower level with sufficient height, stability and rigidity to prevent persons from climbing or overturning the barrier, while the connected panels and reinforcement elements within and between the gabions help to stabilise and hold the gabions together under vehicle impact.

Further features and advantages will be evident from the illustrative examples which will now be described, purely by way of example and without limitation to the scope of the claims, and with reference to the accompanying drawings, in which an embodiment of the invention comprising gabions placed in compression by a tensile element is shown in Figs. 23 - 25, and further features which may be used in combination therewith are shown in Figs. 1 - 22.

Fig. 1 is a front view of a row of gabion containers comprising the first stage in the assembly of a barrier;

Fig. 2 is a front view of the completed barrier showing panels supported by the gabions;

Figs. 3 and 4 show the barrier in plan view, respectively before and after filling the gabion containers;

Figs. 5 and 6 are detail views of one of the posts as shown respectively in Figs. 3 and 4;

Fig. 7 shows components of various alternative posts and post assemblies in side view;

Fig. 8 is a transverse section through one second compartment of the barrier before filling with concrete;

Fig. 9 is a transverse section through one first compartment of the barrier after filling with loose fill material;

Figs. 10A and 10B are transverse sections through one second compartment of the barrier showing a variant post, respectively before and after filling with concrete;

Fig. 11 is a transverse section through one compartment of the barrier showing a further alternative post assembly;

Figs. 12 and 13 show the barrier in plan view, repectively before and after filling the gabion containers, in an alternative arrangement;

Figs. 14 and 15 are detail views of one of the posts as shown respectively in Figs. 12 and 13;

Figs. 16 - 19 are respectively front, end, plan, and perspective views of a further barrier;

Fig. 20 is a transverse section through the barrier of Figs. 16 - 19 showing the post assembly embedded in the concrete block;

Fig. 21 is an enlarged view of part of Fig. 20;

Fig. 22 is a horizontal section through the post of Fig. 20;

Fig. 23 shows a barrier in plan view in accordance with an embodiment of the invention incorporating a post-tensioned steel cable;

Fig. 24 is a transverse section through one second compartment of the barrier of Fig. 23 before pouring the concrete; and

Fig. 25 is a transverse section through the adjacent first compartment of the barrier of Fig. 23 showing one end of the steel cable post-tensioned against the set concrete anchor block.

It will be understood that the various features may be combined together as appropriate, and for ease of understanding, corresponding reference numerals indicate corresponding features in each of the figures.

Referring to Figs. 1 - 9, a security barrier 1 is constructed by arranging a plurality of gabion containers 2 on the ground surface 3. Each container 2 comprises a cage made from panels of wire mesh 6 defining two first compartments 4 and one second compartment 5. The cages are arranged in a row and joined together as necessary. In the example shown, the compartments are defined by generally vertical mesh panels and may include base panels or other interconnecting or reinforcing elements within, around or between the containers as known in the art. They may be fabricated as individual units or as a single assembly comprising multiple containers, and in either case, the containers may comprise integral assemblies or separate panels which are fixed together on site, and may be articulated for rapid deployment, e.g. from a moving vehicle. In the example shown, each of the second compartments 5 is lined with hessian 19 to retain concrete which is poured into the compartment as further described below. Optionally, each of the first compartments 4 may also be lined with a finer mesh or sheet material such as hessian if it is required to contain a finer grained loose fill material such as sand. A plurality of posts 8 are arranged in a row, each in front of a respective one of the second compartments 5, and attached to the front mesh surface of the compartment with a steel tie plate 7 which is arranged inside the second compartment 5 and bolted to the post through the mesh. Conveniently, in order to minimise on-site preparation, the posts are not sunk into the ground.

In this specification, a post is a rigid support element having a length much greater (e.g. at least ten times greater respectively) than its width and breadth. Usually the post will be a metal section such as a hollow round, square or rectangular section as shown, a rolled section having flanges joined by a web, an angled section or the like. Preferably, each post is connected with the gabions via a respective anchor element engaged with the first fill material, as further explained below.

The panels 9 are preferably made from a suitable wire mesh, optionally a security or anti-climb mesh as shown, and fixed to the front surfaces of the posts 8, for example, by means of security bolts 10 and steel strips 11. Rails 12 are fixed between the posts to rigidify the mesh panels.

The first compartments 4 are filled with a first fill material 13 to a fill level 14' defined by the upper surface 14 of the first fill material at a height HI from the ground surface 3, conveniently to the height of the gabion containers, and concrete 15 is cast into each of the second compartments 5 to form a second fill material which hardens into concrete blocks 16, so that each of the filled containers 2 forms a gabion 2'. In this as in the other examples, the second compartments may be filled before, after or simultaneously with the first compartments. Each of the tie plates 7 is embedded in the concrete so that the concrete block 16 acts as an anchor element which is engaged with the first, loose fill material 13 and connects the respective post 8 to the gabion.

Advantageously, the first fill material 13 is a loose fill material, i.e. a material that can be loaded into the container and then later removed in the same state from the container when the gabion is no longer required. A loose fill material will generally be rock, soil, sand or the like, but could be any other suitable material, including for example pre-cast concrete blocks of any convenient size or even containers of water or compacted snow.

Alternatively, the first fill material could be a settable material such as concrete which is cast in the container and which once poured and hardened cannot be removed without breaking it up.

Each concrete block 16 has a depth D1 which extends for at least most of the breadth dimension D2 of the gabions between the opposite front 17 and rear 18 surfaces of the barrier, i.e. D1 is at least 50% of D2 and preferably D1 is substantially equal to D2, so that the concrete blocks present a large surface area transverse to the length dimension LI of the barrier and so are fixed in position by the mass of the loose, first fill material 13 which bears against them.

In order to minimise the amount of concrete required, the concrete blocks may be spaced apart by gaps D3 (defined by the first compartments 4) of at least five times a thickness dimension D4 (defined by the second compartments 5) of the blocks in the length dimension LI of the barrier, and the first fill material 13 is arranged in the gaps. The concrete blocks may help to stabilise and improve the vehicle impact resistance of the barrier.

The gabions 2', posts 8 and panels 9 together form a unitary security barrier 1, with the gabions supporting the posts and the posts and panels extending from the ground surface 3 in front of the gabions and upwardly above the fill level 14' to the upper edge 9' of the panels, which can be at any convenient height to deter climbing and may be at least twice the height of the gabions, as shown.

Referring to Figs. 7, 10A and 10B, in an alternative example, the post 8' is provided with a hooked support element 24 which is welded or otherwise fixed to the post. The support element comprises a first leg 25 which extends horizontally from the post at a point just above the upper edge of the container 2, and a second leg 26 extending generally vertically downwardly from the first leg. The second leg is inserted downwardly into the second compartment 5 (Fig. 10A) before filling it with concrete (or before the concrete hardens) so as to embed the second leg in the concrete (Fig. 10B) so that the concrete block 16 engages the loose fill material in the first compartments and supports the post and panels 9 in front of the gabion. Optionally, the lower end region of the post may also be connected with the concrete block 16, for example, via a tie plate 7 as described above.

Referring to Figs. 7 and 11, in a further alternative example, each gabion container 2 may be filled only with a loose, first fill material 13, with each of the posts 8 being connected with the respective gabion 2' by means of an anchor element 20 comprising at least one plate buried in or under the first fill material. In the example shown, each anchor element comprises upper and lower plates 21, 22 and a rear plate 23 made from steel strips which are bolted to the post through the mesh and to the rear wall of the gabion container and buried in the fill material 13 after the compartment is filled (Fig. 9).

Referring to Figs. 12 - 15, in a further alternative example, rather than arranging the posts and panels in front of the gabions as in the first example, a base portion of each post 8 is embedded in the respective concrete block 16. The panels can be arranged to extend down to the ground surface in front of the gabions, or alternatively can extend from their upper edge 9' down to an opposite, lower edge located at the top of the gabions.

As in the first example, each post is securely fixed in the concrete block by a steel tie plate 7 embedded in the concrete.

Referring to Figs. 16 - 22, a further barrier is constructed generally as described above, except that the post assembly 8" comprises a welded Ά' frame 30 at the lower end portion of the post which is embedded in the concrete block 16, whereby the concrete block acts as an anchor to connect the post with the first fill material 13.

The gabions 2' may include tensile (e.g. steel cables) or other reinforcing elements to bind them together. In accordance with the invention, at least one tensile element is provided, as illustrated by the embodiment of Figs. 23 - 25 which will now be described.

Referring to Figs. 23 - 25, in an embodiment in accordance with the invention, a hostile vehicle mitigation barrier 1' comprises a row of gabions 2' incorporating at least one tensile element (e.g. a steel cable) 30, which is buried in the loose fill material and then post-tensioned against a pair of opposed plates which bear against the loose fill material in the gabions so as to place the loose fill material in compression. The plates may be for example steel plates (in which case the gabions need not include concrete blocks) or may be concrete blocks 16' cast in the second compartments as earlier described. Preferably the plates have a surface area of at least most of the area of the loose fill material in the gabions of the barrier when considered in section transverse to the length dimension LI of the barrier, and preferably each of the respective opposed surfaces of the plates is arranged substantially in a respective plane PI transverse to the length dimension LI of the barrier. The or each tensile element is preferably arranged between the front and rear walls of the barrier so that it extends between its extremities through the first fill material and through the respective intervening cast concrete anchor blocks 16 (if any), or alternatively it or they may be arranged at one or both of the opposite front and rear walls of the barrier.

In the example shown, a steel cable 30 is arranged in a sheath 31 and led through the gabion containers 2 about mid-way from the ground and somewhat closer to the rear wall than the front, with its ends 32 terminating in two of the empty first compartments 4. The intervening first and second compartments are filled respectively with loose fill material and with concrete and then the cable is post-tensioned using suitable terminations 33 as known in the art against the two concrete blocks 16' from which its ends protrude. The cable places the gabions in compression, with the concrete slabs spreading the load over the loose fill, so that the whole row acts as a prestressed beam. Under vehicle impact, each gabion may better resist displacement, so that the impact force is distributed through more of the mass of the fill material. Several tension elements may be provided, in parallel and/or in series along the length of the barrier, and optionally may overlap in the length dimension.

The tensile element or elements may also be used to reinforce a gabion wall which does not comprise posts and panels so as to improve its resistance to vehicle impact.

In the illustrated embodiment, the security barrier has a length dimension LI, a height dimension H2, and a breadth dimension D2. The gabions 2' are arranged on the ground surface as in the previous examples, each gabion including a container 2 and at least a first fill material 13 contained in the container. The tensile element 30, conveniently a steel cable as shown, extends in the length dimension of the barrier, preferably between its front and rear walls through the first fill material in at least two of the gabions, preferably through more than two of the gabions, so as to bind them together in compression. In order to transfer the load from the cable to the fill material, a pair of load spreading elements 16' are spaced apart in the length dimension of the barrier, each load spreading element extending in the height and breadth dimensions of the barrier. The load spreading elements may be respective ones 16' of the concrete blocks 16 as shown, or alternatively could be any other element such as steel plates or the like capable of reacting the tensile load on the cable against a sufficiently large area of the loose fill material 13.

The or each cable or other tensile element 30 is connected in tension between the load spreading elements 16' so that the load spreading elements react the tension load from the cable in compression against the first fill material 13 between the load spreading elements. The first fill material is conveniently but not necessarily a loose fill material, e.g. aggregate or the like.

As in the previous examples, the concrete blocks 16 and 16' are cast in respective second compartments 5 of respective ones of the containers 2, so that the cable extends through a plurality of the intermediate concrete blocks 16 (only one of which is shown in Fig. 23) arranged between the load spreading elements. The intermediate concrete blocks are spaced apart by gaps of at least five times a thickness dimension of the intermediate concrete blocks in the length dimension of the barrier, the first fill material being arranged in the gaps, as earlier described and illustrated in Fig. 3.

Each of the concrete blocks 16 and 16' extends in the height and breadth dimensions of the barrier H2, D2 (which is to say, it has at least some height and breadth transverse to the length of the barrier) so that it engages the first fill material in compression in the direction of the length dimension of the barrier.

The gabions 2' have a breadth D3 in the breadth dimension D2 of the barrier between opposite, front 17 and rear 18 surfaces of the gabions, and a height HI in the height dimension H2 of the barrier between the ground surface 3 and an upper surface of the first fill material 13, and each load spreading element preferably extends in the breadth dimension for at least most of the breadth of the gabions and in the height dimension for at least most of the height of the gabions, and is more preferably substantially the same height and breadth of the gabions, as shown.

Optionally, as in the previous examples, a plurality of posts 8 are connected with the gabions so that the gabions support the posts, and a plurality of panels 9 are supported by the posts, the posts and the panels extending upwardly above an upper surface of the first fill material 13, and the posts may be connected with the intermediate concrete blocks 16 so that the gabions 2' support the posts.

The barrier is constructed by arranging the containers 2 on the ground surface 3; arranging the tensile element 30 to extend in the length dimension LI of the barrier, preferably through the first fill material in at least two, preferably more than two of the containers; providing a pair of load spreading elements 16' spaced apart in the length dimension LI of the barrier, each load spreading element extending to at least some extent, preferably substantially the same extent as the gabions, in the height and breadth dimensions H2, D2 of the barrier, and filling the containers with at least a first fill material 13 to form gabions; and then tensioning the tensile element to apply a tension load to the tensile element between the load spreading elements, so that the load spreading elements react the tension load from the tensile element in compression against the first fill material between the load spreading elements.

Optionally, each container may include a dividing wall 34 defining a front compartment 35 bounded by the front wall 36 of the container 2, the front compartment 35 being filled with concrete cast into the compartment to form a concrete block 37 which provides a hard facing at the front surface of the barrier as shown. A similar arrangement can be adopted at the rear surface of the barrier. The hard facings can help to react the tension load from the cable.

In each embodiment, apertures (not shown) may be arranged between selected ones of the gabions, optionally between respective ones of the concrete blocks 16, with suitable gates, turnstiles, or the like for securing access through the barrier.

In summary, a security barrier comprises a row of gabions containing a loose fill material and resistant to vehicle impact, optionally with a row of posts and panels supported by the gabions and extending above the fill height of the gabions. The posts may be embedded in or otherwise connected to concrete blocks or other anchor elements engaged with the fill material to provide a moment connection between the posts and the gabions. The row of gabions are placed in compression by a post-tensioned steel cable arranged between opposed load spreading elements and preferably embedded in the fill material.

In alternative embodiments the gabions may comprise panels of sheet material or any other suitable containment for the fill material. The tensile element could be any element capable of maintaining a substantial tension force, e.g. a strap, bar, rope, chain or the like, made from metal, polymeric or other material.

In alternative embodiments the panels could be made from solid sheet materials. The base of each post could be sunk or concreted into the ground to provide additional support. The ground surface supporting the gabions could also be made relatively lower than the surrounding ground surface by excavating a shallow trench or the like. The gabions may include rigid support elements such as posts extending into the ground or fixed to plates arranged on the ground surface, the support elements being engaged with the containers or buried in the first fill material to rigidify the assembly.

Of course, the gabions, posts, panels and other components of the fence may be constructed in any convenient way as known in the art. The posts, if present, may be connected to the gabions in any way that adequately supports the posts and panels in use, and preferably by means of anchor elements, which may be any suitable elements for achieving a connection that transfers moment and other forces from the panels and posts to the gabions. For example, each anchor element could comprise a mesh element, a connection to the compartment walls of the gabion container, or a precast concrete block having means for connecting the post to the block and placed within or between the gabions rather than cast in a compartment of the gabion container. Many other adaptations are possible within the scope of the claims.

Claims

1. A security barrier, said barrier having a length dimension, a height dimension, and a breadth dimension, comprising: a plurality of gabions arranged on a ground surface, each gabion including a container and at least a first fill material contained in the container; a tensile element extending in the length dimension of the barrier; and a pair of load spreading elements spaced apart in the length dimension of the barrier, each load spreading element extending in the height and breadth dimensions of the barrier; said tensile element being connected in tension between the load spreading elements such that the load spreading elements react said tension in compression against the first fill material between the load spreading elements.

2. A security barrier according to claim 1, wherein said tensile element is a steel cable.

3. A security barrier according to claim 1 or 2, wherein the tensile element extends through the first fill material.

4. A security barrier according to claim 3, wherein each load spreading element is a concrete block, and the concrete blocks are cast in respective compartments of respective ones of the containers.

5. A security barrier according to claim 4, wherein a plurality of intermediate concrete blocks are arranged between the load spreading elements, the intermediate concrete blocks being spaced apart by gaps of at least five times a thickness dimension of the intermediate concrete blocks in the length dimension of the barrier; each of the intermediate concrete blocks extending in the height and breadth dimensions of the barrier; the first fill material being arranged in the gaps; the tensile element extending through the intermediate concrete blocks.

6. A security barrier according to any of claims 1-5, wherein the gabions have a breadth in the breadth dimension of the barrier between opposite, front and rear surfaces of the gabions, and a height in the height dimension of the barrier between the ground surface and an upper surface of the first fill material, and each load spreading element extends in the breadth dimension for at least most of the breadth of the gabions and in the height dimension for at least most of the height of the gabions.

7. A security barrier according to any of claims 1-6, wherein the first fill material is a loose fill material.

8. A security barrier according to any of claims 1-6, wherein a plurality of posts are connected with the gabions so that the gabions support the posts, and a plurality of panels are supported by the posts, the posts and the panels extending upwardly above an upper surface of the first fill material.

9. A security barrier according to claim 5, wherein a plurality of posts are connected with the intermediate concrete blocks so that the gabions support the posts, and a plurality of panels are supported by the posts, the posts and the panels extending upwardly above an upper surface of the first fill material.

10. A method of constructing a security barrier, said barrier having a length dimension, a height dimension, and a breadth dimension, comprising: arranging a plurality of containers on a ground surface; arranging a tensile element to extend in the length dimension of the barrier; providing a pair of load spreading elements spaced apart in the length dimension of the barrier, each load spreading element extending in the height and breadth dimensions of the barrier, and filling the containers with at least a first fill material to form gabions; and then tensioning said tensile element between the load spreading elements such that the load spreading elements react said tension in compression against the first fill material between the load spreading elements.

11. A method according to claim 10, wherein said tensile element is a steel cable.

12. A method according to claim 10 or 11, wherein the tensile element extends through the first fill material.

13. A method according to claim 12, wherein each load spreading element is a concrete block, and the concrete blocks are cast in respective compartments of respective ones of the containers.

14. A method according to claim 13, wherein a plurality of intermediate concrete blocks are arranged between the load spreading elements, the intermediate concrete blocks being spaced apart by gaps of at least five times a thickness dimension of the intermediate concrete blocks in the length dimension of the barrier; each of the intermediate concrete blocks extending in the height and breadth dimensions of the barrier; the first fill material being arranged in the gaps; the tensile element extending through the intermediate concrete blocks.

15. A method according to any of claims 10 - 14, wherein the gabions have a breadth in the breadth dimension of the barrier between opposite, front and rear surfaces of the gabions, and a height in the height dimension of the barrier between the ground surface and an upper surface of the first fill material, and each load spreading element extends in the breadth dimension for at least most of the breadth of the gabions and in the height dimension for at least most of the height of the gabions.

16. A method according to any of claims 10 - 15, wherein the first fill material is a loose fill material.

17. A method according to any of claims 10 - 15, wherein a plurality of posts are connected with the gabions so that the gabions support the posts, and a plurality of panels are supported by the posts, the posts and the panels extending upwardly above an upper surface of the first fill material.

18. A security barrier according to claim 14, wherein a plurality of posts are connected with the intermediate concrete blocks so that the gabions support the posts, and a plurality of panels are supported by the posts, the posts and the panels extending upwardly above an upper surface of the first fill material.