GB2598908A - Hostile vehicle mitigation system - Google Patents

Abstract

The unit 100 comprises a main body formed of concrete or the like with the main body comprising a rear zone and a forward zone, at least one internal void region 50b being provided within the forward zone and a reinforcing structure 74 being provided within the rear zone of the main body. The main body may comprise first and second external end surfaces, first and second external side surfaces and an external top surface, wherein in use the external first end surface provides an attack facing front face. The main body may define a front wall in part defined by said external first end surface that provides an attack-facing front face, the front wall having a minimum thickness and wherein the at least one internal void region is provided behind said front wall. The at least one internal void region may be defined by a plurality of walls provided by the surrounding material of the main body.

Description

HOSTILE VEHICLE MITIGATION SYSTEM

FIELD OF THE INVENTION

The present invention relates to a vehicle security barrier that can impede a vehicle. The vehicle security barrier comprising one or more hostile vehicle mitigation (HVM) units for preventing vehicles from harming people or property. More specifically, but not exclusively, the invention relates to an HVM unit comprising a main body formed of concrete or the like, the main body comprising a rear zone and a forward zone. At least one internal void region is provided within the forward zone and a reinforcing structure is provided within the rear zone of the main body. Optionally, the reinforcing structure may comprise elements that extend into and provide a reinforcement of the forward zone proximate to said at least one internal void region.

BACKGROUND OF THE INVENTION

It is known to provide street furniture items such as bollards, harriers, planters and blocks that are suitable for withstanding impacts from a vehicle. The Centre for the Protection of the National Infrastructure (CPNI) has defined a variety of standards to be met by such items and is continually assessing how physical defences at the perimeter of a site can be implemented. Innovation in this area is important to ensure that layers of appropriate physical security measures can be applied to protect both users and facilities from vehicle borne attacks and ram raids.

Many existing security barriers comprise concrete blocks placed upon the ground, or vertical posts embedded within the ground. In order to provide sufficient resistance to impacts from vehicles moving at typical speeds (e.g. 30 to 60 kilometres per hour), the concrete blocks must be very heavy and large, and/or any blocks or posts must be deeply embedded in the ground, to enable them to withstand, absorb and/or disperse the high energies involved. For example, an "on-ground-fix" cube concrete bollard available from Townscape Products under their product number BOIS/0297 has a height, depth and width of 450mm and weighs 300kg.

Such barriers cannot be easily moved; or placed in locations that are only temporarily being used to host an event, where crowds of people may be present. For example, a festival hosted over a few days in a field or a festive market held in a town for only a few weeks. Installation of heavy concrete blocks or barriers embedded deeply in the ground may not practical, may cause damage to the site, may be economically prohibitive, may take too long and/or may interfere with utilities.

Furthermore, some existing concrete planters or blocks allow for up to 10m of penetration.

Where the front or rear of a hostile vehicle is used as a ram to breach a perimeter or to target premises or pedestrian areas, such a degree of penetration could have dire consequences. It is therefore desirable to provide a vehicle security barrier that allows for as low a vehicle penetration as possible given the circumstances.

CPNI requires that all vertical elements for prevention of vehicle access should be fit for purpose and successfully tested or conform to ISO International Workshop Agreement (IWA) 14-1 'Vehicle security barriers -Part 1: Performance requirement, vehicle impact test method and performance rating'; or BSI Publicly Available Specification (PAS) 68 'Impact test specifications for vehicle security barrier systems'; or GEN Workshop Agreement (CWA) 16221 'Vehicle security barriers -Performance requirements, test methods and application guidance'. Accordingly, it is necessary for any developed vehicle security barrier (VSB) to at least meet, if not exceed these standards.

The present invention seeks to provide an improvement in the field of vehicle impact barriers that has particular application for situations in which an alternative or improved solution to a heavy-weight concrete block is required.

SUMMARY OF THE INVENTION

According to one aspect of the invention, for which protection is sought, there is provided a hostile vehicle mitigation (HVM) unit for preventing vehicles from harming people or property, the HVM unit comprising a main body formed of concrete or the like, the main body comprising a rear zone and a forward zone, at least one internal void region being provided within the forward zone, and a reinforcing structure being provided within the rear zone of the main body. Said reinforcing structure may comprise elements that extend into and provide a reinforcement of the forward zone proximate to said at least one internal void region. Optionally, the reinforcement of the forward zone is provided by elements of the reinforcing structure that are contiguous with the part of the reinforcing structure within the rear zone and which are shaped to disperse or propagate impact forces toward or into the primary, possibly more substantial, reinforcing structure disposed within the rear zone.

Optionally, said main body comprises: first and second external end surfaces, first and second external side surfaces and an external top surface, and wherein, in use the external first end surface provides an attack-facing front face.

Optionally, the main body comprises a front wall in part defined by said external first end surface that provides an attack-facing front face, the front wall having a minimum thickness, and wherein the at least one internal void region is provided behind said front wall.

Optionally, said minimum thickness of the front wall is between about 30mm and 70mm. Said minimum thickness of the front wall may be about 50mm.

Optionally, said at least one internal void region is defined by a plurality of walls provided by the surrounding material of the main body of the HVM unit. Optionally, said plurality of walls includes a top wall and at least three side walls. The internal void may have a triangular cross-sectional shape. Optionally, said plurality of walls includes a top wall and four side walls. The internal void may have a trapezium-shaped cross-sectional shape.

Optionally, said top wall of the or each internal void region is disposed at an angle ar relative to the external top wall of the main body of the hostile vehicle mitigation (HVM) unit. The angle OT between the internal top wall and the external top wall may be between about 7° and about 15° or may be 10°.

Optionally, the at least one internal void region comprises first and second, side-by-side void regions spaced and separated from one another by an internal wall portion provided by the surrounding material of the main body of the HVM unit. The internal wall portion may be wedge-shaped, having a width at the front wall that is less than its width closer to the rear zone. The wedge-shaped internal wall may act as a bollard and the vehicle being arrested by the HVM unit may be forced and distorted around the internal wall, after impacting the front wall.

Optionally, said first and second internal void regions are the same shape and size.

Optionally, in normal use, the or each internal void region is occluded from view by the external surfaces of the HVM unit.

Optionally, said at least one internal void region comprises, occupies, or has a capacity of no more than between about 15% and about 20% of a total capacity of the hostile vehicle mitigation (HVM) unit. The term "total capacity" is used to mean the volume occupied by the HVM unit as defined by the external dimensions of the HVM unit.

Optionally, said rear zone occupies at least 50% or more than 60% of the total capacity of the HVM concrete block and wherein there is no internal void present in the rear zone. The term "total capacity" is used to mean the volume occupied by the HVM unit as defined by the external dimensions of the HVM unit.

Optionally, the or each at least one internal void region is partially or fully filled with a filler.

Optionally, the filler comprises a material selected in dependence upon a vehicle size for thereby tailoring the HVM unit for preventing harm to people or property by a vehicle of such size. For example, for a 7.5. tonne lorry the filler may be a plurality of air-filled polyethylene balls, optionally housed within a net or cage (which may be made of metal). For a smaller lorry, the filler may be a concrete foam such as a two-part polyurethane resin.

Optionally, the filler includes one or more or a combination of: polyethylene (optionally in the form of balls); plastic material; foam; resin; sand; wood; a plurality of air-filled items, such as air-filled sacks or plastic balls; aggregates (for example, any coarse-to medium-grained particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregate); expandable foams; concrete-foams; epoxy-based resins; and two-part polyurethane resin.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIGURE 1 is a perspective view of an HVM security barrier unit according to an embodiment of the invention; FIGURE 2 is a view of a front of the HVM security barrier unit of Figure 1; FIGURE 3A is a view of an end of the HVM security barrier unit of Figure 1, the direction from which an attacking vehicle may approach is indicated; FIGURE 3B is a view of a bottom external surface of the HVM security barrier unit of Figure 1; FIGURE 4 is a plan view from the top of the HVM security barrier unit of Figure 1; FIGURE 5A is the view of the front of the HVM security barrier unit of Figure 2, wherein section lines AA and BB are indicated; FIGURES 5B and 5C show cross-sections through lines AA and BB respectively; FIGURES 6A to 6D are rear, end, top and perspective views of a re-bar cage used in the HVM security barrier unit of Figure 1; and FIGURES 7A, 7B and 70 are rear, end and top views of the HVM security barrier unit of Figure 1 indicating the re-bar cage and voids therewithin.

DETAILED DESCRIPTION OF EMBODIMENTS

Detailed descriptions of specific embodiments of the HVM units or vehicle security barriers (VSB)s, of the present invention are disclosed herein. It will be understood that the disclosed embodiments are merely examples of the way in which certain aspects of the invention can be implemented and do not represent an exhaustive list of all of the ways the invention may be embodied. Indeed, it will be understood that the HVM security barrier units described herein may be embodied in various and alternative forms. The Figures are not necessarily to scale and some features may be exaggerated or minimised to show details of particular components. Well-known components, materials or methods are not necessarily described in great detail in order to avoid obscuring the present disclosure. Any specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the invention.

In addressing the concern that existing concrete-block style HVM units, installed in a variety of locations, including around the perimeter of buildings and perimeter of pedestrian zones, are extremely heavy weight, hard to re-locate or move and/or still do not offer as much protection (low vehicle penetration) as would be desirable, the applicant has created an HVM barrier unit that may optionally have an appearance very similar to that of existing-style concrete blocks and that is advantageously significantly lighter weight yet at least as effective as an existing HVM concrete block. The lighter-weightedness of the HVM of the present invention makes handling, transport, manoeuvring and temporary use more feasible, more cost effective and/or easier Reference is made to Figures 1 to 50, wherein views of the HVM security barrier unit 100 are shown. It can be seen that the external shape of the HVM block 100 is generally rectangular.

The HVM security barrier unit 100 comprises an external top surface 12 which may be rectangular or substantially rectangular. The HVM security barrier unit 100 comprises an external first side surface 14 which may be rectangular or substantially rectangular. The external first side surface 14 may be disposed at about 90° relative to the external top surface 12. The HVM security barrier unit 100 comprises an external second side surface 18 which may be rectangular or substantially rectangular. The external second side surface 18 may be disposed at about 90° relative to the external top surface 12; and may be positioned opposite to and parallel to the external first side surface 14.

The HVM security barrier unit 100 comprises an external first end surface 16 which may be rectangular or substantially rectangular. The external first end surface 16 may be disposed at about 90° relative to the external top surface 12. The HVM security barrier unit 100 comprises an external second end surface 20 which may be rectangular or substantially rectangular. The external second end surface 20 may be disposed at about 90° relative to the external top surface 12; and may be positioned opposite to and parallel to the external first end surface 16.

In use, the external first side surface 14 is arranged to be the front or attack-side facing surface. In use the HVM block unit 100 is arranged such that the approach of an attacking vehicle (not shown) would be interrupted and halted by the vehicle first coming into contact with the first, front side surface 14. As such, the external second side surface 18 may be considered as a rear surface of the HVM block unit 100.

The HVM block unit 100 is a concrete structure, formed into the structure as shown, by pouring concrete into a mould. A reinforcing structure, optionally comprising a (rebar) mesh 74, which may, for example, be made of rods or bars of steel arranged in a square cage structure 74, such as that shown in Figures 6A to 6D may be disposed within the mould, before the concrete is poured. In this way the reinforcing structure 74 is embedded within the concrete matrix and forms an integrally bonded component of the HVM block unit 100.

The HVM block unit 100 comprises at least one internal void region 50a, 50b (see Figures 2, 3A, 3B, 4 and 5). Optionally, in some arrangements more than one internal void region 50a, 50b may be provided within the HVM block unit 100. The at least one internal void region 50a, 50b does not comprise the same concrete or reinforcing structure 74 that the remainder of the HVM block unit 100 comprises. In some embodiments the at least one internal void region 50a, 50b comprises only air and no other void-filling material. In other embodiments the at least one internal void region 50a, 50b comprises one or more or a mixture of materials other than concrete. Such in-fill materials may include one or more or a combination of: polyethylene (optionally in the form of balls); plastic material; foam; resin; sand; wood; a plurality of air-filled items, such as plastic balls and the like. The foam may be an expandable foam, which has properties similar to concrete, for example, the expandable concrete foam sold as Sike Post Fix. The expandable foam, may be a two-part polyurethane resin which may be characterised by its lightness and strength. The HVM block unit 100, may be formed by pouring concrete into a mould shaped and sized to provide the size and shape of the main body, voids, and walls as required. Once hardened (before or after removal from the mould) the filler may be added to the at least one internal void region 50a, 50b. To add foam for example, the main body may be oriented with its external bottom surface 22 facing upwards and then the foam mix added into the voids through the open-bottom thereof towards the top wall 56. The two-part foam mix may then expand to fill the at least one internal void region 50a, 50b and allowed to harden (cure). Once hardened, any excess hard foam extending beyond the plane of the external bottom surface 22 can be cut off or otherwise removed to leave a flat external bottom surface 22. Alternatively, or additionally, a plurality of polyethylene air-filled balls, may be inserted into the at least one internal void region 50a, 50b, through the open-bottom thereof towards the top wall 56. The plurality of polyethylene air-filled balls may be enclosed in a mesh, such as a wire mesh, netting, bag or cage which can be push-fitted (friction-fitted) in the at least one internal void region 50a, 50b. As an option, expandable concrete foam may then be added into the at least one internal void region 50a, 50b.

In various embodiments, the HVM unit 100 may have its construction tailored for use in a particular risk location or for use to prevent a specific attack. For example, the at least one internal void region 50a, 50b may be partially or completely filled with a filler that is selected in dependence upon an anticipated vehicle size and/or vehicle approach velocity against which the HVM block unit 100 of such embodiments is tailored to protect. In such arrangements, the filler may comprise a variety of materials, components, mixtures, aggregates (for example, any coarse-to medium-grained particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregate), expandable foams, concrete-foams, resins, air-filled sacks or balls and the like.

Optionally, the at least one internal void region 50a, 50b comprises first and second, side-byside void regions 50a, 50b, separated from one another by an internal wall portion 55. Each internal void region 50a, 50b is defined by a plurality of walls provided by the surrounding concrete of the HVM block unit 100. The plurality of walls may include a top wall 56 and at least three-side walls. Optionally, in the present arrangement the internal void regions 50a, 50b are the same shape and size. In other embodiments the internal void regions 50a, 50b may have a different configuration, structure, shape, and size. In the present arrangement, each internal void region 50a, 50b comprises four side walls 51, 52, 53, 54. This may be best illustrated in Figure 4 which shows a top plan view of the HVM vehicle security barrier unit 100 looking down on the external top surface 12. The shape and relative location of the internal void regions 50a, 50b are depicted in dotted outline. It will be understood that in normal use, the internal void region 50a, 50b are occluded from view and cannot be seen through the external top surface 12 of the HVM security barrier unit 100.

The HVM security barrier unit 100 comprises an external bottom surface 22 as shown in Figure 3B. As can be seen, in this arrangement, the first and second, side-by-side void regions 50a, 50b have an open bottom end. In other embodiments the internal void region 50a, 50b may have a bottom closure. This may be provided by a moulded concrete wall; or by an additional plate or wall attached the primary body of the concrete HVM security barrier unit 100.

In Figures 3B, 4 and 5C, it can be seen that the four side walls 51, 52, 53, 54 of each internal void region 50a, 50b define internal void regions 50a, 50b having a trapezium-shaped cross-section. In other embodiments the orientation and number of side walls of the or each internal void region 50a, 50b may define internal void regions 50a, 50b having a triangular-shaped, rectangular-shaped, square-shaped, irregular-shaped, quadrilateral-shaped, pentagonal-shaped, hexagonal-shaped, polygonal-shaped or curved-shaped cross-section.

In Figure 5C a cross-section through the line B-B depicted in Figure 5A is shown. In this illustrated arrangement, each internal void region 50a, 50b is defined by a front wall 51, a rear wall 52, a first side wall 54 and a second side wall 53. In Figure 5B a cross-section through the line A-A depicted in Figure 5A is shown. In this illustrated arrangement, the top wall 56 is disposed at an angle OT (also see Figure 3A) relative to the external top wall 12 of the concrete block unit 100. The angle GT of the top wall 56 may be about 10°. In other embodiments the internal top wall 56 defining the internal void 50a, 50b may be parallel with the external top wall 12 of the concrete block unit 100. In yet other embodiments an angle OT between the internal top wall 56 defining the internal void 50a, 50b and the external top wall 12 of the concrete block unit 100, may be between about 7° and about 15°.

In Figure 3A a side view of the HVM concrete block unit 100 is shown. In this illustrated arrangement, a side wall 54 of an internal void region 50b is depicted in dotted outline. In Figure 3A as well as the top wall 56 being disposed at an angle OT relative to the external top wall 12 of the concrete block unit 100; the rear wall 52 is also disposed at an angle BR. The angle OR of the rear wall 52 relative to a notional perpendicular line 'N' may be about 3°. In other embodiments the rear wall 52 defining part of the internal void 50a, 50b may be parallel with the external front wall 14 of the concrete block unit 100. In yet other embodiments an angle OR between the internal rear wall 52 defining the internal void 50a, 50b and a notional perpendicular line 'N' (disposed parallel with the external front wall 14 of the concrete block unit 100) may be between about 1° and about 6°.

In Figure 4 a top view of the HVM concrete block unit 100 is shown. In this illustrated arrangement, a top wall 56 of a first internal void region 50b is depicted in dotted outline. In Figure 4 it can be seen that an internal first side wall 54 is disposed at an angle as. The angle as of the internal side wall 54 relative to an external first end wall 16 of the HVM concrete block unit 100 may be about 15°. In other embodiments the internal first side wall 54 defining part of the first internal void 50b may be parallel with the external first end wall 16 of the concrete block unit 100. In yet other embodiments an angle as between the internal side wall 54 defining part of the first internal void 50b and the external first end wall 16 of the concrete block unit 100 may be between about 10° and about 20°.

Similarly, in Figure 4 it can also be seen that an internal second side wall 53 of a second internal void region 50a is disposed at an angle a. The angle a of the internal second side wall 53 relative to an external second end wall 20 of the HVM concrete block unit 100 may be about 15°. In other embodiments the internal second side wall 53 defining part of the second internal void 50a may be parallel with the external second end wall 20 of the concrete block unit 100. In yet other embodiments an angle a between the internal second side wall 53 defining part of the second internal void 50a and the external second end wall 20 of the concrete block unit 100 may be between about 10° and about 20°.

Also, in Figure 4 it can also be seen that an internal second side wall 53 of the first internal void region 50b is disposed at an angle e relative to the internal first side wall 54 defining part of the second internal void 50a. In other embodiments the internal second side wall 53 of the first internal void region 50b may be parallel with internal first side wall 54 defining part of the second internal void 50a. In yet various embodiments an angle 0 between the internal first side wall 54 defining part of the first internal void 50b and the internal first side wall 54 defining part of the second internal void 50a may be between about 10° and about 20° and preferably about 30°.

The internal wall portion 55 may be wedge-shaped and may have a width 'B between the internal second side wall 53 defining part of the first internal void 50b and the internal first side wall 54 defining part of the second internal void 50a. The width '13' is lowest, closest to the front wall 34 and is greater closer to the rear zone (DR), which starts along the line of the rear walls 52.

Each internal void region 50a, 50b is optionally, positioned within a section defined as a front third of the HVM security barrier unit 100.

Together the total volume defined by internal void regions 50a, 50b is optionally less than a third of the volume of the HVM security barrier unit 100.

In order to more fully describe an embodiment of the invention, further details regarding the dimensions of an HVM block unit 100 will now be described with specific reference to the example of HVM block unit 100 illustrated in the Figures. It will be understood that the dimensions and dimensional relationships as now described, whilst providing technical detail about various implementations of the present invention, are not necessarily exhaustive or limiting. It will be recognised that the benefits of the invention as taught herein may be obtained in HVM block units having at least one internal void region disposed proximate to an attack face of the unit wherein dimensional relationships and shapes other than that shown in the drawings.

As shown in Figure 2, a distance L' between the external first end surface 16 and the external second end surface 20 may be between about 1000mm and about 2000mm and preferably, but not exclusively, is about 1500mm. The distance 1' may be referred to as the length 1: of the HVM block 100.

A distance 'HT' between the external top surface 12 and the external bottom surface 22 may be between about 400mm and about 800mm and preferably, but not exclusively, is about 600mm. The distance 'HT' may be referred to as the overall height'-1T' of the HVM block 100 and in various embodiments corresponds to the height of each of the first and second external end surfaces 16, 20 and external first and second side surfaces 14, 18.

The overall height 'HT' of the HVM block 100 may be divided into an above ground portion 'HA' and a below ground portion 'He'. Where required, the HVM block 100 can be embedded below ground. Advantageously, owing to the properties of the HVM block 100 taught herein, only a shallow depth of the HVM unit 100 may need to be embedded below a ground level GI.

Advantageously, by having to recess to only a shallow depth below ground utilities are not disturbed. In other embodiments, the HVM unit 100 may be surface mounted. In the presently illustrated embodiment, the HVM unit 100 is embedded below a ground level GI, by a distance 1-1B' as shown in Figure 2. Optionally, the below ground distance 1-1BI (which may also be referred to as a footing depth 1-1B% or embedding depthl-IBI) is between about 50mm and about 150mm and preferably, but not exclusively about 100mm. Additionally or alternatively, the below ground distance 'ITIB' may be between about 10% and about 20% of the overall height HT' of the HVM block 100 and preferably, but not exclusively about 16% to 17% of the overall height 'FIT' of the HVM block 100.

Optionally, the above ground distance 'HA' (which may also be referred to as the visible height HA') is between about 400mm and about 700mm and preferably, but not exclusively about 500mm. Additionally or alternatively, the above ground distance HA' may be between about 90% and about 80% of the overall height 'HT' of the HVM block 100 and preferably, but not exclusively about 83% to 84% of the overall height 'HT' of the HVM block 100.

As shown in Figure 3A, a distance D' between the external first side surface 14 (front -attack side face) and the external second side surface 18 may be between about 800mm and about 1200mm and preferably, but not exclusively, is about 1000mm. The distance D' may be referred to as the depth 'DI of the HVM block 100.

In Figure 3A, the rebar cage 74 is shown in long dash-short dash outline and the first internal void region 50b is shown in dashed outline.

A distance 'DR between the external second end surface 18 and the rear wall 52 of the internal void regions 50b, 50 may be between about 500mm and about 700mm and preferably, but not exclusively, is about 660mm. The distance DR' may be referred to as the reinforcing depth DR' or solid depth 'DR' and is a depth of a second region or rear region thereby defined. Additionally, or alternatively, the reinforcing depth distance DR' may be between about 60% and about 80% of the overall depth D' of the HVM block 100 and preferably, but not exclusively about 69% to 70% of the overall depth DI of the HVM block 100.

A distance 'Dv' between the rear wall 52 of the internal void regions 50b, 50a and the external first end surface 14 (front face) may be between about 250mm and about 400mm and preferably, but not exclusively, is about 300mm. The distance 'Dv' may be referred to as the void depth 'Dv' or hollowed depth 'Dv' and is a depth of a first region or front region thereby defined. (Also see Figure 4). Additionally, or alternatively, the reinforcing depth distance 'Dv' may be between about 20% and about 40% of the overall depth 'D' of the HVM block 100 and preferably, but not exclusively is about 31% to 30% of the overall depth D' of the HVM block 100. The hollowed regions 50a, 50b, may account for no more than about 30% and preferably no more than about 20% of the total capacity of the HVM concrete block 100 A front wall section 34 of the HVM block 100 is disposed between a front wall 51 of the internal void regions 50b, 50a and the external first end surface 14 (front face). A thickness -IF' of the front wall section 34 is shown in Figure 4 and may be between about 50mm and about 200mm.

In some examples, the total capacity of the HVM concrete block 100 may be about 885 litres x x In some examples, the capacity of each internal void region 50b, 50a may be in the region of about 77.5 litres. In various arrangements, the total capacity taken up by internal void regions 50b, 50a may be about 155 litres. In various arrangements, the total capacity taken up by internal void regions 50b, 50a may be between about 15% to about 20% of the total capacity of the HVM concrete block 100 and preferably, but not exclusively may be about 17% to 18% of the total capacity of the HVM concrete block 100.

Referring now to Figures 6A to 70, it can be seen that the reinforcing structure 74 embedded within the concrete matrix of the HVM block unit 100 is a cage-like or wire-frame structure. Optionally, the reinforcing structure 74 may be provided as a single unitary construct. In other arrangement, the reinforcing structure 74 may be provided as multiple pieces. As best seen in Figure 70, it can be seen that the reinforcing structure 74 extends substantially within the rear zone of the block 100, and also has components that extend into the front section, either side of and in between the first and second internal void regions 50b, 50a. Referring to the top view of the reinforcing structure 74 as shown in Figure 60, it can be seen that the reinforcing structure 74 optionally comprises: a generally rectangular outer cage section 76a; a generally rectangular inner cage section 76b; and plurality of void-side frame members 77.

The generally rectangular outer cage section 76a surrounds or encompasses and is welded or integrally formed with the generally rectangular inner cage section 76b. The plurality of void-side frame members 77 may surround, encompass or generally envelop portions of the outer and inner cage sections 76a, 76b. In this arrangement the plurality of void-side frame members 77 are sized, shaped and arranged to complement the shape of the internal void regions 50b, 50a; and optionally extend from proximate to the rear wall 18 of the block 100, toward the front wall 14 of the block 100.

In use, the HVM security barrier unit 100 may be embedded within the ground G at its location, with the front external surface 14 facing in a direction from which a vehicular-borne attack may be conducted. Due to the low-depth 'frIB' of excavation required for installation (when not surface mounted), the HVM security barrier unit 100 disclosed herein may be used as a temporary or re-deployable vehicle security barrier which may be employed at times of heightened threat or pre-planned special events. Without being limited to any particular theory, it is considered that in the event that a vehicle drives into the HVM security barrier unit 100 the front wall 34 will be impacted first. In dependence upon the trajectory, velocity and weight of the impacting vehicle, it is expected that the front wall 34, in the areas directly in front of the internal void region(s) 50b, 50a will break or shatter in response to the impact. The front wall 34 can be broken inwards, into the voids 50a, 50b and it is expected that the velocity of the approaching vehicle will be reduced by this initial impact which will in turn result in removal of energy from the impacting vehicle.

After impacting the front wall 34, the vehicle may then be subject to a further resistive force as it impacts the second, rear region of the HVM block 100 and more energy from the impacting vehicle will be absorbed by the concrete block with reinforced integral matrix. The strength and weight of the concrete unit may impede the vehicle, preventing its further passage and thus preventing harm to people and buildings protected by the HVM unit 100.

The angle 0 between the voids 50a, 50b provides for an optional wall section 55 (which is optionally centrally positioned), which widens as the wall approaches the rear section of the block 100. The wall section 55 is reinforced by one or more of the plurality of void-side frame members 77. The vehicle may impact the internal wall 55. Its wedge-shape and contiguity with the rear zone make this, optionally centrally positioned internal wall act similar to a bollard, which may cause the vehicle to distort. It is anticipated that the vehicle will be impeded, damaged and that the internal wall 55 may become embedded within a front part of the vehicle, causing damage thereto.

It will be recognised that the dimension of component parts, their thickness, their weight, material composition and general configuration may be adjusted for specific applications.

It will be recognised that various components may be formed as combined pieces and/or replaced by structurally equivalent or structurally suitable components. For example, whereas the HVM unit 100 has been described as being formed substantially from concrete, the concrete may be replaced by structurally equivalent or structurally suitable materials or a combination of structurally equivalent or structurally suitable materials. Concrete is generally understood to be a mix of aggregates and paste. Typically, the aggregates are sand, gravel and/or crushed stone and the paste comprises water and a cement, such as portland cement. However, it will be recognised that other suitable materials with similar characteristics to concrete may be used in addition to or in the alternative to concrete. For example, a resin based matrix may be suitable in other applications, such as, but not limited to Additionally, in the description herein, various component parts are described as being "affixed" to other component parts and it will be understood that various of the components may be formed together as integral, unitary formations wherein one component is "affixed" to another component by means of their integral formation.

It will be recognised that as used herein, directional references such as "top", "bottom", "front", "back", "end", "side", "inner", "outer", "upper" and "lower" do not necessarily limit the respective components to such orientation, but may merely serve to distinguish these components from one another.

It will be recognised that as used herein, the term "vehicle security barrier" refers to a device for hostile vehicle mitigation the purpose of which is to stop, halt or otherwise arrest the free passage of a vehicle or at least resist a vehicle impact. It will be recognised that as used herein, the term "vehicle" may refer to a car, van or lorry as examples, such as a 7.5 tonne lorry, a bus, coach or other road-going vehicle that could be used to mount a vehicular-borne attack against a building and/or group of people. It is likely that in such an attack, a vehicle will be moving at speeds of around 30 miles per hour (possibly more). Accordingly, the terms "vehicle security barrier" and "hostile vehicle mitigation (HVM) unit' should be read and understood in this context. The terms "vehicle security barrier" and "hostile vehicle mitigation (HVM) unit", as used herein, refer to a device that is capable of arresting, slowing, stopping or otherwise preventing passage of a (typically moving) vehicle, which may be loaded or unloaded and which may be being driven in person or by remote or automated control. Such "vehicle security barriers" and "hostile vehicle mitigation (HVM) units" may cause, or impart sufficient damage to the attacking vehicle to prevent it from being driven, thus ending the imminent threat posed by the movement of that vehicle.

Claims (19)

1. CLAIMS1. A hostile vehicle mitigation (HVM) unit for preventing vehicles from harming people or property, the HVM unit comprising a main body formed of concrete or the like, the main body comprising a rear zone and a forward zone, at least one internal void region being provided within the forward zone, and a reinforcing structure being provided within the rear zone of the main body.
2. 2. The hostile vehicle mitigation (HVM) unit according to any preceding claim wherein said main body comprises: first and second external end surfaces, first and second external side surfaces and an external top surface, and wherein, in use the external first end surface provides an attack-facing front face.
3. 3. The hostile vehicle mitigation (HVM) unit according to claim 2 wherein the main body comprises a front wall in part defined by said external first end surface that provides an attack-facing front face, the front wall having a minimum thickness, and wherein the at least one internal void region is provided behind said front wall.
4. 4. The hostile vehicle mitigation (HVM) unit according to claim 3 wherein said minimum thickness of the front wall is between about 30mm and 70mm.
5. 5. The hostile vehicle mitigation (HVM) unit according to claim 4 wherein said minimum thickness of the front wall is about 50mm.
6. 6. The hostile vehicle mitigation (HVM) unit according to any preceding claim 2 to 5 wherein said at least one internal void region is defined by a plurality of walls provided by the surrounding material of the main body of the HVM unit.
7. 7. The hostile vehicle mitigation (HVM) unit according to claim 6 wherein said plurality of walls includes a top wall and at least three side walls.
8. 8. The hostile vehicle mitigation (HVM) unit according to claim 7 wherein said plurality of walls includes a top wall and four side walls.
9. 9. The hostile vehicle mitigation (HVM) unit according to claim 8 wherein said top wall of the or each internal void region is disposed at an angle eT relative to the external top wall of the main body of the hostile vehicle mitigation (HVM) unit.
10. 10. The hostile vehicle mitigation (HVM) unit according to claim 9 wherein angle OT between the internal top wall and the external top wall is between about 7° and about 15° or is 10°
11. 11. The hostile vehicle mitigation (HVM) unit according to any preceding claim, wherein the at least one internal void region comprises first and second, side-by-side void regions spaced and separated from one another by an internal wall portion provided by the surrounding material of the main body of the HVM unit.
12. 12. The hostile vehicle mitigation (HVM) unit according to claim 11 the main body comprises a front wall in part defined by said external first end surface that provides an attack-facing front face, the front wall having a minimum thickness, wherein the first and second internal void regions are provided behind said front wall, wherein said first and second internal void regions are the same shape and size and/or wherein the internal wall portion is wedge-shaped having a width at the front wall that is less than its width closer to the rear zone.
13. 13. The hostile vehicle mitigation (HVM) unit according to any preceding claim, where, in normal use, the or each internal void region is occluded from view by the external surfaces of the HVM unit.
14. 14. The hostile vehicle mitigation (HVM) unit according to any preceding claim wherein said at least one internal void region comprises no more than between about 15% and about 20% of a total capacity of the hostile vehicle mitigation (HVM) unit.
15. 15. The hostile vehicle mitigation (HVM) unit according to any preceding claim wherein said rear zone occupies at least 50% or more than 60% of the total capacity of the HVM concrete block and wherein there is no internal void present in the rear zone.
16. 16. The hostile vehicle mitigation (HVM) unit according to any preceding claim wherein said reinforcing structure comprises elements that extend into and provide a reinforcement of the forward zone proximate to said at least one internal void region.
17. 17. The hostile vehicle mitigation (HVM) unit according to any preceding claim wherein the or each at least one internal void region is partially or fully filled with a filler.
18. 18. The hostile vehicle mitigation (HVM) unit according to claim 17 wherein the filler comprises a material selected in dependence upon a vehicle size for thereby tailoring the HVM unit for preventing harm to people or property by a vehicle of such size.
19. 19. The hostile vehicle mitigation (HVM) unit according to claim 18 wherein the filler includes one or more or a combination of: polyethylene (optionally in the form of balls); plastic material; foam; resin; sand; wood; a plurality of air-filled items, such as air-filled sacks or plastic balls; aggregates (for example, any coarse-to medium-grained particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregate); expandable foams; concrete-foams; epoxy-based resins; and two-part polyurethane resin.