GB2519788A

GB2519788A - Safety Barrier

Info

Publication number: GB2519788A
Application number: GB1319173.9A
Authority: GB
Inventors: Steven Dunn
Original assignee: Hill and Smith PLC
Current assignee: Hill and Smith PLC
Priority date: 2013-10-30
Filing date: 2013-10-30
Publication date: 2015-05-06
Anticipated expiration: 2033-10-30
Also published as: GB201319173D0; HK1205540A1; AU2014200471A1; GB2519788B

Abstract

A safety barrier, in particular an 'off highway' safety barrier, for protecting the vehicle occupants, pedestrians and other vehicles. The barrier 10 comprises a plurality of first support members 12 for coupling to the ground and providing a predetermined first amount of energy absorption in the event of a vehicle impact; one or more second support members 50 for coupling to the ground and providing a second predetermined amount of energy absorption less than the first amount of energy absorption, in the event of a vehicle impact; and an elongate restraining member 26, e.g. rail, supported by said first and/or second support members at a height above the ground. The first support members may be deflectable; the second support members may be deflectable, yieldable or breakable and may include a weakened or frangible portion with inclusion of a notch or aperture (158, fig.13)

Description

Safety Barrier The present invention relates to a safety barrier and, in particularly but not exclusively, to an off highway' safety barrier.

Background to the invention

Off highway' barriers are designed with the objective of protecting the vehicle occupants and/or pedestrians, vehicles, plants and buildings. (By comparison, road or highway barrieis aie designed with the objective of lestlaining and/or redirecting a vehicle in the event of an impact -which may be at a significant speed.) Such off highway barriers are often utilized in car parks, logistics yards, warehouses, factories, retail parks, loading bays etc. Theft design considerations differ significantly to those of a road safety barrier, due to the diffeient impact conditions that me likely to occul. Off highway impacts are likely to occur perpendicular to the barrier and at lower speeds than would be typical of a highway barriei impact, which typically involves a low-angle, glancing impact thereon.

Known barriers are provided by Berry Systems, who offer both flexible and rigid barrier systems. In the former case, the barriers are designed to deflect on impact to provide absorption of energy. In the latter case, energy absoiption occurs through energy transmission to the surroundings e.g. the building structure in which they are mounted.

Flexible systems typically inflict less damage to vehicles and vehicle occupants and, even if components of the barrier aie damaged, these are replaceable.

One example is Berry System's spring steel buffer system, a section of which is shown in Figure 1. This system comprises a flexible buffer anchored to the ground. An impact beam is also fixed to the buffer, typically at a height coiiesponding to that of a vehicle bumper, and panelling is piovided in front of the impact beam. A handrail may be provided at the top of the barrier, at a suitable height for pedestrian use.

For safety reasons, off highway barriers must comply with the requirements of British Standaids BS6399 part 1 1996 and BS 6180:1995. These specify the force that the barrier must be able to withstand and place requirements on when barriers and components such as handrails, infill panels etc. are required. Whilst the known spring steel buffer system complies with BS6399 in its entirety, the flexible nature of the system has meant that, when placed under the loading specified in BS6180, the handrail has been found to deflect quite considerably -beyond the limits imposed by BS6180. Since safety -of both vehicles and their occupants, and pedestrians -is paramount, this is clearly undesirable.

The present invention has been designed with the foregoing in mind.

Summary of the invention

In accordance with a first aspect of the present invention, there is provided a safety barrier as defined in claim 1.

Advantageously, the invention provides a flexible barrier that is capable of absorbing energy from an impacting vehicle according to pre-calculated load criteria. Under high loads, the barrier flexes to absorb energy, which provides a reduced loading into the ground via the coupling therebetween. The second support members provide an additional predetermined amount of energy absorption, which advantageously increases the strength and integrity of the barrier and helps to define the energy absorption capabilities to ensure the barrier complies with the relevant safety standards.

In an embodiment, the plurality of first support members are deflectable in the event of an impact by a vehicle on the barrier. Preferably, the one or more second support members are flexible, deformable, yieldable or breakable under loading e.g. in the event of a vehicle impact. In a preferred embodiment, the one or more second support members are yieldable or breakable, i.e. will fail, at a height above ground that is less than the height above ground of the restraining member. In a more preferred embodiment, the one or more second support members are configured to break or fail at a predetermined loading, e.g. at approximately lOkN. Alternatively, the second support member may be configured to break or fail under a different load, e.g. under a loading substantially between 9 and llkN, e.g. at about 9kN, 9.5kN, 10.5kN, llkN, or otherwise, depending on the barrier requirements.

Preferably, the one or more second support members are configured to yield or break under a predetermined load, and the one or more first support members are configured to withstand that predetermined load. The one or more second support members are preferably configured such that any bending moments are restricted to the front of the barrier, which advantageously helps to define the barrier performance and integrity in the event of an impact.

In a most preferred embodiment, the one or more second support members comprise one or more of a weakened portion, a frangible portion, an indentation, an aperture, one or more perforations or a notch. The one or more second support members may comprise a first weakened portion, frangible or yieldable portion, indentation, aperture cut-out or notch on one or both edges thereof and/or a second weakened portion, frangible portion, indentation, aperture or notch within or on the body of the one or more second support members. In an embodiment, the one or more second support members are c-or u-shaped in cross section (extending along the height thereof), and the first weakened portion, frangible or yieldable portion, indentation, aperture, cut-out or notch is provided in or on one or both arms of the c-or u-shaped second support member.

In a preferred embodiment, the second support members comprise a cut-out on each side thereof, and most preferably the cut-outs are substantially symmetrical and aligned with each other across the width thereof The cut-out may be trapezoidal in shape, the sides of which may taper inwardly toward the centre of the second support member. Alternatively, the cut-outs may be square, rectangular, triangular, semi-circular, curved, or be in the form of a slit. In another alternative embodiment, the second support members may be deformed e.g. bent to provide an area of weakness therein. Or, the second support members may be perforated across their width, e,g.

comprising a series of small apertures or slits. In embodiments where the one or more second support members are c-or u-shaped in cross section, the cut-outs may be provided in or on the arms of the c-or u-shaped one or more second support members. Otherwise, the cut-outs may be provided directly in/on the edge of the one or more second support members. Thus, in these embodiments the area(s) of weakness is/are provided on the exterior edge(s) of the one or more second support members. In addition, or instead, the area(s) of weakness may be provided within the body of the one or more second support members, i.e. between the edges thereof, e.g. centrally.

The plurality of first support members may be provided on a first side of the restraining member, and the one or more second support members may be provided on a second and opposite side of said restraining member. I.e. preferably, the first and second support members are provided on opposite sides of the restraining member. The second support members may be provided externally' on the barrier, i.e. on the side with which a vehicle will make contact in the event of an impact. The provision of the second support members, on the opposite side of the restraining member from the first support members, advantageously provides a predetermined amount of energy absorption in the event of an impact, thus improving the integrity of the barrier.

The one or more second support members may be provided substantially aligned with the plurality of first support members (in a direction transverse to the longitudinal direction of the barrier), which advantageously strengthens the barrier. Alternatively, the second support members could be positioned at different locations along the length of the barrier from the first support members, such that they are not aligned in a direction transverse to the direction of the length of the barrier. The alignment of misalignment can be chosen according to the energy absorption requriements.

Preferably, the first and second support members are substantially equally spaced along the length of the barrier, at least along a portion thereof. The spacing can be chosen to suit the barrier performance required. Alternatively, the spacing of the first and/or second support members can be varied e.g. spaced unequally along the length of the barrier, in accordance with the requirements dictated by local surroundings, desired performance characteristics etc. The one or more first/second supports may conveniently be separated by a distance of substantially 800mm. Alternatively, the spacing may be substantially 400mm, 1600mm or 2000m. The barrier has been tested with a spacing of substantially 1600mm (and found to comply with the British Standards). The spacing can, however, be tailored according to the environment and surroundings, and the spacing may for example be any value substantially between 0 and 2000mm, or more if required.

The one or more second support members preferably comprise an elongate plate or strip. In an embodiment, the one or more second support members are substantially L-shaped, and comprise fa oot or base section. In embodiments where the one or more second support members are of a c-or u-shaped cross section (above the base), the material from which it is constructed may be of a lesser gauge than the flat plate' embodiment, although the c-lu-shaped cross section provides additional stiffness in relation thereto. The base thereof preferably provides means for coupling the one or more second support members to the ground. In an embodiment, the base of the one or more second support members is also coupled to the base of a first support member. A washer, e.g. a plate washer may also be incorporated. This washer may be configured such as to force any bending moments to be restricted to the front of the barrier. The upper part of the one or more second support members may be coupled to the one or more first support members, or an extension member attached thereto.

It is an advantage that the second support members are simple and inexpensive to manufacture, and thus to replace if required post-impact.

The safety barrier may comprise a handrail provided at or near the top thereof. The handrail may be a length of tubing or a solid component, e.g. of circular or square cross section. The handrail is preferably attached to the first support member or an extension member attached thereto, in the vicinity of, or just below, the handrail.

In an embodiment, the safety barrierfurther comprises an impact surface, in the form of a panel or cladding adjacent to the one or more second support members. The cladding may present a continuous surface on the impact side of the barrier (i.e. an impacting vehicle will contact this first). The cladding may comprise a sheet of material configured to prevent egress therethrough, e.g. a perforated sheet such as meshing or netting. This has the advantage that it is cheap and simple to replace if damaged in an impact, and that the environs beyond are visible therethrough. In another embodiment the cladding may comprise a solid sheet of material. The sheet of material may be provided within a frame attached to the barrier.

In an embodiment, the restraining member is provided at a height corresponding to a vehicle bumper height. The restraining member may be a beam, e.g. a box beam, an open box beam (i.e. open along one side along the length thereof), a W-beam etc. The beam may also be a Berry beam', provided by Berry Systems, this being a type of open box beam that is substantially trapezoidal in cross section. Alternatively, any rigid profile or section that will perform in a similar manner as the aforementioned support could be utilized.

Preferably, the first support members are configured to deflect, rather than fail, in the event of an impact on the barrier. The first support members may be substantially L' shaped, or comprise a foot'. Preferably, the one or more first support members are anchored to the ground at or near one end thereof, and are flexible/deformable about that anchor point. The first support member may be formed from a plate or an elongate strip of metal or other material, and are preferably formed of spring steel. Preferably, the plurality of first support members are spring steel buffers, such as those manufactured by Berry Systems.

In an embodiment, the first support members extend to a height above ground less than that of the height of the barrier. In this embodiment, an extension member may be provided, configured for coupling to the first support member, to increase the height of the support to or towards the top of the barrier. Alternatively, the first support members may extend to the top of the barrier, without the need for an extension member. The handrail may or may not be integrally formed with the first or second support member or the extension member. In alternative embodiments, the first support members may take other forms e.g. posts, flexi-posts, bollards, flexi-bollards etc..

The second support members may extend substantially the height of the barrier. In an embodiment, the second support members extend between the base of the barrier and the handrail.

According to a second aspect of the present invention, there is provided a yieldable support member as defined in claim 21.

Aspects and embodiments of the present invention provide a flexible barrier that offers a reduced anchor loading to the ground (due to energy absorption by the flexible support members). The claimed barrier has been tested and found to comply with British Standards BS6399 and BS61BO. In particular, such a barrier incorporating second support members not only sustains the loading in accordance with the standards, but also mitigates against deflection of the handrail which might otherwise occur due to the impact. The second support members, which are designed to fail under higher vehicle loading, still also allow the typical performance benefits achievable with spring steel buffer systems after they have tailed.

Brief description of the Figures

Embodiments of the invention will now be described with reference to the following drawings, in which: Figure 2 shows a perspective view of part of a safety barrier according to an embodiment of the present invention; Figure 3 is a cross sectional side view of the barrier of Figure 2; Figure 4 shows an enlarged portion of a part of the barrier of Figure 2 from an alternative angle; Figure 5 shows another enlarged portion of a part of the barrier of Figure 2 from another alternative angle; Figure 6 shows a further enlarged portion of a part of the barrier of Figure 2 from the front (impact side); Figure 7 is an enlarged view of part of the base of the barrier of Figure 2; Figure 8 is an enlarged view of the handrail of the barrier of Figure 2; Figure 9 is a partial front view of part of the barrier of Figure 2; Figure 10 shows a second support member as utilised in the barrier of Figure 2; Figure 11 shows a perspective view of part of a safety barrier according to an alternative embodiment of the present invention; Figure 12 shows an enlarged portion of a part of the barrier of Figure 11; Figures 13 a to c show perspective, front and side views of a support member of the barrier of Figure 11; and Figure 14 shows a cross sectional side view of the barrier of Figure 11.

Detailed description of embodiments of the invention Figures 2 and 3 show part of a safety barrier 10 according to embodiments of the present invention. The barrier 10 comprises a plurality of spring steel buffers 12. The buffers 12 comprise formed strips of metal. The buffer strips 12 are secured to the ground with an anchor bolt 14 at or towards a first end 16 thereof. The anchor bolt 14 is provided in an aperture in a first flat portion 18, configured to rest on the ground between the first end 16 and a portion 20 that curves back toward the first end 16 at an angle so as to form a V or U shaped recess therebetween. The angle is designed and specifically performs to an optimum resistance under loading, and is preferably substantially 45°, but could be substantially between 35 and 55°, or 40 and 50° for example. The strip further comprises a substantially vertically extending second flat portion 22 that terminates in a second end 28. The support 12 thus comprises a base or foot, or could be substantially [-shaped. The second flat portion 22 is attached, via a plate 24, to a beam 26 ator in the vicinity of the second end 28 of the buffer 12 with a bolt 30. In the embodiment shown, the beam 26 is an open box beam (or "Berry beam"), although it will be appreciated that other beams (e.g. a W-section beam) or restraining members may be used. The second end 28 of the buffer 12 is separated laterally (horizontally) from the first end 16 by a distance x.

An extension strip 32 is connected to the buffer 12. The extension strip 32 comprises a flat portion at each end thereof, these being substantially parallel to each other. A first flat portion 34 is located adjacent the second flat portion 22 of the buffer 12 and is connected thereto via bolt 30. A second flat portion 36 is connected to a handrail 38 provided at the top of the barrier 10. An angled portion 39 is provided between the first and second flat portions 34, 36, such that the first and second flat portions 24, 26 are laterally (horizontally) separated by the distance x (and such that the second flat portion 36 is substantially aligned with the first end 16 of the buffer strip 12).

As indicated above, a handrail 38 is provided at the end of the second flat portion 36 of the extension member 32, this defining the upper limit of the barrier 10. The handrail 38 is tubular, although it may take other forms, and extends the length of the barrier 10.

A panel 40 is mounted on a front' side of the barrier 10, this being the side on which a vehicle will impact the barrier 10. Meshing 42 is provided within the panel 40 to present a continuous surface to potentially oncoming vehicles, and to provide a barrier to pedestrians for safety reasons, e.g. when the barrier 10 is used above ground level in a multi-storey car park. The mesh panel 40, 42 is planar and spans the distance from at or slightly above ground level to or slightly below the handrail 38. The panel 40 is affixed to the upper end of the extension member 32 with a bolt 44 and at its lower end to a lestraining member (described in more detail below) with a bolt 46.

An L-shaped restraining or support member or strap 50 is provided, comprising a major planar portion 52 and a minor planar portion 54 provided at substantially 90° thereto.

The major portion 52 extends substantially veitically, and the minor portion 54 extends tiansverse theieto (horizontally). The strap 50 is fixed at an upper end thereof to and between the second flat portion 36 of the extension member 32 and the panel 40, with the bolt 44. As such, the strap 50 is located between the buffer 12/extension member 32 and the panel 40, and sits adjacent thefront surface of the box beam 26. The strap is fixed, towards the lower end of the major surface 52, to the panel 40 with bolt 46.

The minor surface 54 of the strap 50 is fixed to the first flat portion 18 of the buffer 12 via bolt 14 and a plate washer 56. The anchor point of the strap 50, being located on the anchor bolt 14 of the spring steel buffer 12 itself, advantageously avoids the need for any additional fixings! and secures the base 54 to a firm and load tested connection that far exceeds any requirement for the pedestrian loading (as will be discussed below).

Figures 4, 5 and 6 show enlarged views of portions of the barrier 10, depicting various components in greater detail and illustrating the positional relationship of the buffers 12 and the straps 50. In the embodiment shown, the straps 50 aie aligned with the buffer strips 12 in a direction transveise to the plane of the barrier 10 (see also Figure 9, which shows an enlarged view of the central part of the barrier 10).

Typically, the supports 12 are separated by a distance of approximately 800mm. The spacing can, however, be tailored according to the environment and surroundings. The barrier has been tested, successfully to comply with the requirements of the British Standards, using supports separated by 1600mm. In an alternative embodiment, the support separation could be a range either that is a multiple of 400mm centres or at anything from 400mm to 1600mm. In other countries, such as Australia, the sepalation may be 2000mm. Embodiments of the invention can be utilized in all of these scenarios, and the separation may be any value between 0 and 2000mm, or more.

Figure 7 shows an enlarged view of the base of the barrier 10. This Figure shows that the washer 56 extends right up to the bend of the strap 50, between the major and minor portions 52, 54. Fixing the base 54 of the strap 50 with a large plate washer 56 ensures any bending moments are restricted to the front of the barrier 10, and not at the axis of the anchor bolt 14.

Figure 8 shows an enlarged view of the top of the barrier 10. This Figure shows the connection of the strap 50 at the handrail 38 position, secured with bolt 44 via a hole in the buffer extension 32. The hole is required to be a tight tolerance both in diameter and in relative position to the ground due to the length of the restraint strap 50. If the strap 50 is installed without tension being introduced, the test criteria are likely to exceed the performance capacity of the design. The system, when installed, may require the handrail 38 to be pulled towards the front face to make the bolted connection. This will ensure that enough preload is placed in the composite section to resist the loading required in BS6180 (discussed below).

Figure 10 shows the strap 50 in greater detail, including a side view (a), a front plan view (b) and an enlarged view (c) thereof. The strap 50 has a width w1=6Omm along the majority of its length. As can be seen from Figures 10(b) and 10(c), the strap 50 also comprises a thinner portion, or notch, 58 towards the lower end thereof. In the embodiment shown, the width of the strap 50 is reduced to w2=l5mm at the location of the notch 58. The transition from the full width w1 to the reduced width w2 tapers across the lateral extent of the strap 50 so as to form two symmetrical but opposite trapezoidal cut-outs on opposing edges of the strap 50. The angle a of the taper is 72° to the vertical. This provides an opening of extent e130mm on the edge of the strap and a reduced opening of e2=lSmm at the boundary of the reduced strap width w2.

The height h of the strap 50 is substantially 1000mm, and the notch 58 is provided at a height of 225mm above ground level. The base 54 of the strap 50 extends a distance of substantially 150mm. NB. The total height of the barrier, including the handrail 38 is approximately 1100mm. The strap is conveniently manufactured from a grade S275 steel and is 5mm thick. The strap may of course be dimensioned differently -the important feature is the provision of an area of weakness, rather than the dimensions/relative dimensions of the strap 50. (It should also be noted that all values referred to are approximate, and may vary depending upon manufacturing/measurement tolerances etc.).

In embodiment described, the notch 58 comprises cut-outs on either side of the strap 50, although a single notch on one side of the strap could instead be provided. In an alternative embodiment (not shown)! the profile of the notch(es) is not trapezoidal, but is square, rectangular or semi-circular in shape. In another alternative embodiment, one or more holes are created in the strap 50 to provide an area of weakness in the strap 50 -i.e. the cut-out(s) are within the confines of the width of the strap 50, rather than being provided along an edge thereof. Alternatively, the strap 50 could be perforated across the width thereof Or, one or more frangible/yieldable components could be incorporated into the strap 50. In a further embodiment, the strap 50 is provided with a plurality of points of weakness located longitudinally along the length of the strap 50. In yet another alternative embodiment, the strap 50 does not comprise any weakened portions. In all embodiments, the strap 50 is formed of a material or materials suitable for the load under which it will be placed in the event of an impact.

Figure 11 shows a part of a safety barrier 110 according to an alternative embodiment.

Components in common with previously described embodiments are labelled with the same reference numerals utilized before, and are not further discussed here. In the embodiment of Figures 11-13, the barrier 110 comprises a W-section beam 26, although it will be appreciated that beams of other types, such as those described before or otherwise, could also be used. The barrier 110 further comprises a restraining or support member or strap 150 that is used instead of the restraining member 50 of the previous embodiments. Figure 12 is an enlarged view of the base of part of the barrier 110.

Figures 13a-c show the restraining member 150 from various angles. Figure 14 is a cross sectional view through the barrier 110. These figures show that the support or strap 150 is again substantially [-shaped, comprising a major portion 152 (extending substantially vertically) and a minor portion 154 provided at substantially 90° thereto.

The strap 150 has side walls 160 that are substantially perpendicular to the planar major portion 152, and extend the full height thereof. As such the strap 150 has a cross section that is c-or u-shaped. The side walls 160 are a uniform width for the majority of the height of the strap 150. However, towards the base 154 of the strap 150, the width of the side walls 160 increases away from the major portion 152 of the strap 150 such that, at the base 154 thereof, the width z of the side walls 160 is approximately equal to the length z of the base 154. The triangular shaped portion 162 of the side walls thus formed acts as a stiffener to provide strength to the strap 150. As in the previously described embodiments, the lateral extent of the base 154 of the strap may be zlSOmm (approx.).

The strap 150 has a width w3=9Omm, along the entirety of its height h1. The strap 150 again comprises a weakened portion 158. Here, the major planar portion 152 of the strap 150 is provided with an aperture 158a towards the lower end thereof. In the embodiment shown, this takes the form of a diamond-shaped opening 158a that extends the majority of the width of the strap 150. In the embodiment shown, the diamond shaped aperture 158a has a maximum width w4 of 69mm. The maximum height of the diamond aperture 158a is d=4Omm. The vertical centre of the aperture 158a is located at a distance y1133mm above the ground. The thickness t of the base 154 of the strap 150 is 3mm. The strap 150 has a height 1008mm.

The side walls 162 of the strap 150 also comprise a weakened portion, or notch! 1 58b.

A v-shaped notch 158b is provided on the exterior of each side wall 160, tapering to a point about w5=9mm in (about half the width of the side wall 160). The angle of the taper is substantially 22°. The notches 158b are provided in line with the vertical centre of the aperture 158a, i.e. at height y1.

The base 154 of the strap 150 is formed by bending the lower end of each side wall around and in towards each other so as to form a substantially flat surface with a gap (6mm) running therethrough (centrally in the embodiment shown). A larger aperture 164 (width w5=2snim) is also provided substantially centrally in the base 154, for fixing to the base 18 of the buffer 12 via bolt 14 as previously described. Again, plate washer 56 is also utilized. The aperture 164 may be formed in any conventional manner, e.g. cut out, drilled or punched. In the embodiment shown, the aperture 164 is elongate and formed by drilling two holes adjacent each other.

In embodiment described, the notch 158b comprises cut-outs on either side of the strap 150, although a single notch on one side of the strap 150 could instead be provided. It will also be appreciated that in alternative embodiments (not shown), the profile of the notch(es) is not triangular but may, for example, be a slit or be trapezoidal, square, rectangular or semi-circular in shape. The diamond-shaped aperture 158a may alternatively be circular or oval, or the strap lSOcould be perforated across the width thereof. Or, one or more frangible/yieldable components could be incorporated into the strap 150. In a further embodiment, the strap 150 is provided with a plurality of points of weakness located longitudinally along the length of the strap 150. In all embodiments, the strap 150 is formed of a material or materials suitable for the load under which it will be placed in the event of an impact.

Thus, in use in the event of a vehicle impacting the barrier, the strap 50, 150 absorbs energy from the impact up to the predetermined threshold (e.g. lOkN) and then fails at the point of weakness 58, 158a, 158b. The strap 50, 150 will thus shear but remain attached to the barrier 10, 110 at the upper and lower fixings 44, 46. Further energy from the impact is absorbed by the barrier 10, 110 in order to stop the vehicle, e.g. in accordance with the requirements of the British Standards. The provision of the strap 50, 150, in addition to the barrier 10, 110, thus provides some additional energy absorption capabilities as previously described, but notably it has been found that this avoids significant deflection of the handrail 38, which is an important consideration for barrier integrity and safety of pedestrians.

Barrier Performance The loading criteria specified in BS6180 are based upon: * 1.5kN/m UDL to be applied at design height or 1100mm for barrier higher than design height; * 1.5kN/m Point load applied to the most onerous point anywhere on the barrier structure; and * 1.5kN/m UDL to the mesh infill for the system, where UDL is uniformly distributed load'.

BS6180 requires that the total horizontal displacement of the barrier at any point from its original unloaded position should not exceed the deflection limits determined from the relevant structural design code (where applicable) for the material used, or 25mm, whichever is the lesser. Tests of the prior art system described above failed to meet this performance standard, however tests of embodiments of the present invention gave a maximum deflection of 22mm at a height of 1.lm -well within the BS6180 performance requirement.

The strap 50 is specifically manufactured, with a section 58 notched out from the width w1 of the plate 50, to fail under a specific load within the tolerance of the materials grade. This failure, as with any material, may vary slightly but, in essence, the difference in the loading from a vehicle impact and a pedestrian applied state is large enough to cater for the tolerance in the materials failure.

Failure at the notched section 58 is required at occur under a load of circa lOkN on the handrail 38. This has been found to provide for significant restraint of the 1.5kN requirements in all cases of the BS61 80 specification (see above), but a more onerous load of 1 5OkN loading at 450mm causes a failure at the position of the notch 58.

Similarly, the strap 150 is designed to fail under a specific load within the tolerance of the materials grade.

The strap 50, 150 is designed to yield under a load of approximately lOkN, in order to allow a reduced load transfer through the core design of the spring steel buffer 12. The performance below the lOkN threshold ensures it complies with BS6180. Alternatively, the second support member may be configured to break or fail under a different load, e.g. between substantially 9kN and llkN, or at about 9kN, 9.5kN, 10.SkN, llkN, or otherwise depending on the barrier requirements.

Claims

CLAIMS: 1. A safety barrier comprising: a plurality of first support members configured for coupling to the ground, the first support members being capable of providing a predetermined first amount of energy absorption in the event of a vehicle impact; one or more second support members configured for coupling to the ground, said one or more second support members being capable of providing a second predetermined amount of energy absorption, less than the first amount of energy absorption, in the event of a vehicle impact; and an elongate restraining member supported by said first and/or second support members at a height above the ground.
2. The safety barrier of claim 1. wherein said plurality of first suppoit members are deflectable in the event of an impact by a vehicle on the barrier.
3. The safety barrier of any claim 1 or 2, wherein said one or more second support members are flexible, deformable, yieldable or breakable.
4. The safety barrier of claim 3, wherein said one or more second support members are yieldable or breakable at a height above ground that is less than the height above ground of the restraining member.
5. The safety barrier of claim 3 or 4, wherein said one or more second support members comprise one or more of a weakened portion, a frangible portion, an indentation, an aperture or a notch.
6. The safety barrier of claim 5, wherein said one or more second support members comprise a first weakened portion, frangible portion, indentation, aperture or notch on one or both edges thereof and/or a second weakened portion, frangible portion, indentation, aperture or notch within or on the body of said one or more second support members.
7. The safety barrier of claim 6, wherein said one or more second support members are c-or u-shaped in cross section, and said first weakened portion, frangible portion, indentation, aperture or notch is provided in or on one or both arms of said c-or u-shaped cross section second support member.
8. The safety barrier of any preceding claim, wherein the one or more second support members are configured to yield or break under a predetermined load, and the one or more first support members are configured to withstand said predetermined load.
9. The safety barrier of any preceding claim, wherein said plurality of first support members are provided on a first side of said restraining member and said one or more second support members are provided on a second and opposite side of said restraining member.
10. The safety barrier of any preceding claim, wherein said one or more second support members are provided substantially aligned with said plurality of first support members.
11. The safety barrier of any preceding claim, wherein said one or more second support members comprise an elongate strip.
12. The safety barrier of claim 11, wherein the one or more second support members are substantially L-shaped, the base theieof providing means for coupling said one or more second support members to the ground.
13. The safety barrier of any preceding claim, further comprising means for forcing any bending moments towards the front of the barrier.
14. The safety barrier of claim 13, as dependent upon claim 12, wherein said means for forcing any bending moments towards the front of the barrier comprises a member placeable on said base of said second support member adjacent or in the vicinity of the corner of said L-shaped second support member.
15. The safety barrier of any preceding claim, further comprising a handrail provided at or near the top thereof.
16. The safety barrier of claim 15, wherein said one or more first or second support members, or an extension member attached thereto, are attached to said handrail.
17. The safety barrier of any preceding claim, further comprising a panel or cladding adjacent to the one or more second support members, the panel or cladding presenting a continuous surface on the impact side of the barrier.
18. The safety barrier of any preceding claim, wherein said restraining member is provided at a height corresponding to a vehicle bumper height.
19. The safety barrier of any preceding claim, wherein the restraining member is a beam.
20. The safety barrier of any preceding claim, wherein said plurality of first support members are spring steel buffers.
21. A yieldable support member comprising an elongate strip of material comprising one or more of a weakened portion, a frangible portion, an indentation or a notch for use in the barrier of any of claims 1 to 20.
22. A safety barrier as substantially hereinbefore described with reference to the Figures of the accompanying drawings.