EP1870523A1

EP1870523A1 - Safety barrier

Info

Publication number: EP1870523A1
Application number: EP07002710A
Authority: EP
Inventors: Aled Mon Roberts; Martin Batchelor; Michael Richard Lawrence; Lewis Collins; Christophe Bastien
Original assignee: Corus UK Ltd
Current assignee: Corus UK Ltd
Priority date: 2006-02-09
Filing date: 2007-02-08
Publication date: 2007-12-26
Also published as: GB2435066A; GB0602537D0

Abstract

A safety barrier comprises at least one upright post (100,150) supported in a socket (106,156), the cross-section of the post having at least one concavity, and the socket having a cross-section which includes a convex portion shaped to extend into the concavity when the post is fitted in the socket. The convex portion of the socket cross-section preferably extends along the entire length of the socket, but (if desired) the socket can be formed with a cover including an aperture for receiving the post, which can provide the convex portion. The lower end of the socket can be closed if desired. A socket for supporting a post of a safety barrier system (per se) is also described, having a cross-section which includes a convex portion. The convex portion is suitably shaped to extend into a concavity of a post fitted in the socket. Further, a kit is described comprising such a socket and a post, the cross-section of the post having at least one concavity into which the convex portion of the socket is shaped to extend.

Description

FIELD OF THE INVENTION

The present invention relates to safety barriers, of the type useful for roadside installation.

BACKGROUND ART

Safety barrier posts are commonly used alongside beams to form basic safety barrier assemblies for vehicle containment on trunk road and highways. Post can be installed in a number of formats
Driven posts are mechanically driven into the ground using appropriate equipment. Surface mounted posts (aka plated posts) are commonly used on bridges, and are anchored on a hardened surface by means of a number of ground anchors bolted to legs at the bottom of the post. Socketed posts are received in a socket formed in a concrete base by means of a sleeve made from steel, or any other material or forming method. In other formats, the post is cast directly into a concrete base.
Current available safety barrier post types involve the designs shown in figures 1 to 6. Figure 1 shows a 'Z' profile in which the elongate post 10 has, in section, two fold lines 12, 14 running along the length thereof along which the formerly flat section is bent through approximately 135° in opposite directions. Thus, the post takes, in cross-section, a Z shape offering good bending resistance in both planes. This post is fitted into a rectangular shaped recess 16 which may be defined by a sleeve formed from a section of hollow rectangular stock.
Figure 2 shows a 'Sigma' profile. The post 18 has a number of fold lines so that in section it takes up a Z shape, in this case with a serif-like lip at either end. Whilst this involves a greater number of folds and hence greater manufacturing expense, the total projected length of material in any one direction is greater and hence the post 18 offers a correspondingly greater resistance to bending. An identical socket 16 is provided to receive the post 18.
Figure 3 illustrates an alternative post 20 formed with a C-channel profile. Figure 4 shows that the channel 22 may be provided with lips 24, 26 along the section edge to provide additional rigidity.
All of these profiles are traditionally installed in a rectangular socket 16, as shown. The gap around the post is often filled with a low density polyurethane foam injected in situ after the post is inserted. This is intended to exclude rainwater (etc) from the hole and inhibit corrosion.
Other known post types include a simple rectangular hollow section 24 shown in figure 5 and a tubular hollow section 26 shown in figure 6. These posts are normally installed in larger rectangular sockets 28 or concentric hole sockets 30 as appropriate.

SUMMARY OF THE INVENTION

The present invention seeks to improve on socketed designs. It therefore provides a safety barrier comprising at least one upright post supported in a socket, the cross-section of the post having at least one concavity, and the socket having a cross-section which includes a convex portion shaped to extend into the concavity when the post is fitted in the socket.
The post can be, for example, a folded section or a suitably shaped tube.
The convex portion of the socket cross-section preferably extends along the entire length of the socket, but (if desired) the socket can be formed with a cover including an aperture for receiving the post, which can provide the convex portion. The lower end of the socket can be closed if desired.
The post can rest in the socket and (generally) need not be fixed thereto.
A suitable material for the post and/or the socket is steel.
The socket can be set in a concrete base or driven into a ground surface.
The present invention also relates to a socket for supporting a post of a safety barrier system, having a cross-section which includes a convex portion. The convex portion is suitably shaped to extend into a concavity of a post fitted in the socket.
Further, the present invention relates to a kit comprising such a socket and a post, the cross-section of the post having at least one concavity into which the convex portion of the socket is shaped to extend.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described by way of example, with reference to the accompanying figures in which;

Figures 1 to 6 show horizontal sections through known socketed post designs;
Figures 7 to 11 show horizontal sections through socketed post designs according to a first embodiment of the present invention, the post designs corresponding to the posts of figures 1 to 4;
Figures 12 to 16 show horizontal sections through socketed post designs according to a second embodiment of the present invention, the post designs corresponding to the posts of figures 7 to 11; and

Figures 17 and 18 show horizontal sections through socketed post designs according to a third embodiment of the present invention, the post designs corresponding to the posts of figures 5 and 6.

DETAILED DESCRIPTION OF THE EMBODIMENTS

We have found that there are advantages to be gained in providing the socket with a special profile in relation to the post. The presence of a socket profile, which substantially follows the outline of the post (in part or in parallel), can lead to a beneficial reduction in the overall deflection of the post and safety barrier system during dynamic impacts with the post, when compared with traditional socketed post details. Our research has shown that this type of socket can dramatically improve the interface between the post and socket during conventional EN1317 crash tests involving beam and post based safety barrier.
By improving the interface between the post and socket, the overall system deflection during dynamic impacts can be reduced, thereby improving design and performance efficiency. This invention relates to socket shapes that follow the main post profile shape, or alternatively, partially close in upon the open section to increase the level of available contact between the post and the surrounding socket wall geometry.
Figures 7 to 11 show various configurations of a first embodiment of the invention. As can be seen in figures 1 to 6, there are a number of known post sections that include a concavity into which the socket edges can project and which are well characterised in terms of their impact resistance. These are the Z, Σ, C and lipped C sections. I-sections have also been employed. Given that a novel barrier system requires potentially expensive crash testing, there is a preference in the field for familiar designs and thus the illustrated embodiments use the same Z, Σ, C, lipped C and I sections. However, it should be understood that other sections including a concavity are equally possible and that it is not a prerequisite that the section be one known at this time.
Figure 7 therefore shows, in cross-section, a Z-profile post 100 formed from a flat steel plate by imposing two longitudinal bends of 135° in mutually opposing directions. The socket 106 in which the post 100 is received is formed in a closely similar Z shape, but with a small clearance 108 between the post and the socket walls to allow easy insertion. On impact, the scope for deformation of the post within the socket is greatly reduced and after some deformation, the resistance of the post to removal from the socket is greatly increased. This means that a safety barrier incorporating such a post and socket will be able to absorb more energy from an impacting vehicle, which is preferable in order to minimise vehicle intrusion.
The socket can be formed in situ as a suitably shaped hole in a locally cast region of concrete or other material. A mandrel of a suitable shape can be used to act as an imprint around which the concrete can be set. Greater accuracy in the clearance 108 can however be obtained by forming a socket as a prismatic shell of steel or other material, with the required cross-section. This can then be placed into the setting concrete, or driven into the ground, or otherwise retained in place.
Figure 8 shows the application of this invention to a Σ-profile post 110. In this case the concavity 112 into which the socket 114 can extend is more complex and dovetailed, thereby offering the potential for greater pull-out resistance. Figure 9 shows a C-section post 116 which offers a simple rectangular concavity 118 and a socket 120 formed accordingly. Figure 10 shows a lipped C-section post 122 which offers a dovetailed concavity 124 for the socket 126, as compared to the C-section post 116 of figure 9. Finally, figure 11 shows an I-section post 123 which offers a simple concavity 125 for the socket 127, duplicated on either side.
Figures 7 to 11 show the first embodiment of this invention, in which the socket closely follows the outline of the post subject only to a clearance 108. It is however not essential that every aspect of the shape and configuration of the post is reflected in the socket, as shown in the second embodiment of the invention illustrated in figures 12 to 16.
Thus, figure 12 shows a Z-profile post 150 which is, in principle, the same as that shown in figures 1 and 7, fitted in a socket 152 according to a second embodiment of the invention. This socket 152 is largely of a Z-section, but the extreme concave angles of the Z are rounded for example at 154 thereby increasing the clearance 156 in these areas.
Such an arrangement is considerably easier to manufacture accurately and reduces the likelihood of interference between the post and the socket. Nevertheless, the profile of the socket 152 still projects into concavities in the cross-section of the post 150 and the beneficial effects of the invention are therefore still available.
Figure 13 shows the second embodiment as applied to a Σ-section post 158. Again, the socket 160 has been rounded off in some areas so as to locally increase the clearance 162. Figures 14 and 15 show a C-section post 164 and a lipped C-section post 166 respectively, each fitted into a corresponding socket 168, 170.
Figure 16 shows the second embodiment as applied to a I-section post 159. Again, the socket 161 has been rounded off in some areas so as to locally increase the clearance 163.
Figures 17 and 18 show a third embodiment, being the application of the invention to a closed section profile. Figure 17 shows a rectangular section post 172. In such a post, the concavity present in its section is the interior 174 of the post section. Thus, the invention proposes that the socket be formed with a corresponding albeit smaller rectangular section 176 that fits within the interior of the rectangular section post 172. There may also be an externally fitting sleeve 178 if desired. When such a post receives an impact, it will be more difficult to pull the post from its socket as the deflection caused by the impact will mean that the post is no longer properly aligned in the socket and will therefore scrape along the inner section 176 and the outer section 178 if present.
Figure 18 shows a corresponding design to that of figure 17, using a circular section post 180. In this case, a smaller circular section 182 fits within the post 180 in a similar manner. An optional external socket 184 is also shown.
In all the embodiments, the shaped pattern of the socket can go all the way or partially along the length of the socket. However, alternative socket designs are possible where a solid plate is connected to the top, bottom or intermediate height of a rectangular or circular socket void, in which the plate has a similar shape.
The post shape can be any open or closed section of any proportion, thickness or post length.
Posts of this type are not normally mechanically connected to their respective sockets, but could be.
The socket material would usually be steel, but could be a polymer or any other material. Alternatively, a former could be used to cast a shaped concrete recess in the ground.
Socket or post profiles can be assembled from one or more component parts, connected together by one of a number of connection methods including welding, friction fit, gluing, riveting or any other form of connectivity or assembly.
The socket can be capped at its base, or alternatively open ended both ends. Bottom end caps can take the form of welded plates, plastic caps or simple taped up ends, or indeed any other form.
Sockets can be cast in concrete or within a concrete base. Alternatively, sockets can be designed to be driven or installed in the ground without a requirement for supporting concrete.
The inner sections 176, 182 of the sockets shown in figures 17 and 18 may be hollow (as shown) or may be filled. If filled, this can be by providing a solid section of the appropriate external shape, or by filling the interior of a hollow section with a suitable material such as a low density polyurethane foam.
It will of course be understood that many variations may be made to the above-described embodiment without departing from the scope of the present invention.

Claims

A safety barrier comprising at least one upright post supported in a socket, the cross-section of the post having at least one concavity, and the socket having a cross-section which includes a convex portion shaped to extend into the concavity when the post is fitted in the socket.
A safety barrier according to claim 1 in which the post is one of a folded section or a tube.
A safety barrier according to claim 1 or claim 2 in which the convex portion of the socket cross-section extends along the entire length of the socket.
A safety barrier according to claim 1 or claim 2 in which the socket has a cover at its upper opening, the cover including an aperture for receiving the post.
A safety barrier according to claim 4 in which the convex portion of the socket cross-section is provided by the aperture.
A safety barrier according to any one of the preceding claims in which the lower end of the socket is closed.
A safety barrier according to any one of the preceding claims in which the post rests in the socket without being fixed thereto.
A safety barrier according to any one of the preceding claims in which the post and/or the socket are steel.
A safety barrier according to any one of the preceding claims in which the socket is set in a concrete base.
A safety barrier according to any one of claims 1 to 9 in which the socket is set in a ground surface by being driven thereinto.
A socket for supporting a post of a safety barrier system, having a cross-section which includes a convex portion.
A socket according to claim 11 in which the convex portion is shaped to extend into a concavity of a post fitted in the socket.
A kit comprising a socket according to claim 11 or claim 12 and a post, the cross-section of the post having at least one concavity into which the convex portion of the socket is shaped to extend.
A socket and/or a post for a safety barrier system substantially as herein described with reference to and/or as illustrated in the accompanying figures 7 to 18.