EP0379424A2 - Road safety barrier - Google Patents

Abstract

The invention concerns a road safety barrier placed along roads, constituted from metal profiles (11) assembled by partial overlapping and bolting and supported in places by vertical posts, the profile (11) having a central channel (1) enclosed on either side by a lateral channel (2) forming a relief on the road side and having its outer edge (3a) folded back in a direction opposite to that of the road, characterised in that the two outer edges (3a) of the lateral ribs (2) of the profile each extend by a wing (3b) beyond the vertical plane XX' tangential to the bottom of the central channel (1) and over a distance of between half and twice the distance separating the said vertical plane XX' from the point of the lateral ribs (2) which are closest to the road. <IMAGE>

Description

The present invention relates to road safety barriers: it is therefore applicable to traffic infrastructures.

More specifically, it relates to a deformable safety barrier, placed along the roads, consisting of metal profiles assembled by partial covering and bolting, and supported from place to place by vertical posts, the profile having a central groove surrounded by lateral ribs. located on either side of said central groove each having a vertex line located in the same vertical plane parallel to the vertical plane XX ′ tangent to the bottom of the groove, forming a relief on the side of the floor and each having an outer side folded in a direction opposite to the roadway and extended by a wing beyond said vertical plane XX ′ tangent to the bottom of the groove.

The invention relates more particularly to a slide incorporating a conventional metal profile, AFNOR standardized and called type A or B.

We know that along traffic lanes, safety barriers are installed to prevent vehicles from leaving the lane during an incident or accident. These safety barriers are metallic profiles which constitute a strip arranged vertically, having an average line substantially parallel to the raceway of the taxiway and are supported at regular distances by vertical posts disposed on the side of the slide where not find the traffic lane bordered by said slide. The use of these safety barriers is common at the edge of motorway lanes, along the entire length of the lane, but also along the edge of ordinary roadways, either in areas where the exit from the road would be particularly dangerous, or, for busy roads, in the middle areas separating the two directions of traffic.

It can be noted that one of the profiles A or B commonly used, which is bolted to its supports, at a time low inertia compared to a vertical axis passing through its center of gravity: this moment of inertia is of the order of 100 cm⁴. The consequence of this weak moment of inertia is, on the one hand, that the radius of curvature adopted by the slide subjected to a bending moment due to the impact of a vehicle is small: it is indeed proportional to this moment d inertia; the deformation pocket thus created is therefore deep, which causes difficulties in leaving the safety device for the vehicle which created this deformation: on the other hand, the will of the road management services is to limit the distance between the obstacles and the safety barrier, so as not to reduce too much the shoulder of the road. This concern leads to implanting supports close to each other in order to limit the depth of this deformation pocket.

These supports are currently installed approximately every 4 m, or even 2 m where the obstacles are very close to the slides: they can even be reinforced in this case. We can thus see that the low moment of inertia of the profile leads to implanting a greater number of supports than if the profile had a stronger moment of inertia: however, the implantation of the supports represents the major part of the installation cost safety barriers.

The supports in large numbers also lead to drawbacks for the holding of embankment slopes (punching), and create a potential danger for bikers who have slipped on the road, and may come into impact with these supports.

There is therefore both technical and economic interest in trying to reduce the number of these supports, by increasing the moment of inertia, relative to a vertical axis, of the profile of the slide.

The technical advantage is to increase the radius of curvature of the profile following the same impact, which leads to a better distribution of the forces on the supports and to better guidance of the sinking vehicle.

This reduction in the number of supports also leads to technical advantages on the holding of the embankments, and a better safety for motorcyclists, as noted above.

The economic advantage is to be able to reduce the number of supports of the safety barrier for an equivalent depression in the event of an impact and therefore to reduce the cost of supplying and installing the rails significantly.

The resistance calculations of the materials show that it is possible, by increasing the moment of inertia of the profile, to install the supports every 5 or 6 m approximately instead of 4 m in a traditional device or to maintain the supports every 4 m where a profile of lower inertia would have required their doubling.

U.S. Patent 2,776,116 shows a slider as defined above wherein the flanges of the section diverging 45 ^o, thereby providing a low moment of inertia. In addition, the wings tend to open strongly during possible shocks so that the moment of inertia decreases sharply at the moment of impact just when it would be necessary to have a high moment of inertia to maintain the rigidity of the slide.

Another known profile is shown in German patent application 1,960,908 under the designation modified profile A. The purpose of this modified profile A is to allow an increase in the thickness of the wall of the profile while keeping the modified profile roughly the same weight as that of a conventional profile A to which the object of the present invention refers. , also shown in this German patent application published 1 960 908. According to the known proposal, it is possible to increase the thickness of the wall of the profile while retaining the same initial weight by reducing the depth of the central groove by almost half while retaining the initial length of the outer flank of the lateral ribs. This obviously leads to a reduction in the moment of inertia of the modified profile whereas one of the aims of the present invention is to increase the moment of inertia of the profile for a given wall thickness or to decrease this wall thickness of the profile while maintaining the same moment of inertia given. In addition, this profile proposal cannot be superimposed with that of slideway A.

Another slide having a different profile is known from US Pat. No. 2,228,652. In this case, the known slide does not aim to deform under the action of the impact of a vehicle, but, by a particular conformation. , to grasp the hub of the vehicle wheels at its upper part and to exert on this hub a force urging the wheel to remain in contact with the road. In view of the fact that this slide is not fixed to the support post at the bottom of the central groove, but is held by its lateral ends, and that the outer flanks are extended horizontally towards the rear to allow the fixing the slide, in the event of a sudden impact from a vehicle, the profile shears and it can no longer be used as a slide.

The object of the present invention is to provide a safety barrier of the type mentioned, in which the profile has a moment of inertia greater than the moment of inertia of the profiles currently used and which moreover can be assembled with the current profiles without difficulty. .

The object is achieved according to the invention by the fact that the outer flank of the lateral ribs of the profile extends beyond said vertical plane tangent to the bottom of the central groove, over a distance between half and double the distance separating said vertical plane of the plane passing through the top lines of the lateral ribs.

Preferably, this wing is of the same thickness and of the same material as the profile.

It is advantageous that the two wings of the profile are divergent so as to allow the interlocking of the profiles for transport and for assembly.

Thanks to the presence of these wings which extend over the rear of the profile and on the side opposite the roadway, the moment of inertia of the profile, with respect to a vertical axis passing through its center of gravity, is considerably increased. This moment of inertia which is approximately 100 cm⁴ for a current W-shaped profile, the groove depth of which is 80 mm approximately, increases by 10% with 3 cm wings and doubles in value with 6 cm wings.

The profile of the profile on the side of the road is preferably similar to that of one or the other of the two models of slideways commonly used. This allows the adaptation of these models of slides and the slide of the present invention without difficulties.

The installer of slides can therefore successively install traditional slides, then slides according to the invention, with the same tools, the same methods and without additional technical difficulties.

It is interesting that these wings have an orientation approaching the horizontal, so as to thereby maximize the moment of inertia of the slide relative to a vertical axis. This orientation can be obtained by giving the profile the shape of a parabolic arc, on either side of the central groove. This shape also has the advantage of distributing as best as possible in the structure the forces received at the top of this parabola.

It may also be advantageous to fold the end of this wing in a fold parallel to the axis of the road; this fold will stiffen the profile and allow it to be less deformed under the impact of the vehicle.

If we consider the vertical plane passing through the central groove-shaped zone of a profile, the groove of which has a depth of approximately 8 cm, the profile extends accordingly, on the side opposite to the traffic lane, 4 to 16 cm approximately with respect to this plane and preferably 6 to 8 cm.

The folded edge of the rib extended by a wing may have a shape approaching the horizontal, for example of parabolic shape, when one moves away from the taxiway. It can also include a fold of 2 to 5 cm approximately, ribbing the end of this wing. This bend may have an angle between 1 and 90 ^o relative to the horizontal, the bend forming an obtuse angle with the wing.

The metal profiles are fixed to each other by bolts, the bolt heads being on the side of the track. lation. It will be interesting that the locations of the bolts are compatible with those of the sections already in service, so that their reciprocal adaptation is convenient; it will still be necessary to place two bolts in the area of overlap of the profiles, to better secure the assembly.

The strong moment of inertia of the profile with respect to a vertical axis makes it possible to choose the thickness of the latter in a range going from 1.5 mm to 3 mm, with a preference for 2 mm of thickness, which is a interesting compromise between a high impact resistance and the unit mass of a profile element which is then about 60 kg.

This strong moment of inertia (approximately double that of the profiles currently used) allows the supports to be spaced approximately 6 m apart while retaining the impact efficiency of the slides currently in service which have supports spaced 4 m apart; the guide curve of the sinking vehicle is then of greater radius.

It should also be noted that the large development of the edge of the rib makes it possible to conceal from the motorist the top of the supports used, and also gives him a feeling of greater security by the thickness seen from the profile, in a position of normal driving.

To better understand the object of the invention, we will describe below, by way of purely illustrative and nonlimiting examples, several embodiments shown in the accompanying drawings.

• La figure 1 représente schématiquement et en perspective une glissière selon l'invention, boulonnée sur un support, un écarteur maintenant une distance d'environ 20 cm entre la rainure centrale de la glissière et le support.
• La figure 2 représente une coupe selon II - II de la figure 1.
• La figure 3 représente une coupe variante de celle de la figure 2, cette variante comportant deux nervures de forme sensi­blement parabolique se développant sur les parties 4, 2, 3a et 3b du profilé. Le sommet de la parabole est situé sur la partie 2 de la nervure.
• La figure 3 représente de plus le profilé avec un pli raidisseur de 45^o environ avec l'horizontale.
• La figure 4 représente une variante possible de la figure 2, où l'on retrouve toutes les parties caractéristiques du profilé : les nervures y sont moins arrondies et correspondent avec la glissière B couramment utilisée.
• La figure 5 montre le mode de réalisation préféré de l'invention obtenu à partir d'un profilé couramment utilisé de type A.

In these drawings:

• Figure 1 shows schematically and in perspective a slide according to the invention, bolted to a support, a spacer maintaining a distance of about 20 cm between the central groove of the slide and the support.
• FIG. 2 represents a section on II - II of FIG. 1.
• FIG. 3 represents a section variant of that of FIG. 2, this variant comprising two ribs of substantially parabolic shape developing on the parts 4, 2, 3a and 3b of the profile. The top of the dish is located on part 2 of the rib.
• Figure 3 also shows the profile with a stiffening fold of 45 ^o with the horizontal.
• Figure 4 shows a possible variant of Figure 2, where we find all the characteristic parts of the profile: the ribs are less rounded and correspond with the slide B commonly used.
• FIG. 5 shows the preferred embodiment of the invention obtained from a commonly used profile of type A.

The width of the outer borders can vary between 8 and 20 cm, depending on the impact resistance objective chosen.

Referring to the drawings and more particularly to Figures 1 and 2, it can be seen that the metal section of a safety barrier has been designated by 11. The profiles 11 are secured by overlapping on an end zone 12 where we see the additional bolting holes 8. This profile is supported by vertical posts 10. The profile 11 has a W-shaped section and is designated by 1 the central groove, and by 2 the lateral ribs located on either side of the central groove 1.

The external flank 3a of each of these lateral ribs 2 extends beyond a vertical axis XX ′ substantially tangent to the bottom of the groove 1 by two wings 3b of approximately 7 cm.

The total width of the profile (L 1) is approximately 15 cm, but the width of the wing can be chosen between 3 and 12 cm approximately depending on the desired rigidity, depending on the applications envisaged.

Finally, the increase in the rigidity of the profile can also be obtained by creating a fold 5 with a width of 2 to 5 cm at the end of the wing 3b (FIG. 3). This fold can be either practically in the extension of the border (1 ^o minimum compared to a horizontal plane), or on the contrary raised up to 90 ^o .

The general shape of the profile, seen in straight section, could also be composed of two substantially parabolic segments, framing the central groove: each parabola segment will develop on parts 4, 2, 3a and 3b, in continuity. The top of the parabola will be the point of rib 2 closest to the traffic lane. Thanks to this shape, the shock on the ribs 2 is transmitted in the best conditions in the wings 3a and 3b and in the part 4, which rests on the groove 1.

These two substantially parabolic segments connect to the flat of the groove 1 by a curvature of the profile, tangent to the sidewall 4 and to the groove 1.

When the profile is produced according to a choice of moment of inertia clearly greater than that of the existing profiles (of the order of double), it is then possible to support the slides only every 6 m: a 6 m profile, plus the length of overlap between profiles required (approximately 6.31 m in total), can then be manufactured.

For a total developed width of the profile of 61 cm (which corresponds to the traditional profile, increased by two wings of 7 cm), the choice of a thickness of 2 mm allows the manufacture of a profile of 6.31 m long and weighing approximately 60 kg (for 50 kg in the case of a traditional profile having 4 m long and 3 mm thick). This profile, supported every 6 m, notably avoids the installation of a third of the supports, spacers and bolts compared to the traditional profile. Its steel weight is also slightly lower than the linear meter (approximately 10 kg against approximately 11.5 kg).

The great length of the profile makes it possible to vary the possibilities of positioning the supports, according to the maximum displacement desired in the event of an impact: the minimum is of a support every 6 m, then a support every 3 m. It may be advantageous to also be able to implant a support every 2 m, which leads to providing a maximum of five recesses 6 in the groove of the profile: two at the ends 12, one in the middle, and two others sharing the profile in 3 parts of 2 m.

Figure 5 shows a preferred embodiment of the invention. Profile 11 is obtained by extending the outer flank 3a of a standard type A profile commonly used by a wing 3b which extends the outer flank 3a beyond the plane XX ′ tangent to the bottom of the central groove 1 over a distance comprised between half and twice the depth of the central groove 1. The wings 3b extend diverging on the rear of the profile 11. The angle of the wings 3b with the horizontal is approximately 11 ^o , which allows fitting the profiles 11 during transport from the factory to the site and covering the end 12 of each profile with the end 12 of the neighboring profile during installation.

Regarding the standard type A profile commonly used today, the depth of the central groove 1 and the lateral ribs 2 is approximately 8 cm, its developed width is 47 cm, and its moment of inertia is 100 cm⁴ for a thickness of 3 mm. The calculation shows that by extending the outer flanks 3a of the type A profile with wings 3b by 6 cm, we obtain a moment of inertia of 155 cm une with a profile thickness of 2 mm, and a moment of inertia of 232 cm⁴ with a profile thickness of 2.5 mm. If the wings 3b are 8 cm, the moment of inertia is 242 cm⁴ for a profile thickness of 2 mm and 363 cm⁴ for a profile thickness of 2.5 mm. It can be seen that the moments of inertia are considerably increased for a profile weight per linear meter that is greatly reduced with a profile thickness of 2 mm and substantially equal if the profile thickness is 2.5 mm.

Preferably, the length of the extension of the wings 3b and the thickness of the profile 11 are calculated in such a way that the moment of inertia of the profile 11 is increased by at least 50% compared to the standard slides A or B.

It is understood that the embodiments described above are not limiting and may give rise to any desirable modifications, without departing from the scope of the invention.

Claims (4)

1. Deformable safety barrier placed along the roads, consisting of metal profiles (11) assembled by partial covering and bolting, and supported from place to place by vertical posts, the profile (11) having a central groove (1) surrounded lateral ribs (2) located on either side of said central groove, each having a vertex line located in the same vertical plane parallel to the vertical plane XX ′ tangent to the bottom of the groove (1), forming a relief of the side of the carriageway, and each having an outer side (3a) folded in a direction opposite to the carriageway and extended by a wing (3b) beyond the vertical plane XX ′ tangent to the bottom of the central groove (1), characterized in that the outer flank (3a) of the lateral ribs (2) of the profile (11) extends beyond said vertical plane XX ′ over a distance between half and twice the distance separating said vertical plane cal XX ′ of the plane passing through the top lines of the lateral ribs (2). 2. Safety barrier according to claim 1, characterized in that the wings of the profile have at their ends holes for the passage of assembly bolts. 3. Safety barrier according to any one of claims 1 and 2, in which the profile has at each end of the central groove a hole for its attachment to a post, characterized in that the profile also has along the central groove at least one additional fixing hole, said fixing holes and the additional hole or holes being regularly spaced along the central groove. 4. Safety barrier according to any one of the preceding claims, characterized in that the length of the extension of the wings (3b) of the profile (11) and the thickness of the profile (11) are calculated so that the moment of inertia of the profile is increased by at least 50% compared to standard A or B slides.

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