EP0318405B1 - Round timber motorway crash barriers and manufacturing methods - Google Patents

Abstract

A crash barrier according to the invention comprises wooden posts (1) supporting a horizontal rail (2) composed of round wooden elements (31, 32 ...) which are assembled end-to-end by means of two metal strap plates (41, 42) and by means of bolts (5). The strength of the assemblies is reinforced by incorporating, in the ends of each round wooden element, vertical metal rods (8) which intersect the plane of the assembly bolts and which are located on the same side of the bolt (5) as the end of the round wooden element which forms part of the assembly. <IMAGE>

Description

The present invention relates to round wooden safety barriers intended to be placed along roads or motorways and to a method of construction thereof.

The technical sector of the invention is that of the construction of road safety devices.

We know the metal barriers that are placed along the roads to serve as safety barriers. There are also known wooden safety barriers.

Patents U.S.A. 2,085,058 (WOOD), U.S.A. 1,493,088 (VAN EPPS) and U.S.A. 3,989,226 (BURGESS) describe safety barriers with rectangular wooden rails.

The patent application EP.A. 0.184.525 (85.420202.5) (EYNARD) describes road safety barriers made up of a beam of wooden logs assembled end to end by a metal frame in the shape of a T and wooden poles.

The patent application EP.A. 0.228.334 (86.430049.6) (COMPAGNIE FRANCAISE DES ETABLISSEMENTS GAILLARD) also describes road safety barriers comprising round wooden posts and a round wooden boom assembled end to end by two metal fishplates advantageously comprising on their internal face, crampons which penetrate the rails.

The present invention relates to improvements to the crash barriers described in this publication EP.A. 0.228.334.

The problem to solve is as follows:

The wooden slides must meet specifications which impose a determined tensile strength for the healds assembled, for example a resistance of 200 kilonewtons (20 T.), so that in the event of a vehicle impact, the healds do not are unlikely to separate, allowing the vehicle to pass through.

Statistical tests carried out on beams of beams assembled by two fishplates connected together by bolts, have shown that the horizontal diametrical plane in which the bolts are located constitutes a preferential failure plane and that the tensile strengths measured exhibited significant dispersion, of the order of 10%, around the average value. Therefore, it is difficult to meet the specifications of tensile strength unless excessively increasing the diameter of the logs constituting the beams.

The problem is therefore to improve the safety barriers comprising a round wooden beam assembled end to end, so as to improve the static tensile strength of the assemblies between beams by using simple and inexpensive reinforcement means, so that the price of wooden slides remains competitive.

In addition to their static tensile strength, road safety barriers must have specific dynamic behavior. In the event of a vehicle impact, the assemblies between elements must allow a significant overall elongation without rupture of the assemblies in order to absorb the kinetic energy of the vehicle.

The objective of the present invention is therefore to improve the end-to-end assemblies between logs to give them a high static tensile strength while allowing in the event of a vehicle impact, a significant elongation of the assemblies located on either side. else shock.

The BE.A. 883.394 (Yves DURAND) describes butt joints between beams of rectangular section which comprise on the one hand assembly bolts which pass through several juxtaposed beams or which pass through a beam and two junction fishplates and which also comprise hooping reinforcement composed of two plates which are clamped against the fields of each beam, at the end thereof, by threaded rods which pass through the beam and which are perpendicular to the assembly bolts. Such reinforcing hoops compress the wood located in the areas stressed by the assembly bolts.

Such reinforcement by hoops would not be suitable for making assemblies of rails of safety rails because it necessarily includes frets and ends of rods in relief above and below the rails which would be very dangerous. for the safety of vehicle passengers. In addition, frets which compress the wood cannot be used outside because the swelling of the wood due to humidity variations would cause the frets to loosen, which would become inoperative.

Finally, when the hoops are tight and compress the wood, the assembly becomes rigid and in the event of a vehicle impact, it can only undergo reduced elongations.

The road safety barriers according to the invention are of the known type, comprising wooden posts, which are assembled end to end by two metal fishplates, connected together by bolts which pass through said fishplates and said logs and which are located in the horizontal diametral plane of these at least one of said fishplates, preferably at least the fishplate located on the side of the road, being placed in a horizontal groove of the logs.

The object of the invention is achieved by means of safety barriers of the type known above, in which each assembly between two successive logs is reinforced by incorporating in each log metal rods which pass through it, which are placed at the contact or in the immediate vicinity of the fastening bolts of the fishplates and on the same side as the junction between the two nearest logs and which cut across the horizontal diametral plane of the log, the metal rods being provided with a head placed in a housing dug in said log.

Advantageously, the metal reinforcing rods are threaded rods or bolts comprising a nut placed in a housing hollowed out in said logs.

According to a preferred embodiment, the reinforcing rods are vertical.

We can associate with each bolt connecting two metal fishplates a single metal reinforcing rod which is placed in the vertical diametral plane of the log. One can also associate with each bolt connecting two metal fishplates two metal rods of symmetrical reinforcement with respect to the vertical diametral plane of the log. Mixed solutions can be used comprising a single reinforcing rod associated with a bolt and two rods associated with the other bolt.

It is also possible to reinforce the tensile strength by constructing safety barriers according to the invention comprising two identical slides superimposed in contact with one another, which are mechanically connected together by a single plate, located on the opposite side of the road, which is connected by horizontal bolts with two fishplates located on the side of the road.

In this case, the assemblies between successive logs of each stringer can also be reinforced by vertical metal rods associated with each bolt.

Advantageously, each vertical rod can pass through two superimposed logs so that it participates in the mechanical connection between the two superimposed healds.

The invention results in wooden road safety barriers, whose tensile and impact resistance is significantly improved by the addition of reinforcing rods incorporated in the logs, that is to say by means little expensive in material and in installation work.

Statistical measurements have shown that, all other things being equal, the tensile strength is more than doubled by the addition of metal reinforcing rods. These can be incorporated into the logs in the factory, which makes it possible to mechanize this operation and reduce the cost.

The channels intended to receive the reinforcement rods can also be drilled in the factory at the same time as the channels intended to receive the joint bolts of the fishplates and the reinforcement rods can be laid on the site at the same time as the bolts. assembly. We can provide a maximum number of channels and set up a number of reinforcing rods adapted to the specifications of each particular use.

The embodiment comprising two beams superimposed on contact with each other, which are mechanically linked in all cases by a common assembly plate and possibly by reinforcing rods which pass through two superimposed logs makes it possible to construct slides. made of wood with high mechanical properties and, in particular, very good tensile strength and reduce the number of assemblies and therefore also the cost of construction.

• Les figures 1, 2 et 3 sont respectivement une vue en perspective et des coupes transversales d'un premier mode de réalisation d'une glissière selon l'invention.
• Les figures 4 et 5 représentent respectivement une vue en perspective et en coupe d'un deuxième mode de réalisation.
• Les figures 6 et 7 représentent respectivement une vue en perspective et en coupe d'un troisième mode de réalisation.
• Les figures 8 et 9 représentent respectivement une vue en perspective et en coupe d'un quatrième mode de réalisation.
• Les figures 10 et 11 représentent respectivement une vue en perspective et une coupe transversale d'un premier mode de réalisation d'une glissière comportant deux lisses horizontales superposées.
• Les figures 12 et 13 représentent respectivement une vue en perspective et une coupe transversale d'un deuxième mode de réalisation d'une glissière comportant deux lisses horizontales superposées.
• Les figures 14 et 15 représentent respectivement une vue en perspective et une coupe transversale d'un cinquième mode de réalisation d'une glissière selon l'invention comportant une seule lisse horizontale.

The following description refers to the appended drawings which represent without any limiting character, examples of embodiment of road safety barriers according to the invention.

• Figures 1, 2 and 3 are respectively a perspective view and cross sections of a first embodiment of a slide according to the invention.
• Figures 4 and 5 respectively represent a perspective view and in section of a second embodiment.
• Figures 6 and 7 respectively represent a perspective view and in section of a third embodiment.
• Figures 8 and 9 respectively represent a perspective view and in section of a fourth embodiment.
• Figures 10 and 11 respectively show a perspective view and a cross section of a first embodiment of a slide having two horizontal beams superimposed.
• Figures 12 and 13 respectively represent a perspective view and a cross section of a second embodiment of a slide having two horizontal beams superimposed.
• Figures 14 and 15 respectively represent a perspective view and a cross section of a fifth embodiment of a slide according to the invention comprising a single horizontal rail.

Figure 1 is a perspective view of a slide section according to the invention which is composed of round wooden posts 1, carrying a horizontal rail 2, which is composed of wooden logs 3₁, 3₂ ... etc .. ., which are assembled end to end by two horizontal metal fishplates 4₁, 4₂, placed on either side of the ends of the two logs and connected together by bolts 5, which are placed in the diametrical horizontal plane of the logs and which cross both the fishplates and one of the logs.

According to a preferred embodiment, each assembly comprises four bolts 5 at the rate of two for each log.

Advantageously, the logs 3₁, 3₂ have a constant diameter and the splint 4₁ is placed in a horizontal groove of the logs.

The posts 1 are placed at the junctions between two logs 3 and the rail is assembled with the posts 1 by bolts 6 which pass through the rear splint 4₂ and the post 1 as can be seen in FIG. 3.

Fishplates 4₁, 4₂ may have, on their internal face, metal studs 7 which penetrate into the wood.

Slides in accordance with the above are known and described in the publication of European patent application 0.228.334.

The connections between logs must be strong enough so that they do not risk breaking when a vehicle launched at high speed strikes the beam.

The specifications impose mechanical resistance tests.

For FRANCE, for example, the beams must resist a tensile force of around 200 kilonewtons (20 T.).

The tests carried out on slides in accordance with the preceding description have shown that if a smooth assembly is subjected to a tensile force, the horizontal diametral plane in which the bolts 5 are located is a fracture plane because the fibers of the wood located in this plane are subjected to greater tensile and compressive forces than the fibers located outside this plane which participate more weakly in the resistance.

Statistical measurements of tensile strength carried out on numerous samples also show a significant dispersion of the results around the average, the deviations being of the order of 10% of the average value.

According to the present invention, the end-to-end assemblies of the heald elements are reinforced by incorporating metal rods 8, which have a diameter of the same order as that of the bolts 5, into the ends of each log.

The rods 8 are advantageously threaded rods or bolts.

Each rod 8 crosses a log right through. Each rod 8 is placed in contact with or in the immediate vicinity of a bolt 5 and on the same side thereof as the most adjacent junction between two logs, that is to say the junction in the assembly of which participates the bolt 5, so that when traction is exerted on the ribs, each bolt 5 is driven towards the rod 8 which is associated with it. The rods 8 intersect the diametrical horizontal plane in which the bolts 5 are located.

The figures represent preferred embodiments in which the rods 8 are vertical and therefore perpendicular to the horizontal diametral plane of the logs.

It is specified that, as a variant, the rods 8 could be inclined relative to the diametral horizontal plane, but in all cases, they overlap the latter, that is to say that they are not parallel to the bolts 5.

FIG. 1 represents a first embodiment in which, with each bolt 5, is associated a single vertical metal rod 8, which is placed in the vertical diametral plane of the logs 3.

Figures 2 and 3 are cross sections of Figure 1. In this example, the rods 8 are wood bolts. The head 8a of the bolt and the nut 8b screwed onto the bolt are placed in a housing hollowed out in the log, so that they do not protrude outside of the latter. The bolt 8 is housed in a channel drilled through the log.

When a tensile force is exerted on the rail, the bolts 5 bear against the rods 8, which themselves bear against the wood by distributing the forces, so that the fibers of the wood situated in the diametral plane vertical also participate in tensile strength. In addition, under the load, the rods 8 tend to bend, which has the effect of strongly applying the head 8a and the nut 8b against the wood and of compressing the latter and this compression force makes it large part of the fibers of the solid wood, so that they also participate in the resistance of the wood.

Statistical tests have shown that the tensile strength of healds fitted with metal rods 8 was more than doubled compared to the resistance of the same healds without rods 8. In addition, the dispersion of the results is much lower, the standard deviation being of the order of 5% of the average resistance.

Figures 4 and 5 respectively represent a perspective view and a cross section of a second embodiment in which the butt connection of two logs is reinforced by four rods or vertical bolts 8, which form two pairs symmetrical with respect in the vertical diametral plane of the logs, each pair being placed in contact with or in the immediate vicinity of one of the two bolts 5 passing through each log and always on the same side thereof as the end of the nearest log.

Figures 6 and 7 respectively show a perspective view and a cross section of a third embodiment of the invention.

In this mode, the butt connection between the ends of two logs 3 is reinforced by six vertical rods or bolts 8 at a rate of three per log, namely a pair of rods 8₁ and 8₂ which are placed in contact with or near immediate of one of the two bolts 5₁, symmetrically with respect to the vertical diametral plane and a single rod 8₃ which is placed in contact with or in the immediate vicinity of the second bolt 5₂, which is preferably the closest to the junction of the two logs , in the vertical diametral plane.

Figures 8 and 9 respectively represent a perspective view and a cross section of a fourth embodiment of the invention.

In this example, each assembly between the ends of two logs is reinforced by eight rods or vertical bolts 8₁, 8₂, 8₃ 8₄, at the rate of four passing through each log. These four rods form two pairs, each pair being placed in contact with or in the immediate vicinity of one of the two bolts 5₁ and 5₂, symmetrically with respect to the vertical diametral plane.

Advantageously, the spacing between the two rods 8₁ and 8₂ of a pair is different from the spacing between the two rods 8₃ and 8₄ of the other pair, so that the forces are distributed over a greater part of the surface of the log and the stresses in the wood are therefore reduced.

Advantageously, the two rods 8₃ and 8₄ of the pair closest to the junction of the two logs are closer together than the other two rods 8₁ and 8₂. For clarity of the drawing, the rods 8 are represented only by their axis in FIG. 9.

Figures 10 and 11 respectively represent a perspective view and a cross section of another embodiment of a slide according to the invention. In this example, the tensile strength of the slide is strengthened by equipping it with two identical heddles 2 and 2 ′ superimposed and connected together, such so that their tensile strengths add up. Each stringer is made up of logs assembled end to end.

The adjacent ends of two logs 3 forming a single rail are assembled together by means of two fishplates connected together by four horizontal bolts 5 or 5 ′.

The two fishplates 4₁ and 4′₁ located on the side of the road are identical to those which are used in the embodiments according to Figures 1 to 9 comprising a single stringer. The assembly is reinforced by vertical metal rods or bolts 10, which are incorporated in the logs and placed in contact with the bolts 5 and 5 ′ or in the immediate vicinity of these and which are engaged in vertical channels drilled at advance in the logs.

Figures 10 and 11 show an embodiment in which there is associated with each bolt 5 and 5 ′ a single metal rod 10 placed in the vertical diametral plane.

In this example, each metal rod 10 passes through the two superimposed logs 3 and 3 ′ and therefore constitutes a mechanical connection between the two superimposed healds which makes them integral in the event that a tensile force is exerted on only one of the two healds.

However, it is often difficult to engage a single rod through the two superimposed logs because the vertical channels prepared in them are not always aligned after assembly.

This is why the end-to-end assembly between the two rails comprises at the rear a single plate 9, which replaces the two rear bars 4isses and 4′₂ and which is connected by the bolts 5 and 5 ′ to the two front bars 4₁ and 4′₁.

The plate 9 has the same length as the ribs 4₁ and 4′₁. Its height is slightly greater than the distance separating the horizontal diametrical planes from the two beams. The plate 9 has the effect of strengthening the mechanical connection between the two superimposed healds.

In the exemplary embodiment according to FIGS. 10 and 13 comprising two superimposed healds connected or not connected to one another by an assembly independent of that of the ends, the impact resistance of the healds is improved, so that logs can be used more long and reduce the number of connections between logs.

However, for safety reasons, an additional post 11 is then planted between two posts 1 carrying the junctions between logs.

This additional post 11 may include a mechanical connection with the beams. It serves to support these in the event of a vehicle impact against the beams.

Figures 12 and 13 respectively represent a perspective view and a cross section of a second embodiment of a slide having two superimposed healds 2 and 2 'made integral by a plate 9 acting as a joint bar joint to butt joints end of the two rails.

By way of example, there is shown in FIGS. 12 and 13, a plate 9, the internal face of which comprises metal studs 7, which penetrate into the wood.

The embodiment according to FIGS. 12 and 13 differs from that according to FIGS. 10 and 11 by the number of reinforcing rods used which is for each log end of two pairs of vertical rods 10₁, 10₂, 10₃, 10₄ instead of two rods 10 only.

It also differs from it by the fact that the length of the rods is limited to the height of a log, so that the rods 10₁, 10₂, 10₃, 10₄ reinforcing the log are separated from the rods 10′₁, 10′₂, 10 ′ ₃, 10′₄ reinforcing the log placed below the previous one as seen in Figure 13, which avoids having to engage the same rod in two channels which may be misaligned.

In this example, the mechanical connection between the two superimposed healds is produced by the rear plates 9.

In the case of slides comprising two superimposed rails, it is obviously also possible to use metal reinforcing rods 10 arranged in accordance with the examples shown in FIGS. 2, 3, 4, 5, 6 and 7.

Figures 14 and 15 show another embodiment of a slide according to the invention. The parts approved to those of Figures 1 and 2 are represented by the same references. In this embodiment, each assembly bolt 5 is associated with two reinforcing rods 8₁, 8₂ which are not vertical but inclined and symmetrical with respect to the horizontal diametral plane of the logs and which form an angle α between them which can vary for example between 30 ° and 60 °. The rods 8₁, 8₂ intersect the horizontal plane in which the assembly bolts are located 5. The two rods 8₁, 8₂ associated with a bolt are offset longitudinally relative to each other and they are located on the same side of the bolt 5 as the junction between the two logs. FIG. 15 shows two reinforcing rods 8₁, 8₂ which are smooth rods having only one head 12 which prevents the rods from falling. The head 12 is engaged in a housing hollowed out in the log so that the presence of the rods 8₁, 8₂ has no projecting part outside the logs.

This embodiment shows that reinforcing rods according to the invention can be oblique to the horizontal plane and do not clamp the wood which illustrates the difference with rods intended to clamp two frets applied against the upper and lower faces of a smooth.

Claims (13)

1. Road crash barrier (of known type) comprising wooden posts (1) bearing at least one horizontal longitudinal (2) composed of wooden billets (3₁, 3₂) which are assembled end-to-end by two metal butt-straps (4₁, 4₂) which are connected to each other by bolts (5) which pass through the said butt-straps and one of the billets and which are located in the horizontal diametral plane of the latter, at least one of the said butt-straps being placed in a horizontal groove in the said billets, characterised in that each assembly between two successive billets is strengthened by incorporating in each billet (3₁, 3₂) metal rods (8, 8₁, 8₂, 8₃, 8₄) which pass through the latter, which are placed in contact with or in the immediate proximity of the said bolts (5) on the same side of the latter as the closest junction between two billets and which intersect the said horizontal diametral plane, and in that the head (8a, 12) of the said metal rods is placed in a housing hollowed out in the said billets.

2. Crash barrier according to Claim 1, characterised in that the said metal rods (8) are constituted by bolts comprising a nut (8b) placed in a housing hollowed out in the said billets.

3. Crash barrier according to either of Claims 1 or 2, characterised in that the said metal rods (8) are vertical and perpendicular to the said horizontal diametral plane.

4. Crash barrier according to Claim 3, characterised in that each assembly comprises, associated with certain bolts (5), a single vertical metal rod (8), placed in the vertical diametral plane of the billets.

5. Crash barrier according to Claim 3, characterised in that each assembly comprises, associated with certain bolts (5), two vertical metal rods (8) which are symmetrical with respect to the diametral plane.

6. Crash barrier according to Claim 3, characterised in that each assembly comprises, for each billet end, a vertical rod (8₃) associated with one of the bolts (5₂) and placed in the vertical diametral plane of the billet and two vertical rods (8₁, 8₂) associated with another bolt (5₁) and symmetrical with respect to the vertical diametral plane of the billet.

7. Crash barrier according to Claims 3 or 5, characterised in that each assembly between two billets comprises, for each billet, a pair of vertical rods (8₁, 8₂), placed in contact with or in the immediate proximity of a bolt (5₁) and a second pair of vertical rods (8₂, 8₃) placed in contact with or in the immediate proximity of a second bolt (5), the spacing between the two rods (8₁, 8₂) of one pair being different from the spacing between the two rods (8₃, 8₄) of the other pair.

8. Road crash barrier according to Claim 1, characterised in that each assembly comprises two metal rods (8₁, 8₂) associated with each assembly bolt (5), these rods being inclined and symmetrical with respect to the said horizontal diametral plane.

9. Road crash barrier according to Claim 1, characterised in that the said metal rods (8, 8₁, 8₂, 8₃, 8₄) are smooth rods having a rounded head (12).

10. Crash barrier according to Claim 1, characterised in that it comprises two superimposed horizontal longitudinals (2, 2′) which are in contact with each other and composed of wooden billets (3₁, 3₂...3′₁, 3′₂) assembled end-to-end by butt-straps (4₁, 4′₁) and by bolts (5), characterised in that, on the side opposite that of the road, the ends of the four billets constituting two superimposed longitudinals are assembled in pairs by a common metal plate (9) connected by horizontal bolts (5) to two horizontal butt-straps (4₁, 4′₁) located on the side facing the road.

11. Crash barrier according to Claim 10, characterised in that the assembly of the two superimposed longitudinals (2, 2′) is strengthened by metal rods (10), associated with each of the said bolts (5), which pass right through two superimposed billets.

12. Crash barrier according to any one of Claims 1 to 11, characterised in that the said butt-straps (4₁ 4₂) and the said metal plate (9) comprise, on their inside face, metal cramps (7) which penetrate into the said billets.

13. Method of constructing a road crash barrier of the type comprising wooden posts supporting at least one horizontal longitudinal composed of wooden billets which are assembled end-to-end by two metal butt-straps which are connected to each other by bolts which pass through the said butt-straps and the said billets, at least one of the said butt-straps being placed in a horizontal groove in the said billets, characterised in that the strength of each assembly is strengthened by incorporating, in the ends of each billet, metal rods (8) which intersect the plane in which the said assembly bolts are located, these rods being placed in contact with or in the immediate proximity of one of the said assembly bolts (5) on the same side of the latter as the end of the billet which forms part of the said assembly, the head (8a, 12) of the said metal rods being placed in a housing hollowed out in the said billets.

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