AU2019202712A1 - Anchoring System for a Guardrail Post - Google Patents

Abstract

Anchoring system for a guardrail post (1) in a rigid support (2), said post comprising a front face (la) and a rear face (Ib), said system comprising: - a base for the post (3); - an anchor plate (4, 4a, 4b) for the rigid support (2); - a means of anchoring (8, 9, 10) the anchor plate (4, 4a, 4b) to the rigid support (2); wherein said post base (3) is mechanically coupled to said anchor plate (4, 4a, 4b) by a mechanical coupling, said mechanical coupling being a rigid coupling that is flexible in rotation under the action of an applied force F on the post (1) having a horizontal component oriented from the front towards the rear of the post, said mechanical coupling becoming plastically deformed when said horizontal component generates a moment of force M greater than a first threshold value Si on the anchoring system. 1/6 la b x1r Figure!1

Description

1/6

b

la

x1r

Figure!1

Anchoring System for a Guardrail Post

Field of the Invention

[0001] This invention relates to the technical field of guard rails arranged along the road traffic routes to reduce the severity of accidents.

[0002] This invention relates to an anchoring system for a guardrail post.

Description of the Prior Art

[0003] A guardrail is a barrier placed along a road traffic lane to, in case of accident, cushion the shock and to prevent the vehicle from returning to the road in the opposite direction so that it does not bounce to the left lane on the roads. To achieve these objectives, it is advantageous to design the guardrails in such a way that they can deform when they are struck by a vehicle in order to absorb the kinetic energy of the latter. In a vehicle collision, the energy may then be absorbed at different points on the guardrail. In general, a guardrail as understood throughout this text is a retaining device consisting of vertical elements anchored to the ground, the "posts", and horizontal elements, the "rails" being fixed to these posts. These vertical and horizontal elements generally consist mainly of metal, but any other materials having adequate mechanical properties may be considered. By convention, throughout this text, the term "front face" of a post, the face of the post, or one of the elements that compose it, adjacent to the traffic lane and usually found on the first line in case of impact with a vehicle, while the "rear face" is the opposite side to the front face. Most of the energy dissipated by a guardrail is generally absorbed by the deformation of the rails, while a more limited amount of energy may also be absorbed by the deformation of the posts and their anchoring system in the ground.

[0004] Document WO 2015/042656 discloses a system for anchoring a guardrail post to a rigid support in which the force exerted by the post onto the means of anchoring in the event of an impact is reduced by the presence of an anchor plate comprising a hinged zone capable of being plastically deformed. In fact, the front part (i) of the anchoring plate comprises an anchoring zone comprising a means for fastening the coupling of said plate to the rigid support and (ii) a zone secured to the base of the post, these two zones being separated by slots extending from the front of the plate towards the rear thereof to the hinged zone. When a force having a sufficient non-zero component oriented front to back of the post is applied to the post, the hinge area of the anchor plate is deformed. Under the action of this force, the zone secured to the base of the post actually follows the rotation of the post caused by the moment of force associated with the impact force, while the anchoring zone of the plate remains coupled to the rigid support. The deformation thus generated in the hinge zone of the plate makes it possible to dissipate kinetic energy and thus to dampen the impact between the vehicle and the guardrail, but also to reduce the force borne by the means of anchoring coupling the anchor plate to the rigid support. The anchoring means, typically comprising anchor bolts placed through holes drilled in the anchor plate, are subjected to tensile effects when applying a force upon the post oriented from front to rear . Due to the plastic deformation of the hinged zone, the tensile peak of these means of anchoring is therefore reduced, allowing them to be preserved and/or to reduce their number or their individual resistance in order to withstand a given level of impact force on the post. Moreover, this document reveals that the anchoring system advantageously includes a stopping device, such as a notch at the back of the post, to limit the post's range of rotation and thus the plastic deformation of the hinged zone. This increases the strength of the guardrail post once the plastic deformation of the hinged zone has reached the maximum permissible range. Despite the dissipation of energy occurring during deformation of the hinged zone, the forces transmitted to the means of anchoring remain high and the maximum value of these is highly dependent on the specific characteristics of the vehicle that collides with the guardrail and especially on the kinetic energy of the vehicle at the time of impact.

[0005] However, when the guardrail is placed on a structure created by civil engineering such as a bridge or a dike, it is generally very desirable to limit to a maximum value the forces transmitted by the means of anchoring to the rigid support in order to preserve it. In such a case, the rigid support is generally part of a complex civil engineered structure. It is therefore expensive and difficult to repair in the event of damage caused by excessive forces on the anchoring means. In order to limit the forces transmitted to the rigid support via the anchoring means, so-called "fused" systems exist, in which the post detaches itself from the rigid support beyond a threshold value of forces transmitted to the anchoring means. Such systems to control the maximum value of the forces transmitted to the rigid support are for example described in US2010/0293870. These anchoring systems include an anchor plate attached to the base of the post that is anchored to the ground through anchor bolts inserted through holes drilled into the anchor plate. Each anchor bolt is in direct contact with the ground and is closed with a nut tightened above the anchor plate. A washer with a hole that can be deformed is placed between the lock nut of the anchor bolts and the anchor plate. In the event the guardrail suffers a sufficient impact and thus of a sufficient moment of force transmitted to the base of the post, the hole of the washer deforms and tears under the stress transmitted to it by the lock nut. At this moment, the anchor plate and thus the post are cut off from the ground because the locking nut is smaller than that of the through holes in the anchor plate. This decoupling, which therefore occurs beyond a threshold value of forces transmitted to the anchoring system, allows the support in which the post is anchored to be preserved via the anchoring plate. At the end of such a decoupling process, both the post and the anchoring means are at least partially damaged, which prevents them from being reused later. On the other hand, the stress threshold which can be transmitted to the anchoring system and the amount of energy dissipated in the anchoring system before uncoupling, are relatively small as they are directly related to the limited mechanical resistance capacity of the washers between the anchor plate and the lock nut.

[0006] In addition, the anchor bolts comprising the deformable washers disclosed in US2010/0293870 are only "fusible" in traction. Therefore, in case of sufficient force exerted upon the post, only the front part of the anchor plate is separated from the rigid support. The bolts at the rear of the anchor plate, on the other hand, are subjected to compression in case of impact from a vehicle against the guardrail. Since there are no fusible bolts under compression in the anchoring system disclosed, the post is therefore usually partially coupled to the rigid support even after a significant impact between a vehicle and the guardrail. As explained in the document, the absence of total decoupling makes it possible to increase the retentive power of the guardrail as the partially decoupled post continues to obstruct the passage of the vehicle. However, this lack of total decoupling combined with the flexing of the post which is deformed can in some cases have harmful effects, especially if, after partial decoupling of the post, the vehicle still has sufficient kinetic energy and its center of gravity is higher than the height of the guardrail after partial decoupling of the post. Such a configuration can actually cause the vehicle to roll over by tipping the guardrail over. Furthermore, beyond generating the tipping of the vehicle that may be produced, the absence of total post decoupling can also cause the vehicle to pass through the guardrail without tipping. With these systems of the Prior Art, it could be observed that among the posts involved in a collision between a vehicle and the guardrail, the posts which undergo the greatest angular deflection actually become more elements that facilitate the vehicle crossing the guardrail than they act as restraints. The force exerted by their weight upon the horizontal elements of the guardrail then acts to lower the guardrail itself.

[006A] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims.

Summary of the Invention

[0007] One aim is to provide an anchoring system in a rigid support for a guardrail post, making it possible to limit to a threshold value the value of the forces transmitted to the rigid support in order to preserve it, while aiming to generally maximize to the amount of energy dissipated during an impact.

[0008] Another aim is to provide an anchoring system in a rigid support for a guardrail post which can be implemented in existing civil engineered structures, such as bridges or dikes, preferably without the needing to adapt or significantly adapt the civil engineered works.

[0009] Another aim is to provide an anchoring system for a guardrail that reduces the risk of overturning a vehicle colliding with the guardrail.

[0010] Another aim is to provide an anchoring system comprising a rigid support means of anchoring which may potentially be reused following an impact that caused damage to the post.

[0011] This invention is defined in the appended independent claims. Preferred embodiments are defined in the dependent claims.

[0012] According to a first aspect, the invention relates to an anchoring system for a guardrail post in a rigid support, said post comprising a front face and a rear face, said system comprising:

- a base for the post; - at least one anchor plate with a rigid support; - means for anchoring the at least one anchor plate to the rigid support; wherein said post base

is mechanically coupled to said at least one anchor plate by mechanical coupling, said mechanical coupling being a rigid coupling deformable in rotation under the action of a force F applied to the post having a horizontal component oriented from the front to the rear of the post, said mechanical coupling becoming plastically deformed when said horizontal component generates a moment of force M greater than a first threshold value Si on the anchoring system, wherein said mechanical coupling is configured to torsionally fracture in fragile zones of the mechanical coupling when said horizontal component of the applied force generates a moment of force upon the anchoring system that is greater than a second threshold value S2, said fragile zones being configured so that the base of the post is completely decoupled from the at least one anchor plate after the rupture of the fragile zones, said means for anchoring the at least one anchoring plate to the rigid support being configured to withstand a moment of force equal to said second threshold value S2.

[0013] According to an advantageous embodiment, the means for anchoring the at least one anchoring plate to the rigid support are configured to remain at their elastic limit when a moment of force equal to said second threshold value S2 is applied to the anchoring system.

[0014] According to an advantageous embodiment, the fragile zones of the mechanical coupling between the post base and the at least one anchor plate comprise a partial weld between the post base and the at least one anchor plate.

[0015] According to an advantageous embodiment, the fragile zones of the mechanical coupling between the post base and the at least one anchor plate comprise a zone having a thickness less than that of the post base and the anchor plate.

[0016] According to an advantageous embodiment, the system comprises two side anchor plates arranged around the post base, said fragile zones being positioned at the interfaces between each side anchoring plate and the post base.

[0017] According to an advantageous embodiment, the system comprises a central anchoring plate coupled to a post base comprising two side parts arranged around said central anchoring plate, said fragile zones being positioned at the interfaces between the central anchoring plate and each of the two side parts of the post base,

[0018] According to an advantageous embodiment, the at least one anchor plate comprises a through-slot extending from the front to the rear of said at least one anchor plate to a certain depth without reaching the rear edge, so as to structurally weaken under torsion the at least one anchor plate, in order to increase the range of the rotation of said mechanical coupling before its rupture under torsion in the fragile zones.

[0019] According to an advantageous embodiment, the at least one anchor plate comprises at least one through-hole for receiving the means of anchoring to the rigid support, said through-hole being advantageously connected to said through-slot.

[0020] According to an advantageous embodiment, said slot comprises an edge tangential to the through-hole, said edge being in a medial position relative to the through-hole and to a fragile zone of the mechanical coupling.

[0021] According to an advantageous embodiment, the means for anchoring the at least one anchor plate to the rigid support comprise anchor bolts, said anchor bolts comprising screws and nuts.

[0022] According to an advantageous embodiment, the bolts comprise washers inserted between the nuts and the at least one anchor plate.

[0023] According to a second aspect, the invention relates to a kit for assembling an anchoring system to a rigid support as described above comprising a post base, at least one anchor plate mechanically coupled to said post base and a means for anchoring the at least one anchor plate to the rigid support.

[0024] According to a third aspect, the invention relates to a post anchored in a rigid support using an anchoring system as described above.

[0025] According to a fourth aspect, the invention relates to a guardrail anchored in a rigid support comprising a plurality of posts as described above and a plurality of horizontal elements connecting said posts together.

Brief Description of the Figures

[0026] These and other aspects of the invention will be explained in more detail by way of example and with reference to the accompanying drawings:

Figure 1 shows one embodiment a post comprising a post base and anchor plates according to one embodiment of the invention;

Figure 2 is an enlargement of the anchoring zone of the post shown in Figure 1;

Figure 3 shows one embodiment of the anchoring system according to the invention comprising the post shown in Figures 1 & 2 on which an impact force F is applied, just before the fracture occurs;

Figure 4 shows the anchoring system shown in Figure 3 in which the impact force F has caused the rupture of the coupling between the post base and the anchor plates;

Figure 5 shows a schematic cross-sectional view of the anchoring zone of the post of Figures 1 & 2;

Figure 6 shows a schematic cross-sectional view of the anchoring zone of a post in another embodiment of the anchoring system according to the invention;

Figure 7 shows a guardrail comprising the anchoring systems according to the invention;

The Figures are not drawn to scale.

Detailed Description of Preferred Embodiments

[0027] The invention thus relates to an anchoring system for a guardrail post 1 in a rigid support 2, said post 1 comprising a front face la and a rear face 1b, said anchoring system comprising:

- a base for the post 3; - at least one anchor plate 4 with a rigid support 2; - means for anchoring the at least one anchor plate 4 to the rigid support 2; wherein said post base 3 is mechanically coupled to said at least one anchor plate 4 by mechanical coupling, said mechanical coupling being a rigid coupling deformable in rotation under the action of a force F applied to the post 1 having a horizontal component oriented from the front to the rear of the post, said mechanical coupling becoming plastically deformed when said horizontal component generates a moment of force greater than a first threshold value Si on the anchoring system, wherein said mechanical coupling is configured to torsionally rupture in fragile zones 5a, 5b of the mechanical coupling when said horizontal component of the applied force generates a moment of force greater than a second threshold value S2 on the anchoring system, said fragile zones 5a, 5b being configured so that the base of the post 3 is completely decoupled from the at least one anchor plate after breaking the fragile zones 5a, 5b, said means for anchoring the at least one anchoring plate 4 to the rigid support 2 being configured to withstand a moment of force equal to said second threshold value S2.

[0028] In the anchoring system according to the invention, the post 1 thus comprises a post base 3 coupled to the at least one anchor plate 4 by means of a mechanical coupling, said at least one anchor plate 4 being itself coupled to the rigid support 2 by means of the anchoring means.

[0029] In Figures 1 and 2, an embodiment of a post 1 compatible with the anchoring system according to the invention is shown. In this embodiment, two side anchor plates 4a, 4b are mechanically coupled to the post base 3 which is in the medial position with respect to the two anchor plates 4a, 4b. In these figures, the side plates 4a, 4b are coupled to the base of the post 3 by welds. In other embodiments, the side plates 4a, 4b and the post base 3 may be integral parts of the same part;

[0030] The means of anchoring to the rigid support 2 of the anchoring plate 4 may have different embodiments. In Figure 3, the means of anchoring of the side plates 4a, 4b comprise bolts inserted into through-holes 6 drilled into said side plates 4a, 4b. These bolts comprise screws 8 partially embedded into the rigid support 2 to which they are attached by mechanical and/or chemical means. Nuts 9 are used to close the bolts above the side plates 4a, 4b. Washers 10 may also be inserted between the nuts 9 and the side plates 4a, 4b.

[0031] In Figure 3, an embodiment of the anchoring system is therefore shown in its entirety. In this Figure, the post 1 is also subjected to a force F comprising a component oriented along a direction vector -x2, i.e., it is oriented from the front face la, to the rear face lb of the post.

[0032] This force therefore generates a moment M along an axis x1 on the anchoring system, and thus causes the deformation in rotation of the mechanical coupling between the side plates 4a, 4b and the post base 3. In the embodiment shown in Figure 3, the side plates 4a, 4b are designed in such a way that the forces due to the force F and transmitted by the post base 3 generate a torsional deformation of the part of the side plates 4a, 4b attached to the post base 3. This deformation is the consequence of a greater structural rigidity of the post base 3 relative to that of the side plates 4a, 4b. This difference in structural rigidity may be due to the use of materials of different qualities for the side plates 4a, 4b and the post base 3. It can also be a consequence of the shape of these elements or of a difference in thickness between them. In Figure 3, the side plates 4a, 4b comprise a slot 7, which extends from the front edge to the rear of each side plate 4a, 4b to a certain depth without reaching the rear edge. This slot 7 structurally weakens the side plates 4a, 4b which are then more easily deformable in torsion when a moment M is applied to the anchoring system.

[0033] The deformation of the plates 4a, 4b is shown in Figure 3. Such a deformation is observable when the moment M generated by the force F has a sufficiently high value. Moreover, when the value of the moment M becomes greater than a first threshold value SI, the mechanical coupling between the plates 4a, 4b and the post base 3 enters plastic deformation. This plastic deformation in torsion is responsible for a significant energy dissipation in the anchoring system and thus makes it possible to eliminate part of the kinetic energy from the vehicle, and thus reduce its speed at the time of the impact.

[0034] If the collision between the vehicle and the guardrail is such that the force F generates a moment M having a value greater than a threshold value S2 on the anchoring system, the mechanical coupling between the side plates 4a, 4b and the post base will break in fragile zones 5a, b of said mechanical coupling. This torsional rupture occurs when the torsional plastic deformation in the side plates 4a, 4b reaches a certain level beyond which the stress to continue plastically deforming the side plates 4a, 4b becomes too high to bear for the fragile zones 5a, 5b, which then break. This rupture thus makes it possible to limit the forces transmitted by the anchoring means of the side plates 4a, 4b to the rigid support 2 at a maximum value. In this way, the rigid support 2 is preserved from damage that may occur in case of excessive forces generated by the anchoring means of the side plates 4a, 4b. The threshold value S2 of the moment before rupture, which is therefore directly related to the maximum forces transmitted by the anchoring means to the rigid support 2 before rupture, can be customized according to the properties of mechanical resistence to breakage of the fragile zones 5a, 5b. Fragile zones 5a, 5b are moreover configured so that their rupture causes a total decoupling between the post base 3 and the side plates 4a, 4b. Thus, these fragile zones 5a, 5b are advantageously located over the entire interface between the post base 3 and the side plates 4a, 4b so that the end of the rupture process, the side plates 4a, 4b and the post base 3 have become separate entities. These fragile zones 5a, 5b can be made in different ways. In Figures 1-4, the fragile zones 5a, 5b correspond to a weld between the side plates 4a, 4b and the post base 3. This weld may be a partial weld, that is to say a weld not extending over the entire thickness of the interface side plates - post base, to obtain a suitable threshold value S2 for the moment M. When the side plates 4a, 4b and the post base 3 are integral parts of a single piece, the fragile zones 5a, 5b may correspond to less thick areas relative to the thickness of the side plates 4a, 4b and the post base 3.

[0035] This rupture results in a total decoupling between the side plates 4a, 4b and the post base 3. The post is completely detached from the rigid support 2 at the end of the breaking process. Such a total decoupling, shown in Figure 4, thus avoids interactions between the guardrail and the vehicle that could have adverse effects on the stability of the latter. For a given threshold value S2, the maximum deflection angle a that the post 1 can withstand before the mechanical coupling breaks can be customized according to the mechanical deformation properties of said coupling. In the embodiment shown in Figures 1-4, this maximum deflection angle a is mainly governed by the structural torsional rigidity of the side plates 4a, 4b, which depends on the material used, the thickness of the plates as well as the exact location and depth of the slot 7. In the embodiment shown in Figures 1-4, it can be observed that the reduction of the structural torsional rigidity due to the presence of the slot 7 in the side plates, combined with the modulation of the torsional stress rupture value of the fragile zones 5a, 5b, making it possible to obtain a dissipation of energy in the plastic deformation of the mechanical coupling substantially equal to the energy dissipation in the fusible anchoring systems of the Prior Art, but it is for a force value transmitted to the rigid support 2 two times less than that observed for these systems of the Prior Art. Therefore, at an equal level of energy dissipated during an impact, the anchoring system according to the invention makes a much better preservation possible for the rigid support 2, which is highly appreciable in civil engineered works.

[0036] In order to achieve this rupture in the sharp mechanical coupling in the fragile zones 5a, 5b, it is important that the means of anchoring the plates 4a, 4b to the rigid support 2 can withstand the forces generated by the value S2 of the moment M. Indeed, the anchoring means, which typically comprises anchor bolts, as shown in Figures 3-4, must be sufficiently durable in order for the decoupling to occur at the level of the fragile zones 5. The absence of rupture or tearing of the anchoring screws and nuts under the action of the moment of force M equal to S2 makes it possible to guarantee a total decoupling of the post 1 by the breaking of the fragile zones 5a, 5b. This sufficient durability of the anchoring means also makes it possible to prevent unpredictable interactions between these and the rigid support 2, which could be deleterious thereto. The anchoring means, which therefore typically comprises anchor bolts, must therefore have mechanical strength properties sufficient to withstand the forces they must transmit to the rigid support 2 of up to a value S2 of the moment of force. In an advantageous embodiment, the anchoring means is designed and dimensioned to remain at its elastic limit up to the value S2 of the moment of force causing the rupture of the fragile zones 5a, 5b. This means that the various elements constituting the anchoring means undergo only elastic deformations, without entering into plasticity therefore, for values of force transmitted during the rupture of the mechanical coupling. In this way, the integrity of the means of anchoring is completely preserved at the end of the process of breaking the mechanical coupling between the side plates 4a, 4b and the post base 3. Consequently, following a destructive accident of the post 1, these anchoring means can be reused to anchor a new post 1 replacing the previous one in the rigid support 2.

[0037] Figure 5 is a schematic cross-sectional view of the anchoring zone of a post 1 in another embodiment of the invention; The side plates 4a, 4b are thus coupled to the post base 3 which is in the central position. Fragile zones 5a, 5b of the mechanical coupling are located at the interfaces between the post base 3 and the side plates 4a, 4b. As already explained above, in the embodiments described in Figures 1-4, the fragile zones 5a, 5b are welds, possibly partial, between the side plates 4a, 4b and the post base 3. In other embodiments, when the side plates 4a, 4b and the post base 3 are integral parts of the same part. It may be an area with a reduced thickness. The parts 31 and 32 represent the front and rear walls of the post 1 which are anchored to its base 3.

[0038] Figure 6 is a schematic cross-sectional view of the anchoring zone of a post 1 in another embodiment of the invention; In this Figure, the side plates 4a, 4b are replaced by a single central plate 4 coupled to a post base in two side portions 3a and 3b. A fragile zone 5a, 5b is at each interface between the two-part post base 3a, 3b and the central plate 4. The central plate 4 advantageously comprises two through-holes 6 into which the anchoring means is received by the rigid support 2. Embodiments with a single through-hole in the central plate 4 may also be envisaged. The portions 3la, 32a and 31b, 32b represent the front and rear walls of the post 1 which are anchored to the side portions 3a and 3b of the post base. What has been said above about the embodiments comprising a central post base 3 and side anchor plates 4a, 4b is directly transferable this embodiment comprising a single central anchoring plate 4 and a post base in two side parts 3a and 3b.

[0039] As discussed above, at least one slot 7 is advantageously machined in the anchor plates 4, 4a, 4b. This slot advantageously passes through an axis x3, through the thickness of the plate so, and it extends along an axis x2, the front edge of the plate to a certain depth towards the rear, without reaching the back edge. This slot 7 reduces the structural rigidity of the plate under torsion. As shown in Figures 5-6, the slot 7 is advantageously connected to the through-hole 6 used to anchor the plate to the rigid support 2. This configuration has indeed proved interesting because it has been observed that in case of vehicle impact on the rails of a guardrail, the various posts 1 involved in the shock absorption are subject to different forces. Indeed, for example in the case of violent impact, a rupture moment S2 is generated on some posts 1 particularly exposed to the impact and thus causes their decoupling from the rigid support 2. However, it has been observed that this moment of rupture S2 is not necessarily attained for all the posts 1 involved in the collision. Due to the rigidity of the rails of the guardrail, posts 1 relatively far from the location of the impact can indeed be involved in the cushioning of the vehicle. For these posts 1 which are not subjected to a moment S2, the decoupling by rupture of the fragile zones 5a, 5b cannot occur. It has however been observed that it was desirable for these posts to uncouple despite the rigid support 2, to avoid interactions between the guardrail and the vehicle that may potentially have undesirable effects on the stability of the latter. On these posts 1 for which the rupture moment S2 is not reached, the presence of the slot 7 connected to the through-hole provides an additional possibility of obtaining decoupling between the post 1 and the rigid support 2. Under the action of certain forces, plates 4, 4a, 4b can indeed be deformed so as to enlarge the width of the slot 7 and to allow the passage of the anchor screw 8 therethrough. The decoupling between the post 1 and the rigid substrate 2 is then obtained by a translational movement along the x2 axis of the post base 3 still coupled to the anchor plates 4, 4a, 4b. It has thus been observed that this mode of decoupling was sometimes preferentially requested with respect to the mode of decoupling by torsional rupture of the fragile zones 5a, 5b, in the case of an impact force oriented purely along the axis x2, but insufficient to generate a moment of force M greater than the threshold value S2. Therefore, in the case of the side component of the impact force F, along the x1 axis, that is also the mode of decoupling by torsional failure of the fragile zones 5a, 5b, which is predominant. The connection of the slot 7 to the through-hole 6 of the anchor plates 4, 4a, 4b thus adds a possibility of decoupling between the post 1 and the rigid support 2 which is found to be useful at least for certain types of collision, in view to the preservation of the rigid support 2.

[0040] In Figures 5-6, each slot 7 connected to a through-hole 6 of an anchoring plate 4, 4a, 4b advantageously comprises an edge 7a, 7b extending along an axis l a, 1lb parallel to x2 and tangential to the through-hole 6. Moreover, the axis l a, 1lb is in the medial position relative to the fragile zone 5a, 5b of the mechanical coupling and the through-hole 6. By medial position is meant that the axis l la, 1Ib, in addition to being tangential to the through-hole 6, is located between the through-hole 6 and the fragile zone 5a, 5b. In other words again, the edge 7a, 7b of the slot 7 extends along an axis 11 which is parallel to x2 and tangential to the hole 6 on the side of the fragile zone 5a, 5b. In this way, the slot 7, generally narrower than the through-hole 6, is connected to the through-hole 6 while being shifted towards the fragile zone 5a, 5b with respect to the center of the through-hole 6. This configuration for the anchor plates 4, 4a, 4b has proved particularly advantageous. Indeed, during the deformation of the mechanical coupling between the anchor plates 4, 4a, 4b and the post base 3, 3a, 3b under the action of a moment of force M, most of the observable deformation is provided by the part of the anchor plates 4, 4a, 4b located between the axis 11 of the edge 7a, 7b and the fragile zone 5a, 5b, as shown in Figure 3. By positioning the edge 7a, 7b of the slot 7, connected to the through-hole 6, tangentially to this hole, it prevents the appearance of a lever arm generated by the deformed portion of the plate against the anchoring means of the rigid support plate 2, that is to say the screw 8 and nut 9 shown in Figures 3-4. The presence of such a lever arm would indeed be a potential cause of damage for these anchoring means, which could prevent them from being reused later for the anchoring of a new post 1.

[0041] Figure 7 shows a guardrail comprising posts 1 anchored to a rigid support 2, which is here a concrete or metal ridge, with the aid of an anchoring system as described above. The horizontal elements, the tubes 12, connect the different posts 1 between them.

[0042] Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Claims (14)

CLAIMS:

1. Anchoring system for a guardrail post in a rigid support, said post comprising a front face and a rear face), said system comprising: - a base for the post; - at least one anchor plate for the rigid support; - means for anchoring the at least one anchor plate) to the rigid support; wherein said post base is mechanically coupled to said at least one anchor plate by a mechanical coupling, said mechanical coupling being a rigid coupling deformable in rotation under the action of a force F applied to the post having a horizontal component oriented from the front to the rear of the post, said mechanical coupling becoming plastically deformed when said horizontal component generates a moment of force M greater than afirst threshold value Si on the anchoring system,

and wherein said mechanical coupling is configured to torsionally fracture in fragile areas of the mechanical coupling when said horizontal component of the applied force generates a moment of force upon the anchoring system that is greater than a second threshold value S2, said fragile zones being configured so that the base of the post is completely decoupled from the at least one anchor plate after the rupture of the fragile zones, said means for anchoring the at least one anchoring plate to the rigid support being configured to withstand a moment of force equal to said second threshold value S2.

2. Anchoring system according to Claim 1, wherein the means for anchoring the at least one anchoring plate to the rigid support are configured to remain at their elastic limit when a moment of force equal to said second threshold value S2 is applied to the anchoring system.

3. Anchoring system according to any of the preceding Claims wherein the fragile areas of the mechanical coupling between the post base and the at least one anchor plate comprise a partial weld between the post base and the at least one anchor plate.

4. Anchoring system according to any of Claims 1 and 2, wherein the fragile areas of the mechanical coupling between the post base and the at least one anchor plate comprise a zone having a thickness less than that of the post base and the anchor plate.

5. Anchoring system according to any of the preceding Claims the system comprises two side anchor plates arranged around the post base, said fragile zones being positioned at the interfaces between each side anchoring plate and the post base.

6. System according to any of Claims 1 to 4, comprising a central anchoring plate coupled to a post base comprising two lateral parts arranged around said central anchoring plate, said fragile zones being positioned at the interfaces between the central anchoring plate and each of the two side parts of the post base,

7. Anchoring system according to any of the preceding Claims wherein the at least one anchor plate comprises a through-slot extending from the front to the rear of said at least one anchor plate to a certain depth without reaching the rear edge.

8. Anchoring system according to Claim 7, wherein the at least one anchor plate comprises at least one through-hole for receiving the means of anchoring to the rigid support, said through-hole being advantageously connected to said through-slot.

9. Anchoring system according to Claim 8, in which said slot comprises an edge tangential to the through-hole, said edge being in a medial position relative to the through-hole and to a fragile zone of the mechanical coupling.

10. Anchoring system according to any of Claims 8 and 9, wherein the means for anchoring the at least one anchor plate to the rigid support comprises anchor bolts, said anchor bolts comprising screws and nuts.

11. Anchoring system according to Claim 10, wherein the bolts comprise washers inserted between the nuts and the at least one anchor plate.

12. Kit for assembling an anchoring system to a rigid support according to any one of the preceding Claims, comprising a post base, at least one anchor plate mechanically coupled to said post base and the anchoring means of the at least one anchoring plate to the rigid support.

13. Post anchored in a rigid support by means of an anchoring system according to any one of Claims I to 11.

14. Guardrail anchored into a rigid support comprising a plurality of posts according to Claim 13 and a plurality of horizontal members connecting said posts to each other.