EP2981651A1

EP2981651A1 - Support and protection barrier for retaining a moving object

Info

Publication number: EP2981651A1
Application number: EP14722257.4A
Authority: EP
Inventors: Pascal Rambaud
Original assignee: Mecanroc
Current assignee: Swincar
Priority date: 2013-04-04
Filing date: 2014-04-02
Publication date: 2016-02-10
Anticipated expiration: 2034-04-02
Also published as: FR3004199A1; FR3004199B1; WO2014162098A1; EP2981651B1

Abstract

The barrier (1) comprises multiple supports (3) secured to the ground, with nets (4) stretched therebetween. Each support comprises: a pole (10) orthogonal to the ground, the base (11) of which rests on the ground; a lower maintaining element (14) perpendicular to the pole, having an upstream end (15) secured to the ground and a downstream end part mounted on the base of the pole, as well as means (17, 31, 33) restricting the downward movement of the base of the pole; and an upper rigid maintaining element (20) inclined in relation to the pole, having an upstream end (21) secured to the ground and a downstream end part mounted on the head of the pole, as well as means (25, 26, 32, 24) restricting the downward and upward movement of the head of the pole.

Description

SUPPORT AND PROTECTIVE BARRIER FOR RETENTING AN OBJECT IN MOTION

The present invention relates to a support intended to be fixed on a ground for the realization of a protective barrier capable of retaining an object moving relative to said terrain. The invention also relates to such a barrier.

The invention is particularly applicable to barriers capable of holding blocks down a slope.

However, other uses of such a barrier are also covered by the invention, such as the retention of a snowpack on sloping ground, for the prevention of avalanches, or the restraint of a projected object by a machine rotating or by a strong wind or an explosion, etc., for the protection of an installation or its environment.

In the particular, but not limiting, example of barriers on sloping ground, the barrier serves to protect people, infrastructure and property from falling and falling blocks of rock walls. Implanted across the slope, substantially along contour lines, such a protective barrier is sized to intercept the trajectory of the blocks and stop them by dissipating their kinetic energy.

Conventionally, a protective barrier comprises on the one hand metal supports which are fixed in the field, and on the other hand nets, or equivalent, fixed between the supports. The masts are maintained in a position substantially normal to the slope by guy lines, namely upstream stays and downstream stays, and side stays in the case of the end poles of the barrier.

The downstream stays are not, in principle, not directly solicited in the event of impact of an object or block or snow thrust but they are justified in the event of a direct impact on an upstream stay cable - which has for effect to pull the head of the mast upstream - or to counter a whiplash during the rebound of the block.

A first disadvantage of these known barriers is that each stay requires a specific ground anchoring and that these anchors are often difficult and expensive to achieve, especially in soft terrain, even if the traction they support can be moderate, as it is the case of shrouds downstream. Another disadvantage is that the mounting of the barrier is relatively long and can be achieved only on the implantation site, which is often steep, without the possibility of pre-assembly in easy site.

There are also barriers whose supports are faster to install and / or require the implementation of a smaller number of anchors. However, such supports have the disadvantage of requiring relatively heavy and expensive welded parts. Thus, with this type of barriers, anchorage savings can be, in some cases unfavorable, partially offset by an additional cost of the components of the support.

The document FR 1 108 583 describes an avalanche protection barrier in which the foot of the mast is fixed on a support plate resting on the ground. At each mast is fixed:

- A rigid upper tie whose upstream end is anchored to the ground and whose downstream end is fixed in the upper part of the mast;

- And, in some embodiments, a lower tie whose upstream end is anchored to the ground and whose downstream end is fixed to the support plate.

Thus, this document provides for preventing movement of the head and foot of the mast relative to the ground, both at rest and during a solicitation.

Such a barrier can be satisfactory in the avalanche application, preventing the snow from starting to slide down the slope: the movement of the snowpack is blocked before it has time to gain speed and trigger an avalanche .

However, this type of barrier generally does not provide satisfactory protection in all cases, especially to retain blocks downhill slope. Thus, the use of such a barrier is limited to small stone barriers, where the net is sufficient to ensure the dissipation of kinetic energy of the block, this barrier does not provide a sufficient level of safety when the potential solicitations are high.

The invention aims to remedy the aforementioned drawbacks of the prior art.

For this purpose, and according to a first aspect, the invention relates to a support intended to be fixed on a ground for the realization of a protective barrier adapted to retain an object in movement with respect to said ground, the support comprising: - A mast which has a foot adapted to rest on the ground and a head and which, in the mounted position of the support on the ground, is substantially orthogonal to the ground;

- A lower holding element substantially perpendicular to the mast, having an upstream end to be fixed to the ground and a downstream end portion mounted on the foot of the mast;

first limiting means for limiting the movement of the foot of the mast downstream with respect to the ground, in the mounted position;

- A rigid upper holding member disposed obliquely relative to the mast, having an upstream end to be fixed to the ground and a downstream end portion mounted on the mast head;

second limiting means for limiting the movement of the mast head relative to the ground, downstream and upstream, in the mounted position.

According to a general definition of the invention, the first limiting means and the second limiting means respectively comprise a first and a second braking device, the braking devices being designed to prevent movement of the mast downstream at rest, and for braking the movement of the mast downstream under the effect of a bias exerted on the mast, in the mounted position. In addition, the first and second braking devices are separate and arranged so that the braked displacement of the mast downstream, in the mounted position and under the effect of a bias exerted on the mast, is substantially in parallel translation in the field, without modifying the inclination of the mast with respect to the ground.

The terms "upstream" and "downstream" refer to the path of movement of the object. In particular, in the case of a barrier capable of retaining blocks running down a slope, the upstream and downstream terms are used with reference to the slope line of the ground.

Due to the rigidity of the upper holding member and the presence of the second limiting means, the support according to the invention may be devoid of downstream stay, which limits both the number of necessary ground anchors and the required assembly time on site. These advantages are not obtained at the expense of the simplicity of the support structure, since it essentially comprises only three parts, namely the mast and the lower and upper holding elements. The first and second limiting means are intended to limit the movement of the mast relative to the terrain, that is to say concretely with respect to the corresponding holding element, or with respect to the anchoring of this holding element.

The term "limitation" has the meaning of: restricting by imposing limits. In practice, according to the invention, the movement of the mast is blocked at rest (that is to say in the unconstrained state, in the absence of rock impact or snow thrust), and braked during a solicitation, that is to say restricted in its speed and in its race.

More specifically, the first limiting means are intended to slow the sliding of the foot of the mast during a load, and to prevent this sliding at rest in the preferred embodiment according to which the foot of the mast rests on the ground without being anchored, and if the terrain is sloping.

As for the second means of limitation, they are intended to prevent movement of the mast head downstream at rest - when the terrain is sloping - and to curb this movement during a solicitation. The limitation of the upstream movement is not necessary to rest on a sloping ground, because of the inclination of the mast disposed substantially according to the normal terrain. On the other hand, the limitation of the upstream movement is essential in case of stress, because of the absence of downstream stays.

In practice, the support may be substantially located in a vertical plane, in the mounted position, that is to say when it is fixed on a ground. The lower holding member then substantially follows the slope line of the ground, thus being substantially perpendicular to the mast. As for the upper holding element, it is arranged obliquely, that is to say that it forms with the mast an angle α neither straight nor zero, for example between 10 ° and 80 °, and can typically be between 20 ° and 40 °, for example of the order of 30 °.

Thanks to the invention, the movement of the mast downstream is possible (during a load), but limited by the braking devices that allow to dissipate energy.

The braking devices can comprise various elastic, plastic or elasto-plastic means. The kinetic energy dissipation can for example be obtained by deformation or tearing of material. The braking devices may be separate or form a single braking device. One or both of the braking devices may be disposed between the anchor - or the connecting member - and the lower and upper holding members. Alternatively, it can be provided that the first braking device cooperates with the foot of the mast and the lower holding member, and / or that the second braking device cooperates with the head of the mast and the upper holding member. Preferably, the arrangement of the braking devices is symmetrical, they are therefore located both upstream, in the vicinity of the anchor or downstream, in the vicinity of the mast.

In addition, the first and second braking devices are separate and arranged so that the braked displacement of the mast downstream, in the mounted position and under the effect of a bias exerted on the mast, is substantially in parallel translation in the field, without modifying the inclination of the mast with respect to the ground. In concrete terms, this can be achieved by appropriately defining the stroke of the braking devices and their calibration. This arrangement aims to maintain the residual height of the net attached between two adjacent supports after the impact of a block.

It may be provided that the support comprises a connecting means between the mast head and the upper holding member, said connecting means being designed to allow the mast to pivot relative to the upper holding member around a substantially transverse axis, when the mast moves downstream relative to the ground, in the mounted position.

This connecting means may be a simple oblong hole allowing some rotation of the head of the mast relative to the upper holding member. In a variant, this connecting means may comprise a clevis articulated on the head of the mast along a substantially transverse axis, and slidably mounted on the upper holding element along the axis thereof.

According to one possible embodiment, the lower and upper holding elements extend downstream beyond the foot, respectively of the head, of the mast, and:

the first braking device is arranged between the foot of the mast and the downstream end of the lower holding element;

and / or the second braking device is arranged between the head of the mast, or the connecting means, and the downstream end of the upper holding member.

When the lower holding member and the upper holding member are in the form of a rigid bar, each of the devices brake may comprise a sleeve surrounding said bar and disposed between the foot, respectively the head, of the mast and the downstream end of the bar, the sleeve being designed to be compressed - plastic or elastic - between the mast and the mast. downstream end of the bar to curb the movement of the mast downstream relative to the lower and upper holding elements.

The lower holding member may comprise a stay or, conversely, be rigid.

In one possible embodiment, the lower holding member and / or the upper holding member is in the form of a rigid bar.

It can be provided that the upstream end of the lower holding member and the upstream end of the upper holding member are fixed to the same connection element intended to be anchored in the ground. The advantage of such a configuration is that only one anchor is necessary for fixing the support to the ground. A braking device could be interposed between the connection element and the upper and / or lower holding element.

The connection element may for example comprise a transverse axis ring (that is to say substantially orthogonal to the mast and the lower holding element). This is a very simple way to connect the upper and lower holding elements to each other and to the anchorage. In addition, such a ring structure can dissipate a little energy.

Advantageously, the foot of the mast may comprise a base adapted to allow the support to rest substantially stable on the ground before fixing the support on the ground. Therefore, the support according to the invention can be pre-assembled at the factory, and its installation is easier because of its self-stability. For example, the base may comprise a transverse tube portion.

According to a second aspect, the invention relates to a protective barrier intended to be mounted on a terrain in order to be able to retain an object moving relative to said terrain, the barrier comprising, in mounted position:

at least two supports fixed in the field, at least one of the supports being as previously described; - A net - or equivalent - fixed between each pair of two adjacent supports, substantially stretched in the unconstrained state, so as to extend substantially transversely to the path of the object.

Several possible embodiments of the invention are now described by way of nonlimiting examples, with reference to the appended figures:

Figure 1 is a perspective view of a barrier comprising a plurality of supports according to one embodiment of the invention, in the unconstrained state;

Figure 2 is a detail view in perspective of the barrier of Figure 1, showing a single support;

Figure 3 is a side view of the support of Figure 2; Figures 4 to 6 are perspective views of the barrier of Figure 1, showing respectively a single support as a whole, a detail of the support in the vicinity of the mast foot, and a detail of the support in the vicinity of the mast head in the unconstrained state;

Figures 7 to 9 are views similar to Figures 4 to 6, respectively, following a solicitation;

Figures 10 to 12 are perspective views of a support, according to another embodiment which does not form part of the invention, respectively as a whole, in detail in the vicinity of the foot of the mast, and in detail in the vicinity of the mast head.

The following description is made in the case of a barrier installed on sloping ground, it being specified that this application is not limiting. The barrier could also be installed on a substantially horizontal ground, around an installation or a machine for example.

As illustrated in the figures, a barrier 1 according to the invention is intended to be mounted on a slope 2 in order to be able to retain blocks downstream of said terrain and dissipate their kinetic energy, or to limit the crawling of a snowpack.

The reference (X, Y, Z) is defined with respect to the terrain, where X is the direction along the slope line, substantially parallel to the terrain, Y is the transverse direction and Z is the normal terrain, Z is therefore not vertical. . The terms "upstream" and "downstream" are used with reference to the X direction; the term "lateral" is used with reference to direction Y. The barrier 1 comprises a plurality of supports 3 fixed on the ground 2, preferably at substantially regular intervals and along a contour line.

Between each pair of two adjacent supports 3 is fixed a thread 4, or other equivalent means. The net 4 is preferably mounted between an upper rim wire 5 and a lower rim wire 6, the side edge ropes being optional. The edge cables 5, 6 can be divided and modular or, on the contrary, run along the entire length of the barrier 1. The net 4 may for example be a cable net or an anti submarine net. An anti-submarine net, consisting of the monotoron cable ring assembly, has a very high resistance and a large capacity for deformation and dissipation of energy.

As can be seen in particular in FIG. 1, in the unstressed state, that is to say in the absence of a block impact, the thread 4 is fastened in a substantially tensioned manner between the supports 3 and extends substantially transversely to the line of slope X, i.e. in a plane (Y, Z).

The barrier 1 thus has a repetitive modular structure, with module widths, that is to say a distance between two adjacent supports 3, which can be of the order of 10 to 20 m.

In addition, the barrier 1 may comprise a lateral guying system (not shown), namely a left lateral guying system and a right lateral guying system respectively for the support 3 located at the left-hand end of the barrier and for the support 3 located at the right-hand end of the barrier. The other supports do not have such lateral guying systems. Each lateral guying system makes it possible to connect the support 3 to a corresponding lateral anchorage. The dimension and the technique of realization of the anchors depend on the nature of the ground 2.

The support 3 comprises a mast 10 which includes a foot 1 1, to which the lower rim cables 6 are attached, and a head 12, to which the upper rim cables 5 are attached. Typically, the mast 10 can be formed for essential of a metal tube.

The foot 1 1 of the mast 10 is arranged to be able to rest on the ground 2. For this purpose, it may comprise a base 13 adapted to allow the support 3 to rest substantially stable on the ground 2 before the fixing of the support 3 on 2. In the embodiment shown, the base 13 is formed of a stretch of metal tube extending transversely on either side of the mast 10, over a length sufficient to give this self-stability to the support 3. The lower part of the mast 10 can be inserted and fixed in an orifice formed on the upper part of the base 13. Provision may be made for the lower rim cable (s) 6 to pass into the base (13) in order to be fixed to the lower part of the mast (10), as shown in FIG.

The support 3 further comprises a lower holding member 14 which, in the illustrated embodiment, is in the form of a rigid bar, typically metallic. It can be a crenelated and screwable HA bar (high adhesion), for example identical to those used for anchors (GEWI® type bars). These bars have the advantage of being very efficient and economical because very widely used in these applications, and to allow a micrometric adjustment of their length.

The lower holding member 14 is disposed substantially perpendicular to the mast 10. It has an upstream end 15 intended to be fixed to the ground 2 and can extend, downstream, beyond the foot 1 1 of the mast 10, to its downstream end 16. The downstream end portion of the lower holding member 14 is mounted on the foot 1 1 of the mast 10. This downstream end portion can pass through the foot 1 1 with a possibility of sliding which is however blocked as explained below.

The lower holding member 14 serves to limit (that is to say to block or control, according to different embodiments) the sliding of the foot 1 1 of the mast 10 on the ground 2.

In the absence of bias, the mast 10 can be held in position relative to the lower holding member 14 by:

a downstream abutment 17, which may for example comprise a washer engaged on the lower holding element 14;

- And an upstream stop 18, which can be a nut in the case where the lower holding member is a crenelated and screwable bar, optionally coupled to an upstream washer 19 as shown in Figure 12.

The two stops 17, 18 are disposed on either side of the base 13 and substantially in contact therewith.

The support 3 also comprises an upper holding member 20 which is rigid. In the illustrated embodiment, the upper holding member 20 is in the form of a rigid bar, typically metallic. It may be a crenelated bar and screw as discussed above.

The upper holding member 20 is disposed obliquely with respect to the mast 10. It is inclined with respect to the mast 10 by an angle a which can be between 20 ° and 40 °, for example of the order of 30 °. The upper holding element 20 has an upstream end 21 intended to be fixed to the ground 2 and a downstream end 22, the downstream end portion of the upper holding element 20 being mounted on the head 12 of the mast 10.

The upper holding element 20 plays the same role as an upstream stay but its rigidity - in particular its resistance to buckling - is sufficient to support a moderate compression that can be generated by a small support on the net 4, by the self weight of the latter or by a rebound effect. As a result, the support 3 is devoid of downstream stay.

According to an embodiment illustrated in Figures 1 to 9, the upper holding member 20 extends downstream beyond the head 12 of the mast 10. It is mounted on the head 12 of the mast 10 by a connecting means, for example in the form of a yoke 23. This is on the one hand hinged to the head 1 2 of the mast 10, about a substantially transverse axis 24, and secondly slidably mounted around the upstream end 21 of the upper holding member 20, along the axis of the latter.

In the absence of bias, the mast 10 can be held in position relative to the upper holding member 20 by:

a downstream abutment 25, which may for example comprise a washer engaged on the upper holding element 20;

and an upstream stop 26, which may be a nut coupled to an upstream washer in the case where the upper holding member is a crenellated bar and screwable.

The two stops 25, 26 are disposed on either side of the yoke 23 and substantially in contact therewith.

As can be seen in particular in FIGS. 1 to 3, the upstream end 15 of the lower holding element 14 and the upstream end 21 of the upper holding element 20 are fixed to the same connection element 28 intended to be anchored in the ground 2. This connecting element 28 may be in the form of a ring 29 axis transverse. Fixing the holding elements 14, 20 to the ring 28 can be done via a nut screwed to the upstream end of these holding elements, when they consist of a crenelated bar and screwable. A counter-nut (not shown) may also be placed on each of the holding elements 14, 20, close to the ring 28. The function of these lock-nuts is to avoid, during the rebound effect which follows an impact, that the holding element concerned does not move upstream by a few centimeters.

The ring 28 is anchored in the ground, for example by means of a threaded rod 30 fixed to the ring 28 by means of a nut and sealed in the ground 2 to a sufficient depth (for example of the order of 3 to 4 m). Other anchoring solutions can be implemented depending on the nature of the terrain 2.

In practice, the support 3 is designed to be pre-assembled in easy terrain before being cranked or heliborted on its anchor point. During this movement, the main components of the support 3 - namely the mast 10 and the lower holding members 14 and upper 20 - do not move relative to each other, in particular because of the limitation means to the downstream and upstream. It should be noted that the upstream abutment 1 8 is especially useful during such a displacement prior to the installation of the support 3 in the field. Indeed, in operation, the stop 18 is generally not useful in practice because the foot 1 1 of the mast 1 0 does not tend to move upstream during a solicitation.

The shape of the base 13 allows the support 3 to remain erected before the laying of the side ropes 5, 6 and side stays.

In the mounted position of the support 3 on the ground 2, the mast 10 is substantially orthogonal to the ground 2, the lower holding member 14 substantially follows the slope line, and the upper holding member 20 is inclined at an angle , relative to the normal ground, from its upstream end 21 towards its downstream end 22. The support 3 extends substantially in a plane (Y, Z). In addition, the threads 4 are located substantially in the same plane as the poles 10.

According to one embodiment, illustrated in FIGS. 1 to 9, the support 3 is designed so that:

- At rest, the mast 10 can not move downstream; and, under the effect of a load such as a block impact down the ground 2 or the snowpack thrust, the mast can move downstream, but this movement is slowed down.

For this purpose, the support 3 may comprise braking devices comprising one or more elastic elements, plastic or elastoplastic allowing a displacement and / or a rotation of the mast 10. This is in particular used for stone-masking applications, where the barrier 1 is subjected to dynamic stresses.

More specifically, in the embodiment shown, the support 3 comprises:

- A first braking device 31 arranged between the foot 1 1 of the mast 10 and the downstream end 16 of the lower holding member 14;

and / a second braking device 32 arranged between the clevis 23 articulated on the head 12 of the mast 10 and the downstream end 22 of the upper holding element 20.

In the embodiment shown, each of the braking devices 31, 32 comprises a sleeve surrounding the bar constituting the lower holding member 14 or upper 20. The lower sleeve 31 is disposed between the foot 1 1 of the mast 10 and the downstream end 16 of the lower holding member 14, and more precisely between the downstream washer 17 and an end stop 33 formed of a washer and a nut disposed in the vicinity of the downstream end 16 of the holding element lower 14. The upper sleeve 32 is disposed between the head 12 of the mast 10 and the downstream end 22 of the upper holding member 20, and more precisely between the downstream washer 25 and an end stop 34 formed of a washer and a nut disposed in the vicinity of the downstream end 22 of the upper holding member 20.

The sleeves 31, 32 may consist of a metal tube, for example aluminum, able to deform "accordion". This is a very simple and economical way of dissipating energy.

The support 3 is fixed to the ground 2 only at the upstream ends 15, 21 of the lower holding members 14 and upper 20, here by the threaded rod 30. The mast 10, whose foot 1 1 rests on the ground 2 without y to be fixed, is retained in position by the lower holding members 14 and upper 20 fixed to the threaded rod 30, which prevent the mast 10 from sliding in the slope, in the absence of bias. The downstream abutment 17 bears on the first braking device 31, itself bearing on the end stop 33. These elements form first limiting means for limiting the movement of the foot 1 1 of the mast 10 towards the downstream from the field 2.

The downstream abutment 25 bears against the second braking device 32, itself bearing on the end stop 34. These elements form second limiting means for limiting the movement of the head 12 of the mast 10 towards the end stop. downstream from the field 2.

Under the effect of a stress, such as the impact of a stone on a net 4 or on a mast 1 0, the mast 10 of the support 3 is subjected to a force tending to drag it downstream. If the amplitude of the bias is sufficient, the mast 10 will indeed move downstream, this movement being braked.

More specifically, the sleeve 31 will be compressed between the stop 17 - sliding downstream on the lower holding member 14 due to the thrust exerted by the mast 10 - and the end stop 33. And the sleeve 32 will be compressed between the stop 25 - sliding downstream on the upper holding member 20 due to the thrust exerted by the mast 10 via the yoke 23 - and the end stop 34. By their deformation, the sleeves 31, 32 dissipate the kinetic energy of the stone running down the slope and thus slow down the movement of the mast 10 downstream relative to the terrain 2, and more precisely with respect to the lower holding members 14 and upper 20.

The first and second braking devices 31, 32 (here the sleeves) are arranged so that this braking movement of the mast 10 downstream is substantially in a translation parallel to the terrain 2, without changing the inclination of the mast relative to 2. This makes it possible to maintain the residual height of the barrier 1 after impact. A significant residual height after impact is particularly important to meet the requirements of the European ETAG 27 standard for so-called service solicitation.

For this purpose, the races of the braking devices 31, 32 must be different, and their settings. By way of example, with the geometry illustrated in the figures, in which the angle α is of the order of 30 °, the travel of the upper braking device 32 is equal to 2/3 of that of the lower braking device 31 and, to obtain the same energy dissipation, the calibration of the upper braking device 32 must be equal to 3/2 of the calibration of the lower braking device 31.

In addition, preferably, the barrier 1 according to the invention is devoid of energy dissipators - or braking device - arranged on the edge cables, which have the effect of lengthening these edge cables and therefore considerably increase their boom and reduce the residual height after impact.

The guided and braked translation of the mast 10 downstream, without modifying its inclination with respect to the terrain 2, implies a slight angle variation between the mast 10 and the upper holding member 20, which may, for example, be order of 5 to 7 °. This small amplitude pivoting of the mast 10 relative to the upper holding member 20 is allowed by the yoke 23 hinged about the axis 24. Other connecting means allowing the mast 10 to pivot relative to the element However, the upper support members 20 around a substantially transverse axis can be envisaged.

The capacity of deformation and dissipation of energy of the barrier 1 thus results from the elasto-plastic deformation of the thread 4 and the braking devices 31, 32.

In some cases, the mast 10 may be subjected to a bias tending to tilt upstream. This can occur in the event of a direct impact on the upper holding element 20, or following a rebound of the block intercepted by the barrier. This can also occur when the barrier 1 is implanted on slopes with very little support, for example at the foot of the slope.

To prevent such a tilting of the mast 10 upstream, the invention avoids the use of downstream stays and the corresponding expensive anchoring by providing:

that the upper holding element 20 is rigid, as opposed to a stay;

- And that the support 3 comprises second limiting means for limiting the displacement of the head 12 of the mast 10 relative to the ground 2 also upstream. Concretely, in the embodiment shown, these second limiting means comprise the upstream stop 26. The upstream stop 18 makes it possible to prevent the displacement of the foot 1 1 of the mast 10 upstream. According to another embodiment, which is illustrated in Figures 10 to 1 2 and which does not form part of the invention, the support 3 is designed such that, both at rest and under the effect of a solicitation:

- The foot 1 1 of the mast 10 can not move downstream, and preferably not upstream;

the head 12 of the mast 10 can not move either downstream or upstream.

In other words, the position of the mast 10 relative to the anchoring of the support 3 to the ground 2 is blocked.

For this purpose, it is possible to provide an embodiment similar to that of FIGS. 1 to 9, but without braking devices. As a result, it is not necessary for the lower holding members 14 and upper 20 to extend beyond the foot 1 1, respectively of the head 12, of the mast 10 over a length sufficient to allow the interposition of such braking devices. Thus, as illustrated in FIGS. 10 to 12, it is possible to simply provide the downstream stops 17, 25 - here in the form of washers associated with a nut - in contact with the mast 10, and in the immediate vicinity of the downstream ends 16, 22 holding elements 14, 20.

In addition, the degree of freedom in pivoting of the head 1 2 of the mast 1 0 relative to the upper holding member 20 is no longer necessary, and the yoke 23 hinged can be replaced by a connecting piece 35 fixed to both to the upper holding member 20 and the head 12 of the mast 10 and allowing no relative degree of freedom.

Such a barrier 1, including fixed supports 3 even in the event of stress, can be used for small stone barriers, or for avalanche barriers, which oppose a static thrust.

The downstream abutment 17, which may comprise a washer and a nut, forms first limiting means to prevent the displacement of the foot 1 1 of the mast 10 downstream relative to the terrain 2, while the upstream stop 18 prevents the movement of the foot 1 1 of the mast 10 upstream.

The downstream abutment 25 and the upstream abutment 26, each of which may comprise a washer and a nut, form second limiting means for preventing the displacement of the head 12 of the mast 10 downstream and upstream relative to the ground. 2.

Thus, the invention provides a decisive improvement to the prior art, in that it makes it possible to reconcile the advantages of a single-anchor, self-stable and pre-assembled support with a very low component manufacturing cost by removing the downstream shrouds, due to the rigidity of the upper holding member which provides the upstream seat stay function.

In addition, according to one possible embodiment, the invention makes it possible to integrate braking devices into the support which do not generate any residual height loss of the barrier.

The result is:

- a considerable relief of the support,

- increased assembly and installation speed due to the removal of the fittings needed for the cable stays,

- a significant saving,

- efficiency and reliability in terms of energy dissipation due to the simplicity of the system,

- significant residual height conservation after impact. It goes without saying that the invention is not limited to the embodiments described above as examples but that it includes all the technical equivalents and variants of the means described as well as their combinations.

Claims

1. Support intended to be fixed on a ground (2) for the realization of a barrier (1) of protection adapted to retain an object in movement with respect to said ground (2), the support (3) comprising:

a mast (10) which comprises a foot (1 1) able to rest on the ground (2) and a head (12) and which, in the mounted position of the support (3) on the ground (2), is substantially orthogonal to the field (2);

a lower holding element (14) substantially perpendicular to the mast (10), having an upstream end (15) intended to be fixed to the ground (2) and a downstream end portion mounted on the foot (1 1) of the mast (10) ;

first limiting means (17, 31, 33) for limiting the movement of the foot (1 1) of the mast (10) downstream relative to the ground (2), in the mounted position;

a rigid upper holding member (20) disposed obliquely with respect to the mast (10), having an upstream end (21) intended to be fixed to the ground (2) and a downstream end portion mounted on the head (12) of the mast (10);

second limiting means (25, 26, 32, 24) for limiting the movement of the head (12) of the mast (10) relative to the ground (2), downstream and upstream, in position climb ;

characterized in that the first limiting means and the second limiting means respectively comprise a first and a second braking device (31, 32), the braking devices being designed to prevent movement of the mast (10) downstream. at rest, and for braking the movement of the mast (10) downstream under the effect of a bias exerted on the mast (10), in the mounted position, the first and second braking devices (31, 32) being separate and arranged so that the braking movement of the mast (10) downstream, in the mounted position and under the effect of a bias exerted on the mast (10), is substantially in parallel translation to the ground (2) , without modifying the inclination of the mast (10) relative to the ground (2).

2. Support according to claim 1, characterized in that the first braking device (31) cooperates with the foot (1 1) of the mast (10) and the lower holding member (14), and / or in that the second braking device (32) cooperates with the head (12) of the mast (10) and the upper holding member (20).

3. Support according to claim 1 or 2, characterized in that it comprises a connecting means (23) between the head (12) of the mast (10) and the upper holding member (20), said connecting means (23) being adapted to allow the mast (10) to pivot relative to the upper holding member (20) about a substantially transverse axis (24), when the mast (10) moves downstream through relative to the ground (2), in mounted position.

4. Support according to one of claims 1 to 3, characterized in that the lower holding members (14) and upper (20) extend downstream beyond the foot (1 1), respectively of the head (12), the mast (10), and that:

the first braking device (31) is arranged between the foot (1 1) of the mast (10) and the downstream end (16) of the lower holding element (14);

and / or the second braking device (32) is arranged between the head (12) of the mast (10), or the connecting means (23), and the downstream end (22) of the upper holding element ( 20).

5. Support according to claim 4, characterized in that the lower holding member (14) and the upper holding member (20) are in the form of a rigid bar and in that each of the braking devices (31, 32) comprises a sleeve surrounding said bar and disposed between the foot (1 1), respectively the head (12), of the mast (10) and the downstream end (16, 22) of the bar, the sleeve being designed to be compressible between the mast (10) and the downstream end (16, 22) of the bar to slow down the movement of the mast (10) downstream relative to the lower (14) and upper holding members (14) (20).

6. Support according to one of claims 1 to 5, characterized in that the lower holding member (14) is rigid.

7. Support according to one of claims 1 to 6, characterized in that the lower holding member (14) and / or the upper holding member (20) is in the form of a bar rigid.

8. Support according to one of claims 1 to 7, characterized in that the upstream end (15) of the lower holding member (14) and the upstream end (21) of the upper holding member ( 20) are fixed to the same connecting element (28) intended to be anchored in the ground (2).

9. Support according to claim 8, characterized in that the connecting element (28) comprises a ring of transverse axis (29).

10. Support according to one of claims 1 to 9, characterized in that the foot (1 1) of the mast (10) comprises a base (13) adapted to allow the support (3) to rest substantially stable on the field (2) before fixing the support (3) on the ground (2).

1 1. Protective barrier intended to be mounted on a ground (2) in order to be able to retain an object moving relative to said ground (2), the barrier (1) comprising, in mounted position:

at least two supports (3) fixed on the ground (2), at least one of the supports (3) according to one of the preceding claims;

a net (4) fixed between each pair of two adjacent supports (3), substantially stretched in the unconstrained state, so as to extend substantially transversely to the trajectory of the object.