FR2629492A1 - Protective barrier with mobile net - Google Patents

Abstract

The protective barrier according to the invention comprises poles 5 located on the ground in a position pointing uphill. A base cable 12 connects the base of the pole to a front anchoring 13. A front stay 14 connects the pole head to the front anchoring 13. The netting 7 is connected on the one hand to the front anchoring 13 on the other hand to the pole head 5 by braking cables 35, 31 fitted with shock-absorption means 36, 32. Rear stays 16 join the pole head to rear anchorings 17.

Description

PROTECTIVE BARRIER WITH MOBILE NET
The present invention relates to a protective barrier intended to be placed on a ground to brake and interrupt the progression of free masses such as stones in a given direction, generally in the direction of the slope.

 We know already; protective barriers, in particular parrot ladders, comprising uprights anchored in the ground by means of foundation blocks, and connecting horizontal crosspieces.

The uprights are generally stiffened by struts available downstream and a guying on the upstream side. These are static protection devices. The impact of stones on such a device produces significant damage, twisting the uprights and crosspieces. The replacement of deteriorated elements, which is necessary periodically, leads to costly and tedious operations. Furthermore, the static nature of the device fairly frequently leads to ruptures of the uprights or crosspieces under the effect of shocks, so that the effectiveness of the protective device is often insufficient.

We understand in fact that it is economically impracticable to establish, upstream of sites to be protected, such barriers capable of stopping in all circumstances, the largest blocks likely to descend the slopes upstream, without the barriers being break up.

 According to a known solution, provision has been made to attach a sheet of net to posts by means of springs, in order to reduce the brutality of the impacts. This reduction is however limited due to the possible small elongation of the springs. In addition, the action of the springs does not dampen the impact energy, and dangerous rebounds can occur.

 Patent application FR-A-2 414 586 describes a protective and security barrier, in particular against falling rocks, which comprises a mesh network screen maintained deployed downstream of the struts with respect to which this network has the ability to move. proper relative conferred by limited resistance connecting members extending between the screen and anchoring and retaining points. The spacers are posts placed upstream of the mesh network, anchored in the ground in concrete blocks, and kept perpendicular to the slope. The connecting members are traction targets forming retaining members, passing through lumens in the head and the foot of the posts, and connected to anchors upstream. These cables include shock absorbing devices and traction limiters, which are susceptible to allow portions of reserve cable to pass between deformable elastic flanges tightly adjusted in order to define a resistance threshold.

 It is understood that, during the impact of a large block, the reserve cables slide in the shock absorbers while slowing down the movement of the mesh network screen. The screen moves away from the posts, downstream of said posts.

 These known devices have the main drawback that the prior traction cables, which maintain the layers of the mesh network, are directly exposed to the action of stones which descend the slope towards the barrier; their possible rupture leads to the destruction or considerable embrittlement of the barrier, which then no longer fulfills its protective role.

 Similarly, the posts or spacers of deployment of the mesh network layers are directly exposed to the stones, and are frequently damaged or destroyed.

It is further noted that, in their implementation, the moving net barriers as described in the patent application
FR-A-2 414 586 require the provision of a relatively large number of anchors. Anchoring in the ground, generally carried out using the exploded pile technique, about 3 meters deep, is the most expensive part of the installation of these barriers.

 The object of the present invention is in particular to avoid the drawbacks of known barriers, by proposing a new protective barrier structure with a sheet of moving net. According to the invention, the net ply is disposed clearly upstream of the posts which hold it, and upstream or in the plane of the shrouds retaining the posts. As a result, the net protects the posts and guy lines by itself.

 The invention also makes it possible to significantly reduce the number of anchors required, and therefore the cost of implementing the barrier.

 According to another object of the invention, means make it possible to adjust the height of attachment of the net to the posts according to the very shape of the ground on which the barrier is placed.

 According to another object, the invention makes it possible to provide a modular barrier, consisting of several successive elements arranged in the same plane, in which the modules are relatively independent of each other, so that the possible deterioration of a module does not weaken excessively the neighboring modules.

According to the barrier structure of the invention, the number of elements exposed to the stones is considerably reduced, and in particular the posts, the elements allowing the anchoring and the guying upstream of the device such as the shrouds, the braking targets, the brakes, the anchors themselves
To achieve these and other objects, the barrier according to the invention comprises at least one ply of net held in a plane substantially perpendicular to the estimated direction of progression of the masses to be retained, the ply being held deployed in height and in width. by two lateral retaining posts in addition - each post is placed on the ground in a position inclined upstream so that their upper part is upstream of the post base in the estimated direction of progression of the masses, - a cable foot connects the base of the pole to a respective anterior pole anchor located in the ground to the right of the pole and upstream of the foot in the direction of estimated progression of the masses, - an anterior shroud connects the upper part of the pole to the anchor anterior, - two oblique rear shrouds connect the upper part of the post to two rear anchors offset laterally on either side of the post and arranged downstream of the post, - the netting is suspended ndue by its upper bank to the upper part of the two posts, - the netting of net is retained by its lower bank to two previous anchors of net each located at the right of one of the posts and upstream of the net, - the upper bank of net is fixed to the upper part of the posts by means of targets comprising damping members, - the lower edge of the net is fixed to the anterior anchors of net by means of targets comprising damping members in this way, the sheet of net is originally placed in front of the posts, and it can move relative to the posts in the direction of the progression of the masses against the braking force exerted by the damping members. obliques take up the transverse forces applied to the post, and allow the post to be placed in balance thanks to a single anterior stay, and to place the net in an anterior position relative to the posts.

 According to one embodiment, the anterior anchorages of the net are advantageously constituted by the anterior anchorages of the posts themselves. This reduces the number of anchors required.

 Likewise, to reduce the number of anchors, two contiguous layers of net are held together by common anterior anchors.

 Advantageously, common posterior anchorages also connect contiguous posts, each intermediate posterior anchorage serving for the guying of two successive posts.

 According to a first embodiment, each post consists of a linear profile, for example with an H section.

 According to a second embodiment, each post comprises a post body in the form of a linear profile, surmounted by a bracket inclined angularly relative to the post body and oriented upstream of the barrier. Such an arrangement promotes the offset of the web of net upstream of the post, increasing the protection of the post against stones; this arrangement also allows an upper cross bracing of the brackets, favoring the recovery of the retaining forces by the adjacent posts when a central post comes to deform or to break.

 Other objects, characteristics and advantages of the present invention will emerge from the following description of particular embodiments, given in relation to the attached figures, among which - FIG. 1 represents a perspective view of a barrier according to the present invention in a first embodiment - Figure 2 shows a partial view of the barrier of Figure 1, upstream view - Figure 3 shows a partial view of the barrier of Figure 1, downstream view - Figure 4 represents a side view of the barrier of figure 1, to the right of a post - figure 5 represents the barrier of figure 4 after receiving a stone - figures 6 and 7 represent a height adjustment carriage for post according to the present invention - FIG. 8 represents the detail of realization of a sheet of targets forming a net according to the present invention - FIG. 9 represents the detail of a previous anchoring according to the present invention - the Figure 10 shows the detail of the hooks on a post carriage according to the present invention - Figure 11 shows a damping member according to the present invention - Figure 12 is a section of the damping member according to the plane A-A of Figure 11 ;; - Figure 13 is a perspective view of a barrier according to the present invention in a second embodiment - Figure 14 is a partial view of the barrier of Figure 12, seen from downstream - Figure 15 is a partial view of the barrier of FIG. 12, in upstream view; and - Figure 16 is a side view of the barrier of Figure 12, in line with a post.

 There is shown in perspective in Figure 1 a barrier according to a first embodiment of the present invention. The protective barrier consists of several modules, modules 1, 2, 3, 4, which are identical to each other Each module such as module 1 consists of two posts 5 and 6, the posts holding deployed in height and in width a netting 7. The netting 7 is held deployed in a plane substantially perpendicular to the expected direction of progression of the masses such as the stones which one wishes to retain with the barrier. In practice, the web of net 7 is arranged in an orientation substantially perpendicular to the average slope of the ground. In FIG. 1, the direction of progression of the stones is shown by the arrows 8. Thus, the barrier is represented, on this figure, seen from a position slightly downstream of the barrier.

 Each post 5 and 6 is placed on the ground in an inclined upstream position, as best seen in FIG. 4. In this way, the upper part 9 of the post is located upstream of the post base 10, in the estimated direction of progression 8 of the masses.

 Each of the posts of the barrier has the same constitution and the same retaining members. Consequently, in the description which follows, it will be understood that it suffices to describe the structure of a post and its holding and retaining members.

 In the embodiment shown, the post 5 consists of a rectilinear profile with H section, comprising a high part 9 and a foot 10. The foot 10 is stuck on the ground, and comprises a sole 11 with a U-shaped profile , whose lateral ribs are inserted into the ground in the anteroposterior direction 8 of mass propagation. The lateral ribs oppose the movement of the post base 10 in a transverse direction of propagation. A foot cable 12 connects the post base, or sole 11 to a front anchor 13 located in the ground to the right of the post 5 and upstream of the foot 10 in the estimated direction of progression of the masses, as shown in FIG. 4.

 An anterior stay 14 connects the upper part 9 of the post 5 to the anterior anchor 13. Two rear stays 15 and 16 connect the upper part 9 of the post to two respective rear anchors 17 and 18. The rear anchors 17 and 18 are offset laterally on either side of the post 5, as shown in the figures, so that the rear shrouds 15 and 16 are arranged obliquely and take up the transverse forces printed on the post. The posts 5 and 6 are connected by a transverse upper strut 19, each of whose ends is fixed to the corresponding post, to transmit the transverse forces from one post to the other. The end posts 5 and 20, each located at one end of the barrier, are also held by lateral shrouds 21 and 22, the end of which is anchored in the ground.

 As shown in the figures, each of the intermediate posterior anchors such as the anchor 17 is connected to two posts such as the posts 5 and 6. On the other hand, each anterior anchor such as the anchor 13 is connected to a single post such as post 5.

 The sheet of net used in the barriers according to the present invention consists of a mesh network of targets, arranged in two perpendicular directions, as shown in Figure 8. The cables are linked in pairs at each crossing by clips or cable scratches For example, the targets 23 and 24 are connected at their intersection by a clip 25. the clip 25 consists of a cut and folded sheet metal, comprising a central part and foldable tabs, the central part being intended to be placed at the exterior of a first target, the tongues being intended to come to surround the second target on either side of the first cable. The net forming the net ply 7 has a substantially rectangular shape, bordered by a perimeter target 26 as shown in FIG. 2. The perimeter cable 26 forms an upper bank 27, or horizontal upper border, two lateral banks 28 and 29 and a lower bank 30.

 The netting 7 is suspended by the ends of its upper edge 27 from the upper part of the two posts 5 and 6. The netting is held by the ends of its lower edge 30 from the two front anchors 13 and 113 each located at right of their corresponding post 5 and 6, and upstream of the netting 7. The connection between the upper bank of the net 27 and the upper part of the posts 5 and 6 is ensured by braking targets comprising damping members. Thus, the connection with the post 5 is ensured by a braking target 31 and a damping member 32; the connection with the post 6 is provided by a braking cable 33 and a damping member 34. The damping members 32 and 34 are integral with the upper edge 27 of the net. The targets 31 and 33 have a part fixed to the upper part of the corresponding post 5 or 6, and slide in the damping members 32 and 34 in which they are braked by tightening.

 Likewise, the connection between the lower bank 26 of the netting and the 13 ct 113 anchors is provided by braking targets and damping members: the connection with the anchor 13 is provided by a braking cable 35 and l 'shock absorbing member 36; the connection with the anchor 113 is ensured by a braking target 37 and the damping member 38.

 In the standby position, represented in FIG. 4, or initial position in which the barrier members are placed on the ground, the net ply 7 is substantially perpendicular to the slope of the ground, hanging from the top part 9 of the posts 5, and attached to its lower part to the previous anchors such as the anchor 13. The ply 7 is thus located upstream of the post 5. The anterior stay 14 is substantially in the plane of the netting 7.

 The structure composed of braking targets such as the target 31 and shock absorbers such as the shock absorber 32 allows the kinetic energy of the blocks of stones to be absorbed to be absorbed by ensuring braking of the ply of net 7 for a sufficient stroke. . The stroke is permitted by providing cables of adequate length, the reserve length being able to slide in the shock absorbers 32. In the embodiment shown in FIGS. 11 and 12, the shock absorber 32 comprises a hooking bracket 40, with profile in U, in which the perimeter cable can pass 26. In side view in FIG. 11, it can be seen that the U-shaped bracket 40 is connected to two clamping plates 41 and 42 by a removable transverse axis 39. Pins lock the pin 39 in position. The clamping plates 41 and 42 are parallel to each other, and connected to each other by 4 sets of clamping nut-screws such as the 'set 43, arranged at four corners of the clamping plates. The internal faces of the clamping plates 41 and 42, or faces arranged opposite one another, have respective stops 44 and 45. The plates 41 and 42 trap two parallel strands of the cable 31, each of the strands being trapped in an elastic sleeve 46 or 47. The elastic sleeves 46 and 47 are formed from a rolled steel sheet, having a longitudinal slot, having substantially the shape of pins usually used for blocking axes. The sleeves 46 and 47 constitute a particularly hard and resistant wear surface, making it possible to produce the plates 41 and 42 in a softer metal. Furthermore, after the system has operated by braking following the impact of a stone, the wear was worn on sleeves 46 and 47 and on. the cable 31, so that it is not necessary to change the plates 41 and 42. To compensate for the wear of the braking members such as the sleeves 46 and 47, it is advantageous to insert elastic clamping means, by example of Belleville type washers 100, inserted on the screw.

 The target 31 is fixed to the head of the post 5; the sleeves 46 and 47 are arranged in the vicinity of the loop formed by the target 31 in the pole head, and the plates 41 and 42 are tightened around the sleeves 46 and 47, the sleeves 46 and 47 coming to bear against the stops 44 and 45 which prohibit their translation between the plates 41 and 42.

A sufficient length of braking target 31 is provided at the outlet from the plates 41 and 42, as shown for example in FIG. 2. The ends of the braking target 31 are provided with stop devices, for example target clamps 48 and 49, intended to increase the retention force at the end of travel of the target 31 between the plates 41 and 42. The appropriate tightening of the screw-nut assemblies 43 makes it possible to adjust, in the workshop, the braking force exerted by the plates 41 and 42 on target 31. Mounting the protective barrier on the ground does not require the adjustment of this force. During assembly, the stirrup 40 is placed on the perimeter target, the stirrup is fixed to the plates 41 and 42 by positioning the axis 39. The cable 31 and the plates 41 and 42 are previously fixed to the post or to the Anchoring. When purging the net, to remove stones that are retained there, it is enough to remove the pin 39 to separate the netting from its attachment points.

 The structure and operation of the damping members 34, 36 and 38 are similar to those of the damping members 32, with their corresponding cables. Advantageously, stop devices such as cable clamps 148 can be provided on the other braking targets such as the target 35 shown in FIG. 9.

 In the embodiment shown in the figures, the posts 5 and 6 comprise means for adjusting the height of attachment of the plies of net 7 to the posts. These means consist of a hooking piece such as an adjustable carriage 50, shown in FIGS. 6 and 7, having a general structure in the form of a ring with a square section surrounding the H-shaped profile forming the post body 5 .

te adjustable carriage 50, formed of an open ring whose branches are connected by a clamping bolt 51, is slidably mounted on the post 5. Its transverse dimension is substantially equal to the transverse dimension of the post 5, while its dimension longitudinal is slightly larger than the anteroposterior dimension of the post 5, so that the carriage 50 can be slightly inclined as shown in FIG. 6. By inclination, when the targets and guy lines produce on the carriage 50 an off-center effort relative to to the longitudinal axis of the post; the adjustable carriage 50 gets stuck around the post 5.

 FIG. 10 shows the detail of the attachment of the various members to the upper part of the post. The upper part of the post 6 comprises a fixed transverse axis 52 on which the rear shrouds 115 and 116 are hooked. The lateral shrouds 19 and 119 are fixed on the upper part of the post. The other attachment members, namely the front shroud 114, the target 33 and its brake 34, the target 133 and its brake 134, are fixed to the carriage 50, as shown in the figure.

To facilitate understanding, FIG. 10 has been represented in a plane, with the hooking members deployed in this same plane. In the normal position, it will be understood that the netting 7 and the braking cables 133 are in a perpenticular plane, the nets being hung from the head of the posts.

 FIG. 9 schematically represents the detail of the attachment means on the upstream anchor 13. The anterior stay 14 is fixed on the anchor with the interposition of a core terminal. The same applies to the braking cable 35 connecting the anchor 13 to the damping member 36 and to the target around 26 of the lower edge of the net. The braking cable 35 goes around the anchor 13, with the interposition of a heart terminal, and its two strands are secured by a target clamp 53. The foot target 12 is also hooked to the anchor 13 with interposition of a heart terminal, and fixing by a cable clamp.

 There is shown in Figure 5 the state of the device after impact of a stone 54 in the net 7 between two posts. Under the thrust of the stone 54, the dampers 32 and 36 let a length L1 and a length L2 of the braking cables 31 and 35 spin, producing a progressive braking of the stone 54 then its blocking. The net 7 has moved relative to the post 5 in the downstream direction, the displacement being a function of the force exerted by the stone 54.

 Figures 13 to 16 illustrate a second embodiment of the barrier according to the present invention. This embodiment is relatively similar to the embodiment of FIGS. 1 to 12. The differences relate to the shape of the posts, and to the transverse bracing of the posts.

 In this embodiment, the posts 60 comprise a post body 61 formed of a substantially rectilinear profile, with an H section, similar to that of the posts 5. The post 60 further comprises, connected in the upper part of the post body 61, a bracket 62, formed of a section with a similar section at H, angularly inclined relative to the straight section forming the post body 61, as shown in the figures. Preferably, the bracket 62 is oriented in the upstream direction, and is connected by its posterior or downstream end to the upper end of the pole body 61. The rear part of the bracket 62 has a central recess separating two lateral flanges such as the flange 63, between which the post body 61 slides. The front face 64 of the recess between the flanges 63 bears against the front face of the post body 61; a fixed axis 65, connecting the flanges 63, bears against the rear edge of the post body 61, limiting the tilting of the bracket 62 downwards. The anterior shroud 14 is fixed to the free end of the bracket 62, so that the pull which it exerts downwards on the end of the bracket tends to wedge the bracket 62 on the pole body 61. The ply of net 7 is hanged at the end of the bracket 62, in the same way as the net ply 7 was hung at the upper end of the posts 5 in the previous embodiment. The rear shrouds such as the shroud 16 are hooked to the rear end of the bracket 62. As in the previous embodiment, a foot cable 12 connects the foot 10 of the pole 60 to the anterior anchorage 13 which retains also the base of the net 7 and the base of the upstream shroud 14.

 The bracket 62 can be adjusted in height, by sliding on the pole body 61. A tightening means such as a bolt 66 can be provided, for positioning the bracket in an adequate height, during assembly.

 In both embodiments, a protective tube 67 can be fitted to the front shrouds 14, avoiding its possible shearing under the action of a stone.

 In the embodiment with bracket 62, the upper guy can be modified to take advantage of the presence of the brackets 62 in this embodiment, the upper guy is provided, between two successive brackets 62 and 162, as shown in FIG. 13 , by two upper shrouds 119 and 219, crossed, each joining the anterior end of a first bracket to the connecting end of the second bracket.

 Generally, the barrier comprises several successive layers of netting 7. Two contiguous sheets of net are connected along their vertical banks opposite one another, at the right of their common post. A single front anchor such as the anchor 113 independently retains one and the other of the lower horizontal edges of the two layers of net. A single upper head of a common post independently retains the two upper edges of the two layers of net. The vertical banks are connected to each other by connecting rings, capable of breaking under the action of sufficient traction. This improves the behavior of the various plies with respect to each other, but the possible rupture of the connecting rings promotes the independence of the modules from each other. For example, diagrammatically shown in FIG. 2 are such rupture rings 70.

 The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof contained in the field of claims below.

Claims (12)

 1 - Protective barrier intended to be placed on a ground to brake and interrupt the progression of free masses (54) in a direction (8), comprising at least one layer of net (7) held in a plane substantially perpendicular to the direction (8) of estimated progression of the masses, held deployed in height and in width by two posts (5, 6d of lateral retaining, characterized in that) each post (5, 6) is placed on the ground in a position inclined towards the 'upstream so that their upper part (9) is upstream of the base (10) of the post in the direction of progression (8) estimated by the masses, b) a base cable (12) connects the base (10) of the pole with an anterior anchoring (13) respective pole located in the ground to the right of the pole and upstream of the foot in the direction of progression (8) estimated by the masses, c) an anterior shroud (14) connects the upper part (9 ) from the post to the anterior anchor (13) of the post, d) two rear oblique shrouds (15, 16) connect the part ie upper (9) of the post respectively to a first posterior anchoring (18) and to a second posterior anchoring (17) offset laterally on either side of the post (5). e) the netting (7) is suspended by its upper edge (27) from the upper part (9) of the two posts, f) the netting (7) is held by its lower edge (30) with two anchors front of net (13, 113) each located in line with one of the posts (5, 6) and upstream of the net, g) the upper edge of the net (27) is fixed to the upper part (9) of the posts by means of targets (31, 33) comprising damping members (32, 34), h) the lower edge of the net (30) is fixed to the anterior ncrages (13, 113) of the net by means of targets ( 35, 37) comprising damping members (36, 38), so that the netting (7) is originally placed in front of the posts (5, 6) and that it can move relative to the posts in the direction of the progression of the masses against the braking force exerted by the damping members.  2 - Barrier according to claim 1, characterized in that the anterior anchorages of the net (13, 113) are constituted by the anterior anchorages of the posts (5, 6) of the net.  3 - Barrier according to claim 2, characterized in that it comprises several contiguous netting (1, 2, 3, 4), two contiguous netting (1, 2) connecting along their vertical edges corresponding to the right of '' a common post (6), a common front anchor (113) independently retaining one and the other of the lower horizontal strands of net, the upper part of the common post (6) retaining independently both upper horizontal strands of netting.  4 - Barrier according to any one of claims 1 to 3, characterized in that the posterior intermediate anchors (17) are each connected to two successive posts, (5, 6).  5 - Barrier according to any one of claims 1 to 4, characterized in that the upper parts (9) of the posts are further connected by upper transverse shrouds (19), transmitting the transverse forces from a post to the other.  6 - Barrier according to any one of claims 1 to 5, characterized in that the post base (10) comprises a sole (11) with a U profile whose lateral ribs are inserted into the ground in the anteroposterior direction of mass propagation.  7 - Barrier according to any one of claims 1 to 6, characterized in that each post (5, 6) comprises a hooking piece (50, 62), slidingly mounted on the post body, the hooking piece receiving the braking cables (31, 33) from the upper edges of the net and the anterior shroud (14), the hooking piece being able to get caught on the post body in a desired position adjustable when it is subjected by the targets and shrouds at an off-center effort relative to the longitudinal axis of the post.  8 - Barrier according to claim 7, characterized in that the attachment part is a carriage (50) annular sliding surrounding the rectilinear profile forming the post body (5).  9 - Barrier according to claim 7, characterized in that the attachment part is a bracket (62) angularly inclined relative to the straight profile forming the pole body (61).  10 - Barrier according to claim 9, characterized in that the bracket (62) is oriented in the upstream direction, and its free end receives the braking target (31) of the upper edge of the net and the anterior shroud (14) .  11 - Barrier according to claim 10, characterized in that two successive brackets (62, 162) are connected by crossed upper shrouds (119, 219) each joining the free end of a first bracket at the connection end of the second gallows.  12 - Barrier according to any one of claims 1 to 11, characterized in that the damping members (32) comprise - a hooking bracket (40) in U, connected to two parallel clamping plates (41, 42) by a removable transverse axis (39), - 4 sets of tightening screw-nuts (43) arranged along 4 corners of the tightening plates, making it possible to tighten the plates towards each other, - stop stops (44 , 45) provided on the internal faces of the plates facing each other, - two elastic sleeves (46, 47) inserted between the clamping plates (41, 42) and bearing against the stops ( 44, 45), - the elastic sleeves (46, 47) being slidably mounted on two parallel target strands (32) connected to the anchor (13) or to the post, - the bracket (40) being crossed by a cable ( 26) around the net.