FLEXIBLE BARRIER FOR ARRESTING FALLING ROCKS

Abstract: The barrier comprises posts (10) and a rock arresting and collecting net. Each post (10) is pivoted, preferably by means of a cardan joint, to a ground-anchored based plate and is stayed by guy cables (21, 22, 23) secured to its head, two guys (21, 22) diverging to horizontally spaced upstream anchorings, while a third guy (23) is attached to a downstream anchoring. The net is placed on and secured to a series of spaced longitudinal, horizontal ropes (30) which rest on the upstream guy cables (21, 22) and are connected thereto by means through which the horizontal ropes (30) are free to slide. The horizontal ropes (30) extend beyond the ends of the barrier, and their extremities are secured to ground anchoring means (33).

Description: Flexible barrier for arresting falling rocks. The present invention relates to crash barriers. These are normally erected on slopes to protect manufactured articles such as railways, roads, villages, etcetera, from the fall of boulders. The walls of traditional crash barriers are made up of a series of vertical poles placed a few meters apart from each other; between these, metal sheet section irons are placed,, that sustain the impact of falling boulders. This type of barrier has been shown to be very expensive: in fact it has to be extremely strong in order to take up the thrust of the impact of a boulder. Furthermore, after every collapse, one must take care to repair such a barrier. Other crash barriers have been studied, so-called elastic barriers, which have between two rigid vertical poles, a flexible metallic net, 5. or a series of steel cables, arranged horizontally with a distance between them of 0.2-0.3 m, which can better take up the thurst of the impact of the falling boulders. This structure, even if cheaper and having a longer lifespan than the rigid one, still doesn't solve the problem of the poles; these are in 10. fact subject to breakages caused by boulders falling directly on them. The patent FR 1.190.613 envisages poles pivoted at the lower end, and a net anchored at points along its perimeter, so that it becomes subdivided in triangles fixed at their vertices, which act indipen- 15. dently to one another. In this case, the energy dissipation due to the falling boulder must always occur in a very limited area, thus d__m__nishing the total load that the structure can support. The aim of the present invention is thus to realize a crash barrier that is more resistant to impact and less subject to breakage, and 20. thus, as a whole, cheaper than the already known crash barriers. The above aim was attained by forseeing the sustaining poles of the barrier as hinged to a pillar or a plinth in the ground, and kept in position by a group of windbracing cables, whilst the net is sustained by a series of horizontal ropes freely sliding on the windbracing cables placed upstream, so that, at rest, the net is seme distance rαn the poles. Preferably, the pole is fixed to the ground in such a way as to have two degrees of free rotation. 5- The fixed position of every pole is ensured by two upstream and one .... ■-/. n ή h-rxring c__J_l£S- Preferably, the poles are held by the windbracing cables in such a way as to become almost perpendicular to the surface of the ground. Furthermore, the sliding fitting between the windbracing cables and 10. the ropes is achieved by means of two rope clamps inserted one inside the other. The invention will now be clarified by means of an examplary embodiment that has been represented in the enclosed drawings, in which: 15. Fig. 1 is a side view of the whole structure of the proposed crash barrier; Fig. 2 is a front view of Fig. 1 ; Fig. 3 is an exploded view of the pole and its means of attachment; Fig. 4 is the view of the means of attachment of the ropes to the 20. windbracing cables; and Fig. 5 is the perspective view showing the means of attachment of the windbracing cables to the pole. Referring to the drawings, it will be noted that the crash barrier cαπprises poles 10 made up, for eg., by tube 11. The pole rests on the ground T by means of a base plate 12, which is fixed to the ground by anchoring means 13. To base plate 12, is made fast a pair 5. of gussets 14 that are forseen as having two coaxial holes 14a. Between gussets 14, a plate 15 can penetrate, which is provided with coaxial holes 15a. Through coaxial holes 1 a and 1 a passes a pivot 1$ that, permits .the ..reciprocal....rotatlon ..of -the ..two -parts in downstrea -upstream direction and vice-versa. The plate 15 is 10. equipped on the upper side with another hole 15b, perpendicular to the previous one, and bored in a head 15c that can penetrate tube 11. The latter is provided at its lower end with a hole 11a which can be made coaxial to hole 15b. Through holes 11a and 15b penetrates a pivot 17 that permits another rotation, at 90° to the rotation around 15. pivot 16, so that the pole is fixed to the ground by means of a universal joint. The pole's upper side is provided with a pin 18 that enables the fixation of windbracing cables 21, 22 and 23, as illustrated in Fig. 5. The pole 10 is in fact kept in position by cables 21 , 22, 23, two 20. of which (21 and 22) are positioned upstream and form a triangle between each other, whilst the other (23) is placed downstream (Figs. 1 and 2). Each one of these cables 21 , 22 and 23 is ixed to the ground by anchoring means 13. The horizontal ropes 30 rest freely on the windbracing cables 21 and 25.22 positioned upstream and are anchored on the side at 33, at the extremity of the cables (Fig. 2). In Fig. 4 a rope clamp 31 is shown on windbracing cable 21 ; in clamp 31 is inserted another clamp 32 which surrounds rope 30. The rope clamps surround rope 30 and cables 21, 22, 23 so as to enable reciprocal sliding, i.e. without being fixed in a definite position. On the horizontal ropes 30, a net 40 is placed and fixed in the known way. This net 40 is indicated with a 5. broken line only in Fig. 1. As visible from the drawings, both the windbracing cables 21 , 22 and 23 and the ropes 30 are preferably provided with friction loops 24 which increase adaptation to strong boulder collisions.

Claims: β - C L A I M S 1. Structure for elastic crash barrier comprising poles (10) and a net (40) for the collection of boulders, characterized in that the supporting poles (10) are anchored to the ground (T) by means of a plinth or plate so as to have at least one degree of free 5. rotation with respect to the ground (T), the poles head being kept in position by a group of windbracing cables (21 , 22, 23) anchored to the ground ( ) by anchoring means (13), whilst the supporting net (40) is held up by a series of horizontal ropes (30), assembled so they can slide on the upstream windbracing cables (21 , 22), so that 10. the net (40), when at rest, is seme distance from the poles (10). 2. Structure, according to claim 1 , characterized in that the pole (10) is fixed to the ground (T) in such a way as to have two degrees of free rotation. 3. Structure, according to claim 1 , characterized in that 15. the upstream windbracing cables (21 , 22, 23) for the support of every pole are two (21 , 22), set apart so as to orm a triangle with its vertex on the pole's pin, and there is another downstream cable (23). 4. Structure according to claim 1 , characterized in that the poles (10) are held by the windbracing cables (21 , 22, 23) so as to be almost perpendicular to the ground (T). 5. 5. Structure, according to claim 1, characterized in that the sliding fitting between the windbracing cables (21 , 22) and the ropes (30) is achieved by two rope clamps, or rings, (31 , 32) inserted one inside the other, the clamp (31) holding the windbracing cables (21 , 22) and the clamp or ring (32) surrounding 10. the ropes (30) which are free to slide within it. 6. Structure, according to any of the preceding claims, characterized in that the horizontal ropes (30) are anchored (in 33) at their extremities, so that in case of the fall of a boulder, the whole net reacts.

Inventors: CARGNEL GIANANGELO, CARGNEL, GIANANGELO
Applicants: CARGNEL GIANANGELO, CARGNEL, GIANANGELO
Application year: 1986
Main classification: E01F7
IPC codes: E01F7