System and method for mitigating rockfalls
A system of the invention includes at least one barrier layer, a plurality of rockfall attenuators and two primary anchor points to anchor opposite lateral sides of the barrier layer. The attenuators are secured to an upper portion of the barrier layer. The attenuators create a gap between the surfaces of the slope upon which the barrier layer is installed. The attenuators are attached to the barrier mesh by a cable routed through a clevis/eyelet on each of the attenuators. Opposite ends of the cable are secured to the sloping surface by the two primary anchor points. The attenuators are free floating members that are not attached to the sloping surface. The invention also comprises attenuators as a sub-combination and a method of installing the system. One embodiment of an attenuator includes interconnected structural members resembling a closed-shaped frame. Another embodiment includes a covering placed over the structural members.
1. A system for mitigating rockfall events on a sloping surface, the system comprising:
a barrier layer having a width extending laterally across the sloping surface and a length extending down the sloping surface;
a plurality of attenuators spaced laterally from one another and spaced laterally across the width of the barrier layer, each attenuator having a plurality of support members connected to one another in a geometric pattern, each support member having a first end connected to a first connector and a second end connected to a second connector, and wherein each attenuator has a geometric shape with a plurality of sides formed by the support members connected in the geometric pattern;
a supporting cable extending laterally across the sloping surface, wherein an upper portion of the barrier layer is attached to said supporting cable, and each of said plurality of attenuators are secured to said supporting cable;
a first anchor point for securing a first end of said supporting cable; and
a second anchor point for securing a second opposite end of said supporting cable.
2. The system, as claimed in claim 1 , wherein:
said barrier includes a mesh configuration.
3. The system, as claimed in claim 1 , wherein:
said attenuators are substantially evenly spaced from one another laterally across the width of the primary barrier layer.
4. The system, as claimed in claim 1 , wherein:
said attenuators are each of substantially a same size and shape.
5. The system, as claimed in claim 1 , wherein:
said attenuators include at least one attenuator that has a substantially different size and shape as compared to other attenuators.
6. The system, as claimed in claim 1 , wherein:
space between each of said plurality of support members is open, and wherein an interior of each attenuator is open.
7. An energy absorbing attenuator especially adapted for use within a rockfall mitigation system, said attenuator comprising:
a plurality of support members connected to one another in a geometric pattern; each support member having a first end connected to a first connector and a second end connected to a second connector;
each attenuator having a geometric shape with a plurality of sides formed by the support members connected in the geometric pattern; and
wherein space between each of said plurality of support members is open and wherein an interior of each attenuator is open thereby forming a framed attenuator structure.
8. The attenuator, as claimed in claim 7 , further comprising:
a clevis attached to one of said connector.
9. The attenuator, as claimed in claim 7 , wherein:
said plurality of support members are constructed of at least one of aluminum, iron or steel.
10. The attenuator, as claimed in claim 7 , wherein:
said plurality of support members are constructed of carbon fibers or metallic tubing.
11. The attenuator, as claimed in claim 7 , wherein:
said carbon fibers or metallic tubing includes square tubing.
12. The attenuator, as claimed in claim 7 , further including:
an exterior covering placed over said plurality of support members.
13. The attenuator, as claimed in claim 12 , wherein:
the exterior covering is made of a flexible elastomeric material.
14. The attenuator, as claimed in claim 12 , wherein:
the exterior covering is continuous over said plurality of support members.
15. The attenuator, as claimed in claim 12 , wherein:
the exterior covering is continuous over said plurality of support members and wherein the interior of said attenuator is pressurized.
16. The attenuator, as claimed in claim 15 , further including:
a valve secured to said exterior covering for controlling pressurizing of said interior by a compressed air source that thereby inflates said exterior covering.
17. A method of mitigating rockfall events on a sloping surface, the method comprising:
positioning a primary barrier layer having a width extending laterally across the sloping surface and a length extending down the sloping surface;
installing a plurality of attenuators that are spaced laterally from one another and spaced laterally across the width of the primary barrier layer;
securing a supporting cable to extend laterally across the sloping surface, wherein an upper portion of the primary barrier layer is attached to said supporting cable, and each of said plurality of attenuators are secured to said supporting cable;
installing a first anchor point for securing a first end of said supporting cable and installing a second anchor point for securing a second opposite end of said supporting cable; and
wherein each attenuator has a plurality of support members connected to one another in a geometric pattern, each support member having a first end connected to a first connector and a second end connected to a second connector, and further wherein each attenuator has a geometric shape with a plurality of sides formed by the support members connected in the geometric pattern.
18. A method, as claimed in claim 17 , wherein:
at least one attenuator of said plurality of attenuators traverses laterally along the sloping surface from a first position to a second different lateral position separated from the first position in response to a rockslide contacting said primary barrier or said plurality of attenuators.
19. A method, as claimed in claim 17 , wherein:
at least one attenuator of said plurality of attenuators moves vertically away from and separated from the sloping surface from a first position to a second different separated position separated from the first position in response to a rockslide contacting said primary barrier or said plurality of attenuators.
20. A system for mitigating rockfall events on a sloping surface, the system comprising:
a barrier layer having a width extending laterally across the sloping surface and a length extending down the sloping surface;
a plurality of attenuators spaced laterally from one another and spaced laterally across the width of the barrier layer, each of said attenuators having a plurality of support members connected to one another in a geometric pattern, each support member having a first end connected to a first connector and a second end connected to a second connector, and wherein each attenuator has a geometric shape with a plurality of sides formed by the support members connected in the geometric pattern;
a supporting cable extending laterally across the sloping surface, wherein upper portions of the barrier layer is attached to said supporting cable, and each of said plurality of attenuators are secured to said supporting cable; and
first and second anchor points for securing opposite ends of said supporting cable to the sloping surface.
21. A system, as claimed in claim 20 , wherein:
said attenuators are substantially evenly spaced from one another laterally across the width of the primary barrier layer.
22. A system, as claimed in claim 14 , wherein:
said attenuators are each of substantially a same size and shape.
23. A system, as claimed in claim 14 , wherein:
said attenuators include at least one attenuator that has a substantially different size and shape as compared to other attenuators.
24. A system for mitigating rockfall events on a sloping surface and an adjacent grade, the system comprising:
(a) a first barrier mounted on the sloping surface comprising:
a first barrier layer having a width extending laterally across the sloping surface and a length extending down the sloping surface;
a plurality of first attenuators spaced laterally from one another and spaced laterally across the width of the first barrier layer, each of said first attenuators having a plurality of first support members connected to one another in a geometric pattern, each first support member having a first end connected to a first connector and a second end connected to a second connector, and wherein each first attenuator has a geometric shape with a plurality of sides formed by the first support members connected in the geometric pattern;
a first supporting cable extending laterally across the sloping surface, wherein upper portions of the first barrier layer are attached to said first supporting cable, and each of said plurality of first attenuators are secured to said first supporting cable; and
first anchor points for securing opposite lateral ends of said first supporting cable to the sloping surface; and
(b) a second barrier mounted on the adjacent grade comprising:
a second barrier layer having a width extending laterally across a grad surface;
a plurality of second attenuators spaced laterally from one another and spaced laterally across the width of the second barrier layer, each of said second attenuators having a plurality of second support members connected to one another in a geometric pattern, each second support member having a first end connected to a first connector and a second end connected to a second connector, and wherein each second attenuator has a geometric shape with a plurality of sides formed by the second support members connected in the geometric pattern;
a second supporting cable extending laterally across the grade surface, wherein upper portions of the second barrier layer are attached to said second supporting cable, and each of said plurality of second attenuators are secured to said second supporting cable; and
second anchor points for securing opposite lateral ends of said second supporting cable to the grade surface.
25. A system for mitigating rockfall events on a grade surface, the system comprising:
a barrier layer having a width extending laterally across the grade surface and a length extending substantially perpendicular to the grade surface;
a plurality of attenuators spaced laterally from one another and spaced laterally across the width of the barrier layer, each attenuator having a plurality of support members connected to one another in a geometric pattern, each support member having a first end connected to a first connector and a second end connected to a second connector, and wherein each attenuator has a geometric shape with a plurality of sides formed by the support members connected in the geometric pattern;
a supporting cable extending laterally across the grade surface, wherein an upper portion of the barrier layer is attached to said supporting cable, and each of said plurality of attenuators are secured to said supporting cable;
a first anchor point for securing a first end of said supporting cable; and
a second anchor point for securing a second opposite end of said supporting cable.
26. A system, as claimed in claim 25 , further including;
at least one braking elements connected to the barrier layer for dissipating energy form an impact against the barrier layer.
27. A system, as claimed in claim 25 , further including;
at least one secondary anchor secured to said barrier layer to provide additional anchoring capability, said secondary anchor being spaced longitudinally from said barrier layer.