| For Information on RXI Catch Fences, please see below; |
|
For information on TECCO-mesh, please click here |
| |
|
RXI Catch Fences
With the Rocco® steel wire ring nets and the Optus® planning concept, Geobrugg and Rock Africa can design modular protection systems for any rockfall hazard. Dynamic barriers erected to intercept falling rocks and absorb their kinetic energy are very effective and have proven their worth as reliable protection from rockfall events and as the most economical solutions.
All the catch fences are tested (and certified) by the Federal Expert Commission on Avalanches and Rockfall (FECAR) at the jointly run test facility in Wallenstadt.
Test "Rock"
The only rigid component in the system is the steel post, which is mounted with a hinge pin on a ground plate that is anchored into the ground. The posts hold the flexible ring nets in the correct position. In a hazard event, the ring nets are the first to absorb energy, the rings deform to their extension limit, then pass on the residual energy to the braking elements in the bearing, anchor and retaining ropes. The optimal interaction of all components determines the capacity for energy absorption.
The Components of the System:
|
| 1
|
|
Rocco® Steel Wire Ring Net
Central to the operation of the catch fences is the Rocco® steel wire ring net. Compared with conventional protective nets the Rocco® ring net, with its four-fold suspension, has outstanding energy absorption properties. In a rockfall event, a significant portion of the kinetic energy is dissipated over the sum of deformation of all of the rings.
Rocco Steel Wire Ring Net
The forces are evenly passed on to the net and the entire system, without placing extreme strain on the anchorages. In the impact zone the ring net instantaneously reinforces itself by pulling together a higher density of ring bundles. The rings have a diameter of 300 mm and are made of high-tensile 3mm diameter steel wire. Between 5 and 19 spirals are bundled together, depending on the desired energy absorption capacity.
Deformation of Rocco Rings
|
2 |
|
The Ground Plates
The anchoring system for the steel bearing posts is adapted to the local ground conditions – whether it is unconsolidated ground or solid rock. |
|
|
Geobrugg Ground Plates |
3 |
|
The Steel Posts
The system utilises HEB profiles for barrier heights of 2 to 7 m, which are fastened to the ground plate with a hinge pin. These hinge pins act as predetermined shear keys and protect the anchorage from destruction in case the posts are directly hit by falling objects. |
|
|
The Steel Posts |
4 |
|
Bearing, Anchoring and Retaining Ropes
Steel wire ropes hold the steel posts and ring nets in the correct position for the existing terrain conditions. Shackles are used to fasten the ring nets to the upper and lower bearing ropes. The steel posts are anchored laterally to the ground with anchor ropes and at the back with retaining ropes. Depending on the hazard and energy potential, these ropes may be doubled or quadrupled using diameters between 12 and 22 mm. |
|
|
Bearing, Anchoring and Retaining Ropes |
5 |
|
The Brake Rings
Where necessary the bearing, anchoring and retaining ropes are guided through pipes bent into loops, which act as brake rings. In larger rockfall events as they contract these brake rings dissipate the residual energy without damaging the ropes. |
|
|
The Geobrugg Brake Rings
|
6 |
|
The Spiral Rope Anchor
Because flexible elements are essential for rockfall protective structures, we recommend the use of anchors made of high-strength steel wires with a tensile strength of 1770N/mm2. In contrast to conventional steel anchor bars, they are protected by a steel tube against mechanical damage caused by falling rocks and are able to transmit forces in the pulling direction that can deviate by up to 30 degrees from the borehole axis without any loss of load-bearing capacity. |
|
|
Spiral Rope Anchor
|
|
|
The Dimo® Brake Concept
All of the above elements combine into the Dimo® brake concept, which in the case of a maximum event allows for the energy to be incrementally dissipated. This stepped process through planned and predetermined breaking points reduces ring deflection and allows for the barriers to be installed closer to the object to be protected, simplifying both installation and maintenance, with associated cost savings. Furthermore, the effective height of the barrier is better conserved after a rockfall event, making its protection fully available for the next event, particularly important in situations where maintenance crews have not yet had time to clear out the fences or carry out maintenance work.
If an object hits the protective structure the elements are strained in the following order: ring net, brake rings, bearing ropes and posts. This means that minor events usually have no consequence, and after a major event only the affected components need to be replaced, if at all. To this end the predetermined breaking pints protect the most expensive system components from damage. |
|
|
|
|
|
Optus® Dimensioning Concept
Geobrugg’s barrier systems are composed of standard components which allows for provision of structures of any length, and the layout tailored for any topographical conditions and risk situations. The model allows for the establishment of applicable fundamental parameters for each design and has demonstrated its worth in hundreds of cases. The risk profile and particular protection needs determine which energy absorbing capacity protective structure is necessary and an exhaustive analysis provides the basis on which this decision is made. Commercially available rockfall simulation programmes allows for realistic determination of the design parameters using clearly defined inputs.
The Optus® dimensioning concept permits proper dimensioning of the individual components and the system as a whole, as well as determining the degree of protection afforded by the system. In this instance less is indeed sometimes more, as the protective structures with more widely spaced posts achieve a higher energy absorbing capacity due to an increase in overall flexibility. |
| |
|
|
The entire system is beautifully engineered to provide a cost effective solution to any geohazard which might present itself. The systems can be used on civil engineering projects and in mines, protecting both lives and infrastructure. One of the advantages from a mining point of view is the potential of increasing pit angles, which reduces the amount of overburden which needs to be removed but still keeping the risks to within acceptable levels. |
