Rockfall barrier stop rocks ranging in size from a few dm3 to several m3 (100 to 5000kJ).
- Nets for low energy levels: from 100kJ to 500kJ.
- Dynamic barriers for high energy levels: from 750kJ to 5000kJ.
These deformable screens are designed to intercept rocks and may be fitted with braking systems. To check their performance levels and increase their efficiency, they are continually tested in the presence of independent organisations.
A draft European standard is currently being validated with a view to defining and regulating the use of rockfall protection screens.
They are particularly fast to install and offer protection at a reasonable cost. While their particular geometry may vary, they all consist of:
- Nets to intercept the rocks and absorb part of their impact energy. These may consist of:
- ANONET type ring nets;
- ELITE type cable nets;
- HPN netting;
- Double-twist netting.
- Posts to hold the nets. These may be made of galvanised or painted steel or wood treated against attack by lichens and mosses.
- Braking parts to dissipate residual impact energy.
- Steel cable stays to hold the structure on the ground via anchors (bars or cables).
Location: After an inventory of the unstable rocks, the energy absorption capacity (class), height and location of the rockfall protection screens are defined using a project geography software. This is carried out by an independent design office approved by Rockfall Barrier Corporation.