The “AC” (from Italian ‘interlinked links’) rockfall barriers has been designed to contrast the problem of rockfall events generating, on impact, high kinetic energy.  The system’s peculiar feature is that of representing a multi-impact continuous screen. Such attribute makes it possible for AC Series barriers to withstand the impact of rockfall showers which may occur at different times, always providing the barrier’s ultimate impact energy threshold is not exceeded.  The barriers’ ideal application is in areas of high risk of rockfalls; this may depend on a variety of factors such as the slope morphologic and lithologic characteristics, the flow of rainwater, seismicity patterns, any wood fire incidents etc.  If such factors subsist,  the geological risks for the slope are very high and this requires safeguard measures for buildings and roads against possible and frequent rockfalls,  by laying systems capable of withstanding repeated rockfall strikes.
Furthermore, because of the continuity of the capture sytem, the barrier is capable of absorbing and dispersing very high energy loads, ensuring top performance whilst increasing the safety factor.

 Series "AC" barriers are presently manufactured in the following models:

1. AC   250 AC
2. AC   500 AC
3. AC 1000 AC
4. AC 1500 AC
5. AC 2000 AC

• SUPPORT STRUCTURE, consisting of S 275 HEA180 hot-dip galvanized steel section uprights of a height between 3.00 and 6.00 m and laid at a nominal center distance of 10.00 m; hot-dip galvanized steel base plates, with 4 holes for anchor bolts and universal joint for the linking to the upright; or, in the case of model AC250AC,  S 275 HEA160 steel section uprights, 3.00 m high laid at a nominal center distance of 10.00 m, with downslope 90x90x8mm or 140x60x7mm section strut, welded to a double back-to-back 140x60x7mm ‘C’ section; hot-dip galvanized materials according to EN ISO 1461 standard;
  

• CAPTURE AND/OR CONTAINMENT STRUCTURE, consisting of interlinked link steel rope net panels  with four or six linkages and link diameter not exceeding 350 mm, manufactured in 3 or 4 mm diameter galvanized steel wire with unitary strength of individual wires of 1570N/mm2, twisted upon itself to achieve a continuous strand of a diameter of no less than 9/12mm; double-twisted hexagon 80x100mm mesh, 2.7mm diameter wire and heavy zinc coating to capture minor detritus, connected to the main panel;
  

• LINKING STRUCTURE, consisting of top and bottom horizontal ropes, guylines at the beginning and end of the section, upslope guylines set in ‘outstretched arms’ configuration and downslope guylines (not in model AC250AC); all linkings in steel rope with varying strand diameter according to the barrier model;
  

• GROUND FOUNDATION, beneath the support structure, comprising four B450C steel bar anchor bolts or, in  model AC250AC, two micropiles of which the downslope one is type B450C improved stability steel bar and the upslope one consisting of a Dywidag high performance steel bar; the linking structure comprises anchorage points in double spiroid rope of suitable cross-section and length.

The crash-test procedure is carried out with reference to the “Testing guidelines for rockfall protection” Issue 15/03/2000, drawn up by the WSL of the Swiss Conferedation, consisting in the rolling down of a test boulder of varying size of approximately 800-6,400 kg at a minimum rolling speed of 25 m/sec against the central panel of a working module formed by three panels that are located at center distances of 10.00 m.  Measurements are taken of the kinetic energy on impact and the value of maximum barrier deformation after impact, from which the test boulder potential energy at the point of impact (referred to the maximum deformation point) may be calculated.