Evaluation of Behaviour of Rockfall Restraining Nets by Full Scale Tests

Rock restraining net is a device engineered to stop large rockfalls. The system consists of a net vertically supported by steel posts with ``energy dissipators'' able to dissipate high kinetic energy by large displacements. These fences have been usually placed to protect against rockfalls in mountainous areas but few tests have been developed correctly to de®ne the behaviour of these structures. In this paper full scale tests on passive defence against rock falls are presented. The tests have been carried out in a ®eld test site especially designed and built. The test site has been provided of camera apparatus able to monitor the impact of the block against the fence. The impact energy and the consequent forces and displacements of the fence are studied. The tests have been carried out on many different fence types and have allowed the de®nition of a wellestablished design procedure.