This study examines hybrid barrier systems, incorporating field performance, limited rockrolling tests, and finite-element modeling. A hybrid barrier is a passive rockfall protection system consisting of a flexible fabric suspended from a top horizontal cable raised off the ground by posts or by anchoring across a chute; it includes no internal, side or bottom anchoring of the fabric. They address rockfalls occurring both underneath the fabric and upslope of the installation, controlling their descent under the fabric and into a containment area at the base of the system. Systems installed in North America have proven to be durable and highly effective. Limited rock-rolling tests demonstrated these systems to be effective for moderate energies (< 500 kJ) requiring no maintenance during repeated impacts with less than 0.5 m height loss. Finite-element modeling examined deformation and loads for a variety of system and slope configurations exposed to a range of impact energies. Modeling results showed comparable deformation behavior and performance results as the rock-rolling tests. These systems protect more slope area with less coverage than would be required with a full drapery, and they capture higher energies with less robust fence infrastructure. These combined benefits typically result in highly cost-effective and low-maintenance systems.
