Rockfall barriers **without upslope anchorage** are interception systems that rely primarily on **base foundations/anchors, end anchors, and posts** to provide stability and serviceability. They are often selected when access to the upper slope is limited and when the hazard level and expected impact energy can be managed with a simpler configuration that is faster to install.
In this case as well, the structure exploits controlled deformation and energy dissipation devices, but with fewer structural elements on the upslope side, simplifying works and logistics on complex slopes.
Our products guarantee energy absorption capacity **up to 500 kJ**.
Schematic of a barrier without upslope anchorage: load paths through longitudinal ropes, lateral bracing, end connections, and energy dissipators
### Principle of operation
During impact, the interception net deforms and transfers actions into:
- posts (vertical structural elements),
- upper and lower longitudinal ropes,
- lateral/end connection and bracing ropes,
- energy dissipators installed on selected ropes (depending on configuration).
The barrier is designed for **progressive and controlled** deformation, reducing peak forces and ensuring containment, preventing override or underride to the extent possible.
### Typical configuration and components
A self-supporting barrier without upslope anchorage generally includes:
- **Steel posts**: define the barrier alignment and support the net.
- **Net panels** (e.g., ring net / high-strength mesh): intercept and distribute loads.
- **Upper longitudinal rope**: distributes load along the top edge of the net.
- **Lower longitudinal rope**: stabilizes the bottom edge and transfers forces to foundations/anchors.
- **Lateral bracing and end connections**: ensure alignment and close the force path towards end anchors.
- **Energy dissipators**: braking devices to absorb energy and limit peak loads on posts and anchors.
Compared to configurations with upslope anchorage, this solution depends more strongly on correct design of the **end zones** and on the capacity of base/end anchors.
### When it is the right choice
Barriers without upslope anchorage are often preferable when:
- access and drilling on the upslope side are difficult, risky, or not permitted,
- installation time and complexity must be reduced,
- adequate **deflection space** is available downslope of the barrier,
- expected impact energy is compatible with the selected class and geometry,
- geotechnical conditions allow reliable base and end anchoring.
### Advantages
- **Simpler installation** (fewer upslope anchors and less work "above" the barrier line),
- **Reduced logistics** on slopes with limited access,
- **Faster installation** for urgent mitigation works,
- Suitable also for **temporary works** or retrofit interventions with fixed geometric constraints.
### Design and maintenance notes
- **End zones are critical**: end anchors and lateral connections significantly influence the overall response.
- **Deflection verification**: ensure terrain and structures are not involved during maximum deformation.
- **Post-event inspection**: check dissipators, rope tensioning, connections, net damage, and post verticality.
### Related application: shallow landslides and debris flows
Where the hazard includes shallow landslides or debris flows, the interception concept can be adapted to pressure-type loading and retention requirements (net geometry, dissipator placement, bracing scheme, and foundation detailing).
Example installation on a slope
### Support for selection and detailing
With slope geometry, available deflection distance, and geotechnical information, we can support configuration selection through trajectory/energy assessment and preliminary sizing.
