Romanshorn/Walenstadt
Rockfalls increasingly threaten roads, railways, and settlements. Standard tests for flexible rockfall barriers have in the past focused on a standardized single-impact scenario, which does not reflect real-world conditions. With the development of the new ROCCO barrier, Geobrugg has already introduced 1:1 additional tests to demonstrate performance under realistic conditions. The next step into the future is the world’s first test of a barrier subjected to simultaneous multiple impacts.

On October 1, 2025, Geobrugg tested a flexible rockfall protection barrier designed to withstand two simultaneous impacts for the first time; and the rockfall protection fence withstood the multiple impacts. The findings will feed into the further development of future protection systems. This replicates natural scenarios: multiple rocks hitting simultaneously, not always in the standardized ideal load case, but simultaneously at two different points.

The ROCCO rockfall protection barrier, approved in 2024 with a nominal energy of 3000 kJ, was subjected to two blocks, each carrying 50 percent of the maximum energy. One impact targeted the barrier’s center field, and the other targeted the adjacent border field.

Geobrugg’s rockfall experts expect a different response because the load is distributed across two fields. The goal is to demonstrate the performance of barriers under realistic, variable load cases throughout their entire service life.

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Quote – Helene Lanter, Head of Research and Development at Geobrugg (CTO)“With these additional tests, we close the gap between standards and reality. ROCCO protection barriers are designed for robustness – to protect against natural hazards in high-risk zones where frequent impacts are expected.”
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Realistic Testing
The standard testing method, according to the EAD guideline, uses a single impact, always in the center of the middle field. While reproducible and cost-efficient, this setup does not reflect reality. In practice, multiple rock fragments often hit simultaneously, not in the middle field. Impacts on border fields, posts, and corners, as well as block rotation and shape, significantly influence load distribution.

Field observations and large-scale tests show that rotating and flat blocks generate higher peak forces and asymmetric loads. As a result, conventional approval tests overestimate a protection barrier’s residual load-bearing capacity.

Insights from the First Simultaneous Test in Walenstadt
According to an initial test at maximum energy level (MEL), simultaneous impacts tend to produce higher forces due to limited net deformation.

Here, the butterfly nets of the latest generation of rockfall barriers (ROCCO system) play a decisive role. Their geometry provides additional deformation paths and significantly reduces peak forces at the post heads.

Outlook: Computer Simulations and Multi-Hazard Resilience
In parallel with 1:1 field tests, Geobrugg is advancing computer simulations of flexible barriers. In addition, the ROCCO line has been specifically tested for multiple hazards—tree impacts in Walenstadt and shallow landslides in Japan—which addresses the increase in such events due to climate change.

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Why This Test Matters
• Rockfalls are increasing due to climate change and extreme weather
• Standardized procedures do not reflect reality
• Multiple impacts and fragmented blocks are the rule in nature
• Geobrugg is the first company worldwide to implement a new testing method
• Simultaneous maximum energy level test with two blocks (each 50% energy) – center field + border field
• 32 meters/105 ft fall height, 25 m/s 82 ft/s impact velocity, two blocks of 4.8 t / 10'580 lb each 
• Expectation: higher peak forces than standard MEL tests; net geometry is crucial
• Context: supplementing established test procedures with more realistic load cases (EAD 340059-00-0106, formerly ETAG 027)

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What Sets the ROCCO Line Apart
Butterfly net geometry for load redistribution and additional deformation paths. Designed for multiple and eccentric impacts. Extended testing philosophy for critical impact zones, such as border fields or post hits. Multi-hazard approach: tree impact and landslide tests

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About Geobrugg – Safety is our nature
True to this guiding principle, we have been developing and manufacturing protection solutions since 1951. High-tensile steel wire nets and matching services monitor and protect against natural hazards such as rockfall, landslides, debris flow, avalanches, or coastal erosion. They ensure safety in tunneling and mining, motor racing tracks, industry, and test facilities. With experience, research spirit, continuous internal training, and close cooperation with research institutes, we drive innovation and industry standards forward.

More than 500 specialists worldwide are committed to Geobrugg. Production facilities on all continents and a presence in over 50 countries ensure proximity to customers and fast project implementation—from needs analysis to final acceptance. Geobrugg, headquartered in Romanshorn, Switzerland, is an independent company within the BRUGG Group.

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Images for download
Video Multiple Impact Test