Paper contribution

A step forward in the resilience of flexible rockfall protection systems

Roberto J. Luis-Fonseca; Werner Gerber; Remo Dudler; Helene Lanter; Vjekoslav Budimir

Proceedings
EUROCK 2026
Pages
441-449
Submitted
28 January 2026
Accepted
15 June 2026
Published
12 August 2026

Summary

Abstract

Flexible rockfall barriers are crucial for protecting roads, railways, and settlements in mountainous regions. Their capacity to absorb high-energy impacts while remaining functional over time is essential for geological risk management. Resilience—absorbing, adapting, and recovering from extreme events—is particularly important in areas prone to rockfalls on steep slopes or tectonically active zones. The development of flexible barriers has advanced significantly since the first Swiss guideline in 2001. Numerous full-scale tests have been conducted worldwide, but differing methodologies make comparisons challenging. A major advance was the European guideline ETAG 027, now standardized as EAD 340059-00-0106, which has guided engineering design and market practices. Current certification, however, is based on an idealized scenario: a single block striking the center of the middle field. This does not reflect real conditions, which often involve multiple blocks, fragmentation, irregular shapes, block rotation, and impacts on posts or edges. Consequently, real service loads are more chaotic and less predictable than those represented in standard tests. Research shows that trajectory and block fragmentation strongly influence impact behavior. Rotating and platy blocks produce higher forces and uneven load distributions, and field failures confirm that edge and post impacts are critical yet not considered in certification. To address these gaps, the SLF proposed two additional tests: MEL-S, a central impact accounting for block rotation, and MEL-E, an eccentric upper-field impact loading the stiffer barrier part asymmetrically. Fragmentation produces near-simultaneous multiple impacts, creating complex stress states not captured in single-block tests. Real-scale MEL-M tests with two simultaneously released blocks showed slightly higher forces than traditional MEL tests, demonstrating that current procedures underestimate actual demands. In conclusion, while the EAD procedure is reproducible and cost-effective, it overlooks key real-world factors—block shape, rotation, fragmentation, edge/post impacts, and multiple simultaneous loads. Incorporating more realistic impact scenarios is essential to improve barrier design, certification, and infrastructure safety.

Contributors

Authors

  1. Roberto J. Luis-Fonseca Geobrugg AG, Romanshorn, Switzerland
  2. Werner Gerber WSL, Birmensdorf, Switzerland
  3. Remo Dudler Geobrugg AG, Romanshorn, Switzerland
  4. Helene Lanter Geobrugg AG, Romanshorn, Switzerland
  5. Vjekoslav Budimir Geobrugg AG, Romanshorn, Switzerland ORCID 0000-0001-6623-7981

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References

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