A rockfall barrier — also called a rockfall fence, catch fence or flexible rockfall barrier — stops a falling block with a net, ropes and braking elements that deform. Its class is certified by a 1:1 impact test under EAD 340059-00-0106 (predecessor ETAG 027), from 100 kJ to above 4,500 kJ; the choice follows the measured energy, the bounce height and the space available.
- 100 – > 4,500 kJ
- Energy classes 0–8 (MEL)
- EAD 340059
- 1:1 impact test, vertical or inclined trajectory; replaced ETAG 027
- MEL ≥ 3 × SEL
- SEL: two impacts, no repair between
- A ≥ 50 %
- Residual height after the MEL test, category A
What it does
A flexible rockfall barrier stops a block that has broken off a slope on a catch line. The energy is absorbed by the deformation of the net and the support ropes and by the controlled elongation of the braking elements; the posts carry the net and the forces go into the ground through the anchors. Compared with rigid structures such as a concrete gallery or an embankment, it takes the same energy with far less mass and in a narrower space.
A barrier is defined by two numbers: the energy it can stop (kJ) and the height at which the net keeps holding the block after an impact. Both are established by testing, not by a catalogue sentence.
Classes: MEL and SEL
EAD 340059-00-0106 (predecessor ETAG 027) classifies a barrier by 1:1 impact tests; the block trajectory may be vertical or inclined, and the test set-up is stated in the product document. MEL (maximum energy level) is the energy stopped in a single impact; SEL (service energy level) is the energy stopped in two consecutive impacts with no repair in between. According to EAD 340059 Table 2, MEL is at least three times SEL (MEL ≥ 3 × SEL); the MEL and SEL values of a system are read from its declaration of performance.
| Class | SEL (kJ) | MEL (kJ) |
|---|---|---|
| 0 | no test required | 100 |
| 1 | 85 | 250 |
| 2 | 170 | 500 |
| 3 | 330 | 1,000 |
| 4 | 500 | 1,500 |
| 5 | 660 | 2,000 |
| 6 | 1,000 | 3,000 |
| 7 | 1,500 | 4,500 |
| 8 | > 1,500 | > 4,500 (open-ended; the actual value is in the ETA) |
After the MEL test the residual height is declared in three categories of the nominal height: A ≥ 50 %, B 30–50 %, C ≤ 30 %. In the SEL test, after the first impact and with the block still in the net, the residual height must be at least 70 % of the nominal height. These figures are written in the system's European Technical Assessment (ETA) and declaration of performance (DoP); a quotation refers to the same documents.
Barrier families
| Family | Energy range | Where | Page |
|---|---|---|---|
| GBE | Certified types from 100 to 5,000 kJ (GBE-100A-R … GBE-5000A V2); with and without retaining ropes | Road cuts, slopes above settlements; lines with room for elongation | GBE barriers |
| RXE | 500 – 12,500 kJ assessed types (RXE-500 – RXE-12500 V2) | High energy, tight space, lines close to infrastructure | RXE barriers |
Both families are Geobrugg AG products. The net panel is either a ring net (ROCCO) or a high-tensile woven mesh (TECCO); which one comes with the system is stated in its documents.
Barrier, drape mesh, gallery or ditch?
- Barrier or drape mesh. If the block breaks away and bounces down the slope, an energy-absorbing flexible barrier; if it detaches from the surface and rolls, a drape mesh that covers the surface. The bounce height and the position of the source zone decide it, not the budget. Full answer
- Barrier or concrete gallery. A flexible barrier is the lighter, faster-built answer for single impacts below the certified energy limit. When the block mass or the fall height goes beyond the certified classes, or events are very frequent, a concrete gallery or an embankment is discussed. Full answer
- Barrier or catch ditch. With enough width and depth a ditch is the easiest solution to maintain; it has no certified energy class, and its performance is defined by width, depth and floor slope. Where the road platform is narrow or the land cannot be acquired, a barrier takes its place.
Selection: four inputs
| Input | Where it comes from | What it decides |
|---|---|---|
| Design energy | Kinetic energy E = ½ · m · v² of the design block (m: block mass; v: impact velocity from the trajectory analysis; rotational energy calculated separately); ONR 24810 takes E_k as the characteristic value and the design value E_d = γ · E_k with γ = 1.00 / 1.05 / 1.15 (CC1 / CC2 / CC3) | Class: the design resistance MEL/γ must be at least E_d, i.e. MEL ≥ γ² · E_k (on sections with frequent events SEL is checked as well) |
| Bounce height | 95 % fractile of the trajectory analysis, terrain roughness | Nominal barrier height |
| Space | Distance between the line and the protected structure | Maximum allowed elongation; whether a low-elongation type such as RXE is needed |
| Ground | Anchor ground, rock quality | Anchor type and length; pull-out test programme |
These inputs are measured on site. The energy class estimate gives the first order of magnitude; the final class comes from the trajectory analysis. The clauses for a tender specification are ready on our barrier specification page (Turkish).
Is your barrier really certified? A checklist
In Europe a rockfall barrier is certified not part by part but as a kit: net, ropes, braking elements, posts and connections go through the full-scale test together, and the European Technical Assessment (ETA) is issued for that whole on the basis of EAD 340059-00-0106, which replaced ETAG 027. An ETA is voluntary for the manufacturer; a barrier without an ETA has no declaration of performance and no CE marking, so it is not an assessed kit. If one part of the kit is replaced with another product, the system on site is no longer the assessed system. You can run the checks below yourself at quotation, at handover and during maintenance; they rely on documents you can request from the seller and on publicly available records.
| Check | Where to look | What you should find |
|---|---|---|
| Is there a declaration of performance (DoP) | Ask the seller. For a kit with an ETA, a paper or electronic copy of the declaration must be supplied (Regulation (EU) 305/2011, Art. 7; in Türkiye the Construction Products Regulation, Art. 9); it may also be published on the manufacturer's website, and in Türkiye it is drawn up in Turkish | The product-type code on the DoP clearly links the product in the quotation and delivery note to the trade name in the ETA (the sales name and the ETA name may differ); energy class, MEL, SEL and residual height category are stated |
| Is the ETA number real | Search the ETA number from the DoP in EOTA's public list (eota.eu/etassessments); try both spellings, such as "ETA-25/0896" and "25/0896" | The number is listed; the product name and ETA holder there match the DoP, or the link between them (change of company name, group company) is explained in writing |
| Certificate and notified body | The number of the certificate of constancy of performance on the DoP (e.g. 1301-CPR-… or, in older numbering, 1301-CPD-…) and the name and number of the notified body | The number and body are stated. "CPD" in the number does not by itself mean the document is old or invalid; confirm validity in writing with the manufacturer or the notified body, and check in the EOTA list that the ETA is current |
| Is the energy stated in figures | DoP and quotation | MEL is written in kJ, and so is SEL (sometimes as a lower bound, e.g. "> 2,667 kJ"; only class 0, below 250 kJ, has no SEL). "Class 8" alone is not enough: that class covers every system above 4,500 kJ |
| Is the height within the assessment | The height range stated in the ETA itself; in the data sheet, the "certified heights acc. ETA" line, not the "standard heights" line | The height to be installed is within that range. Under EAD 340059 the range extends at most 1 m (0.5 m for systems below 4 m) above the tested height; heights outside it are not covered by the ETA |
| Were the installation manual and system drawing supplied | Ask the seller; the Regulation requires the product to be accompanied by instructions and safety information (305/2011, Art. 11(6); in Türkiye Art. 13(6), in Turkish) | The declared performance applies only when the kit is installed to the manufacturer's manual: post spacing, number and position of braking elements, anchor type and forces follow that drawing |
Material check on site. Only the parts defined by the ETA holder in the ETA and the installation manual should be used; some of them (such as ropes or grips) may come from the ETA holder's suppliers. Net type (for ring nets, ring diameter and number of wire windings), rope diameters and the number and position of braking elements are compared with the parts list in the manual. Completing a kit with another barrier manufacturer's net or braking element leaves it without an assessment, whatever the brand; for example, the data sheets of Geobrugg also list the failure to use original parts among the factors that can reduce the level of protection. Elements that the ETA treats as outside the kit, such as anchor bars, may be sourced locally; they are designed for the anchor forces given by the manufacturer and proven by pull-out testing. The CE marking is on the product or a label attached to it or, where that is not possible, on the packaging or accompanying documents; it is followed by the year it was first affixed, the manufacturer, the product-type code, the DoP number, the declared class, the EAD number and the notified body number. Individual parts need not each carry a manufacturer's mark. Galvanising is specified to EN 10244-2 for wire and net, EN 10264-2 and EN 10244-2 for rope, and EN ISO 1461 for posts and base plates; the coating type and mass are stated in the ETA and compared with the material certificates.
Warning signs:
- Instead of a declaration of performance and an ETA number, only a "test report", a "test certificate" or a note saying "complies with ETAG 027" is supplied.
- The ETA number on the DoP cannot be found in the EOTA list under either spelling, or a different company appears there and the seller does not explain the link in writing.
- The product-type code on the DoP differs from the product offered, or the copy supplied has hand-corrected dates or numbers, missing pages or is illegible (in that case request the document directly from the manufacturer).
- The installation manual and system drawing are not supplied.
- The quotation offers "equivalent" material for individual parts of the kit (net, rope, braking element). Another manufacturer's complete kit with its own ETA can be an equivalent; equivalence at part level leaves the kit without an assessment.
- The energy is stated only as a class, without an MEL figure (and, except in class 0, without SEL).
None of these signs on its own proves bad faith: documents can arrive late, and the EOTA list may show new ETAs with a delay. But a written explanation should be requested before handover. These checks are the same for every manufacturer's system, Geobrugg included; we carry out an inspection against that manufacturer's ETA and installation manual. If you would like us to carry out these checks and review the documents and the installation on site for you, see rockfall barrier monitoring; to check your specification text, use the specification checker (Turkish).
Installation, step by step
- Setting out. The line axis, post and anchor positions are marked from the design.
- Anchors and base plates. Drilled and grouted to the ground; pull-out tests follow the programme.
- Posts. Erected on the base plates.
- Support ropes and braking elements. Installed to the manufacturer's installation manual.
- Net panels. Hung and connected; the number and torque of the rope clips are checked item by item at acceptance.
- ID tag. Every installed line gets a barrier tag: system type, class, installation date and the next inspection in one place.
What to do after an impact and how often to inspect is in inspection and maintenance.
Sources: EAD 340059-00-0106 Table 2 (predecessor ETAG 027, EOTA, April 2013); Geobrugg AG RXE brochure EN.170808 and current RXE declarations of performance; ONR 24810.
Frequently asked
How is the energy class of a rockfall barrier determined?
The kinetic energy E = ½·m·v² is found from the mass and impact velocity of the design block; under ONR 24810 the partial factor is applied to this energy and again to the barrier resistance (MEL ≥ γ²·E), and the smallest certified MEL level that meets this is chosen. The velocity comes from a trajectory analysis or the energy-line approach, not from a catalogue. Full answer
How is the barrier height chosen?
For the bounce height expected at the barrier axis; it does not follow from the energy calculation. The bounce height comes from the trajectory analysis and is checked against impact marks on site.
Where on the slope is a rockfall barrier installed?
Not next to the structure to be protected, but where the energy of the block drops and the ground can hold anchors. Moving the line upslope lowers the energy but makes access harder and raises the cost.
What is done after a rock hits the barrier?
First the line is made safe and the event is recorded; then the block is emptied from the net, the brakes, ropes and anchors are checked and damaged parts are replaced with identical ones. The system is re-tensioned in the order the manufacturer defines. Full answer
What decides the cost of a rockfall barrier?
Seven things: energy class (kJ), barrier height, line length, access to the slope (road, rope access or helicopter), anchor length and drilling metres for the ground type, scaling along the route, and transport. One class up, the same line grows in posts and anchors as well; that is why the class is set by measurement, not by estimate. Full answer
What do you need from us for a quotation?
The site coordinates, slope height and angle, the asset to be protected, the observed block size and, if available, photographs and records of earlier events. These give an order of magnitude; the firm quotation follows the site survey. Full answer
Tools for this solution (Turkish)
Energy class estimateTrajectory pre-analysisResidual height checkSpecification completer