Rockfall protection for the deepest gorge in the Alps

Around 200,000 people visited the Liechtensteinklamm gorge each year – until spring 2017 when a rockfall deposited around 300 tonnes of rock in the gorge. In doing so, a portion of the tourist paths was destroyed. Thanks to the energetic, in the most literal sense of the word, actions of workers from Felbermayr specialised civil engineering, the gorge has been cleared again.

Rockfall protection measures

A total of 58 individual measures were established in the gorge, which is up to four kilometres long and up to 300 metres deep. "These included steel nets lying directly against the rock face as well as rockfall protection nets mounted on supports and reinforced concrete bars anchored in the rock, intended to prevent rock material breaking away", explains Felbermayr's construction manager Johann Bugelnig. The material logistics are also difficult. Bugelnig explains further: "We have a large storage area near the gorge, but nonetheless all of the material had to be flown in with the helicopter, starting from the anchors, through the drilling devices and on to the nets and the cement required".

Extraordinary efforts

"Our workers have special alpine training", explains Bugelnig. This is absolutely essential, explains Bugelnig, as some of the heavy work has to be carried out approximately 200 metres up on bare rock and under the most difficult of climate conditions. "The gorge has its own weather system", Bugelnig knows. So "outside" it can be the most beautiful of summer days, whilst rainfall from previous days results in torrents of water running down the rock walls in the gorge for several days afterwards, driving temperatures all the way down. You have to surpass yourself every day, says one of the workers before negotiating the rock wall, doubly-secured, ready to tackle the next work. For the rockfall protection, the rock anchors are manufactured beforehand with the corresponding individual foundations and then the supports can be flown in and fitted to the vertical wall. "In this way, rockfall protection nets with a length totalling 1200 metres and heights of more than five metres, are created", reports Bugelnig.

At the end of October, the majority of the restoration work was completed by Felbermayr. "The six months of work was an on-going battle against time and the forces of nature, and it was a hard battle to win. But, thanks to the good cooperation of everyone involved it was possible in the end", says a delighted Bugelnig. As a result it will be possible to explore the natural treasure of the Liechtensteinklamm gorge again on safeguarded paths from next spring.                                    

All of the material had to be flown in with the helicopter, starting from the anchors, through the drilling devices and on to the nets and the cement required.

For the rockfall protection, the rock anchors are manufactured beforehand with the corresponding individual foundation.

Reinforced concrete bars were anchored in the rock to prevent a new rockfall.

The rockfall destroyed large sections of the path system.

The installation of the rock anchorages and the rockfall protection nets required an optimal cooperation of all involved parties.

A total of around 10,000 square metres of rockfall protection nets were installed by Felbermayr.

The heavy work in special civil engineering requires special training to ensure the safety of the workers.

A total of 58 individual measures were established in the gorge, which is up to four kilometres long and up to 300 metres deep.

Due to the difficult conditions, the workers had to outgrow themselves on a daily basis.

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