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K27 Bristenstrasse, renovation 2020

Facts and Figures
Principal Canton Uri, Office of Civil Engineering
Location Bristen UR - Switzerland
Type Rock technology, Structural engineering
Runtime 05.2020 - 10.2020

Safe connecting paths for Uri's side valley.

In March 2017 a landslide occurred between the towns of Bristen and Amsteg. As a result, the connecting road between the two mountain villages was impassable over a length of more than 10m. In spring 2017, PORR therefore took urgently necessary measures to ensure safety.

In 2020, comprehensive safety-relevant precautionary measures were taken in a subsequent section. In that section of Bristenstrasse, the retaining wall on the downhill side had to be strengthened. Additionally, the very narrow stretch of the road was widened.


The contract for PORR SUISSE AG included the partial reconstruction of retaining walls, roadway and drainage in the affected section of road. The construction of a 130m long, grouted anchor retaining wall, which had to be founded on micropiles, proved to be particularly technically challenging. The work has been carried out under a strict traffic regime, partly with ongoing traffic. A major challenge was the logistical complexity: the narrow and winding mountain road was only passable with a maximum of 18t. The works started in May and were successfully completed in October 2020, when the road was reopened to traffic.