Silvaplana bypass, road and tunnel

Canton of Grisons, Switzerland

Silvaplana bypass and tunnel.


The Julierstrasse connects the valley of Oberhalbstein with the Engadin. The "Silvaplana bypass" has relieved Silvaplana of the transit traffic. The overall length of this by-pass road is about 1.5 km. A central component of the project is the Silvaplana tunnel which is approx. 720 m long. It is built as a multi-lane road tunnel with two lanes each for oncoming traffic, including safety tunnels, 2 escape tunnels, underground operations centre and 2 underground ventilation plants.
Most of the tunnels and galleries were excavated by blasting in rock of good quality (granite). In the entrance areas, in soft rock, machine-assisted excavation was applied. During construction, the consortium supported the client in the technical site management.

Technical data

  • Excavation and safety measures  of 3 trenches;
  • Excavation and safety measures  of 720 m of road tunnel, of which 10 m through weak rocks and a total of 730 m between safety and escape tunnels;
  • Realisation of the raw construction of the tunnels;
  • Realisation of an underground operations centre of about 1’250 m3;
  • Realisation of 2 underground ventilation plants

Total cost

CHF 50.0 Mio.


Design: 2010 - 2014    
Execution: 2014 - 2018    


Technical office Canton Grisons, Coira (CH)


  • Tender design 
  • Final construction design
  • Contract supervision

Date: 21.04.2020