A4/A20 Hafnerberg Tunnel, Birmensdorf

The Hafnerberg Tunnel forms part of the A4/A20 Zurich west bypass. It connects the Birmensdorf junction with Reppichstal. Each direction (Basel and Lucerne) has a separate tunnel bore with two driving lanes and a shoulder lane.

Main heading from Reppichstal with two access points. Drill and blast heading with emulsion explosives. In unconsolidated ground a total of 17 pipe umbrella sections. In Lunnerental, counter heading from 3 access points. 19 stage pipe umbrellas from the portals.


Specific figures

Contract value

CHF 90 million

Construction period

2000 - 2004


3400 m

Total excavated surface

135 m2