N08 Escape Passage Sengg Tunnel, Safety Galleries Chüebalm and Giessbach Tunnels

The Chüebalm and Giessbach tunnels will receive a total of 15 emergency exits. To this end, a safety gallery will be constructed parallel to each tunnel, to which it is connected via cross passages. The safety gallery for the Giessbach tunnel will be bored using an open gripper TBM, where-as the safety gallery for the Chüebalm tunnel will be excavated by conventional drill-and-blast method. Both galleries will be equipped with air locks and technical chambers at the portals.

The Sengg tunnel will just be equiped with an emergency passage at the centre of the tunnel, leading to the surface via a gallery and a staircase shaft. At the head of the shaft an operating building with integrated air lock is being constructed.

Main Data

Safety gallery Giessbach tunnel

  • Length: 3319 m
  • Diameter: 5.20 m

Safety gallery Chüebalm tunnel

  • Length: 1150 m
  • Cross-section: 3.20 m x 4.50 m

Escape passage Sengg tunnel

  • Shaft depth: 10 m
  • Shaft diameter: 6.60 m
  • Gallery length: 50 m
  • Cross-section: 2.60 m x 3.20


Federal Roads Office (ASTRA), Regional Office Thun


Consortium „Notausgang N8“, lead by IUB Engineering Ltd.

Construction period


Construction costs

96 Million CHF

Scope of services

General planning contract from detail design to site supervision for driving and linig the galleries, air locks and exterior appurtenances, surveying and provision of electromechanical equipment.