- Client: Bergen Light Rail
- Main contractor: Veidekke Entreprenør AS
- Contractor: Metrostav Norge AS
- Construction period: 11/2021 – 04/2022
- Price: 32 400 000 NOK w/o VAT
D18 Kronstadtunnelen og inntrekkstunnelen
The project contains 77,5 m of dead end Intrekks tunnel and the extension of the old 370 m Kronstad railway tunnel into a pedestrian and cycling tunnel in the inner city of Bergen.
Basic information
Project characteristics
It is part of a new urban railway development in Bergen. Metrostav Norge performed excavation and securing of Kronstadtunnelen and a service tunnel.
Kronstadtunnelen tunnel was an existing 460 m long tunnel with a protected stone-walled portal. The work included widening the tunnel from a profile of 30 m2 to 58 m2 in length of 370 m, in an urban area near a hospital. The work was limited not only by noise and seismic requirements, but also by very limited places for construction. The work also included securing the tunnel with bolts. The newly operated tunnel will be used by pedestrians and cyclists.
Inntrekkstunnelen is a new parking tunnel for the light rail, with a length of 89 m. Tunnel with profile 85 m2 was excavated in quartzite in urban areas. Part of the work was injection and securing of the tunnel with bolts.
Project data
2 pcs (370 m + 89 m)
Tunnel:
Widening 28 m2 + 85 m2
Tunnel profile:
17 636 m3
Excavated volume:
70 000 kg
Grouting:
2 062 pcs
Rockbolts:
Challenges / Specifics of the project
- Minimal space for construction site, impossible to build a workshop tent, minimal space for storage of materials
- Strict noise and vibrations limits – Excavation near the hospital, large time limitations
for performing blasting work and other noisy activities - Kronstadtunnel – due to coordination of other works, excavated from both portals.
- Protection of a historical portal made of rocks
- Major restriction of blasting works
- Low overburden up to 30 m
- Use of electronic detonators
