- Client / Design: Statens vegvesen Region South, P.O.B 723 Stoa, 4808 Arendal, Norway
- Contractor: Joint venture Metrostav – Bertelsen & Garpestad – HAG Anlegg (NRC Group)
- Contractual time period: 1/2017 – 9/2019
- Contractual price: 643.519.647 NOK excluding VAT, 65,7 million EUR (Approx.)
Project Description
The main objective of the whole project was to construct a by-pass of Kongsberg city centre. The 4,7 km long section Trollerudmoen – Saggrenda were the last of the three parts of the by-pass. The project consisted of a new two-lane road, two interchanges and other local roads. Among other structures in this project, there are tunnels Moane (350 m) and Vollås (500 m) with the width of 14,5 m, Saggrenda bridge with the length of 310 m and two shorter bridges, three underpasses, four tunnel portals and four technical buildings. Metrostav excavated and secured the tunnels and constructed the reinforced concrete structures of two underpasses and four tunnel portals.
Project data
| Section length: | 4 700 m |
| Tunnels: | 2 pcs |
| Bridges: | 4 pcs |
| Underpasses: | 3 pcs |
| Technical buildings: | 4 pcs |
| Blasting on surface: | 480 000 m3 |
| Mass transport total: | 710 000 m3 |
| Tunnel profile: | T14,5 (136 m2) |
| Blasting in tunnel: | 105 000 m3 |
| Water and frost protection: | 20 000 m2 |
| Concrete for structures: | 19 500 m3 |
| Reinforcement: | 3 400 t |
| Asphalt: | 45 000 t |
Challenges / Specifics of the project
- Drill&Blast excavation in the whole length of the tunnels with profile T14,5 and area of 136 m2 (in emergency bay 165 m2)
- Complex geology with low overburden
- Excavation close to an inhabited area, challenging logistics
- Reinforced concrete tunnel portals with irregular shape spanning up to 20 m concreted in one step using the SCC technology
- Difficult climatic conditions in wintertime demanding special measures for concreting when freezing
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