Grimstad-Kristiansand Tunnel, E 18

The E 18 Grimstad-Kristiansand is the third pilot project to be based on a PPP model in the Norwegian transport system. The section between Grimstad and Kristiansand is part of the highway system that runs from Oslo along the coast to the south of the country. The European Highway 18 represents an important transport artery linking Norway with continental Europe and at the same time serves to carry both goods and passenger traffic in the region. On average the volume of traffic amounts to some 10,000 vehicles per day, a figure which shoots up by around 60 % during the July holiday season. The project embraces the construction and operation for a 25-year period of a roughly 38 km long, four-lane motorway from Grimstad to Kristiansand. ln addition to several bridges and engineering structures 7 motorway tunnels each with two-lane tubes and individual lengths ranging from 130 to 2,210 m have to be produced. The length of all the tunnels amounts to roughly 11,700 m. The twin tubes are linked by cross-passages at 250 m gaps and possess a breakdown bay per direction of travel every 500 m. A total of 800,000 m³ of excavated material has to be removed from the mined tunnels by drill+blast. The tunnels are supported by anchors and by shotcrete in accordance with the "Norwegian construction method". The tunnel routes largely run in gneiss. Zones with ingressing underground water are sealed in advance in keeping with contractual requirements by injecting the rock (pre-grouting). Residual water that is present is removed by a drainage system. The tunnel's inner lining is produced by the customary method applied in Norway, which foresees a bolted precast shell being used. In areas where the geometry deviates from the standard cross-section (e.g. breakdown bays), the vault area is secured by a 50 mm thick sealing membrane and frost insulation to offset the enlarged span width. The 8 cm thick reinforced shotcrete layer that is then applied serves fire protection purposes as well as supporting the seal.

• Country: Norway
• Region: Grimstad- Kristiansand
• Tunnel utilization: Traffic
• Type of utilization: Road Tunnel
• Client: Agder OPS Vegselskap
• Consulting Engineer: Bilfinger Berger/Ramböll
• Contractor: Bilfinger Berger/E. Pihl & Son
• Main construction method: Trenchless
• Type of excavation: Drill-and-blast
• No. of tubes: 14
• Tunnel total length: 38 km (total),11.7 km (tunnels)
• Cross-section: 75 m²
• Contract Volume: 398 mill. euros
• Construction start/end: 29 months