In June 1992 the Norwegian Parliament decided that the main trunk road between Bergen and Oslo should be built via Aurland, to Laerdal and over Filefjell. The 24.5 kilo-meter long road tunnel between Aurland and Laerdal will be the final link on the new main highway connecting Oslo and Bergen without ferry connections and difficult mountain crossings during the winter.
In western Norway, narrow winding roads prone to landslides and avalanches have gradually been replaced by modern tunnels and roads.
In the county of Sogn og Fjordane, many long tunnels have been built in order to ensure improved, safer travel. The Norwegian Public Roads Administration is highly skilled in tunnel construction and has considerable experience in the field, and was therefore able to take on a project to plan and construct the world’s longest road tunnel. Work on Laerdalstunnelen began on 15 March 1995.
IMPLEMENTING THE PROJECT
The tunnel is driven using computerised drilling jumbos and traditional methods of drilling and blasting. Drilling takes place from three different sites or faces. There are three blasting crews working on the construction of the tunnel. This intensive work means that construction time is shortened and ensures better use of large Investments than if drilling had only taken place from two sites. The Norwegian Public Roads Administration Sogn og Fjordane is responsible for an 11 km Stretch from Aurland and will also drive a 500 m Stretch from the mouth of the tunnel starting at Häbakken in Laerdal. NCC Eeg-Henriksen Anlegg A/S is responsible for the section from Tynjadalen in Laerdal: starting with the construction of the 2.1 km long Ventilation tunnel which leads from Tynjadalen into the main tunnel, and then drilling in two directions – 6 km towards Laerdal and 7 km towards Aurland.
EXCAVATION AND LANDSCAPING
A total of 2.5 million cubic metres of excavated material have been removed. Some of the material has been used to upgrade the E16 motorway in Aurland and some of the material has been used to construct a new footpath and cycle path along Aurlandsfjorden and a small marina. In Laerdal, the excavated material has been transported to Tynjadalen, a branch valley which opens into Laerdalsdalen 8 km east of Laerdal town centre. All the excavated material transported to Tynjadalen has been covered with topsoil and sown with grass seed so that it blends in with the environment. Some of the excavated material has also been used for new roads and other construction work.
PROJECTFACTS
| Project cost | |
| (NOK value in 1998): | NOK 976 million |
| Construction period: | 1995-2001 |
| Tunnel length: | 24.5km |
| Access adit/ventilation tunnel: | 2.1km |
| Turning points: | 16 |
| Emergency lay-bys: | 48 |
| Maximum hourly traffic: | 400 vehicles |
| Average annual daily traffic: | 1,000 vehicles |
NEW WORLD RECORD
| LAERDALSTUNNELEN (Noreg/Norway) | 24500m |
| St. Gotthard (Sveits / Switzerland) | 16918m |
| (Austerrike / Austria) | 13972m |
| (Frankrike-Italia / France-Italy) | 12901m |
| Mont Blanc (Frankrike – Italia / France – Italy) | 11600m |
| Gudvanga (Norge / Norway) | 11400m |
| Kan Etsu (Japan) | 11090m |
Source: Information board on site