The work for Norwegian Public Roads Administration involves the renovation of the Nordby and Smiehagen tunnels in Akershus.
The two-bore Nordby tunnel is 3,850m long with two lanes in each direction, while Smiehagen is 892m in length, with two lanes running in one direction. The tunnels opened in 1993 and 1999 respectively, and are being upgraded to comply with latest regulations. In the Nordby tunnel, fire safety and rock support will be improved. In the Smiehagen tunnel the road surface will be replaced and the drainage system repaired. A new purification plant that takes water from both tunnels will also be built.
Construction starts next month and the project is due for completion in February 2019.