21 km Tunnel Construction

E4 Förbifart Stockholm is a major infrastructure project designed to extend 21 kilometers from Häggvik in the north to Kungens Kurva in the south, with 18 kilometers of this stretch running in rock tunnels. The project further involves building several connecting ramp tunnels and ventilation shafts, with two 3.6 km long parallel road tunnels and four vertical shafts for ventilation, each approximately 10 meters in diameter and between 30-50 meters deep. The entire construction is expected to conclude by January 2024.

Budget and Contractors

The project is managed by Trafikverket, with engineering support from URS and ÅF. The primary construction contractors include Implenia Sweden, Veidekke, AF Gruppen, NCC, and Skanska. The overall budget is estimated at 37.7 billion SEK based on 2017 price levels. Implenia Sweden executed a specific contract worth 2.1 billion SEK to construct the rock tunnels in Johannelund, encompassing 12,000 meters of tunnel with a cross-sectional area of 220 m².

Challenges and Delays

A number of significant challenges have been encountered during the construction, most notably extensive water leakage, particularly affecting the northern section of the tunnel network. These water leaks have already threatened to delay the project by several years, potentially increasing costs by an additional five to nine billion SEK. Efforts to mitigate these leaks include drastic measures such as the possible use of concrete linings, although legal hurdles have complicated these remediation efforts, with the Swedish Land and Environment Court denying requests to modify groundwater permits.

Long-Term Benefits

The Förbifart Stockholm tunnel project promises substantial long-term benefits for society by improving traffic flow around the central areas of Stockholm, thereby reducing congestion and enhancing connectivity within the city. Upon completion, it aims to provide a more efficient route for commuting and transport, thereby facilitating economic activities and reducing travel times.