To circumvent the cost of constructing conventional subsea tunnels, and still reap the benefits of reduced energy consumption and pollution, the Norwegian Public Roads Administration (NPRA) and Dr.techn. Olav Olsen AS are working to develop new concepts for submerged floating tunnels based on offshore structures and made from reinforced concrete.
Although no such tunnel has yet been built in Norway, detailed feasibility studies reveal that a submerged floating tunnel would be an excellent choice for the Høgsfjord Crossing near the city of Stavanger in southwestern Norway. The fjord is both wide and deep, making all other forms of fixed crossings - even a conventional immersed tunnel - extremely difficult to construct. A 1.4-km submerged floating tunnel is being planned, with an estimated total concrete volume of 60,000 m3. The tunnel is the best choice for preserving the area's natural beauty and is also competitively priced.
SHOTCRETE: FACTS & FIGURES
The main advantages of wet-process shotcrete are:
- Higher capacities - up to 25 m3/h with advanced equipment
- Controlled water-cement ratio
- Reduced rebound, typically 5-10 per cent
- Improved working conditions
- No extra fibre rebound
- Evenly high quality
- Superior ductility
- Exceptional flexibility
- Reduced construction time
- Reduced construction costs