DUCI NORGE AS is currently operating in the Region of Northern Norway on the project “New Transmission line 420 kV Balsfjord-Reisadalen” for the construction of the foundations (Contractor Statnett SF). Balsfjord – Reisadalen (twr 413) TL Length 123 km Galvanized lattice type towers. Concrete foundations and Prefabricated steel foundations
Duci Norge AS is responsible for mapping and classifying soil and rock conditions and the selection of correct foundation type. The soil condition and rock classification is recorded in a foundation report for each and every foundation. Duci Norge AS’s geologists and surveyors are always available on site during the foundation work and decide if it might be necessary to use measures to stabilize the excavations in wetland areas with sheet piles or similar. DUCI NORGE AS is responsible for building on this site 2 types of foundations: concrete and prefabricated steel foundations. For towers in “bad rock” conditions DUCI NORGE AS is excavating the rock and placing a prefabricated steel foundation instead of extensive strengthening of the rock. “Bad rock” is made into soil and prefabricated steel foundations are used instead of extensive rock anchoring.
The scope of work foreseen the construction of 276 foundation for the new 420 kV power line.
The foundation were divided in three tipology:
- rock foundation (112);
- soil foundation in concrete (36);
- soil foundation in steel (128).
The choice of which type of foundation to construct was made after a rock/soil investigation made by our geologist.
PHASES OF THE WORK
The phases of the works foreseen were:
- Rock foundation – preparation anc cleaning of the rock, drilling and grouting of reinforcement rebars in the rock, concrete casting for the pads and chimneys and reinstatment of the terrain;
- Soil foundation in concrete – excavation, formwork and laying of the reinforcement rebars, concrete casting for pads and chimneys and backfilling;
- Soil foundation in steel – excavation, assembling of the steel foundation placing it into the pit and backfilling.