"This is a milestone in the project, and an historic event for Statnett. This is because tower number 9 is the first Statnett 420 kV tower to be built on prefabricated steel foundations," says Jacob Grønn, Balsfjord – Skaidi project manager.
Over the course of the winter, 32 steel foundations were buried, and 8 tower sites prepared for the erection of towers on steel foundations. In addition, 22 concrete foundations were cast and prepared in the autumn and during periods with mild weather.
The use of steel foundation was a condition for the investment decision in the Balsfjord – Skaidi project, as the use of prefabricated foundations enables much more winter work, thus reducing the total construction period for the project by one - 1 - year.
"The reason for this major reduction in construction time is that we during normal construction periods - when using concrete foundations - face major restrictions due to considerations for the reindeer industry," Jacob Grønn explains. "By using steel foundations we can install foundations also in the winter, without disturbing the reindeer industry," Grønn points out.
We have used steel foundations in the ground, and will use such foundations for about half of the 880 tower sites. Traditional concrete foundations will be used for the remaining tower sites in rock.
Using steel foundations significantly reduces the use of helicopters in the project, and thus also the risk of undesirable HSE incidents.
Statnett started construction on the Balsfjord – Reisadalen section last autumn, and will also start work on the next section, from Reisadalen to Skillemoen in Alta, in June this year.