Jetgrunn AS completed work on the prestigious “Karlatornet” in December 2018
Gothenburg. Jetgrunn AS was awarded the assignment in competition with several European players, i
mainly based on the requirement that was made for the strength of the construction. The works were
completed within the framework of the contract both with regard to time, costs and quality.
Karlatornet, with its 245m and 73 floors, will become the tallest building in the Nordics and stand out
as a landmark in the new district of Karlastaden, which is under development and construction
Serneke at Lindholmen in Gothenburg. In addition to apartments of all categories, the building will also
house a new hotel with around 300 rooms. The building is scheduled to be completed and put into use in 2021.
See karlastaden.se.
In total, Karlastaden will consist of 8 blocks with a total of approx. 2,000 apartments, offices,
restaurants, shops, school, cultural center and green areas.
Illustration: Karlastaden Development AB
Karlatornet is founded on rock at a depth of approx. 70m with 58 concrete piles, each with one
diameter of 2 m. Jetgrunn’s task in this regard has been to produce a
stabilizing plate composed of 469 jet piles (J2 piles) partly to prevent bottom compression
during excavation and partly to act as a stabilizing element that links
the concrete piles that go to the rock together and ensure optimal transmission of horizontal forces
between the concrete piles. Walls and the bottom of the building’s lift shaft were also established.
Construction was completed approximately 6.5m below ground level where the injection rigs operated.
The building will be established at Lindholmen, which is located a stone’s throw from Götaälven in Gothenburg.
The ground mainly consists of clay with a water content of 50-75%, but with areas of
silty clay and water content up to 95%.
Static calculations concluded with a requirement for characteristic compressive strength in the pile material
after 28 days, fck, cube, at 5MPa. Jetgrunn’s production parameters were set to achieve a
strength of 5MPa in the areas with the least favorable ground conditions. Achieved
characteristic strength was thus 7.2MPa with a minimum value of 5.2MPa and an average
compressive strength of 11.2MPa.
Jetgrunn’s work at Karlatornet started on 01.10.2018 and ended within
the contract’s framework both with regard to time and costs. The excavation down to the plate should
will be completed at the end of February/March 2019.
