Tallest building in the Nordics rising with Doka expertise

In Sweden’s second largest city, Gothenburg, a new district called Karlastaden is being built in the Lindholmen port area. The centrepiece is the 247-metre high Karlatornet, or "Karla Tower", which is being built by Serneke Group AB. The building contractor brought Doka on board for the formwork of the complex structure. The company’s decades of expertise in the construction of the world’s tallest buildings played a decisive role in the decision to commission Doka, as David Salekärr, assistant construction manager of Serneke Sverige AB, explains: "For the realisation of our first skyscraper, we were specifically looking for a partner in high-rise construction who could support us with extensive know-how and strong expertise in finding solutions."

Doka has a lot of experience in the construction of high-rise buildings. In Dubai, the Burj Khalifa, the world's tallest building at 828-metres, was built using Doka formwork. For the construction of Karlatornet, the high-rise experts from the company’s headquarters in Amstetten, worked together with Doka Sweden, to implement a sophisticated formwork concept.

Safe working environment at lofty heights
The exposure to very high wind speeds during construction called for tailor-made Doka solutions, specially adapted to the requirements of the Karlatornet project. The self-climbing forming and working platform for high-rise SCP 400 was used to form the core. It guarantees a safe working environment whilst providing space for the site equipment. The corners of the platform were modified to allow for the installation of massive steel nodes. The high-performing steel-framed formwork Framax Xlife was used for the large-area forming of the building’s core.

The biggest challenge in terms of structural design was the building’s narrow silhouette. To master this task successfully, outriggers and belt walls were created twice throughout the building using Doka Top 100 tec. Additionally customized SL-1 trusses had to be installed to ensure fresh concrete load transfers into the columns and core while guaranteeing stability. The Doka self-climbing formwork Xclimb 60 was adapted to provide a customised platform solution to facilitate the installation and stressing of post-tensioning cables outside the belt walls at the upper outrigger, at a height of around 210-metres above ground level. For the complex task of dismantling the tower crane, the Doka team developed a tailor-made solution. By re-using the SL-1 trusses, Unikit components and a special slide-rail system, the team created a heavy-duty support structure that increased the reach of the derrick crane enough to ensure safe and efficient dismantling.

Skyscraper planned entirely in 3D
For Doka, this project is special in several respects. While construction was already underway, Doka replaced the original 2D planning of the building's core with 3D planning. One of the biggest benefits of this upgrade is that collisions can be identified more quickly, prior to execution. This allows for potential problems to be resolved more efficiently. Close collaboration between the parties involved further facilitated significant improvements, especially in terms of coordinating the construction site schedule. The Doka BIM experts used the planning software DokaCAD for Revit to create the 3D formwork solution.

Transforming the skyline
With its sleek profile, Karlatornet clearly stands out from the rest of the cityscape and gives the Gothenburg skyline a new look. The design was created by the prestigious architectural firm Skidmore, Owings and Merill (SOM), who added an aesthetically appealing touch, particularly with the distinctive curves from the 38th to the 58th floor. The 74 floors will be used primarily for residential purposes. In addition to the planned 611 apartments, the building will also include offices, a hotel and a skybar on the 69th floor. The superstructure topped out in July 2023 and completion is scheduled for 2024.