The new city district Arenastaden will be home to Scandinavia’s biggest shopping malls and Stockholm’s tallest hotel. The arena itself will have a streamlined profile that curves outwards and a capacity of 50,000 spectators. The roof will be 32,000 square metres in area, with two opening sections totalling 7,000 square metres.
Prior to any major construction project, engineers must establish the effect wind will have on the structure and the wind impact on people in the vicinity of the completed building.
One of the central questions surrounding the arena construction was to estimate the lift forces on the roof, since large vaulted roof structures are affected much like aircraft wings. Other concerns included the strength of the wind let in by the roof, and the way in which it would affect the wall construction.
To find out the answers to these questions Sweco Structures consulted SMHI’s experts in wind calculations, including David Segersson. He explains that the calculations provide a basis for decisions for a construction that is neither too strong nor too weak.
"In simple terms you could say that if you just use enough steel, a building will cope with most conditions. However, trying to limit both costs and the environment impacts, there is no reason to overdimension the structure. The important thing is to build in ‘enough’ strength, so that the structure will cope with all kinds of weather and loads."
3D data simulation
At SMHI the wind load is calculated using 3D flow simulations known as Computational Fluid Dynamics (CFD) technology.
“When it comes to the wind load on the arena, we discovered that the aerodynamic design and vaulted roof lower the loads, and that only a fraction of the wind comes through the roof opening. Had the building been constructed in line with the more approximate formulas in the standard building norms, the arena would have been overdimensioned. CFD technology provides very interesting data for all larger buildings that are not simply square blocks,” David Segersson concludes.