The supporting structure of the stadium façade is made of concrete, while the support structure of the roof is made of steel trusses cantilevered approximately 50m, which are supported by stringers and braces. Perpendicular to this structure rise steel rungs to which diamond-shaped ETFE cushions are attached. The length of the bars varies in the diagonal from 7.3m to 17.7m. The rungs, which run from the foot of the façade over the shoulder of the building spiral onto the roof surface and continue to the edge of the roof, where they lend the exterior shell its characteristic diamond shape. Due to the complex geometry, only two of the approximately 2,784 ETFE cushions have the same shape. 3D computer visualizations of almost 1,400 custom sizes had to be developed – a particularly significant logistics and planning challenge. The roof's air cushions consist of two-ply ETFE-foil, whose light permeability minimises shading on the playing field and allows good lawn growth. The stadium's façade consists of two-ply printed membranes with variable backlighting. The building shell has a total surface area of 66,500sqm.
Regulating the significant fluctuations in the temperature of the shell was one of the major technical challenges. To accomplish this task, covertex GmbH, whose employees today work partly for seele cover GmbH, developed a new mounting system that was subsequently patented. Additional technical refinements are hidden in the details of the portable awning, in the drainage system and in the systems for air management in the ETFE cushions. The entire building shell was completed in just 15 months – from cutting the cushions to assembly.
Reference overview, header, 1st & last slide image © seele / Matthias Reithmeier; 2nd & 3rd slide image: © Ducke