Responsible for the striking roof is Hightex, a leading designer of large area membrane roofs and façades, from Bernau, Germany. The roof construction of the Ukrainian capital's stadium follows the spoke-wheel principle, with two rotating compression rings. The outer steel compression ring is connected to the inner cable compression ring through 80 radial axes or spokes. The high-tensile construction uses approximately 4,700km of steel cable and is fully self-supporting. Schlaich Bergermann and Partners provided structural design and planning, and architects von Gerkan, Marg and Partners supplied the overall design for the reconstruction of the stadium, originally built in 1923.
The stadium's 50,000 square metres of roof is covered by 80 membrane fields. They are made of glass fibre fabric coated with 3M Dyneon PTFE and have a tensile strength of up to 10,000 N/5cm, provided by Verseidag Indutex GmbH. This high-performance material provides an elongation of up to 600 per cent and protects against environmental effects including UV exposure and moisture. It has been used in textile architecture for many years, proving to be extremely durable.
Hightex integrated eight elevated light domes, with diameters of up to 3.2 metres, into each membrane field. The coating, made of highly transparent foils made of 3M Dyneon ETFE by film specialist Nowofol in Siegsdorf, Germany, provides a unique interplay with the translucent membrane surfaces. In this way, the lightweight roof offers bad weather protection - and a realistic open air atmosphere.
PTFE and ETFE are both part of the fluoropolymer family. Dyneon, a 3M company, was the first manufacturer to embrace sustainable processes in the production of these high-performance materials, and also developed a patented method to fully recycle them. Fluoropolymers provide near-universal chemical resistance and are essentially self-cleaning due to their smooth surface, significantly reducing maintenance costs. Fluoropolymers do not require the use of plasticiser or stabilisers that dry out in time and can cause coatings to become brittle. This means that there are no cracks in which bacteria and fungi can lodge, even after decades of use.
Fire protection plays a key role in stadium construction. PTFE does not burn in an atmosphere containing less than 95 per cent oxygen, which means it is virtually fireproof in normal use. This prevents any fireworks, set off illegally inside the stadium, from starting a roof fire. PTFE-coated glass fibre materials meet the requirements of fire protection classes B1 and A2 in accordance with DIN 4102, depending on the carrier material and construction.