Rising to a height of 246 m the ThyssenKrupp Test Tower in Rottweil is one of Germany’s tallest structures. The tower structure is used to test and certify high-speed elevators. It thus contributes considerably towards reducing the development time of future skyscrapers throughout the world, including those presently in the design phase. However, the test tower is more than just a functional building reserved for research and development. A visitors’ viewing platform offers 360° views of the region around Rottweil from a height of 232 m. As a consequence, the test tower boasts the highest visitors’ platform anywhere in Germany.
The ThyssenKrupp Test Tower is located in the historical town of Rottweil, one of Germany’s oldest urban agglomerations, dating back to Roman times. Rottweil is particularly famous for its medieval towers and spires. The landscape around Rottweil is dominated by the lush hill country of the high plain between the Black Forest and the Swabian Alb. The high-rise building itself is highly visible from within a radius of 15-20 km. Given this particular urban and scenic setting, a sensitive design of the tower’s overall shape and especially of its façade was particularly important.
The facade of the structure is the tallest textile-clad building in the world. Designing and engineering this textile facade was a particularly demanding challenge. It not only involved taking such questions as installation and wind loads into account, but also required the consideration of diverse aspects of maintenance, weather resistance, etc. This necessitated numerous coordination meetings with various contractors as well as a range of tests, material evaluations and experimental assemblies.
The Test Tower’s textile facade consists of PTFE-coated glass fibre fabric. This is attached to six round steel tubes that run around the tower in a helical arrangement. The tubes are positioned at a distance of 1.80 metres away from the outer edge of the concrete construction. The full height of the textile facade is made up of various different fabrics whose thread compositions become less tightly woven and less opaque as they travel towards the top of the building. This makes the concrete structure behind the textile facade increasingly visible the further up the tower you go.
Beyond its aesthetic function, the textile cladding also provides various technical advantages. Reminiscent of a Scruton helix, the facade’s spiral arrangement influences the vortex shedding around the tower and minimises the stress from lateral oscillation by approximately 40 per cent. Furthermore, the textile covering also offers protection from the elements. It shades the tower shaft, thus reducing the (sometimes significant) stresses induced in the concrete by solar radiation.
The structure consists of a thin reinforced concrete hollow tube with a diameter of 20.80 m. The wall thickness tapers from 40 cm at the bottom to 30 cm at the top. Due to the highly effective supporting structure the maximum horizontal deformations resulting from wind loads are a mere 331 mm, corresponding to a ratio of L/725.
A pendulum is suspended at a height of 200 metres on cables of approximately 9 metres in length. Normally the pendulum is passive and only reacts to oscillations induced by the wind. However, the pendulum can also be used actively to make the tower oscillate on purpose. This allows the simulation of various wind and/or earthquake loads, making the tower the only high-rise building in the world that can deliberately be made to oscillate.
Werner Sobek stands throughout the world for engineering, design, and sustainability. The firm has offices in Stuttgart, Berlin, Buenos Aires, Dubai, Frankfurt, Istanbul, Moscow and New York. The work of Werner Sobek is defined by premium design on the basis of high-class engineering combined with sophisticated green technologies. Founded in 1992, the studio has now more than 300 employees. They work on all types of buildings and materials. Special emphasis lies on lightweight structural design, transparent facade systems, and sustainable building concepts. The overall objective is to reach the highest quality possible – this is also reflected in the company’s quality management system which has been certified according to ISO 9001.