Tailor-made elegance of glass fabric and steel

“What’s the best way to test elevators?«, the development engineers of thyssen-krupp Elevator may well have asked themselves before building this top-class test laboratory. A simple question, and a plausible answer – under authentic conditions.

But if you’re interested not only in testing but also in conducting practical research, you need a building that’s as tall as possible. And one with a large number of elevator shafts that are rarely in use. And, failing the existence of such a building, then it has to be built – or, as in this case, dreamed up, designed and then built.

Architecture and elevators that change the world

And now that the Test Tower in the idyllic countryside of Rottweil has been built, the architecture and elevators have the potential to change the cities of the future for good. Two key themes have been addressed here in a single structure: resource-conserving construction and efficient passenger transportation in the high-rise of the future.

Intelligent tower envelope

The tower’s load-bearing system consists of a reinforced concrete tube measuring almost 21 meters in diameter and a multifunctional membrane envelope. The latter not only makes it more attractive, but also plays an important part in reducing the tower’s exposure to thermal and wind loads. The membrane’s strategy thus enables a sustainable, material-saving and futuristic building design. The membrane has been attached to a spiral tubular steel substructure that describes a highly aerodynamic helix.

MULTI – the elevator of the future

Today, half of the world’s population lives in towns. And this share will increase to 70 percent by the end of the century. For numerous future challenges, high-rise buildings represent the most efficient solution economically and ecologically. It is therefore essential that tall buildings can be efficiently accessed as part of the forward-looking strategies of modern and intelligent cities.

Reason enough, then, to rethink the basically 160-year-old concept of the conventional elevator. With 10 test shafts and travel speeds of up to 18 m/s, the Test Tower offers previously undreamt-of experimental opportunities. With the MULTI system, for example, the world’s first-ever cable-free elevator. With this highly innovative approach, several lift cabins can be propelled at the same time in a single shaft. By adopting the technology of the magnetic levitation (maglev) train, transportation performance can be boosted by up to 50 percent and the space required in buildings considerably reduced. This will make it possible to build tower blocks with a slimmer core and much reduced mass.

Perfect test environment

To prevent the tower from swaying even when exposed to the highest wind loads, a pendulum damper system weighing 240 metric tons has been installed – as conventionally in many tall buildings – at a height of 200 m. So far, what you would expect. But the damper system in Rottweil can also be artificially reversed. The Test Tower is thus the world’s only high-rise structure that can be deliberately made to sway. The goal, after all, was to be able to test elevators in authentic conditions – inclusive of simulated wind loads and earthquake tremors.

Perfect-fit steel tubes

Mannesmann Line Pipe supplied the HFI-welded tubes with a diameter of 356.6 mm and a tube wall thickness of 10 mm on behalf of thyssenkrupp Schulte in Leipzig to STURM Metallbearbeitung in Daaden. There the tubes were given the specified radii in a cold bending process and primed for further processing.

Challenging installation work

While the construction of the tower’s reinforced concrete tube proceeded bottom-up, the attachment of the outer membrane was to go top-down. The specially designed platforms were built in a ring around the tower and lowered bit by bit. Problems were posed, however, by the inclement and changeable weather in summer 2017, causing work to be suspended several times. To make up for lost time, 20 experienced industrial climbers were in action in two shifts around the clock to attach the membrane.

17,000 m² of high tech

The membrane itself is also newly developed. The material consists of glass fibers and was developed in Munich, produced in Krefeld and cut to size in Poland, having been previously tested and approved at DEKRA in Stuttgart. What at the start of installation looked like faulty material was soon rectified by the sun. The material of the approx. 12 x 18 meter hydraulically pre-tensioned lengths was bleached by UV radiation, and the dirt-repellent Teflon coating keeps it permanently white. Against a bright blue sky, this is undoubtedly the most appropriate color for the new technological landmark in Germany’s Southwest.