Going Up: ThyssenKrupp's Test Tower in Rottweil Is a Twisty Engineering Wonder

CC BY 2.0. Lloyd Alter/ Tower in June, 2017

Werner Sobek puts a negligee on a concrete pipe and it's not just for looks.

ThyssenKrupp Elevator recently launched their new MULTI elevator at their new testing facility in Rottweil, Germany. It’s not yet finished and I thought that I would wait until it was complete before covering it, but I seem to be alone in that, and it is an interesting story in its own right.

Rottweil is a long way from ThyssenKrupp’s headquarters in Essen, but Essen is smack in the middle of some major air traffic routes, and Rottweil is actually close to 10,000 university students studying engineering. It is a beautiful historic tourist attraction knows as the “town of towers” and I was surprised that they opened their arms for this new one on their skyline, but according to ThyssenKrupp, they are greeting it warmly, thanks to the jobs and economic development it provides. The mayor says that “the investment represents a long-term boost to Rottweil as a business center in the technology and innovation corridor extending from Stuttgart to Zurich.” It also will be a tourist attraction in its own right, with the tallest observation deck in Germany.

rendering of completed tower

© ThyssenKrupp/ rendering of completed tower

Right now the 246 meter (807 foot) tower is unfinished exposed concrete, but it will soon be covered in 170,000 square feet of Polytetrafluoroethylene (PTFE) treated fiberglass. Co-architect Werner Sobek jokes that, “After we designed a concrete pipe we had to throw a negligee over it to make it look good.”

Werner Sobek

Lloyd Alter/ Werner Sobek speaking to the Council on Tall Buildings and Urban Habitat/CC BY 2.0

But in fact it is a lot more than that. Sobek believes that everyone has an obligation to use less stuff.

Every German citizen is responsible for 490 tons of material in the world; the average is 110 ten tons of material per person. It does not work. There is no chance to dream of tomorrow when we running out of materials, even sand. Lightweight is a need to survive.

The cladding shades the tower which reduces thermal stresses in the concrete, reducing the amount of reinforcing needed.

vortex strakes

Wikipedia/CC BY 2.0

It also causes “vortex shedding”, as is often done on chimneys with metal strakes or fins, “to deliberately introduce turbulence, so the load is less variable and resonant load frequencies have negligible amplitudes.”

tuned mass damper

© ThyssenKrupp/ Tuned mass damper

The amount of concrete and reinforcing is reduced even further by the 240 tonne tuned mass damper that acts as a pendulum, and can be used to offset the motions of the tower. This is used often in tall modern slender buildings, but this one has a twist to it; ThyssenKrupp can actually use the damper to induce vibration and swaying into the tower, to test elevators under conditions similar to what they find in real buildings. The building is designed to deflect up to three inches.

“That means we can simulate all kinds of building heights and weather conditions,” says Andreas Schierenbeck, CEO of ThyssenKrupp Elevator. “And of course, this also goes for buildings that haven’t even been built yet, so we can carry out initial tests on our elevators well before construction work is completed.”
elevator shaft

Lloyd Alter/ Don't look down/CC BY 2.0

The working side of the tower has 12 shafts, including one giant shaft for hauling equipment up and down, a special wide shaft for the MULTI testing, and one for visitors to the observation deck and conference centre.

view from deck

Lloyd Alter/ Observation deck/CC BY 2.0

The view from the top is lovely. If you go to a conference there, make sure that the air conditioning is working. There is also a great theatre in the base under the green roof. Sobek and Helmut Jahn have done a great job of turning what could be a strictly utilitarian facility into one that is interesting and educational.

rendering of tower

© ThyssenKrupp/ rendering of completed tower

Lloyd Alter was a guest of ThyssenKrupp, who paid for his transportation and accommodation in Rottweil.