Tubes illuminated with LEDs are woven into an aluminum structure and characterize the unusual facade cladding of the WWK Arena in Augsburg. This design would not have been possible without PLEXIGLAS®.
“Wrap up the opponent.” This is the idea behind the intertwined structure of the stadium facade which resembles a pick-a-stick game. Designed by architect Titus Bernhard, the WWK Arena is the home of Bundesliga soccer team FC Augsburg, and also hosts the German national team thanks to its designation as a FIFA stadium. But it took over eight years for the design idea to become a real facade.
The new symbol of Augsburg
Originally, architects Titus Bernhard and Peter Kögl from B&K Stadionplanungsgesellschaft planned to create a stadium shell from Profilit glass in the club colors of red, green and white. The idea was deemed too expensive, however, and the stadium was initially left without a complex exterior facade.
When the insurance group WWK Versicherungsgruppe became the main sponsor of FC Augsburg before the 2015/16 season, new life was breathed into the project: “We like seeing our logo on a building with an eye-catching exterior,” says Jürgen Schrameier, CEO of WWK Versicherungsgruppe. “This is definitely the case for the WWK Arena and we would be delighted if the stadium became the new landmark of Augsburg.”
Combination of aluminum and light
As the building developer, WWK Versicherungsgruppe opted for a combination of round aluminum profiles totaling 36,000 meters in length and illuminated tubes totaling 1,300 meters in length as the facade cladding for FC Augsburg’s stadium. Over eight years after the stadium was officially opened, the facade was finally completed in September 2017.
Where visitors to the stadium were previously met with raw concrete, they are now greeted by an extraordinary architectural design: During the day, the exterior shell of the arena resembles a symmetrically woven nest, as the white light tubes are hardly noticeable when not illuminated. The facade therefore appears to have an almost homogeneous aluminum color. At night, however, the illuminated elements of the exterior cladding can be seen from miles away. “Light is an extremely striking and attractive design element,” explains stadium architect Titus Bernhard. “Light can almost literally turn architecture into a lighthouse.” The light tubes are not just a design element, however, but are also integrated as a static, load-bearing element in the facade. “From a construction standpoint, this installation was a huge challenge,” Bernhard explains.
This presented a huge challenge even for the light experts from the Atelier of Light at the Zumtobel Group, which implements architectural projects requiring specialized solutions for the European market leader in professional lighting systems: “We had never before created an eight-meter-long light tube which was also to be a static and constructive part of such a large facade, and I don’t think anyone else had either,” says Oliver Mosselman, who was responsible for the project at Zumtobel. The lighting technology required to create a continuous and homogeneous illumination of the tubes – even at the ends – also represented a complex task.
Homogeneous light distribution
"PLEXIGLAS® is the most advanced product for applications such as this."
- Oliver Mosselman
Project Manager in the Atelier of Light at the Zumtobel Group
The light designers at Zumtobel designed special “light tubes” up to eight meters in length and with circumferences of 20 centimeters – corresponding to the dimensions of the round aluminum profiles. Every light tube is constructed from a 6-mm-thick, glossy white-colored PLEXIGLAS® XT WN370 tube. The tubes are illuminated by IP67-RGB-LED light strips, which ensure even light distribution and are equipped with a light-scattering cover. “We chose PLEXIGLAS® for the simple reason that it is the most advanced product for applications such as this,” says lighting expert Mosselman. “PLEXIGLAS® helps us achieve an even and high level of luminance on the tube surface, thus enabling the tubes to stand out from the background.” This impression is further underlined as the stadium exterior is painted in an anthracite color.
Giant light tubes
The color and brightness of each tube can be controlled separately. When not illuminated, the tubes are simply glossy white in color; however, they can theoretically be illuminated in more than 16 million colors, including the colors of FC Augsburg, red, green and white. The energy-efficient LED illumination means that the yearly energy consumption is less than EUR 10,000, which is an important factor for the CO2-neutral stadium.
The lighting concept is further supplemented by 36 spotlights from Thorn, another member of the Zumtobel Group. These spotlights were installed on the existing masts around the stadium. The compact and powerful LED spotlights supplement the light tubes in illuminating the imposing stadium facade and provide the background lighting for the facade structure.
Implementation of the design turned into a mammoth project. “After all, it wasn’t just a single light tube, but 135 of them,” says Mosselman. “This is just another reason why we, along with our specialist installer Heinz Fritz GmbH, decided to use PLEXIGLAS®. We were convinced that only Röhm would be able to deliver the requisite amounts in the desired size and of consistently high quality.”
The experts for plastic processing at Heinz Fritz GmbH initially stored the individual tubes in a heated cabinet for 24 hours to allow the tension in the material to dissipate. The next step was to mill each tube along its entire length. The groove created during this process allowed the tubes to be slid onto an aluminum profile containing the LED strip, while the ends of the tube were closed off using lids also made of PLEXIGLAS® XT WN370.
“Despite the lids at the tube ends, the tubes have been constructed as an open system, which enables vapor pressure equalization and prevents the possible accumulation of condensation,” explains Mosselman. The LED light strips are therefore waterproof and the tubes themselves are unaffected by wind and weather: “PLEXIGLAS® is extremely weather-resistant,” says Mosselman. “This was our main criterion and is a very important reason why we selected this material.” After all, the unusual stadium facade in Augsburg is continuously subjected to sunlight, rain or even snow and must retain its spectacular appearance even after many years.
Incidentally, to add another level of sheen to the facade, 35 additional light tubes will be installed in summer 2018.