After a long wait, the Karlsruher Sport-Club (KSC) is getting a new, structurally unique stadium – the perfect accompaniment for a return to the first tier of the German Bundesliga.
The Wildparkstadion in the Hardtwald – built in 1955 – originally had 55,000 seats and was, at that time, one of the most modern sports facilities in Germany. Over the course of time, the building was extended and modernized several times. As of 2006, the venue – which was previously also used for athletics – was to be converted into a pure football stadium in the coming years. In the same season, the KSC was promoted to the first Bundesliga, but the promised upgrade did not go ahead. Two seasons later, the club was relegated. In 2014, KSC and the city of Karlsruhe announced that they wanted to build a completely new stadium with around 35,000 seats instead of a renovation. Construction work on the new stadium was begun in November 2018, which features a unique structural design using 3D modeling to develop the offset, Y-shaped supports – just as KSC make their return to the first tier of the Bundesliga.
Challenging Construction Conditions
ASSMANN BERATEN + PLANEN AG are the structural designer for the project and have had a major impact on the final design. “A stadium can largely be seen as an engineering structure, because the structural design determines the final geometry,” says project manager Manfred Klawonn. In the case of the new Wildparkstadion, this is even more demanding than usual: the old sports facility is gradually being dismantled during the stadium’s operation, while the new one is being built simultaneously so that at least 15,000 seats are available to the spectators at any time. Accordingly, many construction requirements must be considered in the structure. For optimal planning, the engineers therefore generated a 3D model in Allplan Engineering.
© ASSMANN BERATEN + PLANEN
3D modeling has been used to plan the stadium from the early stages. “Because a stadium is very demanding geometrically, the 3D model helps enormously here,” says Manfred Klawonn. “In the grandstand area, many details are resolved, which would be difficult to recognize in 2D.” The modeling in Allplan has been set up so that IFC models can be exchanged with the other project members. In addition, structural and architectural properties were assigned to the 3D components, which greatly facilitated the design work. For example, the data could be used to create formwork and reinforcement plans or mass calculations, while other designers could build on the exchanged information and use it in their work.
Complex Construction with Unusual Supports
In addition to the parallel construction process, the construction itself was no small challenge. In particular, the outer roof supports proved to be an extremely complex installation. Unlike classic stadium construction, these are not aligned to the grandstand beams, but are offset by half the distance. This results in an extraordinary, Y-shaped geometry. The difficulty this poses was that the geometry at the non-symmetrical intersection points needed to be adjusted so that an architecturally harmonious image is created. “The easy-to-use 3D modeler from Allplan was a very big help here, as in the rest of the stadium,” Manfred Klawonn says. Thanks to Allplan, the engineers were able to see that the originally planned geometry of the Y-columns caused the upper support points to deviate considerably from each other in the Z-direction, when viewed from the inside of the stadium. “In the Allplan model, we were finally able to develop solutions for the architects that were feasible in terms of design.”
Since the assembly of this unique structure is not an easy task, the construction was first started with the “simple” supports in the straight area, before one dared to venture to the more complicated ones. The successful assembly of the latter ultimately proved that the details developed with Allplan fit reliably. If everything else goes just as smoothly, the KSC 2022 team can count on its new first-class stadium – just in time for the Bundesliga football season.