Bus station canopy in Kronenburg: A structure of steel, Lexan and courage
An undulating, seemingly paper-light bus station canopy that shelters passengers from the elements while adding an iconic accent to the stony architecture of Arnhem’s Kronenburg district. The new canopy was designed by Designer Ruud-Jan Kokke, technically elaborated by Iv, and is being produced by Moors Constructie Bergharen (MCB). Together, they are building a structure out of steel, Lexan and a little courage.
The Kronenburg district is undergoing a revamp. What was once built in the realm of concrete, angled corners, and hard edges is now being given a more playful look. “If you look closely at this district, you will see bevelled 45-degree angles everywhere,” says Designer Ruud-Jan Kokke, who submitted the winning design for the bus station canopy to the municipality of Arnhem. “They can be seen in the buildings, the roads and even the footbridge from the shopping centre to the adjacent district. These 45-degree angles served as my source of inspiration. I wanted the structure’s roof to be positioned at a 45-degree angle to the platform. But, of course, it had to be high enough to allow buses to pass underneath, yet low enough to provide shelter above the platforms. The combination of these requirements led to the undulating shape the design now enjoys.”
There will be two similar canopies, a large one and a small one. The undulating designs with the blue openings look fantastic but are anything but simple. How do you make something like this a reality? The municipality of Arnhem announced the contest. MCB worked with Iv on the winning plan. “Not all dared to take it on,” says Wouter Visser, commercial manager at Iv. “The majority of the pre-selected companies quickly dropped out, mainly due to the challenges concerning wind load. The design is such that it can easily become a wind catcher. But we dared to take it on, because we have often been involved in very complex projects.” The same applies to Barry Moors, owner of MCB. “We love a challenge. And this, the new bus canopy in Kronenburg is going to be such a leading project in the region. So that’s something you want to be part of, right?”
Curved, undulating, concave and convex – the challenge of the bus station canopies lies in the multitude of shapes. “This design combines everything,” says Structural Engineer Marius Molenaar of Iv, the man in charge of aligning it all – a task that caused him many headaches. There are no standards or Eurocodes for this shape. And so Marius had to make many calculations. “The technical design we have now delivered is tenable,” he says. “But it was definitely an intensive task. Everything had to be exact: the vibrations, the stiffness, the foundation…” Wouter concludes with a wink: “With his many years of experience, Marius can handle this. And besides, this bus station canopy is so fantastic that even the wind won’t know what to do with it.”
According to Project Leader Lennard van Geel of Iv, the ribs under the roof of the bus station canopy are a story in themselves. “They wind under the undulating roof and are positioned perpendicular to the surface above,” he says. “The transfers from concave to convex are so tricky, but they also give the canopy its unique character. That’s why we did everything possible to keep them in the technical design, just as the designer intended.”
The designer also had some preferences that Iv could not go along with. “We always try to follow the designer’s vision, of course,” Lennard continues his story, “however, some aesthetic desires were not structurally feasible.” He refers, for example, to the ends of the ribs, which the designer wanted to end in a wafer-thin point. “A nice idea, but then we can no longer weld them.” We also advised and suggested adjustments at a structural level. “According to Marius’ calculations, placing the canopy on concrete blocks was insufficient. We therefore advised driving piles into the ground to provide the required stiffness.” Fortunately, Designer Ruud-Jan was always willing to collaborate in such adjustments. “As a result, his idea became feasible.”
The bus station canopy is currently in production at MCB. Barry: “We will produce everything – from the foundations to the roof. And most of it will be made by hand. Ten people are currently working full-time on the canopies. I think we will eventually reach 3000 man-hours.” What is the most challenging part to make? “The ribs,” he says without hesitation. “They are curved in several places, must flow smoothly and connect perpendicularly to the roof. That is real precision work.” The blue areas of clear Lexan with film also have a challenging shape. “It is an unprecedentedly complex project in almost all respects, but fortunately, we have a lot of experience with station canopies and complicated steel projects. It also helps that we have worked with this designer and Iv before. Together we will make it a success.” The bus station canopy will be installed in Kronenburg at the end of this summer. Wouter concludes, laughing: “Perfect, just before the storm season gets underway.”
Jaco, managing director Consult, would be delighted to discuss this with you! Get in touch via +31 88 943 3100 or send a message.
