The major infrastructure project for the replacement of the Rader High Bridge is yet another example of the extensive in-house capabilities of Hünnebeck by BrandSafway. The new 1,500-metre-long motorway bridge over the Kiel Canal is a steel composite structure employing an ambitious construction method that intricately combines off-site prefabrication with on-site operations. Steelwork and concrete construction occur side by side, ensuring rapid progress while keeping traffic disruptions to an absolute minimum.
Under the technical leadership of Implenia Construction GmbH, Hünnebeck’s role in this exceptional project involves the design and supply of efficient standard and customised formwork solutions for all structural elements constructed in situ, including foundations, abutments, pylon shafts, pier heads, and parapets.
The vast southern canal pier is currently attracting particular attention. At a height of over 40 metres, a cantilevered formwork carriage is being used to construct the V-shaped steel-composite hammerhead. This specially designed carriage was supplied by Strukturas, a globally active specialist and long-standing partner of Hünnebeck. Once complete, the hammerhead will cantilever 44 metres to either side of the pier axis and will be cast monolithically with the composite deck – something that has never been achieved anywhere on this scale. It enables the 220-metre main span across the canal to be constructed. While the V-shaped segments are being formed simultaneously on both the canal and land sides, the steel box girder is advanced using the incremental launching method. Ultimately, the two systems will be joined seamlessly on site.
Self-Climbing Formwork: Safe, Efficient, and Economical
The 44-metre-high pier shaft was constructed in advance using Hünnebeck’s SCF 60 self-climbing formwork system – an enhanced model of the long-established SCF system, presented at this year’s bauma. Given the uniform climbing geometry, the height involved and the wind loads resulting from the site’s proximity to the water, this high-capacity, hydraulically self-climbing system was the logical choice. It offers a completely enclosed and safe working environment, even at significant heights.
To form the geometrically complex pier head, Hünnebeck’s engineers developed three-dimensionally curved special formwork boxes and a customised support solution using suspended brackets to safely accommodate the concrete loads. The northern canal pier is currently being constructed applying the same method.
Tailored Solution for Highly Variable Pier Geometries
The bridge’s thirteen so-called “standard piers” – ranging in height from 21 to 41 metres – are now nearing completion. Due to their highly complex geometries, these too required a carefully adapted formwork strategy and an exceptionally flexible climbing system. Each cycle differed so significantly from the last that a conventional, adjustable formwork solution would not have been feasible.
Hünnebeck engineers developed a safe and efficient solution: a crane-operated climbing system based on the CS 240 climbing scaffold, equipped with retractable formwork units made up of H 20 timber beam formwork and customised formwork elements. “Because of the dramatically changing dimensions, the team simply replaced the entire formwork set for each stage,” explains the supervising Hünnebeck engineer. “It was a straightforward and reliable solution that ensured rapid construction progress.”
Standard Systems for Foundations and Abutments
The bridge’s foundations and abutments were formed using tried-and-tested standard systems, including MANTO and RASTO panel formwork as well as the ES 24 timber beam formwork system – complemented by customised solutions for specific detail areas.
Progress on Schedule
“We are proud to be playing such a central role in this major project and to be demonstrating the full breadth of our bridge construction expertise,” says the lead Hünnebeck project manager from the infrastructure division. After more than two years on site, the construction management team at Implenia praised Hünnebeck’s contribution to the project: “All formwork systems met our expectations. They are efficient, easy to handle, and offer a high level of site safety. Everything fit!”
Provided work continues smoothly, the first section of the new bridge is expected to be completed next year and will handle traffic from the existing Rader High Bridge (originally opened in 1972).
