5 minutes - magazine 02 | 2024
Compact. Flexible. Strong.
There are over 25,000 bridges in the German railway network. Almost half of them are more than 100 years old. An extensive renovation program has been underway for several years now, during which around 900 bridges have already been renewed.
A Liebherr LR 11000 crawler crane from Wiesbauer recently replaced a 130-year-old steel bridge in Fridingen an der Donau in southern Germany with a solid new truss structure. Only thanks to its variably adjustable ballast frame V-Frame® was the crane able to compensate for the limited space on the construction site and carry out the lift on the banks of the Danube.
Space miracle: LR 11000 The overview shows the cramped conditions on the construction site on the banks of the Danube. Made up for by good positioning and the folding ballast frame V-Frame®.
This was the fifth large and heavy bridge structure that Wiesbauer has renewed for Deutsche Bahn and for which a 1,000-tonne class crawler crane was required. In 2020, after purchasing its first LR 11000, the company replaced a river crossing from the imperial era. Depending on the space available, these operations with Liebherr cranes were always more or less complex. However, the most recent job was the most challenging for both the planning team and the crane crew. A very limited construction site area and a new abutment drastically restricted the freedom of movement for the huge machine. In addition, at 440 tonnes gross weight, the heaviest and longest of the railway bridges installed to date was suspended from the craneʼs hook at a large radius.
Narrow point: In order to be able to swing past the new abutment with the 450 tonne suspended ballast, the radius over the folding frame had to be reduced.
“Without the highly flexible ballast frame, we wouldnʼt have been able to do the job here,” says Marco Wilhelm after the successful installation of the new flyover in the Danube valley. The graduate engineer is a project manager and authorised signatory at Wiesbauer GmbH & Co. KG, a major crane and heavy-duty specialist in Baden-Württemberg. As with the previous projects, he had also meticulously planned this bridge replacement in Fridingen. “Even accessing the construction site was problematic,” says Wilhelm. “The bottleneck here was the old railway subway, which was only 3.9 metres wide and through which we had to bring the entire crane equipment – up to 3.7 metres wide – to the construction site.”
The area directly on the riverbank was elaborately prepared in advance for the operation. Special foundations and a concrete slab provided sufficient stability under the crane pad. “With the crane and attached load, the subsoil had to bear a total weight of around 1,780 tonnes,” explains Marco Wilhelm. The extra-wide 2.4 metre crawler tracks ensured optimum distribution of the surface pressure.
Self propelled modular transporter: The new bridge construction was transported with two SPMT units from the pre-assembly site to the lifting position of the crane.
V-Frame® enables swivelling process
However, the fact that the radius of the derrick ballast could be adjusted hydraulically via the V-Frame® was crucial to the success of the project. For the necessary swivelling and turning movements to position the bridge over the river, one of the abutments was in the way of the suspended ballast after the load had been lifted at a radius of 32 metres. Thanks to the folding frame, crane driver Joachim Göckelmann was able to reduce the ballast radius effortlessly and at the same time reduce the radius of the load. The pallet, loaded with 450 tonnes, then swung past the concrete structure without any problems. Both radii were then enlarged again and the LR 11000 reached the required radius of 29 metres to lower the steel structure over the Danube.
Mission accomplished: The new bridge is in place – time for a group photo (from left to right): Marco Wilhelm, Philip Eberlein, Tim Lippa, Nancy Koch, Sylvio Hieronymus, Jochen Wiesbauer, Joachim Göckelmann, Mathias Frenz and Tim Moll
The installation of the 62 metre long Danube bridge – the new one weighs more than twice as much as its predecessor – went smoothly and after two hours the lifting means between the crane and load were released again. After the lift, Marco Wilhelm draws a positive conclusion about the job and the crawler crane: “For me, the LR 11000 from Liebherr is the perfect combination of compactness, flexibility and lifting capacities in the 1,000 tonne crawler crane class. Itʼs always a pleasure to plan and work with this crane.” The engineer can be pleased: The next railway bridge is due to hang on the hook of the LR 11000 as early as October.
This article was published in the UpLoad magazine 02 | 2024.
