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The German island of Fehmarn in the Baltic Sea, between Germany’s mainland and Denmark, has for decades played an important role in the transportation connectivity between mainland Europe and Scandinavia. One of the most important routes involves crossing from the German mainland to the island by means of the Fehmarn Sound Bridge, and onward from the island by ferry across the Fehmarn Belt to Denmark. But due to the importance of this transport corridor, new tunnels are to be constructed by the end of this decade – the Fehmarn Sound Tunnel connecting the island to the German mainland, and the Fehmarn Belt Fixed Link connecting it to Denmark. The Fehmarn Sound Bridge will not be replaced by the shorter of these two new tunnels, but complemented by it, and must therefore be maintained in good condition for the foreseeable future.
The Fehmarn Sound Bridge was opened in 1963, carrying road and railway traffic across the first stretch of Baltic Sea water to the island. It has an overall length of 963 m, and a main span of 248 m which is bridged by one of the world’s largest network arch structures. In the course of regular inspections, it was established that the two bearings on one of the bridge’s piers, of the pot type, required to be replaced. It was decided to replace them with modern spherical bearings, which are very well suited to the marine environment, and mageba’s RESTON®SPHERICAL bearings were selected for use. But it was not only the quality and reliability of the RESTON®SPHERICAL bearing that was relevant in the choice of bearing solution, but also the ability of the supplier to reliably carry out the replacement work in the very challenging circumstances.
The bearings were designed to carry loads of 25,000 kN and to accommodate movements of 500 mm, and each was fabricated with a weight of 2000 kg – a significant weight in any circumstances but a particular challenge in this particular case. Since it was not permitted to cause any disruption to the road or railway traffic on the bridge, the work had to be carried out from the water below. Mageba’s German team developed a method involving the use of a telescopic forklift operating off a barge on the water, and hydraulic jacks to temporarily lift the bridge superstructure. Following design and fabrication of the bearings, and delivery to site, they were then installed successfully and on schedule by mageba’s local team of installation experts.
Such challenges are nothing new for mageba, and our teams around the world are always happy to figure out the optimal way of installing our products considering all of a project’s needs – including minimising costs, impacts on the main structure and traffic disruption (both immediately and from a long-term perspective), while always ensuring the quality of the installation which is important in ensuring good long-term performance.
This project had similarities to another mageba project in Germany, reported on in our newsletter of June 2020, relating to the replacement of bearings of the Hochheim Railway Bridge over the River Main near Frankfurt. So when the engineers at Germany’s national railway company need to replace bearings in hard-to-reach places on their river and sea crossings, they evidently know who to get in touch with!
Bridge designers: Gutehoffnungshütte Sterkrade AG, Gerd Lohmer
Owner: Deutsche Bahn AG