German contractor Bilfinger Berger has won contracts worth €230M (£193M) to build an underground railway in Berlin.
The two contracts are for the construction of a new underground rail line in the centre of the German capital and a link between the main station and the urban rail ring.
The new U5 line will link the Alexanderplatz with the main station and connects the Brandenburg Gate to the existing section of the U55. The project, on behalf of Berlin’s transportation authority, comprises construction of two tunnel tubes around 1.6km long as well as framework construction work for a track-switching system and two new stations.
The tunnel tubes will be built using the shield driving method requiring a tunnel boring machine. The Museum Island station will be built using an underground excavation technique while the cut and cover method will be used for the construction of the Unter den Linden station.
For the new stretch of the S21, which will connect the main station to Berlin’s ring line in a north-south direction, a joint venture under the leadership of Bilfinger Berger will construct, on behalf of Deutsche Bahn, a trough structure and several tunnel sections using both the open construction and cut and cover methods. One of the technical challenges of the project is that the sections near the main station will be built beneath girder grids and connected to existing excavation pits with the help of pressurized air.