Zurich - a new terminal under the main train station

The various public transportation systems are concentrated in and around Zurich's Main Train Station. It is the most important transit point in Switzerland. The railway authority predicts a significant increase in traffic over the next few years. The existing tracks of Zurich's Main Train Station will not be able to cope with this growth. That is why, the realization of the train station Loewenstrasse is impatiently awaited in 2013. The placement of the new transit station 16 m below the Main Station results in the best solution for assuring short transfer connections. This will require tunnelling under existing tracks as well as two other subsurface obstacles: a river and a future highway tunnel. The Loewenstrasse station is designed with four tracks comprising of two 420 m long median platforms. The intermediate floor, above the new platform level, contains the transit ways for the rail passengers. These are meant to be used commercially and will result in attractive shopping opportunities. The operation of the Main Train Station must not be disturbed during any of the construction activities. Furthermore, none of the tracks may be blocked after 2004, since all 20 tracks within the hall will be needed for scheduled rail traffic. This necessitates the use of the top-down construction method plus the early construction of particular portions of the future station. For this first construction phase, the site will dispose of two surface tracks and a platform with a width of 9 m. Logistics will be rendered more difficult due to the island configuration of the site, which can only be accessed across the tracks. The foundations of the medial supports pose an unusual challenge. These carry the top slab upon which the above-ground tracks and platforms are positioned. These involve solid steel struts connected to the top of diaphragm piles. Due to the high load impacts and the need for very precise placement, special solutions were developed to assure proper load transfer of the diaphragm elements by the solid steel struts. In the middle section of the station, the surface tracks cross over a river. Subsequent construction work will be performed out of the river bed under the bridges so as not to impede train operations. The dried-out excavation will allow the drilling of micro piles as a temporary foundation for the railroad bridges. The lateral diaphragm walls can be trenched using a special compact excavator. The top-down construction must therefore be executed under ground. (A). "Reprinted with permission from Elsevier". For the covering abstract see ITRD E124500.