PORR to build two tunnels for Stuttgart 21
Deutsche Bahn awarded the first tunnelling contracts on 30 July 2011 for Stuttgart 21 to a joint venture lead by the PORR Group. After considering all competitive factors that joint venture was chosen out of four building consortiums bid for the European-wide tender. With tender packages PFA 1.2. and PFA 1.6a (Filder Tunnel and Ober-/Untertürkheim Tunnels) now having been awarded around a quarter of the tenders for this railway project have been completed. Deutsche Bahn claims to still be within the planned budget.
As part of Lot 1a "Filder Tunnel" (PFA 1.2) the joint venture consisting of PORR and the companies Oestu-Stettin Leoben, Hinteregger Salzburg and Swietelsky Tunnelbau will build the roughly 9.5 km long Filder Tunnel as well as branching tunnels to Ober- and Untertürhkeim and connect to the southern end of the new central station. The other Lot 1b "Ober-/Untertürkheim Tunnels" also awarded to the JV consists of a roughly 6 km long tunnel which leads from Stuttgart Central Station in the direction of Ober- and Untertürkheim. Both tunnels have two parallel single-track tubes which are connected laterally at regular intervalls. Construction is scheduled to begin in August 2011 with completion expected in February 2018.
Lot 1a "Filder Tunnel" includes amongst others 18.7 km of trenchless tunnels including a branching structure, 19 connecting structures with lengths varying between 17 and 24 m, and a roughly 250 m long underground emergency access gallery and a roughly 255 m long cut-and-cover tunnel. The single-track tunnels will be machine driven. They lie to roughly 40% withing gypsum keuper and to roughly 60% in marly sandstone layers.
Lot 1b "Ober-/Untertürkheim Tunnels" include roughly 12.3 km of trenchless tunnels, 13 connecting structures with lengths varying between 2 and 173 m, an access shaft and gallery as well as a starter pit. Along the trenchless tunnels, two crossing structures, one of wich passes underneath the Neckar river, and a branching tunnel must also be built. The tunnels will be driven using the shotcreting method. Roughly 80% of the length lies within unleached gypsum keuper and the remainder to roughly equal parts within unleached keuper and quarternary.