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Development of Mittlerer Ring (B2R) - East Richard StraussTunnel, Effner Tunnel

The development of the Mittlerer Ring in the east of Munich is the second of three major tunnel projects, which were decided upon on the basis of a citizens' referendum dating from 1996, after the building of the Petuel Tunnel in the north. The project comprises the 1,495 m long Richard Strauss Tunnel with a connecting roughly 500 m long side tunnel including a link with the BAB A 94 Munich-Passau. The 102 m long Effner Tunnel was produced close by in the northern section. On account of the shallow overburden of roughly 1.50 m the tunnels were produced by the top cover construction method. On account of the extremely constricted space conditions the work on the surface took place in eight different main phases, most of which were further split up into various sub-phases. The main tunnel consists of two tubes with a clear height of approx. 4.80 m. The width of the two-lane tube with emergency footpaths at both sides amounts to roughly 11.80 m. A continuous central wall separates traffic in the east tube from the west one. In the deeper lying sections an approx. 80 cm thick base slab protects the carriageways from groundwater, which is to be encountered at 8 to 10 m below ground level. Emergency call recesses in the outer wall set at gaps of 120 m apart per tube, a total of 9 emergency exits, slotted gutters integrated on the edge of the carriageway as well as extinguishing water lines, ventilation fans, traffic guidance system, radio equipment and lighting cater for the latest level of safety technology. After completing the bored pile wall and the covers the excavation of the tunnel commenced under the covering. Step by step, floors with drainage, central walls, partition walls, emergency footpaths and the carriageway structure were completed. Four operating Stations and three pump works are foreseen for operating the two tunnels. Metro Line 4 passes beneath the tunnel at the Böhmerwaldplatz. As a result this area was produced using cut-and-cover. The length of individual construction sections was reduced on account of the Metro's uplift in groundwater. The project's high light is the connecting of the side tunnel with the main tunnel. In this way the BAB A 94 Munich-Passau is linked with the Mittlerer Ring without crossroads. The southern part of the side tunnel dips below the main one prior to connecting up with the northern part. At this point the structure is approx. 14 m deep and forms the heart of the complex hub together with a centrally located operations centre with 3 levels and a pump works. The excavation activities in the tertiary formation were accompanied by water drainage through deep wells.


  • Country: Germany
  • Region: Bavaria
  • Tunnel utilization: Traffic
  • Type of utilization: Road Tunnel
  • Client: Regional Capital of Munich, Baureferat Ingenieurbau
  • Consulting Engineer: Dorsch Consult, ISP Scholz/IB Schönenberg (design); ISP Scholz, Köhler+ Seitz/Cordes +Partner (execution)
  • Contractor: Max Bögl Bauunternehmung GmbH & Co. KG, Ed Züblin AG, Züblin Spezialbau GmbH
  • Main construction method: Open
  • Type of excavation: Top cover construction method
  • No. of tubes: 2
  • Tunnel total length: 3.1 km (total length of section), 2 x 1,495 m (two-lane tunnel), 2 x 500 m (single-lane side tunnel), 2 x 102 m (two-lane tunnel)
  • Contract Volume: 105 mill. Euro net. (roughwork)
  • Construction start/end: July 2003 till December 2008