Bramschstraße Tunnel

The Bramschstraße Tunnel with its two 660 and 667.5 m long bores forms the core of the A 17 link with the inner-urban main traffic system of the City of Dresden. The chosen standard cross-section RQ 26t foresees 2 lanes per tube with a total width of 7.5 m as well as two 1 m wide emergency pathways. The tunnel was driven by mining means over a length of 475 m (northern drive) and 485 m (southern drive), the remaining 185 and 182 m were excavated by means of cut-and-cover. In addition, 85 and 105 m long groundwater troughs were created in front of the 2 tunnel portals. The roof overburden in the section created by trenchless means beneath a densely populated residential district varies from 5 to 13 m. The subsoil encountered around the tunnel is mainly a series of sedimentary rocks from the White Chalk Formation that is typical of the region comprising clay, silt, fine sand and lime in greatly varying compositions. The range of types of prevailing rock varies from weakly consolidated, fine layered marl extending to extremely solid, thick bedded limestone and sandstone. The Bramschstraße Tunnel was produced by the NATM. The excavation was undertaken in 3 sections - divided into crown, bench and floor using a tunnel excavator and gentle blasting to loosen the rock. On account of the shallow overburden, an advance support with 15 m long pipe umbrellas (altogether 13,000 m) was required to minimise the Settlements where the excavation passed beneath buildings. After the completion of the tunnelling work that took place simultaneously in both tubes, a pressure water tight, continuous membrane seal was installed as well as the 40-60 cm thick permanent lining consisting of reinforced wt concrete B 35 - divided up into 2 parts - base invert and vault. The tunnel sections produced by cut-and-cover and the trough sections were produced shielded by a construction pit that was built in advance comprising overlapping bored piles supported with shotcrete.

Country: Germany
Region: Saxony
Tunnel utilization: Traffic
Type of utilization: Road tunnel
Client: Regional Capital of Dresden, Office for Roads and Foundation Engineering
Consulting Engineer: Bung Beratende Ingenieure, Köhler und Seitz
Examination: Prof. Dr.-Ing. Dieter Kirschke
Contractor: Max Bögl Bauunternehmung GmbH & Co. KG
Main construction method: Trenchless
Type of excavation: Drill-and-blast
Lining: Concrete formwork
No. of tubes: 2
Tunnel total length: 2 tubes each 664 m long, 480 m of each produced by trenchless means
Cross-section: 100 m²
Contract Volume: € 21 million
Construction start/end: October 1999 to November 2002
Opening: November 2002