Press Release

Large-scale Project for Bauer Spezialtiefbau at Luise-Kiesselbach-Platz in Munich.

Munich – The Bavarian capital Munich is resolving a difficult traffic situation in the southwest of the city with an extensive tunnel construction project. Due to a massively intertwined intersection of major approach roads, the daily commuter traffic is severely affected on a regular basis by long traffic jams. Through a programme of strategic civil engineering works due for completion in 2015, traffic will be redirected below grade into tunnels and allowed to flow more smoothly as a result of cleverly designed access roads.

The civil engineering works at Mittlerer Ring Southwest and Luise-Kiesselbach-Platz include the construction of a six to eight-lane road tunnel with an overall length of 2,400 m and a further 400 m long open-cut section. The road tunnel links up directly with the A 95 and A 96 federal motorways. BAUER Spezialtiefbau GmbH of Schrobenhausen was awarded all major foundation construction works by the main contractor, a Joint Venture between W&F Ingenieurbau AG, Berger Bau and Bauer Spezialtiefbau.

The tunnels are constructed by the environmentally friendly top-down cut-and-cover technique and at the Luise-Kiesselbach-Platz in open-cut construction. The walls of the tunnel consist of secant bored pile retaining walls. In addition to the actual tunnel, ancillary structures are also erected, such as traffic-control and safety facilities, operating stations and emergency exits.  These require up to 16 m deep excavations.

The foundation works carried out by Bauer Spezialtiefbau include 9,400 secant piles with diameters of 880, 1200 and 1500 mm totalling 87,000 linear metres for secant pile walling, as well as 24,000 m² of king-pile retaining wall, 800 bored piles of 1500 mm diameter as central supports and finally 8,000 linear metres of tie-back anchorages. Further works include jet grouting and the installation of steel props.

The bored piles are installed by rotary drilling rigs of the BG series manufactured by BAUER Maschinen GmbH. The speccific types deployed are the BG 20, BG 28 and BG 40.  At times, up to six drilling rigs are operating concurrently on site. The geological conditions prevailing across the entire site are the familiar soil conditions of the Munich gravel plains. These comprise an upper layer of quaternary gravels that vary in thickness between 12 and 18 metres and are underlain by tertiary silts and sands.

The overall contract value for the Joint Venture amounts to 183 Million Euro, with the Bauer share totalling 36 Million Euro. The foundation construction works by Bauer commenced in August 2009 and are due for completion in the middle of 2013.