Blow by blow: Steel pipe pushing under Zurich's tramways

In the middle of Zurich, on Uetlibergstrasse, a section had to be connected to the sewer network using trenchless construction methods as part of a new sewer construction project. Along the route in the middle of the roadway and under tramway tracks, several power blocks, an existing sewer and a gas pipeline had to be crossed underneath. As there was no possibility of setting up an abutment for press fitting, the only option was steel pipe pushing. The GRUNDORAM Goliath solved the task aplomb within just one and a half weeks.

For the connection of the sewer, steel protection pipes with a diameter of no less than 2,000 mm were to be installed under the Laubegg tram loop. Because of the fixed duct heights, tunnelling required a high degree of dimensional accuracy. To ensure this, the GRUNDORAM Goliath was precisely aligned on a launch pad. One after the other, the steel pipes were driven along the 18 m long section in the extremely clayey soil in just nine hours. Afterwards, the concrete sewer pipes could be pushed in and connected without any problems. At no point in time throughout the entire tunnelling operation did any other tram lines need to be closed down.