At the beginning, we were given an exciting project presentation by engineer Franz Urban, who explained the Stadtstraße project to us, from project development and the UVP through to implementation. Stadtstraße is an important infrastructure project that is intended to promote the development of the rapidly growing 22nd district and relieve the existing roads. The construction of the 2x2-lane Stadtstraße requires the construction of two tunnels, one in the area of Emichgasse and the other at Hausfeldstraße.

The tunnels will be constructed using the cut-and-cover method on the one hand and the cover method on the other. SOB piles with a DSV gusset seal are used to enclose the excavation pit. In the cut-and-cover method, excavation is carried out under water using long arm excavators. Once the micropiles have been sunk and anchor plates attached, the underwater concrete base can be constructed. The excavation pit can then be drained and the actual tunnel construction can begin. Alternatively, sections of the tunnels are constructed using the cover method to protect residents from noise and emissions. In this case, the micropiles are drilled through the ground and then the floor slab is constructed using the jet grouting method, thus grouting the ground between the micropiles. The cover is constructed directly on the ground and then poured over. Only then is the excavation and construction of the actual tunnel carried out.

As part of the Stadtstraße project, the world's largest research project for in-situ tests in special foundation engineering, initiated by the City of Vienna in collaboration with the Institute of Geotechnics at Vienna University of Technology, was also carried out, in which around 100 typical special foundation engineering elements were examined. Thanks to the knowledge gained about the load-bearing behavior, it was possible to manufacture the elements of special foundation engineering more economically. In addition, great added value was created for future construction projects in typical Viennese soil.

The presentation was followed by a tour of the Hausfeldstraße tunnel. On site, we were able to see the SOB piles with DSV spiral waterproofing, the underwater concrete base and the production of the DSV floor slab. The project and construction managers told us more details about the production on site and answered the students' questions.

The excursion ended with snacks and a discussion of open questions.

A big thank you to the client, represented by engineer Franz Urban, engineer Stefan Wegschaider, engineer Markus Haslwanter and Evelyn Schönangerer, who provided the catering, as well as the consortium, represented by engineer Dr. Klaus Meinhard, engineer Dominik Rabl and Roland Schelch, who all made this exciting excursion possible and accompanied us on it.