After the challenging months of the COVID lockdown, the Research Department for Foundation Engineering, Soil and Rock Mechanics of the Institute of Geotechnical Engineering received the invitation to visit one of the most exciting current projects of Keller Grundbau. As part of this excursion on 01.07.2020, we were able to observe the compensatory injection for the abutment of the Reichsbrücke on site and learn more about the project.

Our employees were welcomed by DI Jakob Pelzl (Keller Grundbau) and DI Martin Pelzl (3P Geotechnik), who guided us through the creation of the project and its execution. Near the DC Tower in Vienna, right next to the northeastern abutment of the Reichsbrücke in Vienna's 22nd district, a 150 m high residential tower is being built with the so-called "Danube Flats". Without appropriate measures, its construction would, cause subsidence in the subsoil, which would also have an impact on the heavily trafficked road and subway bridge. In order to counteract these, preventive uplift injections (soilfrac process) were carried out below the existing abutment of the Reich Bridge at the time of the excursion. By means of a measuring system installed at the abutment by means of hose scales, additional injections compensating for the settlements can then be introduced during the construction of the residential tower.

After this theoretical presentation of the project, we were guided through the construction site by J. Pelzl. During our visit, one of the last preventive injections was observed. This was carried out within the injection excavation pit built for this purpose (bored piles with a DSV gusset infill). Finally, we got a detailed presentation of the Soilfrac process of the company Keller Grundbau by Mr. J. Pelzl.

A big, heartfelt thank you to Mr. Jakob Pelzl and Martin Pelzl for the opportunity to get to know this great construction project better and to witness a moment of execution!