Improvement of foundation soil behavior for Gründerzeit buildings in Austria using polyurethane resin injections

The second half of the XIX century signed a period of comprehensive industrial and cultural development in Austria known as Gründerzeit. The architecture was deeply influenced during this epoch by the construction of large masonry buildings, called “Gründerzeit Häuser”, which represent today the historical heritage of the most important Austrian cities. Due to the increasing demand for apartments in the centre of these cities, renovations and adaptations of existing buildings has been performed in the last decades. These modifications of the buildings structure represent, besides a business opportunity for the real estate economy, an increase/variation of the load for the foundations. Hence, the renovation and preservation of this architectural heritage often involve the improvement of the foundation soil. This article illustrates how the soil treatment with expanding polyurethane resin represents an efficient solution to achieve this goal. A case study of a historic building in the city of Salzburg is presented.