Restoring the foundation of a historic Viennese building using injections of expanding polyurethane resins
Restoring the foundation of a historic Viennese building using injections of expanding polyurethane resins
During the investigations conducted prior to the construction of an underground railway, it became clear that the foundations of a listed event building, erected in 1887, were severely deteriorated and no longer load-bearing. The timber pile foundations, which were originally positioned above the groundwater level, had completely rotted away, leaving only voids where the original foundations once existed. As a result, the load-bearing capacity could no longer be verified, and in some areas, the foundations were entirely hollow. Refurbishment was necessary, as constructing an underground railway beneath a building in this condition was impractical. The building had recently undergone renovation, including refurbishments in the basement, so a minimally invasive solution was required. The chosen soil improvement method involved using hand drills to reach the base of the foundation and injecting an expanding two-component urethane resin to fill the voids. The expanding material creates a friction-locked connection; although it is technically possible to lift the building, this is not desirable. After the injection, exploratory excavations were conducted at two test pits. It was found that the cavities had been successfully filled and that the injection material permeated through the loess clay in fine veins, demonstrating the effectiveness of the method. The treatment was then extended to the entire foundations of the building to restore the uniform distribution of the loads to the foundation soil.
Andrea Dominijanni; Matteo Gabassi; Fritz Kopf; Daniel Metz; A. Minardi; A. Pasquetto; Juergen Polansky
4th International Symposium on the Preservation of Monuments and Historic Sites
Restoration Engineering and Structural Interventions
https://doi.org/10.53243/tc301-2026-23