The BERNARD Gruppe was asked by Swietelsky AG to monitor the vibrations occurring during the demolition of the old viaduct arches “Viaduktbögen” and insertion of the newly built arches.

In the course of the construction of the Karwendelbahn railway line, which connects the provincial capital Innsbruck with the Olympic resort Seefeld in Tyrol via a spectacular single-track route through the Karwendel Mountains, the Viaduktbögen were built in 1910 between the Innrain and Egger-Lienz-Strasse in the Innsbruck district of Wilten.

Eight of the 35 viaduct arches now need to be replaced due to permanent rail traffic. First, the new reinforced concrete bridge elements were erected on movable foundations next to the existing line. The next step was to interrupt rail traffic on the line in order to remove the existing arches.

When demolition work began, the BERNARD Gruppe monitored the vibrations for ÖBB Infrastruktur AG caused by the demolition work and the subsequent launching of the new bridge into the correct position using hydraulic presses. For this purpose, vibration measurements were carried out both in the area of the abutments before and after the viaducts to be renewed and at the foundations of the neighboring buildings. As soon as the vibrations caused by the construction activities exceed a limit value defined in the standard, an alarm will be sent automatically by the measuring system. This precaution is a common practice at construction sites in sensitive environments to protect buildings from potential damage.

George Scheiring, BERNARD Gruppe