A9 Pyhrn highway, completion of Tunnelkette Klaus, Austria
As part of a construction project completing improvements to the A9 Pyhrn highway, the construction of four bridge structures with lengths from 83m to 278m and heights from ca. 25m to 50m is foreseen. The bridges are located in an 8-km-long section of the highway known as “Tunnelkette Klaus”, which connects Klaus and St. Pankraz-Hinterstoder in Upper Austria. Two of the bridges, one crossing the Steyr valley and the other crossing the Pertlgraben valley, will be constructed using a free cantilever method, while the other two bridges crossing Rettenbach and Teichl are planned as arch bridge structures.
The geotechnical conditions at the project locations are characterized topographically by deeply-cut river valleys, with the valley flanks almost vertically inclined. The subsoil conditions vary locally and are characterized by carbonate material, conglomerates, terrace gravels and loosely bedded fluvial sediments.
INSITU Geotechnics was tasked by the ASFINAG (Austrian highway authority) with providing geotechnical consultation and construction supervision services related to the construction of the bridge structures.
ASFINAG, Wien / ASFINAG Bau Management GmbH, Bruck/Mur