Innovative hybrids: Glulam-concrete combination for the S37 expressway

Innovations are an important driver to be fit for the future in all areas. Together with STRABAG, ASFINAG and the HASSLACHER Group implemented such an innovation along the S37 Klagenfurt Expressway. One of the bridge structures to be rehabilitated along this road was designed and executed as a wood-concrete composite bridge.

What is wood-concrete composite?

Wood-concrete composite combines the positive features of both materials and is used to build superstructures in which the concrete manages the compressive and the wooden parts the tensile loads. In this case, the shear connection was made using rectangular notches and a few screws to protect against lifting. For shear connection, one could also use screws, glued-in steel elements or glued in hardware with prefabricated concrete elements. In this bridge superstructure, the top concrete slab protects the wood underneath from the weather. In this bridge superstructure, the top concrete slab protects the wood underneath from the weather.

Carbon storage capability of wood, beam design and sensors & monitoring

Thanks to a total of 82 m³ of glulam that is installed in the bridge, some 70 tons of carbon could be removed from the atmosphere and stored in the wooden elements. The entire wooden superstructure was equipped with a network of sensors that continuously monitor and document wood moisture content and climatic conditions. As a so-called composite element, the glulam beam itself is glued together from 15 individual glulam elements. It is 21 m long, 1,000 mm thick and approx. 3.9 m wide.