The rehabilitation of the Starzenbach culvert in the centre of the municipality of Feldafing, located on the shores of Lake Starnberg, was unavoidable. Gaping cracks, erosion, voids and misalignment of components had created a risk of collapse and restricted water flow. The channel structure was originally built using the cut-and-cover method with a cover depth of up to 4 m. At present, the culvert is even being driven over.

The load-bearing capacity of the underground egg-shaped channel structure, which is approximately 1.8 m high and 1.2 m wide, was restored over a length of 260 m and overlaid with CRC. Initially, the damaged, 1.0 m long unreinforced concrete sections were repaired using shotcrete in accordance with DIN EN 14487 and carbon reinforcement grids. The overlay, consisting of 2 layers of carbon reinforcement grids, was applied under conditions of very limited working space and permanent dewatering. Partially infiltrating groundwater and leachate was temporarily sealed by resin injection until full completion of the CRC overlay. In addition, the inspection shafts, which provided access to the culvert, and the adjacent inlet structure were refurbished with a bridge superstructure and also structurally reinforced with shotcrete.