ABSTRACT

The 64 km long Brenner Base Tunnel (BBT) between Tulfes/Innsbruck, Austria, and Fortezza, Italy will become the world’s longest railway tunnel. The service life was set at 200 years for the tunnel structures with a regular annual inspection and maintenance of the inner linings. The design for a life-cycle time of more than 200 years considers the ultimate limit state with a probability of failure of Pf=10-7. The partial safety coefficients γR have been defined by FORM-analysis according to ɣC=1.6 (concrete) and ɣS=1.2 (reinforcing steel). A life-cycle time of more than 200 years and a high availability of the tunnel require concrete mixed with an eye to durability. Besides the concrete compressive strength, water penetration, permeability and gas porosity have also been tested on site. With an optimized concrete mixture, crack development due to shrinkage constraints as well as due to temperature development has been achieved.