The Brenner Base Tunnel Sill Gorge construction lot, which includes the northern portal, is officially finished. 

The €60m contract was carried out by Porr and completed within the 52-month timeline. 

The stretch between the BBT’s northern end and the main station in Innsbruck is only 600m but it required some highly challenging engineering. This included inserting 60 anchor bolts, each 120m long, into the loose rock of the Viller Berg slopes at the northern portal. 

The works were also complicated above and below ground by the close proximity to the Sill River and the narrow gorge. The construction team also had to consider nearby infrastructure, including the A12 Inntal and A13 Brenner highways, the Tirol Panorama Museum, the Untere Sill power plant and the ÖBB rail line in the Bergisel tunnel. 

Project manager Keinprecht said the range of complex structures for the Sill Gorge lot was also challenging.

“We bored 170 pilings for the reinforced concrete retaining wall and built three 50m steel bridges, a 55m span bridge, a reinforced concrete pre-tunnel and the structure of the north portal itself. This goes to show the variety and complexity of the structures built as part of the lot,” he said.

The construction of the two bridges over the Sill was an important feat of engineering. At the same time, the recreational area in the Sill Gorge had to be preserved.

The revegetation to restore the construction site to its original state is under way. In spring next year the two stretches of a hiking loop that run through the gorge will be reopened. 

BBT SE’s board directors Martin Gradnitzer and Gilberto Cardola welcomed the completion of a further construction lot for what will be the world’s longest rail tunnel.

“The portals are clearly visible from the outside and these two north and south entrances to the BBT in Innsbruck and Fortezza will be the clear and unmistakable face of the Brenner Base Tunnel,” they said.