The segment production for the Brenner Base Tunnel at the Isocell plant in Hinterrigger has been completed. The TBM Flavia is steadily approaching its destination.
Around 26,000 rings and more than 38,000 base segments for the main tunnels and the exploratory tunnel of the BBT construction lot Mauls 2-3 were manufactured in the factory near Brixen. Production is now continuing for the Franzensfeste-Waidbruck section, the southern approach to what will be the longest railway tunnel in the world.
On December 13, 2017, segment production started at the Isocell plant in Hinterrigger. A prime example of how excavated material can be reused efficiently and sustainably, in this case for the production of precast concrete parts that form the inner shell of the tunnel tubes of the Brenner Base Tunnel. Around 30% of the excavated material generated in the Mauls 2-3 construction lot was used for segment production.
It was a large-scale production, as Alessandro Marottoli, project manager for the “H61 Mauls 2-3” construction lot, explains: “Between September 13, 2017 and September 19, 2024 – the day on which the segment production for the BBT ended in Hinterrigger – 16,285 base segments were produced for the main tunnels as well as 9,456 rings and 21,762 base segments for the exploratory tunnel . ”
Each ring consists of seven segments and one base segment in the main tunnel or two base segments in the exploratory tunnel. A total of 218,247 segments were produced for the Brenner Base Tunnel in Hinterrigger. A segment for the main tunnel weighs an average of 9 tons, a segment for the exploratory tunnel about half that.
From Hinterrigger to the BBT
The two main tunnels and the exploratory tunnel were and are being excavated on the Mauls construction site by three tunnel boring machines (TBMs): Serena, Flavia and Virginia. The TBMs not only work their way through the mountain, they also install the segments that form the inner shell of the tunnel.
These tons and tons of concrete are not delivered to the construction site by truck, but are transported by rail to the tunnel boring machines, which then install the inner shell of the tunnel. Each train transports two rings, i.e. 14 segments. This avoids traffic congestion on the SS12 road and at the same time implements an environmentally friendly solution.
The TBM Serena started in May 2018 and reached the national border below the Brenner Pass on November 24, 2021 after 14 km in the exploratory tunnel. The TBM Virginia started exactly one year after Serena, in May 2019, also covered 14 km and reached the state border on March 28, 2023.
Virginia’s twin sister Flavia set out in April 2019 and is still on the way, but she already has her goal in sight: she still has around 1.5 kilometers to go to her destination, the state border. Production in the segment plant in Hinterrigger is not standing still, however: precast concrete parts are still being manufactured for the Franzensfeste-Waidbruck section, the heart of the southern approach to the Brenner Base Tunnel.
With the reuse of around a third of the excavated material, Hinterrigger is a concrete and efficient example of a successful circular economy. Further proof that the Brenner Base Tunnel will be a concrete alternative to road traffic in the future and that the natural habitats in the project area will also be protected during the construction phase.
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