Reported in January 2022
Brenner Base Tunnel largest construction lots has gotten off the ground. This involves work on Lot H41 Gola del Sill-Pfons. The tender, worth €651m, was on November 2021 awarded to a joint venture comprising Webuild and its Swiss subsidiary CSC Costruzioni, which have a 50% stake, as well as the Swiss Implenia, also with 50% share. A European public limited company BBT is the project’s client. The latter was created for railway tunnel development between Austria and Italy under the Alps.
Lot H41 involves a part of the mega project in Austria and comprises of the building of the railway between Gola del Sill, close to Innsbruck, south and the town of Pfons. Additionally, it will lead to construction of a 22.5km of main tunnel tubes as well as 38 cross passages all with a length totaling to around 2.3km. Lot H41 will be accessed mostly from the current Ahrental lateral access tunnel and work is set to be completed in summer 2028.
Brenner Base Tunnel’s environmental sustainability.
Two TBMS set to carry on the excavation have a diameter of over 10m. The project design aims at environmental sustainability during development and measures include the logistics of the work sites modelled to lower travel times for the transport of materials as well as noise and dust reduction. Other lots still to be constructed at the Brenner Base Tunnel include Lot H71 Isarco River Underpass and Lot H61 Mules 2-3. Webuild has already completed constructing the 43.3km Lot 33 Tulfes-Pfons. The construction specialists are also working on the railway from Fortezza to Ponte Gardena in the southern side of the tunnel.
Upon completion, the Brenner Base Tunnel will become world’s longest railway tunnel at 64km. It will be an important part of the Scandinavian-Mediterranean Corridor of the Trans-European Transport Network (TEN-T) which will link Helsinki in Finland with La Valletta in Malta. It also plays a crucial part in linking Italy with Austria with a high-speed/high-capacity railway.
Brenner Base Tunnel (BBT) is a twin-tube (each 8.1 m wide, running 40 to 70 m apart from one another), straight, flat underground railway tunnel that is being constructed through the base of the Eastern Alps beneath the Brenner Pass to connect Innsbruck, the capital of Austria’s western state of Tyrol and Fortezza, a commune in South Tyrol, northern Italy.
The main tunnel, 55-kilometres long, begins in the Innsbruck suburb of Wilten and penetrates the Alps reaching a height of about 840 meters above sea level. The tunnel will be up to 1,720 meters below the surface at its deepest point in the gneiss section stretching south from the Italian border.
In the case of unforeseen events, the tunnel has three emergency stopping areas located at Trens (in Freienfeld), St. Jodok, and towards the northern end of the tunnel, where the trains can halt underground in the tunnel. The two tubes are linked every 333 meters by connecting side tunnels that can be used in the case of emergency as escape routes. ETCS Level 2 will be installed to provide train control.
On its north end, the BBT has two entrances that will go underground a few kilometers before the junction with the main tunnels. One of the two entrances leads from the main Innsbruck station under Bergisel and the other connects with the Innsbruck bypass.
About two-thirds of the entire tunnel construction will be undertaken through tunnel boring machines and the remaining (one-third) through cyclical and conventional methods e.g. explosives, mechanical diggers with hydraulic hammers, and drilling equipment.
Upon completion, the BBT is expected to become the longest continuous railroad tunnel in the world. It will have the capacity to withstand a weight of 400 trains (222 goods trains and 42 passenger trains in the base tunnel) and it will allow trains to cross the Alps much faster. The goods trains will run at a speed of 160km/h, and the freight trains at 250 km/h, reducing the travel time between the two regions from 2 hours currently to 50 minutes roughly.
Brenner Base Tunnel (BBT) project timeline
In July, Austria and Italy signed a memorandum of understanding to support the Brenner Base Tunnel (BBT) for shifting the traffic from road to rail.
In the summer of the same year, work started on a pilot tunnel to run along the line of the future tunnel and to be used for removing water and spoil during the major BBT construction phase.
The project was submitted for authorization in the spring of 2008.
In October the southern construction lot of the Brenner Base Tunnel was awarded to the Isarco consortium composed of Webuild (formerly Salini Impregilo), Strabag AG, Strabag S.p.A., Consorzio Integra, and Collini Lavori.
In May, the government approved and gave a go-ahead for the project.
In July, two Austrian segments were connected, and an unbroken 36 km long tunnel (approximately 65% of the tunnel’s entire BBT length) was formed.
In October, the project’s contractor, (Austro-Italian tunnel construction company Brenner Basis Tunnel (BBT SE), which is jointly owned by Austrian and Italian national rail infrastructure managers ÖBB and RFI), canceled a key contract to construct the 18km section known as Lot H51 between Pfons and the border at Brenner.
The contract also included around 9km of exploratory tunneling, an emergency access adit, and an underground emergency evacuation halt at St Jodok.
In March, infrastructure manager Italian Rail Network (RFI) awarded a 51:49 consortium of Webuild and Implenia a €1.07bn contract to design and build a 22km high-capacity railway between Fortezza and Ponte Gardena to increase capacity at the southern end of the Brenner Base Tunnel.
In the same month, Austrian-Italian BBT SE announced an average daily advance rate of 27.7m for “Virginia” with a best daily performance of 36.75m.
Webuild Group and its Swiss subsidiary CSC in a joint–venture with Swiss partner Implenia were awarded a close to US$ 737.5M contract to carry out works on Lot H41 Gola del Sill-Pfons on the Austrian side.
The scope of works includes the construction of the railway from Gola del Sill near the city of Innsbruck in the north to the town of Pfons located further south, the excavation of approximately 7.3km tunnel, and auxiliary tunnels using traditional methods, and excavation of another 16.5km using mechanized methods.
It also includes the lining of the walls of completed tunnels, an underground emergency stop at Innsbruck, access tunnels, exploratory tunnels, and parts of other secondary tunnels.
Late November 2021
A new milestone was reached in the Brenner Base Tunnel project following the excavation of more than 14 kilometers within a span of three and a half years. The 14km long tunnel was dug by the Tunnel Boring Machine (TBM) dubbed “Serena”.
Reportedly, Serena has a diameter of 6.85m, a length of nearly 300m, a weight of 1,500t, and a driving power of 2,800kW. The TBM dug through at least 4km of rock every year along the 14km route that ends at Brenner.
The milestone marks the end of work on the exploratory tunnel on the Italian side for the tunnel, and it brings the excavation to 82% on Lot Mules 2-3, the biggest construction lot of the project.
During the December Tunneling Festival conference, Alberto Paddeu, the BTC JV senior project engineer stated that all three tunnel boring machines (TBMs) deployed on the Mules 2-3 lot of the Brenner Base Tunnel (BBT) were progressing as scheduled. It was just few weeks after BTC JV had completed the section’s exploratory tunnel on time after three and a half years of tunneling. On the main west tunnel, completion was at 67%, excavating 9.5km, while the main east tunnel was 75% complete, at 10.5km. Paddeu revealed that the tunneling will be completed by the end of next year.