Five construction sites are currently in operation, three in Austria and two in Italy. If you simply click on a construction lot, it will take you directly to its brief description, the overview plan and the photo gallery.
The excavation progress of the individual tunnel structures in the various construction lots is updated regularly. Work progress is shown on a graph.
The ongoing works on the construction lot H21 "Sill gorge" - scheduled to run from August 2020 to the end of 2024 - will provide the link between the Brenner Base Tunnel and the central station in Innsbruck.
A stretch of approx. 600 metres and several different works will be built within this lot. River engineering works will be also carried out. The estimated construction costs for this stretch are 59.5 million Euro and Porr Bau GmbH Kematen will be in charge of the works.
Compared to other construction sites in Austria, whose works are mostly underground, the works in this construction lot are largely performed above ground.
The "Sill Gorge" stretch basically includes the following construction works: a supporting wall (200 metres long), a cut-and-cover tunnel (130 metres long), 2 railway bridges over the Sill, the northern portal of the BBT, as well as a subsequent tunnel stretch (120-130 metres long). In spite of the relatively short stretch, this construction lot comprises very complex construction activities.
The stretch leads through the narrow and thus logistically challenging Sill Gorge. The area is characterized by several infrastructural facilities such as the A12 Inntal highway, the A13 Brenner highway, the "Tirol Panorama" museum, the "Untere Sill" power plant of the municipal undertakings "Innsbrucker Kommunalbetriebe", as well as the existing ÖBB railway line with the Berg Isel tunnel.
The narrow brook gorge - which is mostly in its natural state - is an important recreational area for the people of Innsbruck and can be reached via several hiking trails. In order to keep ensuring access to the Sill Gorge during the construction period, an alternative hiking trail was built. In addition, for easier orientation, a system showing the various trails was installed and interesting spots near the construction site marked with information boards.
At the construction site, the new 42-metre-long access bridge over the Sill has already been built, the demolition of the old bridge has been completed, and the scarp stabilisation at the Viller Berg for the construction of the northern portal of the BBT was successfully carried out, as well as the scarp stabilisation for the construction of the retaining wall for the new line. River engineering works are well underway as well.
Excavation works for the western main tube southwards started at the end of October. Drill-and-blast excavation at the future northern portal started in November 2021.
CURRENT CONSTRUCTION WORK
From north to south, the planned works for this construction section include:
• the "Silltal" tunnel through the Bergisel mountain (approx. 130 metres long), partly constructed using the cut-and-cover method and with a pile foundation
• two railway bridges (each 50 metres long) over the Sill for the east and west tracks - one will be built as an open steel trellis bridge and the other one will be enclosed
• northern portal of the BBT
• stressed ribbon bridge over the Sill (55 metres with long) as part of the hiking trail network of the Sill Gorge
An important part of the construction lot is the restoration of upstream fish passage in the Sill. The AGA weir, located at the entrance to the Sill gorge with a drop height of approx. 8 metres, will be therefore removed and replaced by a roughly 350-m long fish ladder with a low-lying meandering channel. Within these river engineering works, the river course will be moved about 8 metres eastwards in order to have enough space for the supporting wall and the two-track line on the western side. Flood-proof and long-lasting embankments will be constructed.
At the end of the works, renaturation measures will bring about an upgrade and improvement of the popular recreational area.
|Main tunnel East|
|Main tunnel West (completed)|
Works on this construction lot began in mid-January 2022 with the set-up of the construction site.
The H41 "Sill Gorge-Pfons" construction lot is located in the northern area of the BBT between Tulfes in the east, Innsbruck in the north and Pfons in the south. The Ahrental access tunnel, which has already been completed in the E41 "Ahrental" prospection lot, is used for the main excavation.
This construction lot represents the continuation of the construction works carried out in the H33 "Tulfes-Pfons" preliminary lot. The tender for the H41 construction lot was awarded on 17/11/2021 to the bidding consortium H41 Sill Gorge-Pfons comprising the companies Implenia Österreich GmbH, Implenia Schweiz AG, Webuild S.p.A, csc costruzioni sa. The total bid amount offered by the bidding consortium is 651 million euro.
In total, approx. 22.5 km of main tunnel tubes and 38 cross passages with a total length of approx. 2.3 km will be excavated by the summer of 2028 in this construction lot. In order to ensure the fastest progress possible in the whole project, the "Sill Gorge-Pfons" project area was extended southwards by three kilometres of main tunnel tubes, where it will connect to the future construction lot H53 "Pfons-Brenner".
The works basically include the following:
The following optional work was also tendered:
Since the end of September 2021, all work in this construction lot has been completed.
This construction lot was awarded to the Strabag SE / Webuild S.p.A. (ex Salini-Impregilo) bidding consortium in Summer of 2014.
construction time: 2014 - 2021
section of the tunnel to be driven: 43.3 km
contactual amount: € 491 million
It consists of several structures:
The emergency tunnel was being driven parallel to the existing Innsbruck railway bypass. It is 9.7 km long and the excavation cross-section is 35 m². The drill-and-blast excavation work on this tunnel started from three points at the same time: from Tulfes westwards, from the Ampass access tunnel eastwards and again westwards. The emergency tunnel was completed in Summer of 2017.
The main tubes have been excavated by blasting according to the so-called New Austrian Tunnel Construction Method. The ceremonial first volley was set off on 19/03/2015 in the presence of EU Commissar Violeta Bulc and the Ministers of Transportation of the 7 Alpine countries (Austria, Italy, Germany, Switzerland, France, Liechtenstein and Slovenia. This stretch includes about 6 km of main tunnels with an excavated cross-section of about 70 m2 .
Construction has been under way since summer of 2015 on the two connecting tunnels between the Brenner Base Tunnel and the existing Innsbruck bypass. The connecting tunnels were also excavated by blasting, with a cross-section of about 115 m². Excavation work was completed in Spring of 2017.
The construction lot Tulfes-Pfons included the construction of the stretch of exploratory tunnel between the Ahrental junction point and the town of Steinach am Brenner. The gripper TBM, 200 m long, started work on September 26th, 2015 and excavated about 16.7 km southwards, completing its work on July 6th, 2019. Since the breakthrough, the construction lot has been connected to the Pfons-Brenner lot.
Restoration of the collapse "Iris"
This collapse is a cavity that formed in a fault zone during the excavation of the exploratory tunnel. This had to be backfilled by means of cement mortar injections from an injection tunnel in order to rule out any effects on the overall tunnel system. As part of these repair works, the main tunnel tubes in the fault zone were excavated from July 2020 to May 2021 in advance by blasting using an auxiliary drivage from the exploratory tunnel. This allows to reduce interferences when the next TBM arrives.
Works on this construction lot began in February 2022 with the set-up of the construction site area at Wolf. On 4 May 2022, the ground-breaking ceremony took place in the costruction lot.
The H52 - Hochstegen construction lot, located within the area of the Steinach am Brenner township, is a part of the previous lot H51 - Pfons-Brenner which has now been restructured. This stretch of the project was divided in several construction lots, in order to guarantee the fastest and most efficient continuation of the works with an aim to driving the entire project forward quickly. The Wolf lateral access tunnel is used as a main access and supply route.
The Hochstegen lot is located in a fault zone characterized by extremely complex geological conditions. The stretch is about 500 m long, with mainly water-bearing, carbonatic rock layers, meaning that the tunnel excavation in this stretch is particularly challenging. The contract for the works in the H52 - Hochstegen construction lot was awarded to Swietelsky Tunnelbau GmbH & Co KG on December 15th, 2021. The bid was around 102 million Euro and construction time is expected to be 23 months.
The core of the project is the excavation of the exploratory tunnel southwards through the geologically challenging stretch known as "Hochstegen", where excavation will take place with the protection of preliminary sealing and stabilisation injections.
The works basically include:
|Connecting side tunnels|
The tender for construction lot H53 Pfons-Brenner was issued on January 19th, 2022.
The construction lot "Periadriatic seam", carried out between October 2011 and the summer of 2015, comprised the excavation of 3.7 km of the main tubes and 1.5 km of the exploratory tunnel. The crossing of the Periadriatic fault line, one of the biggest geological fault lines in the Alps, was accomplished without a hitch.
In May 2016 the biggest construction lot of the Brenner Base Tunnel project, known as "Mules 2-3", with a contract volume of 993 mln euro, was awarded to the bidding consortium Astaldi S.p.A., Ghella S.p.A., Oberosler Cav Pietro S.r.l. (until June 2018), Cogeis S.p.A. and PAC S.p.A. Works started in September 2016.
This lot reaches from the construction lot "Isarco river underpass" up to the State border with Austria. In the course of a 7-year construction period, 39,8 km of the main tubes and 14.8 km of the exploratory tunnel will be excavated, including the emergency stop in Trens and its access tunnel as well as the bypasses which connect the main tubes every 333 m. A total of approximately 65 kilometers of tunnels will be excavated.
Once this construction lot is finished, all excavation activities in the Italian project area will be complete.
On 24/11/2021, the tunnel boring machine in the exploratory tunnel successfully reached its destination at the state border, after 14 kilometres and 3.5 years of excavation northwards. For the first time, the excavation for the tunnel tubes in the BBT project reached the Brenner Pass, which represents a historic milestone.
Emergency stop in Trens
The blasting work to connect the Mules access tunnel with the future emergency stop in Trens started in December 2016. The excavation works on the 3,8 km long tunnel with a cross-section of approximately 80 m2 were finished by June 2020. Works are currently underway for the construction of the emergency stop itself.
The drift of the main tubes northwards resumed on the 13th of march 2017. The excavation for the first 0.8 km was carried out by drill and blast, followed by two tunnel boring machines heading north in spring 2019.
The first blast of the southwards drift took place on the 3rd of april 2017. The southern end of the construction lot was reached in October 2020.
|Access tunnel to the emergency stop (completed)|
|Exploratory tunnel (completed)|
|Safety and logistics tunnels|
The southernmost construction lot of the Brenner Base Tunnel, worth 301 million Euro, was awarded to the bidding consortium Isarco s.c.a.r.l. composed of Webuild S.p.A. (formerlySalini-Impregilo), Strabag AG, Strabag S.p.A., Consorzio Integra and Collini Lavori S.p.A. bidding consortium in October of 2014. This lot links the Brenner Base Tunnel with the existing Brenner line and the railway station in Fortezza.
Since in this section the tunnel tubes are just a few meters below the surface, a portion of the activities pertaining to this construction lot is be carried out building artificial tunnels. Furthermore, as loose fluvioglacial materials and the groundwater layer will be crossed, it is be necessary to adopt specific ground consolidation procedures including ground freezing and the so-called jet grouting.
As part of the preparatory work, by the end of 2016 the state road SS12 was re-routed and two bridges, an underpass under the Brenner railway line and a direct highway access were built. This means that both supply and removal transports can take place while avoiding traffic through the surrounding towns.
The current phase (main construction phase) provided for the construction of four shafts, 20-25 metres deep, to access the rock faces of the Isarco River Underpass. Furthermore, it includes the excavation - already completed - of the access tunnel on the right side of the valley using drill and blast, and of part of the main tubes and the connecting tunnels, to be built with the drill and blast method. The excavation of all four main tubes under the Isarco rover has been completed. With the breakthrough on May 19th, the excavation of the main tubes in the Isarco river underpass construction lot is complete. The ""H61 Mules 2-3" and ""H71 Isarco River Underpass" construction lots, which began separately, are now connected.
|Main tunnels (completed)|
|Connecting side tunnels|
|Access tunnel (completed)|