The Gotthard road tunnel has aged and requires extensive renovation. To ensure that this vital road connection remains open during the refurbishment, the Swiss Federal Roads Office (ASTRA) is constructing a second tunnel – a ten-year mega-project for a safe journey through one of the most important Alpine routes.
AUTHOR: EUGENIO SAPIA, FEDERAL ROADS OFFICE (ASTRA)
Since its opening in September 1980, the Gotthard road tunnel has been a vital transport artery for the economy, commerce, and tourism in Switzerland and across Europe. To ensure its long-term functionality and safety, the Swiss Federal Roads Office (ASTRA) must renovate the tunnel by 2035 at the latest. This requires a full closure of the entire tunnel for several years. A new second tunnel will allow this crucial route to remain open throughout the renovation. The Swiss electorate approved the construction of this second tunnel on February 28, 2016.
Technical details of the new tunnel tube
The new tunnel tube is being built 70 meters east of the existing one and is also 16.9 kilometers long. The already existing service and infrastructure tunnel runs between the two tubes. Two tunnel boring machines drive the construction forward from Göschenen in the north and Airolo in the south, creating a circular tunnel profile with a diameter of 12.3 meters. The roadway in the new tube, including emergency lanes, is eight meters wide. Beneath the roadway, conduits for tunnel operations, communication, and a new high-voltage power line from Swissgrid are installed. Above the roadway, exhaust air ducts are located. Additionally, five new underground ventilation centers will be built to regulate the air in both tubes. The planning and execution of the project focus not only on increasing safety but also on sustainability and environmental responsibility. Of the total 7.4 million tons of excavated material, 7.2 million tons will be reused. Nearly half of the material will be used to create new shallow water zones in Lake Uri near Flüelen. A quarter will be used for terrain modeling and the covering of the highway in Airolo. The remaining quarter will be processed into aggregates for concrete, which will be used for the inner lining of the new tunnel tube and the renovation of the old one.
Schedule and Costs
The total cost for the construction of the second Gotthard road tunnel amounts to approximately 2.14 billion Swiss francs. Construction of the second tube began in spring 2020 with initial preparatory work. The project is expected to take around ten years. Currently, work is focused on the final preparations for the main excavation using the tunnel boring machine. This includes excavating the launch tunnel and setting up the infrastructure for material management. In August, excavation work will begin on the two geological fault zones, Mesozoic and Guspis, each approximately 300 meters long. Since the tunnel boring machine is unsuitable for these sections, they will be excavated using conventional methods. For this purpose, two access tunnels, four and five kilometers long, respectively, have been built to reach the fault zones since 2022.
When will the new tunnel be open for traffic?
Starting in February 2025, the two tunnel boring machines will begin their journey through the massive rock formations of the Gotthard Massif. The plan is for the two tunneling teams to meet in the middle of the Gotthard in the summer of 2027 to celebrate the breakthrough. The first vehicles are expected to drive through the new tunnel in 2030. Afterward, ASTRA will renovate the first tunnel tube over a period of three years. Once the renovation is completed, both tubes will be available to traffic in 2033. Traffic will continue to flow through the Gotthard with no capacity increase but in two separate tubes—an improvement for safety.