The second tube of the Gotthard Road Tunnel – An engineering structure of extraordinary scale for the future

Abstract The Gotthard Road Tunnel, which is around 17 km long, is one of the longest road tunnels in the world and was opened in 1980. After almost 50 years of intensive use, a comprehensive refurbishment is necessary for safety and structural reasons. To enhance safety and maintain traffic flow during the refurbishment work, a second tube is being constructed parallel to the existing tunnel. This article describes the Gotthard Road Tunnel Second Tube project and focuses on selected key challenges during construction. These include the demanding conventional tunnelling in the portal areas, the long mechanised tunnelling through variable rock formations, and the penetration of the two 300‐metre‐long Kakiritic fault zones North and South, which are characterised by highly compressive rock.