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The Gotthard Pass has been a vital route across the Alps for centuries, connecting Italy and the Roman Empire with much of the rest of Europe. Its importance is demonstrated by the tunnels that have been constructed through the mountain below the pass to reduce travel times, three of which have held world records:
When opened in 1882 with a length of 15 km, the Gotthard Tunnel, a railway tunnel, was the longest tunnel in the world.
Opened in 2016 to form a much quicker rail connection through the Alps, the Gotthard Base Tunnel (at the level of the base of the mountain and therefore saving the need for trains to follow a slow, winding path up and down the mountain) is currently the world's longest tunnel with a length of 57 km.
From its opening in 1980 until 2000, the Gotthard Road Tunnel, with a length of 16.9 km, was the world's longest road tunnel, carrying Switzerland’s A2 motorway through the mountain.
A 9-kilometre stretch of the A2 motorway at the south end of the Gotthard Road Tunnel, part of the so-called Gotthard South Ramp, is currently undergoing a complete renovation – including the four viaducts along its length. The decision was made to replace all the expansion joints along the route with mageba finger-type expansion joints – mostly TENSA®FINGER type RSFD cantilever finger joints where the movements are limited to 450 mm or less, and a TENSA®FINGER type GF sliding finger joint at one location where movements of up to 1000 mm must be accommodated. The choice of these expansion joint solutions was very sensible, considering in particular the high longitudinal slope (up to 5% gradient) of the viaducts as they climb towards the tunnel, since the high longitudinal forces exerted by accelerating and braking trucks and cars can be efficiently transferred to the main bridge structure by the longitudinally oriented fingers of these joint types. This has been well demonstrated – on another Alpine pass, the Brenner Pass in Austria – by the TENSA®FINGER type GF sliding finger joints of the Europa Bridge, which have been in service on a similar highway viaduct with very heavy truck traffic since 2003.
It is good to see the world-beating tunnels through this mountain getting the approach viaducts they deserve, properly maintained and renovated – and to see the viaducts getting the sensibly selected, high-quality components they deserve to help them fulfil their equally important role in getting traffic to and from the tunnels!
Project engineer: Project Partners Ltd Consulting Engineers, Lugano
Contractor: CSC Webuild Group, Lugano