The new train line “Citybanan” was under construction in the heart of Stockholm: a 6-kilometer-long tunnel that passes under the city center and will help improve the current traffic situation. The Söderström Tunnel, as part of the Citybanan project, includes an approx. 300-meter-long submerged tunnel in the Söderström and also crosses a tributary of the Mälaren Sea and runs between two rock tunnels.
A cross-section of the box-shaped tunnel – measuring 20 x 9 m – reveals a two-track main tunnel beside a service tunnel.
Three approx. 100-meter-long tunnel elements, consisting of concrete enclosures with steel reinforcement, were shipped into place, sunk and connected. Then underwater, the BBV L19 tendons, which run through two sections, were built into the floor, ceiling and walls of the tunnels and then be prestressed and injected with mortar.
Awarding authority: Banverket Östra Regionen
Client: JV Söderström tunnels HB (Züblin/Pihl), Stockholm
Design: COWI A/S, Denmark