New immersed tunnel planned for Gothenburg

Swedish firm Züblin Scandinavia, a subsidiary of 3669 Strabag, will head the joint venture partnership building the Marieholmstunnel project in Swedish city Gothenburg. This project will be for an immersed tunnel, which will pass under the River Göta älv. The design & build agreement also comprises the mechanical and electrical works and has a total contract value of around €170 million. The owner of the project is the Swedish road and railway authority 4672 Trafikverket, to which the tunnel is to be handed over in October 2020. Marieholmstunnel is a road tunnel featuring three lanes in either direction with a service tunnel in the centre and a design lifetime of 120 years. Züblin will construct three tunnel elements of 100 m in length each on site in a drydock and immerse them at their final location in a trench dredged into the river bed. On either side of the immersed tunnel section, cut & cover tunnels will be built in deep excavation pits continuing in ramp and trough sections. Special consideration will be given to the environment, such as the flora and fauna of the river Göta älv, during all phases of construction. The installation of all mechanical and electrical systems also forms part of the contract, which includes an option to operate and maintain the tunnel for five years after completion. The project will start just after the handover of Trafikverket’s Söderströmstunnel in Stockholm, a project of similar size and complexity executed by Züblin also as an immersed tunnel.