Västlänken – Göteborg Centralstation

Prefabricated reinforcement cages and diaphragm walls

Västlänken is a new double-tracked railway tunnel, constructed to increase the capacity of the railway as well as create more space for travelers and decrease travel-time to Gothenburg. The subarea “Göteborg Centralstation” includes a bridge over the E6 in the east, a new underground station and about 2 kilometers connecting railway tunnel of which some pass through a mountain.

NCC has contracted CN3 in two different parts of the project.

For area 4, which contains 600 meters of cut- and cover tunnel (designed by Centerlöf & Holmberg), CN3 developed a system of prefabricated reinforcement cages in close cooperation with the contractor and designers. Furthermore, CN3 developed several fixtures for quick and effective mass production of the reinforcement cages, which were produced on the construction site. A detailed 3D model ensured a shared understanding of every single component, its assembly order as well as an effective process of execution.

CN3 also developed reinforcement cages for the reinforcement of the diaphragm walls, which encircles the whole station area (area 5-7) – this was done in close cooperation with the contractor, suppliers, and designers. The station area was designed by COWI. The reinforcement cages are 24 meters tall and with a weight of up to 39 tons. They consist of three or six smaller cages which are welded together at the construction site. Together with the design team and the contractor, CN3 thoroughly prepared the layout of the cages to ensure that the European standards were met as well as ensuring that the concrete could be properly poured and vibrated. Lifting and placement of these massive reinforcement cages entailed several logistic and safety challenges. To overcome them, CN3 closely collaborated with the designer to ensure rigidity and stability during lifting by integrating the as-built 3D reinforcement model with the stability analysis software. Several simulations were done, and multiple data packages were exchanged between the software until the right configuration of additional stiffeners and lifting points was found.