Prefabricated reinforcement cages and diaphragm walls

Västlänken is a new double-tracked railway tunnel, with the purpose to develop 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 some of which pass through mountain.

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

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

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

CLIENT: Trafikverket
ENGINEER: Centerlöf & Holmberg / COWI
PHASE: Design and execution

Risk Assessment
3rd Party Control & Optimization
Advanced Modeling
Design Optimization
Methods & Value Engineering
4D/5D Assembly Planning
Production Data & Drawings