Project description
The Marieholm Tunnel is part of the large-scale Marieholm Connection Project in Gothenburg, Sweden. The project improves the infrastructure between Tingstad and Marieholm through the construction of both a bridge and an immersed tunnel.
The approximately 500-metre-long tunnel consists of three immersed tunnel elements and a cut-and-cover section. Construction began in 2014, and the tunnel was built as a sustainable solution to accommodate increasing traffic volumes in the region.
MH Poly became involved as an engineering partner within the consortium in 2013 and played a key role in both the technical preparation and execution of the immersion operations.
Approach and engineering
During the tender phase, MH Poly actively contributed to the development and assessment of various immersion methods. Following the award of the contract, the focus shifted to the design of all temporary structures required for a safe and controlled immersion process.
The engineering took complex factors into account, including water depth, currents, positioning and installation tolerances during immersion.
Project activities
MH Poly carried out the following activities:
- Preparation of a design memorandum containing all design principles, assumptions and boundary conditions
- Design of immersion-related structures through to detailed construction design, including:
- Immersion pontoon
- Access shaft
- Bulkheads
- Ballast tanks
- Temporary supports
- Underflow system
- Anchor points and winches
- Closure joint structure for a watertight connection
- Development of 2D and 3D visualisations of the immersion process
- Technical supervision and support during the immersion of the tunnel elements
