Project Overview
The Weser Tunnel is an approximately 1-kilometre-long immersed tunnel beneath the River Weser. It consists of six immersed tunnel elements and a cut-and-cover section. The elements range from 113 to 125 metres in length and are approximately 23 metres wide.
The tunnel elements are constructed in a dry dock in Bremerhaven. Once completed, they are floated out and transported approximately 60 kilometres by water to a temporary mooring location. After installation of all required systems, the elements are carefully immersed and positioned at their final location.
Due to variations in the tunnel cross-section—including ventilation niches, emergency lanes, and technical service areas—the project demands a high level of precision in both engineering and execution.
Our Role: Engineering of Temporary Immersion Structures
In collaboration with Immontec B.V., MH Poly was responsible for the complete engineering of all temporary structures required for the immersion process. From concept development through detailed design, safety, constructability, and precision were central to every stage of the project.
The engineering focused on controlling forces, currents, and positioning throughout transport and immersion operations.
Scope of Engineering
Underflow System
Developed to control water flow beneath the tunnel elements during immersion, ensuring stability and controlled installation.
Temporary Supports
Engineered to provide temporary structural support for the tunnel elements during installation.
Deck Layout
Optimised deck arrangement to facilitate efficient transport and safe immersion operations.
Ballast System
Designed to ensure controlled and uniform ballasting of the tunnel elements during immersion.
Realignment System
Provides highly accurate positioning of the tunnel elements at their final location.
Mooring System
Designed to securely moor and stabilise the tunnel elements at the temporary holding location prior to immersion.
Anchor and Winch System
Engineered to maintain the precise position of the tunnel elements during immersion despite external forces such as currents and wind.
