Bridge foundation new Sotra Bridge

The project at the New Sotra Bridge involves advanced work both underwater and on land, with high demands for precision and safety. During this period, there has been a particular focus on the foundation of the bridge foundations in the sea, where both the land and marine contractors have worked closely together to carry out a number of complex tasks.

About the project

Two of the bridge foundations for the new Sotra Bridge are placed out at sea. At the start of the project, the land contractor had already blasted out and cleaned two excavations using land-based machinery. The marine contractor then took over the work, which involved a number of specialised diving tasks. First, the excavation pits were thoroughly cleaned with compressed air to ensure a clean and stable foundation for further construction. Then, 20 manhole rings were cast with a tolerance of +/- 5 mm, which demands significant accuracy and quality of the work. Additionally, two lean concrete slabs, each around 110 cubic metres, were cast to provide extra stability to the structure.

Another central aspect of the project has been the planning and execution of heavy lifts, carried out in collaboration with Tronds Marine Service AS and CCB. This included the installation of two caissons weighing 220 tonnes and two reinforcement cages weighing 50 tonnes, where the tolerance requirement was set to +/- 35 mm. Around the caissons, two sealing pours were then cast, each about 50 cubic metres, to protect and strengthen the bridge foundation. Finally, two internal casts were carried out inside the caissons, each about 300 cubic metres, with a tolerance of +/- 50 mm.

The work has demanded great precision and good collaboration across disciplines, and the tasks carried out have been crucial for the progress and quality of the project. The successful coordination between land and marine contractors has been central to ensuring a solid and safe foundation for the new bridge.