The project
The Marieholm tunnel will be positioned on the riverbed in three separate sections. Each element is approximately 100 metres long, 32 metres wide, 10 metres high and weighs about 25,000 tonnes. The tunnel elements are made in a dry dock, which will then fill with water and the element will start to float. Subsequently, each tunnel section is pulled into place and immersed. The first part was positioned in December 2017, the second will follow in March 2018 and the last part will be immersed by August 2018.
Our approach
While the dry dock is being filled, it is important that the tunnel element is kept in position. To this end, Hydrauvision has provided (on a rental basis) 4 manual winches of 10 tonnes each. Hydrauvision has also supplied cables, slings and D-connections in order to allow the tunnel element to be moved. 4 pontoons are used during the immersion process. The immersion process will be carried out with Hydrauvision cable sheaves with 3 and 4 discs hanging from the pontoons. The positioning of the pontoon that holds the tunnel element in place is done by using 8 winches of 10 tonnes. Hydrauvision has provided (on a rental basis) a total of 16 winches that are powered by 8 power packs.
