Busan-Geoje Fixed Link

In South Korea, OTN took part in one of the largest infrastructure projects in the country’s history, an 8.2 kilometre motorway link between the city of Busan and the Geoje peninsula. Before the project, the trip from Busan to Geoje used to take three hours by car. The new link has cut approx. 40 minutes off this time. The project has therefore resulted in significant economic and social benefits.

Client:
Strukton Afzinktechnieken
Location:
Busan - Geoje
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IMG_9229 (Medium)

Project

The project consisted of two suspended bridges and an immersed tunnel. Strukton Afzinktechnieken was commissioned by Daewoo E&C to immerse the tunnel elements. OTN, as part of the immersion team, focused on the activities around the tunnel immersion. The immersed tunnel consists of 18 tunnel elements with a total length of 3,200 metres. The elements were manufactured in a graving dock, transported one after the other, and then immersed into a pre-profiled gravel bed using two catamaran pontoons and divers at a depth of 50 metres.

Due to the depth of the immersion location, the tunnel elements were immersed unmanned. If a technical problem had occurred underwater, there was always the possibility of directing the repair crew into the element. OTN devised a solution for this using a submarine called a Self-Propelled Diving Bell (SPDB). The SPDB is nine metres long, is operated by a pilot and a co-pilot and can fit five people. The SPDB can dock itself at an access port on the tunnel and so ensure watertight access.