Monitoring system Fehmarn Belt Fixed Link

The Fehmarn Belt Fixed Link is a permanent and direct road and rail link between Scandinavia and the European mainland under the water of the 20-kilometre wide Fehmarn Belt strait. The connection runs from Puttgarden in Germany to Rødbyhavn in Denmark and is currently under construction.

In 2011, the immersed tunnel concept was chosen as the best option for this connection. The Femern A/S organisation was set up in order to plan, finance and realise the connection. The design team supporting Femern A/S consists of a joint venture between Ramboll, Arup and Tunnel Engineering Consultants (TEC: a collaboration between Witteveen+Bos and RHDHV). This team supplied the reference design and is now working as a consultant to Femern A/S during the construction phase.

As part of the contract, a team of engineers from Ramboll, Arup and TEC – all specialised in monitoring civil structures – are developing monitoring concepts to measure and analyse the performance and behaviour of the tunnel. Specific areas of concern are the effects of the settlement of the subsoil, deformations of the tunnel joints, the loads in the tooth structures between the tunnel segments and the potential for corrosion.

The effects at locations where the tunnel intersects with a transition between hard soil layers and soft clay are particularly important. In this project, we are working closely with researchers from Delft University of Technology who specialise in specific new monitoring technologies. We want to come up with the best overall concept for this unique project. Our team is currently working on applying and testing sensors in the trial concrete elements and preparing load tests for the calibration of the monitoring system.