Femern Link Contractors (FLC) har indgået kontrakt med danske KBT Waterproofing A/S (KBT) om epoxybelægning på Femern tunnelens såkaldte skidding beams. Skidding beams er de massive betonskinner, som de tusind-tons tunge tunnel-elementer skal glide på, når de skubbes ud fra fabriksanlægget til tørdokken, for efterfølgende at blive sejlet ud til den endelige nedsænkning på havbunden.
Each skidding beam (rail) is approximately 500 meters long, so the requirements for both precision and strength are enormous, both in terms of the concrete the rails are cast in and the epoxy that KBT applies on top.
Friction-free transport that runs on rails
It is KBT’s epoxy coating on the concrete rails that ensure that the tunnel elements can slide as smoothly and friction-free as possible from the factory to the dry dock with the lowest possible energy consumption.
The weight of the element itself is concentrated at a few points under each jack, which lifts the entire element free of the rails. The surface must therefore be extremely hard and very smooth, completely without air holes or bubbles and with an evenness that, in this case, is +/- 2 mm longitudinally on each of the 500 meters long and 70 cm-wide rails.
Necessary with new methods
In order to live up to the project’s requirements, casting the epoxy coating on the Fehmarn tunnel’s skidding beams required the development of completely new methods. The chosen solution from KBT is thus a combination of a unique epoxy material, special rails for moulds, and a detailed workflow with measurement of heights both before, during, and after execution. In addition, there is documentation of target fulfilment, which, in collaboration with FLC’s surveyors and quality team, provides certainty for the correct execution of each stage.
Before starting up, it was necessary to prepare and train a number of employees at KBT’s test centre in Lynge, so that everyone knew how the tasks should be solved in the best possible way.
A win for the environment
– We are, of course, proud to once again have the opportunity to contribute to this fantastic project, says Andreas Hensen, project director at KBT. The company is already part of the Fehmarn project with waterproofing of the project’s 10 special tunnel elements.
– We have focused on delivering a solution that both FLC and we have full confidence in. This has required us to develop all methods and workflows ourselves after extensive tests of both materials, methods, and tools. In return, we can deliver a solution that can be carried out within a tight schedule and meets the requirements. The method is also more environmentally friendly, as less energy must be used to move the elements, says Andreas Hensen.
Double-digit million amount
The contract for epoxy coating on the Fehmarn tunnel’s Skidding Beams amounts to a double-digit million sum. KBT expects the task to be solved by a team of around 15 people, some of whom will be hired locally through the Femern Agency.
