The client, Sund & Bælt, and the main contractor, Femern Link Contractors, have found a model that keeps work going on the disputed tunnel trench beneath the Fehmarn Belt. It provides a provisional solution to one of the biggest points of contention in the construction project.
Until now, the parties had only agreed on rectification works for the first 650 metres of the tunnel trench. That was the section that had to be prepared before the first three tunnel elements could be immersed off Rødbyhavn.
Sund & Bælt now tells FemernBusiness that FLC is also preparing the tunnel trench beyond the first 650 metres. The work is being carried out as the next tunnel elements are prepared for immersion.
It is an important development in the construction of the Fehmarn Belt link. The tunnel trench is the 18-kilometre excavation on the seabed where the 89 tunnel elements will be placed one by one. The trench forms the foundation for the world’s longest immersed tunnel, and before an element can be lowered into place, the seabed must be cleared and built up so the element can rest securely.
Most expensive solution
According to Sund & Bælt, the work is continuing according to the same technical model used for the first 650 metres. The trench is being cleared, and a gravel bed is being laid to create an even and load-bearing foundation for the coming tunnel elements. Sund & Bælt will describe the technical work, but not the financial terms.
The first 650 metres were prepared on a time-and-materials basis. FemernBusiness understands that the same financial model is now also being used as FLC continues work farther out in the trench.
That is by far the most expensive solution for the client. Sund & Bælt pays for the actual time spent, equipment and manpower while FLC prepares the trench stage by stage. The final cost therefore depends on the scale of the work required and will only be known once the work has been completed.
One of the biggest points of contention
For the past year, the tunnel trench has been one of the most sensitive issues in the Fehmarn project.
The trench was excavated by the consortium Femern Belt Contractors, FBC, and was subsequently accepted and taken over by Femern A/S under Sund & Bælt. It was then supposed to form the basis for FLC’s work on immersing the tunnel elements.
That is where the conflict arose. FLC refused to approve and take over the trench in the condition in which it had been handed over. The main contractor pointed to significant deviations in the first sections off Lolland and made the quality of the trench a condition for moving ahead with the immersion works.
Sund & Bælt has long maintained that the problems could be handled through adjustments. In September, the client said the process was proceeding as expected, although with a greater need for adjustments to the tunnel trench than first assumed. Parts of the trench had been excavated slightly deeper than planned, and according to the client this could be compensated for by laying a thicker layer of gravel beneath the elements.
FLC’s own measurements painted a different picture. On the first 650 metres, the contractor’s surveys showed local deviations of up to 1.8 metres, and according to the material only 1.84 per cent of the seabed met the technical requirements. Later surveys showed that the problems continued farther out in the trench.
Paid extra for the first section
The first practical solution came with the agreement on the first 650 metres. In an interview with Ingeniøren on 4 May, Mikkel Hemmingsen, chief executive of Sund & Bælt, said the parties had agreed that Sund & Bælt would pay more to get the trench ready for the first immersion.
FemernBusiness has previously reported that the Dutch consortium Femern Belt Contractors, FBC, paid compensation because parts of the trench had been excavated too deeply. FBC was the consortium responsible for excavating the tunnel trench.
The compensation was paid to the client, Femern A/S under Sund & Bælt, which was then to hand the trench over to the main contractor, Femern Link Contractors, FLC. FLC is the contractor that will use the trench to immerse the tunnel elements.
According to Mikkel Hemmingsen, the compensation from FBC does not cover the additional payment Sund & Bælt is now making to FLC to prepare the trench.
When Ingeniøren asked whether FLC was being paid a little more, the answer was “much more”. However, he rejected the suggestion that the agreement for the first 650 metres runs into the billions.
