ABSTRACT
The Coentunnel is a prefabricated submerged tunnel, which has been built as part of the national high way network enrolment, in 1967. The tunnel exists of two tubes that underpass the North Sea Channel that runs from North Sea coast line at IJmuiden to the Amsterdam harbour, in The Netherlands. The tunnel, which is part of the belt way A10 that surrounds the city of Amsterdam (Figure 1) is build up from sections which are prefabricated in a dock near the site. The concrete used for the sections contained Blast furnace slag cement comparable with a today’s CEM III/B (300 kg/m3) with a water cement ratio of 0.5. After finishing the tunnel sections, the dock was filled with water and the tunnel sections were floated into position and submerged towards their final destination. At the north and south side of the tunnel, the sections were connected to the entrance heads of the tunnel which were cast in situ. In terms of service life assessment, it has been required that the existing tunnel with a current age of 40 years should extend its service-life with another 60 years in order to last for a design life of 100 years.
