THEEMSWEG ALIGNMENT, ROTTERDAM

In the harbour area of Rotterdam, the harbour railway is to be re-aligned: this is the first part of the Betuwe route.

The reason for this is not only that the Caland bridge (a lift-bridge built in 1969) has reached the end of its technical life, but also that a bottleneck in capacity is foreseen: it is expected that in future more freight trains will travel along the railway and more sea-going ships will sail to and from the Britannia harbour.

The new alignment, the Theemsweg alignment, is about 4 km long and it uses an elevated concrete structure (railway viaduct) along the Theemsweg and the Neckarweg. The alignment consists of two steel railway bridges providing passage over the Rozenburg lock and over the Thomassen tunnel. The construction work started in September 2018 and the railway will be ready for use in 2021.

GEO2 Engineering B.V. is, within the construction consortium SaVe, responsible for the geotechnical design (the definitive design and the design for implementation) of the substructure for the Theemsweg alignment and for various temporary structures and construction-aids relating to the pre-installation locations and the (provision of) foundations.

The geotechnical challenges include:

• The pile foundations of the substructures – the design of cast in place concrete piles using a temporary casing and lost screwpoint technique;
• Connections with the existing railway tracks – anchored sheet pile walls, pile matrasses and elevations with and without reinforced soil, during the construction of which the existing railway remains in use (with the exception of a few train-free periods);
• The influence of activities and constructions to be realised at various locations where cables and pipework are present, and existing structures such as the Rozenburg lock and the Thomassen tunnel – worked out in close consultation with the commissioning party, and with the implementation of management guidelines;
• Design of structural supports in the slopes along the windshields and analyses of liquefaction potential of existing foundations;
• Taking account of substantial variations in the top 6m of soil – the level of the island Rozenburg has in the past been substantially raised using mainly loose-packed sand and different, locally present, layers of clay;
• Supply and placement of steel bridges with self-propelled modular transporter arrangements and the temporary placements on the pre-assembly locations – working out the design of the RoRo (Roll-on Roll-off) landing stage, cutter soil-mix bearings/supports, coverings, etc.