With over 800,000 residents to cater for, Amsterdam’s public transport is overstretched. While the city centre lacks the space for even more trams and buses, the underground infrastructure presents opportunities. The new ‘Noord/Zuidlijn’ (‘North/South Line’) on the city’s metro connects Amsterdam North and Amsterdam South, enabling 121,000 passengers to be transported through the city centre quickly, safely and comfortably each day.
With a contractual term exceeding 15 years, the Noord/Zuidlijn is Heijmans’ longest-running project. The work has been divided into two subprojects. On the city centre side of Amsterdam’s Centraal Station Heijmans created three caissons, and on the River IJ side of the station Heijmans worked on the immersed tunnel.
100% Heijmans work
Three caissons were sunk right in front of Amsterdam Centraal Station. Heijmans was responsible for both the earthworks and the foundations. Restoration work put the finishing touches to the three caissons.
River IJ side
The tunnel under the River IJ was constructed for the Noord/Zuidlijn in conjunction with Strukton. A total of four elements were linked together, each made of concrete and measuring 144 metres in length, 12 metres in width and 6 metres in height. In order to sink this ‘immersed tunnel’, three large ballast tanks of water were required for each element.
Following the sinking, the concrete was poured in a phased approach and the tanks were removed. This process was temporarily finalized in 2014. Two years on, in 2016, Heijmans brought the work to a state of completion. The final 300 m3 of concrete were poured in order to seal the ‘construction hole’ in Amsterdam North. This signalled the end of a magnificent project for Heijmans.
Working in the heart of Amsterdam entailed the inevitable logistical challenges. Day-to-day harmonization of the work being performed was required with parties such as the Dienst Milieu en Bouw (‘Environment and Construction Service’), the Noord/Zuidlijn Information Centre and the emergency services.