The preferred contractor will be announced this month on Amsterdam’s North/South Line (Noord/Zuidlijn) after the project got the go-ahead on 9 October.

The metro includes the construction of two, 3.8km long, 6.5m diameter tunnels, using two US$9.8M Herrenknecht EPBMs. Other tunnelling works include construction of a 350m long immersed tube tunnel under the IJ river, and 350m of cut and cover tunnel. The shortlisted contractors are: Strukton Betonbouw; Ma Bögel; Vermeer Beton- en Waterbouw B V; and Heijmans Beton- en Waterbouw

Work will commence with the underground section of the North/South Line between the Central station and the future Ceintuurbaan metro station. This is considered the most difficult part of the line, both technically and position wise. The first stations will be Rokin, Vijzelgracht and Ceintuurbaan, with construction taking place between 2003 and 2004.

Construction of the launch chamber for the TBMs will also start in 2003, alongside construction in and around Central station. The other tunnels will be constructed between 2005 and 2007.

The US$1.4bn project has been restricted by settlement restraints, because the route passes through the historic centre of Amsterdam. Soldata is undertaking a mammoth six-year US$12.5M settlement survey, which includes feeding 140,000 readings into engineers’ computers each week.

Design consultant, Witteveen + Bos, has been working closely with TBM manufacturer Herrenknecht to construct a full face EPB machine capable of exerting minimal subsoil disturbance, and therefore minimal surface settlement. (See T&TI January 2001 p20, and December 2001 p47.)

Amsterdam sits on a mixture of clay, turf and sand, requiring buildings to be built on piles, some of which are wooden – buildings can settle up to 5mm a year. The tunnel will be bored in sand, 20m-30m underground.

The construction start date should be announced in March next year. It is hoped that the metro will be up and running by 2011, servicing up to 300,000 passengers per day.

Related Files
Longitudinal section of Amsterdam’s North/South Line