'The Groene Tunnel', IJburg,
2000 - 2011
Lock 124 - part of the project for two locks and seven bridges on IJburg
Project Bureau IJburg/
Amsterdam City Development Company
Concrete Award 2011 - category constructions in water works
On the eastern fringes of Amsterdam, IJburg has been developed as a new residential neighbourhood on the IJmeer lake. Amsterdam City Council approached a number of architects for the design of the neighbourhood’s bridges and locks. MVSA designed the bridges and locks for the ‘Groene Tunnel’, a waterway that runs through IJburg.
Lock 124 is the first in the world with lock gates made of high strength concrete. This world premiere for Amsterdam represents a breakthrough in the use of concrete in moveable dam structures. The gates are cheaper in terms of initial costs and maintenance, and are also more environmentally friendly. When the gates are opened and closed, pumps force an extremely thin (0.1 mm) layer of water under them. This layer, known as a ‘hydrofoot’, reduces friction to a minimum. It was decided to use two sliding gates rather than a double set of hinged gates, in the same way as lock 121. The machinery and gearing are housed in concrete vaults. Because the lock has been designed to cope with higher water levels in the future, it projects half a metre above the dyke.
Lock 124 forms an element of IJburg’s primary water defences. It also provides a pleasant spot to sit and watch boats passing through the lock. A robust appearance, in keeping with a work of hydraulic engineering, was chosen for the architectural design of the lock, with added refinement in the finishing and detailing. The concrete deck is constructed using Stelcon plates with black steel edges. Linear channels have been added to enhance drainage, and their seamed pattern has been continued in the grooves of the lock’s walls, creating a rhythm of recesses for bollards and grab lines. Some of these recesses feature images in brass: while waiting in the lock chamber you see images of IJburg or of the Ijsselmeer, depending on which way you are sailing.
Pedestrians can cross the lock over a U-shaped steel bridge, which has lighting integrated in its handrail. On the upper deck, a recreational area has been created, with a wooden seating element next to an elm tree. Because space was available in the vault for a tub for the tree’s roots, it does not interfere with the function of the dyke as a water defence, and the tree emphasises the lock’s special character. The moorings and stairways on the lower level are made of wood, and are partly designed as a floating mooring for canoeists.