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Deltares | R&D Highlights 2015 Delta Infrastructure
After almost 100 years of service, the Noordersluis (Northern lock) in IJmuiden, the Netherlands, needs to be replaced. A new, bigger lock will provide access to the harbour of Amsterdam for larger seagoing vessels and will therefore stimulate the economy in the region. Lock construction will commence in early 2016. The new lock is expected to be available for the first vessels in 2019. With a width of 70 m, a length of 545 m, and a depth of almost 18 m, it will be the largest lock in the world. Deltares conducted extensive hydraulic research in 2014 and 2015 on the reference design for the levelling system of the new lock. The main objective of the study was to determine feasible levelling times while keeping the forces on vessels within acceptable limits. The hydrodynamic forces on a ship must not become too large during the lock cycle because mooring line forces may then exceed operating limits, possibly resulting in unacceptable ship movement or even line breaks. The design ship for the levelling system is a bulk carrier with a length of 330 m and a beam of 52 m. The maximum draft of vessels passing the lock will be 13.75 m in salt water due to restrictions upstream in the canal.
One of the most important boundary conditions is the density difference in the water since the lock is located between salt water on one side (the North Sea) and fresh water on the other side (the canal).
The hydraulic design of two levelling systems was investigated in a 1:40 scale model. The two levelling systems considered used openings in the gates or culverts in the lock heads. The complete levelling process was simulated in the scale model, including the lock exchange process after the opening of the gate. All the relevant physical flow phenomena were included automatically in the scale model.
More than 200 parameters were measured, including the most important ones such as water levels, forces on the ship and the density distribution of the water. Levelling tests with a density difference showed that the forces due to these differences in density were significant and could exceed allowable force criteria. As well as providing valuable insights into the process of the complete locking cycle, the measurements were also used to validate various numerical models.
Many aspects of the locking process that are important for the safe operation of the lock were considered in the study. They included the position of the vessel in the lock, different lifting programs, different density distributions, and the type of design vessel (container ship or bulk carrier). In the light of the results of the scale-model study and the validated numerical simulations, the contractual requirements for levelling times were adjusted. These new requirements were included by Rijkswaterstaat in the tender for the lock construction.
Levelling in the new IJmuiden
lock, the Netherlands
arne.vanderhout@deltares.nl T +31(0)88 335 8008
One of the most important boundary conditions is the density difference in the water since the lock is located between salt
