Deltares tests armour blocks for reinforcement closure dam Afsluitdijk
Research institute Deltares tested a combination of two new types of armour blocks for reinforcement of the closure dam Afsluitdijk, the Netherlands. The two armour blocks, Quattroblock and Levvel-bloc, are specially designed for the Afsluitdijk to be used on the upper and lower slope on the seaside of the dam.
The test was commissioned by Dutch national water authority Rijkswaterstaat and joint venture Levell consortium. The test took place in Deltares’ largest flume where typical super storm scenarios can be simulated on a 1:3 scale.
The outcome of the stabilization test makes it possible to optimize the design of the new revetment more accurately for the different parts of the closure dam.
The work on the 32 km long dam was officially started in March and the first blocks will be put in place soon.
Over the next four years, some 75,000 heavy Levvel-blocs will be placed on the lower end of the sloping revetment. On the higher end of the slope the much lighter Quattroblocks will be used, covering a total surface of 700,000 square meters.
The new revetment for the 85 years old dam, is needed because of the expected sea level rise and the ability for the dam to withstand a super storm that statistically can happen once in 10,000 years. In such a case a maximum overtopping of 10 liter/second/meter is allowed.
Rijkswaterstaat has awarded the Afsluitdijk Enforcement Project to the Levvel consortium and includes the design, reinforcement and 25 years of maintenance. This joint venture is formed by Van Oord Aberdeen, BAM PPP PGGM Infrastructure and RebelValley. The net present value of the project is 550 million euro.