Concrete floodgates in Amsterdam
The two floodgates of Sluis 124 in Amsterdam Oost IJburg are a world first. The structure consists of two steelfibe reinforced high strength concrete sliding doors, that glide across a film of water (hydro feet). Haitsma Beton produced the unique doors and transported on behalf of Schuurmans Betonbouw. The concrete doors are much cheeper due to lower construction costs and maintenance costs than the steel version would. The doors are ten centimeters thick and more than 6 metres long. They weigh approximately 14 tons each.
With the realization of gate 124 is high strength concrete (HSC strength class C90 / 105) thé alternative material for steel floodgates. HSB has a high density so that no water can penetrate the concrete, to get to the steel reinforcement which would corrode. Ing. Niek Kaptijn of Engineering Hageman specializes in HSB and on behalf of the precast concrete manufacturer as a consultant in the Amsterdam locks project: "In itself, the reinforce-ment in the concrete doors is sufficient to absorb the loads; yet there are also steel fibers added." Haitsma Beton developed a special HSB mixture ( C90 / 105) for the concrete doors. Through the use of very fine aggregates, the concrete is extremely compact , robust and low in maintenance. The surface is very smooth so algae are unable to adhere. 12 mm long stainless steel fibers are added to the mixture. Due to the fibers the concrete stays sufficiently tough after hardening. Also, the fibers prevent the formation of any surface cracks.
With the opening and closing of the doors pumps press a very thin layer of water (0.1 mm) below the doors. These so-called hydro-foot reduces the sliding resistance to a minimum. As a result, less energy is required to operate the doors and pollution under the doors minimal. Also hydro feet are less vulnerable and maintenance prone than sliding systems with moving parts.