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Oosterscheldedam

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Oosterscheldedam Each column weigh 18.000 tons. By using the right materials, a good plan, a perfect design and intensive maintenance this flood barrier could survive at least 200 years. With this barrier a serious flood was reduced to one time in 400 0 years.

First the area where the barrier was planned the bottom was covered with special designed an manufactured mats. For the first time in the world history a project like this was done and special vessels for each activity had to be designed.
The threshold
The columns were not fixated on the threshold and the foot of each column was embedded by stones. Also these stones were needed to close the gap between the slides and the threshold. Several layers of stones were needed the lowest were the smallest. The top layer was made of blocks each weighing between 6 and 10 tons. In two years more than 5 million tons of stones and rocks were dropped. The rocks were imported from Germany, Finland an Belgium. The density of each stone lies between 2.8 and 3.0 kg/l.

The columns
The hollow columns were prefabricated in a huge construction dock of 1km2. This dock was surrounded by a dike and the bottom of the pit was 15.2 meters below sea level.

 2 mensen lopen op de mat die op de zeebodem komt te liggen
Cross section of the Oosterscheldedam
Specifications:
weight: 8.000.000 kilograms
height: 30.25 meters to 38.75 meters
concrete: 7000 m3
time: 1.5 years per column

The construction dock was divided in several sections. When the columns in one section were finished this section was flooded. A lifting vessel came in and transported the column to it’s place on the threshold. Every two weeks they started to built another column.
A column was finished by placing

  • hollow road pieces
  • tops
  • horizontal top bars
  • horizontal bottom bars
  • the road pieces
Columns in dock
Columns in the dock This is a hollow construction for the road on top and the equipment for moving the slides inside. Each piece weigh 1.200.000 kilograms, is 45 meters long and 62 of these pieces were needed.

The top pieces
These are concrete constructions which are placed on top of each columns. The slides hang on these pieces. For each column two top pieces are needed.

The horizontal bottom bar
This bar is 39 meters long and hollow and weigh 2.500.000 kilograms. It was placed on the threshold between the columns. Just before placing small adaptations could be made on this bar. After placing this bar was filled with sand.

The horizontal top bar
This bar is placed on top of the gate which is opened an closed by a slide. These hollow concrete elements are 4 to 5 meters long and weigh 1.100.000 kilograms.

The slides
The steel slides are placed between the columns. The have a length of 42 meters, the height depends on it’s place in the barrier and is 5.9 to 11.9 meters. They weigh between 300.000 and 500.000 kilograms.

To move the slides up and down a special hydraulic system had to be designed. From one central point al the 124 hydraulic cylinders can be operated

 The columns, waiting for workers.