| A threshold under
the steel slides must be made. This was necessary for the flow of the water could wash the
sand away when the slides are lowered. For each slide a threshold was needed. Because of
the complexity and the water flow each threshold must be made in two parts. The foundation
of each threshold was formed by a concrete plate of 2.5 meter thick concrete resting on
poles which are 27.5 meters deep driven into the grounds. With the making of the pits
there were troubles because the power of the water was so immense that sometimes the water
got trough, or came up from underneath. To prevent the pils from frooding they made a sort
of concrete porrige. They dropped 3 meters of concrete porrige on the bottom of the pit.
In that way no water could come from underneath. On this base they made the thresholds.
Finally the thresholds became 55 meters wide and 80 meters long.
The towers were build also in pits. At the end the
towers were 45 meters of height. The towers were made of concrete. They slowly grow and
became 3 meters higher every week. In the autumn of 1957 the first of the four towers was
finished.
After the first two towers were ready they wanted to place
the first gate, because "Safety above all!" they said. The meganism for the
opeing of the gates was holed into the top of the two towers and was installed. After that
the lock-doors for the locks came for the lock that had become 120m long and 24m of width.
After that the moving aprt of the bridge came and the not moving part. In that way the
linkage of the two sides of the river ws completed. A few days before christmas the
chimax. The first gate was placed.
After the other two towers were ready and the second gate
was places. The 'dam' was ready and could prevent the low-laying areas behind it.
Nowadays the dam is not very much neede anymore because of
a new dam in the Nieuwe Maas. This dam is called the Maeslandkering and prevents also
Rotterdam from flooding |
