Maslantkering or Maslant barrier is a storm barrier in the Nieuwe Waterweg arm of the Rhine Delta, located between the Dutch cities of Hoek van Holland and Maassluis. It is designed as a gate that closes in the event of a storm. The creation of Maslantkering was part of the Europoortkering project to protect the harbor of Rotterdam, Europort and the surrounding towns and lands from flooding.
The construction of the barrier began in 1991. First of all, two dry docks were built on the shores, as well as a support platform running along the bottom of the Nieuwe-Waterweg. At the docks, 210 meter steel gates were built with a height of 22 meters, after which 237 meter trusses were attached to them. For comparison, the height of the Eiffel Tower is 300 m, but the weight of each of the barrier wings is twice the weight of the entire Parisian landmark.
The main task of such supports is to redistribute the forces acting on the barrier in the closed position to the attachment points. When opening or closing the gate, the mount works like a ball joint, like a person's arm or thigh. The bindings were made by the Czech company Skoda Holding and are the largest ball joints in the world - each of them has a diameter of 10 m and a weight of 680 tons. After six years of construction, on May 10, 1997, the barrier was put into operation in the presence of Queen Beatrix. $ 450 million was spent on the project.
The barrier is controlled by an automated system that tracks weather and sea level data. Under normal conditions, the doors are hidden in the docks and the ships can easily navigate the 360-meter arm. In the event that the water rise is expected in Rotterdam by more than 3 m, the barrier is automatically closed. The procedure starts 4 hours before the gate closes, the ships are informed that the passage is closed. Two hours before the closure, traffic on the Nieuwe-Waterweg stops. When there are 30 minutes left before closing, water begins to flow into the docks, and when the gate begins to float, two so-called "locomobiles" are activated, moving the doors. When the distance between the shutters decreases to 1.5 m, the voids inside the gate begin to fill with water, which lowers them onto a support platform that runs along the river bed. In case of prolonged closure of the barrier, a mechanism is provided for the descent of the Rhine water - air is pumped into the flaps, they rise, and excess water flows into the sea.
The software for the barrier is written in C ++ and consists of 200 thousand lines of code for the working part and 250 thousand lines of code for simulation systems. Test closings of the barrier are made once a year, usually in September or October. Maslantkering is expected to close at least once every 10 years due to the storm. Taking into account the rise in sea level, then in 50 years the closure frequency will be increased to once every 5 years.