The pillars are built on the dry-ground construction docks on Neeltje Jans. As soon as the last pillar is finished, the dike is stabbed and the pillars are in about 15 metres of deep water. The lifting vessel, Ostrea, picks up a pillar, transports it to its position in the barrier and places it, together with the Macoma, with centimetre-specificity, on the foundation.
The Macoma also ensures that there is no sand between the foot of the pillar and the foundation mat. After the pillars are placed, they are embedded in an underwater threshold of a landfill. In the end, about five million tonnes of landfills have been processed, which are transported and stored on Neeltje Jans over a period of four years. In the original design of the Storm Surge Barrier, 63 slides and 66 pillars were planned. Because of the higher costs of construction, the 63rd slide was cut out. However, pillar 66 was built and was called the Universally Applicable Pillar (Universeel Inzetbare Pijler, U.I.P.). If anything were to go wrong with one of the other pillars during transport or installation, the U.I.P. was available as a reserve. But everything was going perfectly, and the U.I.P. was never moved. Now it’s acting as a climbing object.
The Storm Surge Barrier is built in strong flowing water. Therefore, a good foundation is very important. The barrier must not, of course, sink or shift!
The Mytilus is equipped with large vibrating needles. One of these needles can be seen in the outer exposition of Deltapark Neeltje Jans. The vibrating needles cause a thickening of the sand layer, which makes it stronger.
Two foundation mats under each pillar are there to ensure maximum stability. The mats are produced at the mat factory on Neeltje Jans. The Cardium slowly rolls the foundation mats over the bottom. More information about the construction of the Oosterschelde barrier can be seen in the film Delta Finale. This film can be seen continuously in one of the main building’s movie halls.
The 62 slides are made of steel, and almost 42 metres long. The height varies according to the depth of the current hole on the spot; from 6 metres to almost 12 metres.
The motion mechanism is a hydraulic system. Each slide is moved by two hydraulic cylinders. The system is operated from the J. W. Topshuis.
After the application of the underwater threshold, the superstructure of the barrier is then completed. First, the traffic chocks are fitted; tube-shaped beams carrying the road over the barrier and housing the movement equipment. This is followed by the pillar hubs, which raises the pillars to that which the slides are attached to. Followed by the upper beam, which is placed on top of the underwater threshold.
Finally, the upper beams form the upper limit of the openings through which the water flows and which can be closed with the slides.