Pioneering work on the Rüstersiel Sea Dyke (1963)

Max Nods of HUESKER Synthetic smiles quietly to himself as he says, "When HUESKER materials were being used more than 40 years ago, the term 'geotextile' was hardly known at all." Today, the German company in Münsterland can look back on over 40 years' successful experience with geotextiles, covering the widest range of applications. The company's product portfolio is as wide and versatile as the scope of use of its materials, anything from dyke construction, leisure waterways and roads to landfill, earthworks and foundations. The Gescher concern manufactures custom-made geosynthetics for the construction industry, as well as technical textiles for agriculture, industry and commerce.

A quick glance at the list of standard products shows just how widespread HUESKER materials are used in construction projects today, extending from high-strength synthetic fabrics through composites and clay liners, nonwovens, erosion protection mattresses right up to asphalt reinforcing grids and Fortrac® geogrids.

It is precisely these products that underline how important engineers are in the company's success story: the HUESKER engineering team has always sought to extend innovatively the product portfolio with materials such as high-tensile Fortrac® geogrid, used in ground reinforcement, or the geosynthetic clay liner, NaBento®, used in hydraulic engineering and environmental protection.

In addition to these high quality standard products, HUESKER has developed over many years individual solutions for various engineering applications through close cooperation with its customers, consulting engineers, research institutions and testing laboratories - each one innovative, economical, environmentally friendly and well conceived.

Every success story has to start somewhere. For HUESKER it began here in 1963.

At that time a dyke was being built to the north of Wilhelmshaven to contain the Rüstersieler Watt mudflats and reclaim almost 600 hectares of land. The use of geotextile materials in the construction of the dyke represented a pioneering achievement: for the first time a sea embankment toe was constructed using large sand-filled nylon containers - and the use of a geofabric to ensure slope stability was another first.

Construction was able to start in April 1963 after a long, icy winter. First the undulations in the dyke foundation soils were levelled and the location of the future dyke toe stabilised. 25,000 containers would later be used to make the toe into a barrier, resilient against the pounding of the sea. Each container was 1.50 metres wide, 2.25 metres long, weighed 1.5 tonnes and held a cubic meter of sand.

The filled nylon containers were carried on rails to their final position. They could be transported to the flooded site, even at high tide. The working conditions imposed great demands on men, materials and equipment, with some of the containers being placed underwater and piled up using giant grabs. Equipment and materials had to be very robust to resist any damage, with even the excavator being strengthened with thick steel.

Above all, the side of the dyke, facing the sea, had to resist the ever-present impact of waves and the fury of winter flood tides. The main function of the nylon containers was to ensure the resilience of the dyke during the initial construction, then a ten centimetre thick layer of sprayed concrete was applied to the containers to give the structure additional protection.

A substantial volume of sand had to be transported and placed in the course of building the dyke: 1.6 million cubic metres had to be deposited in the dyke core. A dyke of dredged material, covered with plastic tarpaulins, was used as initial protection of the deposited sand.

One in five of all the nylon containers used was required to form the dyke wall, which were made of a double- layer nylon filled with a sand core. On 29 July 1963, at the height of summer, it was possible to start constructing the dyke wall. The 5,000 HUESKER containers were temporarily stockpiled. Initially a 12 by 50 square metre HUESKER nylon tarpaulins were laid out, then the nylon containers positioned before large earthworks machines deposited the sand into the core.

Tidal considerations meant that engineers and technicians were particularly dependent on the reliability of the material supply, as the programme had to be followed precisely in order to complete the dyke wall at low tide.
On 18.12.1963, just under nine months after the start of construction, the dyke at the Rüstersieler Watt was ready to be formally brought into use.

Press information "40 years of experience with geotextiles - HUESKER Synthetic"

How have things changed in the 40 years since this dyke was constructed? HUESKER has gained more experience with geotextiles. The HUESKER engineering team has developed further geotextile innovations that are used all over the world and, within a few years of the construction of the dyke, HaTe® woven filter fabrics from Gescher were making dykes even more reliable. Today, geosynthetics such as the geosynthetic clay liner NaBento® are an obvious way of providing a watertight feature in a dyke.

Max Nods observes that construction methods have not changed greatly over the intervening 40 years. ''And the HUESKER company philosophy has remained the same'' says Nods: to offer clients and partners custom-made solutions, in which the geosynthetics are optimised to meet local circumstances and engineering requirements. The engineers in Gescher design and develop made-to-measure materials, often overcoming particularly difficult problems by coming up with geotextile innovations. Laboratory tests, trial sections and long-term research projects are used - here just as much as with standard products - to achieve a single objective, namely reliability.

In the end, the structures, in which HUESKER geotextiles are used, have to be as successful as the dyke at the Rüstersieler Watt: it is still standing and continues to resist the raging sea.

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