The New Waterway Storm Surge Barrier

The New Waterway Storm Surge Barrier is the last stage in the 40 year long Delta Project to protect the southwestern Netherlands from the North Sea. One of the world's largest hydraulic projects, it is located in the entrance to the Port of Rotterdam, the world's biggest harbour and Rhine river gateway to Europe's industrial heart.

The barrier consist of two semi-circular floating steel gates attached by three-dimensional trusses to a huge pivoting ball joint. Each gate assembly measures 300 meters, the height of the Eiffel Tower, and is twice the Tower in weight.



WHAT ARE STORM BARRIERS?

Storm surge barriers are a relatively new class of hydraulic structures designed to protect large segments of the population from massive flooding. The now-famous Thames river barrier was completed in the early 1980s to safeguard the London metropolitan area. Other structures have been proposed to enclose the lagoon and historic city of Venice. Construction of storm barriers to protect the Rhine-Maas River Delta in the southwestern Netherlands was the largest infrastructure project in Dutch history. The resulting closure of the Delta estuaries shortened the Dutch coast by 700 kilometers.

NEW STEEL FACT FILE

  • Because it combines low weight with high strength and reliability, steel made it possible to design the largest floating barrier ever built.
  • Some 25,000 tons of vacuum degassed low sulphur and low phosphorous thermomechanically rolled fine grain steel were used, with a yield stress of 355 N/mm2.
  • These newly developed steels made possible complex and heavy structural design with low manufacturing risks and economic welding costs. They permitted easy welding of the entire structure without preheating, even with plates up to 200 millimeters thick.
  • Higher strength steels would have raised problems with stability of the plates, fatigue due to wave action, and higher welding costs during fabrication.

TECHNICAL REQUIREMENTS WERE EXTREMELY SEVERE

  • A 360 meter wide opening with a depth of 17 meters, slightly wider and deeper than the present navigational channel, to permit the normal flow of water
  • No obstacles in the channel or risks to passing ships
  • Operation in all extreme circumstances: high current velocities, heavy storm surges, intense wind gusts, and deposits of sand or silt in the channel
  • Maximum lifetime of 100 years with inexpensive maintenance
  • High reliability (since it is the only protection available)

SECURITY AND STEEL - SUMMARY

  • Newly developed steels have made it possible to build a unique storm surge barrier to protect Rotterdam port and urban areas.
  • This remarkable structure is as high as the Eiffel Tower and the two gate assemblies weigh four times as much. The force of the water on the gates during a storm is 350 megaNewtons (35,000 tons)
  • The risks that water levels in Rotterdam will exceed more than 3.6 meters above normal are now reduced to once every 10,000 years.
  • The failure risk of the barrier is once in 10 million years.