J.G.M. Kerstens, The Netherlands
After the major flooding disaster in 1953, the Dutch Government decided to carry out The Delta plan, which ensures the reduction of flooding risk in the Delta area of South-West Holland. The first step was the completion of the Oosterscheldedam project.
Later, due to rising water levels, the last piece in the sea defense chain has been 'taken off the shelf', i.e. A project to reduce the water levels in the Rotterdam area.
Several joint ventures competed for the contract to design and construct the Rotterdam Storm Surge Barrier. After fierce competition, it was awarded to a joint venture in 1989. In nearly every sense the project was innovative in that new ways were found to design and construct the superstructure which bears a striking resemblance in size and appearance with the Eiffel Tower in Paris.
For instance, the probabilities of failure specified in the contracts are more stringent than the implicit safety in design codes and therefore a probabilistic design approach had to be developed. Attention is also given to the description of the design philosophy of the various subsystems such as the water retaining wall, truss structure and the ball bearing which due to its sheer size is a world record.