After being prefabricated in a dry dock, elements of the Wijker tunnel (the Netherlands) have been transported over the North Sea to the location of the tunnel where they have been submerged. For transport operations an upper limit had been defined with respect to the probability of an element not being able to withstand the wave loads to be expected offshore. Implementation of this safety criterion necessitated an assessment of two sources of uncertainties. One of them is that only a forecast of wave conditions is available at the moment of deciding upon initiating or postponing a transport operation. The other is that this forecast concerns general characteristics of wave conditions, whereas wave loads on the element depend on the properties of individual waves. To deal with these uncertainties, a probabilistic tool has been developed that relates a wave forecast to the probability of meeting the safety criterion for transport.
展开▼
