The Exceedence Probability of Wave Crests Calculated by the Spectral Response Surface Method

The prediction of extreme crest elevations is fundamental to the design of marine structures, irrespective of whether they are intended for deep-water offshore locations or shallow-water coastal locations. In undertaking design extreme crest elevations, specified in terms of either a 1 in 100 year or 1 in 10,000 year event, are relevant to both the overall geometry of the structure, particularly the setting of deck elevations, and the sizing of individual members necessary to support the applied loads. For example, in the design of a fixed structure deck elevations are traditionally set to maintain an effective air-gap, thereby preventing the impact of even the largest wave crests on the underside of the deck structure. In contrast, the wave-induced forcing acting on the legs of the structure cannot be avoided and must be carefully assessed. If the relevant Keulegan-Carpentar number (KC) is large,