Reliability Assessment of TLP Air-Gap in Nonlinear Waves

The present study demonstrates effects of the CresT JIP (Cooperative Research on Extreme Seas and their impacT) findings regarding extreme and rogue waves through a simplified structure reliability analysis of a generic TLP structure defined by the project. The study demonstrates effects of wave nonlinearity beyond the second order, diffraction-radiation of incoming waves with the structure, spatial variations of crest statistics, a vertical displacement of the TLP system at the deck location as well as sea water level variations due to surge and tide. In order to account for these effects a stochastic model is suggested. Sensitivity studies are carried out to identify importance of analysed parameters and their stochastic behaviour to the failure probability. Uncertainties related to the analysis are identified and ranked given special attention to the effect of wave nonlinearities beyond the 2nd order. Recommendations for future research needs are suggested.