DESIGN EXTREME LOADS OF TYPHOON INDUCED EXTREMES SEA STATES

摘要

It is widely recognized that the frequency and density of the typhoon have been rising with the elevated global temperature and the sea level. More effort should be done in the prevention and mitigation of disaster. In view of the extreme sea state for the offshore platform,the joint probability of multivariate extreme environmental loads should be considered. API recommended to use “100-yr return period wave height” with “associated” wind and “associated”current, but the meaning of “associated” is somewhat ambiguous. Based on aforementioned reasons, this paper proposes a new model —Multivariate Compound Extreme Value Distribution (MCEVD) to predict combined extreme loads for a fixed platform in South China Sea.Comparison of the calculated results by API recommendation, MCEVD and annual response (OTM) statistics shows the advantages of MCEVD model. The uncertainty analysis of the design environments for the platform risk assessment are taken into account.