You are hereOn the Effects of a Joint Environmental Description & Uncertain Parameters on the Extremes of a Drag Dominated Structure

On the Effects of a Joint Environmental Description & Uncertain Parameters on the Extremes of a Drag Dominated Structure


Report No. : 
RMS-5
Authors: 
S. Haver
Published: 
August 1989
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An idealized shallow water jacket structure is considered.  The structure is exposed to the simultaneous loads from wind, waves and current and, additionally, the water level is also assumed to vary.  A joint description of all environmental variables is deduced based on hindcast data during the most severe storms from 1966-87.  The effect of accounting for a realistic degree of correlation between the variable is demonstrated using first- and second order reliability methods. The effects of introduction uncertain parameters are also demonstrated and the relative importance of the variuos parameters is pointed out. Finally, the coefficient of variation of the longest shear force at mudline during the time period of T years is considered of various values of T. In the this condition, the total uncertainty is separated into inherent randomness and uncertainties introduced due to for example a limited amount of data.  The randomness is assumed to be independent form year to year, while the uncertainties are assumed to be completely correlated.