Novel reliability method validation for offshore structural dynamic response

Abstract

The paper validates novel structural reliability Gaidai-Fu-Xing (GFX) method, particularly suitable for multi-dimensional structural responses, versus well established bivariate statistical method, that is known to accurately predict two-dimensional system extreme response levels. Classic reliability methods, dealing with time series do not have an advantage of dealing easily with system high dimensionality and cross-correlation between different dimensions. An operating Jacket located in the Bohai bay was taken as an example to demonstrate the proposed methodology. Novel state of art bimodal extrapolation technique was applied to predict system reliability with five years return period, which is of practical importance for design of fixed offshore structures.Unlike other reliability methods the new method does not require to re-start simulation each time system fails, in case of numerical simulation. In case of measured structural response, an accurate prediction of system failure probability is also possible as illustrated in this study.Jacket offshore platform subjected to large environmental wave loads, thus structural stresses in different structural critical locations were chosen as an example for this reliability study. The method proposed in this paper opens up the possibility to predict simply and efficiently failure probability for nonlinear multi-dimensional dynamic system as a whole.