Accurate Estimation of the 100-Year Responses From the Probability Distribution of Extreme Surface Elevations

Abstract

Accurate estimation of the 100-year responses (derived from the long-term distribution of extreme responses) is required for the safe and economical design of offshore structures. However, due to nonlinearity of the drag component of Morison’s wave loading and also due to intermittency of wave loading on members in the splash zone, the response is often non-Gaussian; therefore, simple techniques for derivation of the probability distribution of extreme responses are not available. To this end, conventional Monte Carlo time simulation technique could be used for predicting the long-term probability distribution of the extreme responses. However, this technique suffers from excessive sampling variability and hence a large number of simulated response records are required to reduce the sampling variability to acceptable levels. This paper takes advantage of the correlation between extreme responses and their corresponding extreme surface elevations to derive the values of the 100-year responses without the need for extensive simulations. It is demonstrated that the technique could be used for both quasi-static and dynamic responses.

Offshore Structural Reliability Assessment by Probabilistic Procedures—A Review

“…In a previous study, Mallahzadeh, et al [137] conceived an extremely efficient simulation technique known as the Relationship Time Simulation (RTS) procedure. At the beginning of its appearance, this RTS technique is established by taking advantage of their relationship from ETS methods [138].…”

Comparison of Extreme Surface Elevation for Linear and Nonlinear Random Wave Theory for Offshore Structures

“…In this study, the behavior of wave generation according to linear and nonlinear wave theory is discussed. The result will focus on the evaluation of extreme surface elevation and it is sufficient enough to describe the extreme response since those two are linear correlated [19,20]. The following section is devoted to a brief description on the superposition of waves that detailed on the wave generation based on linear theory.…”