TY - JOUR

T1 - Long-term performance assessment and design of offshore structures

AU - Zhang, Yi

AU - Beer, Michael

AU - Quek, Ser Tong

PY - 2015/7/1

Y1 - 2015/7/1

N2 - The design of an offshore structure is highly dependent on the operating environmental parameters, where a realistic statistical model of the latter is essential to produce a representative estimate of the performance and failure probability. Establishing an accurate model of the offshore environment can be a challenging task. The use of simple probabilistic models may lead to biased results in the stochastic structural analysis since the environmental impact to an existing offshore structure is associated with a wide range of inter-dependent factors. In this paper, the specification of long-term design loads for offshore structures considering multiple environmental factors is investigated where the dependency between several commonly used sea state parameters are instituted through a copula-based multivariate probabilistic model. Several copula functions, capable of modeling both linear and non-linear dependence structures, are considered. The developed multivariate model based on copula concept is compared with the available approaches in the literature using actual environmental data. The modeled sea state parameters are then utilized to characterize the sea load for the reliability analysis of a real jacket structure where the prediction of the long term load is derived in a discretized form. The applicability of this approach in a high dimensional multivariate problem is also discussed.

AB - The design of an offshore structure is highly dependent on the operating environmental parameters, where a realistic statistical model of the latter is essential to produce a representative estimate of the performance and failure probability. Establishing an accurate model of the offshore environment can be a challenging task. The use of simple probabilistic models may lead to biased results in the stochastic structural analysis since the environmental impact to an existing offshore structure is associated with a wide range of inter-dependent factors. In this paper, the specification of long-term design loads for offshore structures considering multiple environmental factors is investigated where the dependency between several commonly used sea state parameters are instituted through a copula-based multivariate probabilistic model. Several copula functions, capable of modeling both linear and non-linear dependence structures, are considered. The developed multivariate model based on copula concept is compared with the available approaches in the literature using actual environmental data. The modeled sea state parameters are then utilized to characterize the sea load for the reliability analysis of a real jacket structure where the prediction of the long term load is derived in a discretized form. The applicability of this approach in a high dimensional multivariate problem is also discussed.

KW - Copula model

KW - Extreme value distribution

KW - Jacket structures

KW - Nonlinear dependencies

KW - Reliability estimation

KW - Significant wave height

UR - http://www.scopus.com/inward/record.url?scp=84927167294&partnerID=8YFLogxK

U2 - 10.1016/j.compstruc.2015.02.029

DO - 10.1016/j.compstruc.2015.02.029

M3 - Article

AN - SCOPUS:84927167294

VL - 154

SP - 101

EP - 115

JO - Computers & structures

JF - Computers & structures

SN - 0045-7949

ER -