Finite element-based reliability assessment of quay walls

Abstract

While reliability methods have already been widely adopted in civil engineering, the efficiency and robustness of finite element-based reliability assessments of quay walls are still fairly low. In this paper, the reliability indices of structural and geotechnical failure modes of two real-life quay walls are determined by coupling probabilistic methods with finite element models, taking into account a large number of stochastic variables. The reliability indices found are within the range of the targets suggested in the design codes presently in use. Nevertheless, neglecting model uncertainty and correlations between stochastic variables leads to an underestimation of the probability of failure. In addition, low sensitivity factors are found for time-independent variables, such as material properties and model uncertainty. Furthermore, the results are used to reflect on the partial factors used in the original design. Important variables, such as the angle of internal friction, are subjected to a sensitivity analysis in order to illuminate their influence on the reliability index. Port authorities and terminal operators might be able to use the findings of this paper to derive more insight into the reliability of their structures and to optimise their service life and functionality, for example by deepening berths or increasing operational loads.

Time-dependent reliability analysis of service-proven quay walls subject to corrosion-induced degradation

“…Recent developments have shown that advanced finite element models of soil retaining walls can be successfully coupled to reliability tools [5,9,49,60]. However, performing a finite element-based Monte Carlo analysis requires too much calculation effort and was not feasible within the framework of this study.…”

“…In addition, the reliability index, the sensitivity factors and the design point found were also evaluated by performing Blum-based and finite element-based reliability assessments. The latter was undertaken using the reliability interface ProbAna Ⓡ [49], in which the gradientbased FORM algorithm Abdo-Rackwitz [1] was selected. ProbAna Ⓡ facilitates the coupling between Plaxis and the open-source probabilistic toolbox OpenTURNS [5].…”

“…It is worth noting that the authors of this paper recently performed a finite element-based assessment of the reference quay wall concerned in this study. The reader is therefore referred to Roubos et al [49] for a detailed description of other random variables.…”

“…In addition, dependency between input variables was taken into account in order to prevent underestimation of the probability of failure. Table 2 presents the correlation matrix considered [49]. It is worth noting that the unsaturated (γ dr ) and saturated (γ sat ) soil weight densities were assumed to be fully dependent.…”

“…This is a direct consequence of the a The number of samples is too low to determine the reliability index; a more accurate result should be obtained with a higher number of samples. b Results were derived in Roubos et al [49]. Fig.…”