Assessment of characteristic values of the ultimate strength of corroded steel plates with initial imperfections

This paper presents an approach for the assessment of percentiles of the response of any structural system with random properties. Different approaches are first introduced that differ on the level of accuracy of their predictions, which increases with the complexity of the approach adopted. The simpler approaches are built upon the concept “Level of Certainty” (LoC). The essence of the LoC-approach is the use of all input parameters (treated as random variables) with exactly the same Probability of Exceedance (PoE). An alternative and more accurate approach is suggested based on the assessment of the First-Order Second Moment sensitivity values of the random input parameters that are then used to calculate their design values and to predict the percentiles of the response. timate strength of a corroded steel plate with random initial distortions and random material and geometrical properties predicted by semi-empirical design equations or by means of non-linear Finite Element Analysis (FEA) is adopted as a case study to demonstrate the accuracy of the proposed approach. The percentiles of the ultimate strength of the plates calculated using these simplified approaches are compared with the ones obtained by Monte Carlo simulation.