Probabilistic Compressive Strength of Stiffened Steel Plates Exhibiting Column-Like Behavior: Ultimate and Serviceability Limit States

Abstract

The strength of longitudinally continuous stiffened steel plates, exhibiting column-like behavior under uniaxial compression, was investigated at ultimate as well as serviceability limit states. Compressive strengths were determined from nonlinear elastoplastic FE analysis, where both material and geometric nonlinearity were taken into account. In the parametric analysis, the reduced slenderness parameter (RR) was varied from 0.4 to 1.4, and for each RR, thick plates and high-performance steels (SBHS) were considered along with thin plates and ordinary steels. The probabilistic distribution of the strengths was obtained through Monte Carlo simulation, in association with a response surface method. The response surface function comprises three independent variables, upon which the uncertainties in estimating the compressive strength of a certain stiffened plate depend, i.e., the residual stress, the initial out-of-plane whole-plate deflection, and the initial out-of-plane local deflection. Comparing the ultimate strength with a 5% non-exceedance probability indicates that the AASHTO, Canadian Code, and Japanese specification provides significantly conservative design, specifically for RR>0.8. Based on the obtained probabilistic information, partial safety factors for each RR were proposed, considering the mean value strengths as the nominal strengths, as an example.