Numerical Investigation of Stiffened Steel Plates

Because of their high strength to weight ratio, stiffened steel plates are often used in light structures where plates are placed into compression. The stability of steel plates stiffened with longitudinal tee-shaped stiffeners and subjected to uniaxial compression or combined axial compression and out-of-plane bending formed the basis for this research project. The research was conducted to develop a simple approach to assess the post-buckling behaviour of stiffened steel plates and provide a limit states design procedure that accounts for the post-buckling stability in the assessment of the resistance factor.;Based on a better understanding of the behaviour of stiffened steel plates, a set of design equations were developed to calculate the strength of stiffened steel plate subjected to compression in the direction of the stiffener and out-of-plane bending.;The proposed design equations were compared with current design guidelines through a comparison of the design approaches with the finite element analysis results. The proposed method showed much better accuracy than the current design approaches.;A reliability analysis was conducted to provide appropriate resistance factors for limit states design. Due to the complexity of the design formulas, the Monte Carlo simulation technique was used to generate the statistical distributions of the predicted strength. The second-moment method was used to calculate the resistance factors for different values of safety index. The resistance factor varied from 0.90 to 0.65 for values of safety index from 2.5 to 4.5, respectively.;The behaviour of stiffened plates was investigated using a finite element model that had been validated through comparison with test results. An exhaustive parametric study, including 1440 finite element analyses, was conducted to investigate the strength and behaviour of stiffened steel plates. A virtual work model was developed to explain the effect of the formation of a plastic hinge mechanism on the post-buckling strength and behaviour. Combined with the numerical results, the theoretical model confirms that the plastic hinge mechanism can cause a sudden loss of capacity. The required lateral deflection for a plastic hinge development can be calculated using the virtual work model for prediction of the unstable behaviour.