Finite Element Analysis on Axial Compressive Behaviors of High-Performance Steel Stiffened Plates in Bridge Application

In order to investigate the mechanical behavior, the buckling performance and failure reason of stiffened high performance steel (HPS) plates, three-dimensional finite element (FE) models considering initial imperfections and residual stresses are compressed with axial force. Various influential factors such as element size, constitutive relations, second order effects of structure and membrane effects in buckling area were discussed to achieve a better validation with experimental data. As load increasing, the plastic strain in the U-rib near the end stiffener increases gradually under the influence of initial imperfections and stress concentration. Local buckling occurs after yielding of the whole section. With the refined model, the sensitivity of stiffened structure to the residual stresses and imperfections are investigated, and parametric studies on the material properties, geometric dimensions are conducted. The results show that the initial imperfections have a major influence on the ultimate capacity while the residual compressive stresses govern the elastic capacity and the ductility. Proper values of the imperfections and residual stresses are suggested for FE stiffened plate simulations. HPS stiffened plates with short length is more sensitive to initial imperfections. The effects of length, thickness and spacing are similar to the ordinary steel plates. Both equations in American and Chinese standards are used to evaluate the ultimate capacity of stiffened HPS plates, and formulas in AASHTO provide a more accurate estimate on capacity and failure mode, while Chinese specification is more conservative comparatively.