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Currently, in the EN1993‐1‐5 the ultimate strength of a longitudinally stiffened webs is calculated based on a design procedure which considers the ratio between the yield resistance and the critical buckling load. In the available formulation which is based on numerical modelling, the critical load increases with the relative position of the longitudinal stiffener. This behaviour contrasts with that observed at ultimate limit state, several experimental results have shown that the ultimate strength increases when the longitudinal stiffener is placed closer to the loaded flange. To solve this problem, new hypotheses of boundaries restrictions at the stiffener location are presented to model the elastic buckling behaviour of webs subjected to patch loading. A comprehensive finite element model is presented in this study to evaluate theses hypotheses by varying the web and longitudinal stiffener dimensions. Finally, a methodology to model the buckling behaviour of stiffened webs is presented. [ABSTRACT FROM AUTHOR]

This paper presents a numerical investigation on the design resistance of extruded aluminum beams subjected to concentrated loads. The study is conducted through nonlinear finite element analysis considering large displacements, initial imperfection, and taking into account the strain hardening characteristics of common aluminum alloys. The numerical model is validated against experimental works taken from the literature. Thereafter, an extensive parametric study is carried out covering a wide range of beam geometries and slenderness ratios. Resistances computed numerically are compared with those calculated using the current design provisions in the EC9 for aluminum beams subject to concentrated loads, indicating that the EC9 provisions underestimate the resistances. Then, a new resistance function is calibrated performing a statistical evaluation of experimental and numerical results. The reliability of the recalibrated resistance function is assessed according to EN 1990, the results show improvements in the predicted resistances. Finally, the use of more accurate structural design provisions enhances the possibility of higher economic benefits, and by using less material, the carbon footprint originated from aluminum production can be reduced. • The patch loading resistance of extruded aluminum beams is analyzed. • An extensive numerical study is performed through GMNIA. • The effect of several geometrical parameters on the resistance are investigated. • A statistical evaluation is conducted to calibrate a new resistance function. [ABSTRACT FROM AUTHOR]

In the current edition of the EC3 Part 1–5, the design provisions for longitudinally stiffened plate girders subjected to patch loading result in an enhanced resistance for an increasing distance of the stiffener, measured from the loaded flange. This is in contrast to the actual behavior observed experimentally, which shows a decreasing resistance for an increasing distance of the stiffener. The problem lies in the determination of the critical buckling load, which increases with the stiffener location, also affecting the calculation of the slenderness of the plate girder. At ultimate load level, the longitudinal stiffener restricts the vertical and the out-of-plane displacements of the web panel. This paper investigates the impact of various hypotheses regarding these displacements on the determination of the critical buckling load of plate girder webs with a single longitudinal stiffener. At first, the study is performed through linear buckling analysis using the finite element method, in which various displacements restrictions are applied to investigate their influence on the buckling response of the stiffened girders. The results show that a full restriction of the displacements of the stiffener in the vertical, as well as in the out-of-plane direction, lead to an improvement in the determination of the slenderness of the web panel, and hence the resistance to patch loading at ultimate load level. Finally, experimental results are compared to those obtained with a validated methodology attaining a good agreement. • The patch loading resistance of plate girders with one longitudinal stiffener is investigated. • Critical loads are calculated considering various displacement restrictions offered by the stiffener. • Imposing a nodal line at the stiffener location improves the calculation of the web slenderness. • Compliance between the behavior of the critical buckling and ultimate load is attained. • Results show an improvement in the predicted resistances for strong stiffeners (γ s ≥ γ t ). [ABSTRACT FROM AUTHOR]