Browsing by Author "Zizza, Antonio"

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Open Access
Buckling behaviour of unstiffened and stiffened steel plates under multiaxial stress states
(Stuttgart : Institut für Konstruktion und Entwurf, 2016) Zizza, Antonio; Kuhlmann, Ulrike (Prof. Dr.-Ing.)
Modern steel constructions such as long span bridges are characterised by slender plated structures and the optimisation of their fabrication. Since often several internal forces act at the same time on the cross-section, very complex multiaxial stress states may develop. The aim of this work is to investigate the buckling behaviour of unstiffened and stiffened steel plates under several load combinations and especially to analyse the inﬂuence of tensile stresses. As in EN 1993-1-5 according to the reduced stress method multiaxial stress states are already considered in the determination of the single plate slenderness, this theoretically allows for taking into account the positive effect of tensile stress on the buckling behaviour. However, only few studies looked at this effect until now and systematic investigations are missing, so that this work clarifies this open issue. Experimental investigations on stiffened and unstiffened steel plates are conducted showing the buckling behaviour under several multiaxial stress states, which are observed also for the numerical investigations. The validated numerical models are used for the realisation of studies including the variation of a wide range of parameters by the multi-purpose code ABAQUS considering the interaction cases tension-compression, tension-shear, compression-shear and bending-shear on unstiffened plates as well as biaxial compression on stiffened plates. Based on the presented parametric study a new proposal is developed and compared to the numerical results showing good agreements for the investigated load cases justifying the utilisation of positive effects from tensile stresses and an improvement of the interaction considering bending-shear. The outcomes of this work allow the consideration of tensile stresses for the design of plated structures and is in full accordance with the principles of the reduced stress method for the current design procedure in EN 1993-1-5. Furthermore, the numerical analyses highlight issues regarding the modelling and the realisation of buckling analyses using the Finite Element Method, especially in terms of initial imperfections.