Advanced Steel Construction

Vol. 5, No. 2, pp. 120-126 (2009)



J. Melcher 1,*, M Škaloud 2, Z. Kala 1, M. Karmazínová 1

1 Brno University of Technology, CZ-602 00 Brno, Czech Republic,

2 Professor, Academy of Sciences of the Czech republic, Prague

*(Corresponding author: E-mail:This email address is being protected from spambots. You need JavaScript enabled to view it.)




The objective of the paper is to analyse the influence of initial imperfections on the behaviour of thin-walled girders welded of slender plate elements. The girder was modelled, using the geometrically and materially non-linear variant of the shell finite element method, by the ANSYS program. The ultimate static load-carrying capacity and the state of stress were considered as the output analysed quantities. The influence of the variability of initial imperfections on the variability of ultimate static lo ad-carrying capacity and on the variability of the state of stress studied was calculated by sensitivity analysis. The sensitivity analysis was evaluated on a computer by applying the numerical simulation LHS method and statistical characteristics evaluated, based on the experiments. Real tests of girders with random initial imperfections the occurrence frequency of which is equivalent to experimental results are simulated numerically. In each LHS method run, both load-carrying capacity and state of stress are evaluated on the model based on nonlinear variant of shell finite elements. The stress state was evaluated by bending stresses developing in the crack-prone areas of a web "breathing" under repeated loads, which–as it was demonstrated by the experiments- occurred at the toes of the fillet welds connecting the "breathing" web with the girder flanges and stiffeners.


Keywords:Steel structures, fatigue, imperfection, sensitivity, reliability, plated girder.


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