Variation in the cross-sectional geometry of hot-rolled I-sections: Measurements, statistics, probabilistic modelling

This paper presents the evaluation of an extensive measurement campaign on the cross-sectional dimensions of hot-rolled I-sections. As a preliminary step, the reliability of the measuring process was quantified as well as checked to what extent the cross-sectional dimensions remain constant along a beam. In the main part of the investigation, a total of 561 statistically independent I-sections with a wide range of different sizes were surveyed and statistically analysed. Overall, the observed variation of the dimensions revealed a good agreement with the characterisation in the new Annex E of EN 1993-1-1. However, a more detailed evaluation showed that there is a certain dependence of these statistical parameters on the nominal size of the dimensions. Furthermore, several other aspects were checked, such as the correlation between the individual dimensions, the compliance with manufacturing tolerances according to EN 10034 and the uniformity of the web and flange thickness at various positions within the cross-section. Subsequently, the measured profiles were also analysed based on the resulting cross-sectional properties. In addition to a statistical evaluation in respect to the corresponding nominal values, the influence of the common shape idealisation to a perfectly double-symmetrical cross-section with constant flange thicknesses was addressed. Finally, a comparison of several options for the probabilistic modelling of the geometric variability was carried out, based on the lower 5%-quantiles of the resulting cross-sectional properties.