On the Origin of I Beams and Quick Analysis on the Structural Efficiency of Hot-rolled Steel Members

In the current paper the origin of steel I beams has been analysed from historical-technological and structural points of view.

First, the way leading to discover the most famous structural member of the modern Steel Engineering has been reconstructed. Later on, parameters of structural efficiency, allowing for a quick numerical evaluation of the effects produced by the rolling process on the semi-finished casting products, have been defined as a function of the difference in terms of weight between the solid billet and the member final shape on the basis of the more or less raw material centrifugation. By using the above mentioned structural efficiency parameters, the design criteria used for development of the European list of sections, with particular reference to IPE and HE profiles, have been comprehended.

Finally, the proposed method, if applied to members having the same area, allows defining, without considering local buckling phenomena, the best profile for each performance category of steel members.