Rationalizations of Section Properties Tables

Round-off to nearest (and usually larger) available standard cross section involves a component of waste in design that, together with other relevant costs, should be minimum. Commonly available cross-sectional assortments do not appear optimal in this sense. A methodology to perform the optimization is outlined and some practical aspects are illustrated by an example (an assortment of beams in flexure). Two of many possible objectives are examined in some detail. One, based on the traditional deterministic view of structural safety, is a constant weighted average safety factor in service. The other, based on reliability theory, is to minimize expected socioeconomic costs. The results are different, but not markedly so for the example studied. A general procedure to produce an optimal world catalog of metric structural cross sections is suggested.