ABSTRACT
Q c Normalized wall slenderness for local buckling ofCHS
Qij Knockdown factor for cylindrical shells (Tiej Theoretical elastic local buckling stress for
cylindrical shell J.L Poisson's ratio
Circular tubes were widely used as structural members in some of the earliest examples of steel bridge construction, e.g. Forth Road Bridge in Scotland and the Eads Bridge in St Louis. However, as technology developed efficient methods of producing other hot-formed structural shapes, the use of steel tubes in construction did not flourish. Only in the last few decades has the use of steel tubes, both circular and rectangular, encountered a regeneration. Consequently, tubes are thought of as a relatively new type of structural element. Many design codes do not take full advantage of the
92 D.R. Sherman
structural properties of tubes and most designers are not as familiar with their use as they are with other shapes.
