2 Dimensions of sections

2.1 Masses

The masses per metre have been calculated assuming that the density of steel is 7850 kg/m3.

In all cases the tabulated masses are for the steel section alone and no allowance has been made for connecting material or fittings.

2.2 Ratios for local buckling

For circular hollow sections the ratios of the outside diameter to thickness (d / t) are given.

For square and rectangular hollow sections the ratios (cf / t) and (cw / t) are given where: cf = b − 3t and cw = h − 3t

For square hollow sections cf and cw are equal. Note that these relationships for cf and cw are applicable to both hot-finished and cold-formed sections.

The dimensions cf and cw are not precisely defined in EN 1993-1-1 and the internal profile of the corners is not specified in either EN 10210-2 or EN 10219-2. The above expressions give conservative values of the ratio for both hot-finished and cold-formed sections.