Z35030 - Section Properties

Z35030 has a mass of 15.23 kg/m, tabulated to Continental Steel. A 12 m length therefore weighs about 183 kg, which is the figure to use for a steel take-off or when checking a lift.

Z35030 has a depth of 350 mm, a width of 129 mm, a wall thickness of 3 mm, with a cross-sectional area of 19.1 cm². These are the nominal dimensions from Continental Steel; rolling tolerances apply to the delivered section.

The elastic section modulus about the major axis, Wel,y, is 17.8 cm³. Use it with M_el,Rd = Wel,y x f_y / gamma_M0 for an elastic check.

The second moment of area about the major axis, Iy, is 32.8 cm⁴, and about the minor axis Iz is 36.1 cm⁴. Iy is the value deflection depends on - for a simply supported beam under a uniform load, the midspan deflection is 5wL⁴/384EIy - so on spans where a deflection limit governs rather than strength, this is the number that decides the section.

iy is 593 cm about the major axis and iz is 1070 cm about the minor axis. Column buckling is governed by the SMALLER value: the slenderness is lambda = L_cr / i, so with iz = 1070 cm a 107.0 m effective length already gives lambda = 100. Minor-axis buckling almost always controls unless the weak axis is restrained.