PC 150x65-9.36 - Section Properties

PC 150x65-9.36 has a mass of 9.36 kg/m, tabulated to Continental Steel. A 12 m length therefore weighs about 112 kg, which is the figure to use for a steel take-off or when checking a lift.

The plastic section modulus about the major axis, Wpl,y, is 63 cm³, and the elastic modulus Wel,y is 53.4 cm³. Wpl,y is what sets the moment capacity of a Class 1 or 2 section: M_pl,Rd = Wpl,y x f_y / gamma_M0, so at S355 with gamma_M0 = 1.0 this section reaches about 22 kNm before any stability check.

The second moment of area about the major axis, Iy, is 401 cm⁴, and about the minor axis Iz is 47.6 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 5.79 cm about the major axis and iz is 2 cm about the minor axis. Column buckling is governed by the SMALLER value: the slenderness is lambda = L_cr / i, so with iz = 2 cm a 0.2 m effective length already gives lambda = 100. Minor-axis buckling almost always controls unless the weak axis is restrained.

The St Venant torsion constant It is 0.856 cm⁴, and the warping constant Iw is 1.81 dm⁶. Open sections carry torsion mainly by warping rather than uniform torsion, which is why Iw appears in the lateral-torsional buckling resistance - both values feed M_b,Rd.