Formulas: Doubly Symmetric Rolled Compact Members Subjected to Single-Axis Flexure and Compression

Formula 1

For doubly symmetric rolled compact members, with the effective length for torsional buckling less than or equal to the effective length for y-axis flexural buckling, $L_{c z} \leq L_{c y}$, subjected to flexure and compression with moments primarily about their major axis, it is permissible to address the two independent limit states, in-plane instability and out-of-plane buckling or lateral-torsional buckling, separately in lieu of the combined approach provided in Section H1.1,

Formula 2

For members with $M_{r y} / M_{\mathrm{cy}} \geq 0.05$, the provisions of Section H1.1 shall be followed.

Formula 3

where

• $\begin{aligned} C_{b} & =\text { lateral-torsional buckling modification factor determined from Section } \\ & \text { F1 }\end{aligned}$
• $M_{c x}=$ available lateral-torsional strength for major-axis flexure determined in accordance with Chapter F using $C_{b}=1.0, \mathrm{kip} \cdot \mathrm{in} .(\mathrm{N}-\mathrm{mm})$
• $P_{\mathrm{cy}}=$ available compressive strength out of the plane of bending, kips (N)

Found in

• DOUBLY AND SINGLY SYMMETRIC MEMBERS SUBJECTED TO FLEXURE AND AXIAL FORCE