Select the lightest W$12$ section $($A$992$ steel$)$ for column $($CD$)$ of the unbraced frame.

The column is resisting a factored axial force Pu of $500$ kips and it is pinned at the bottom.

Mux $=60k-ft=$ factored moment about the $"x"$ axis.

Out$-$of$-$plane, the column is considered braced for buckling about the weak axis. It has an additional bracing at mid$-$height that could be considered a pin support.

Disregard second order effects.

A$,$ C$,$ E are pinned supports

$P_u=$ factored axial load

$M_{ux}=$ factored bending moment