The A$36$ built$-$up column $10$ m long consists of W$35090$ with two plates welded to form a box section.

With respect to the $x-$axis, the column is fixed, the $y-$axis column is braced at mid$-$height. Properties of $W$ shape

section $A=11540m{m}^2,I_x=266({10}^6)m{m}^4,I_y=44({10}^6)m{m}^4,t_f=16mm,t_w=10mm.$ Compute the

design compressive strength of the column.

Calculate the maximum length of W$1482$ section if it is used as a hinged column to support a service dead

load of $450$ kN and a service live load of $900$ kN $.$ Fy $=248$MPa. Use LRFD$.$

$A=15548m{m}^2,r_x=153\mathrm{.}66mm,r_y=62\mathrm{.}94mm$

Design an A$36$ wide flange steel column with a nominal depth of $450$ mm that can resist service dead load of

$400$ kN and a service live load of $1300$ kN $.$ The effective length kL is $8$ m $.$

$($a$)$ Use LRFD and ASD methods

$($b$)$ Check the chosen section against local stability