Question $4(20$ Marks$)$

Using the LRFD method, calculate the design compressive strength of a W$1265$ column, $20ft.$ long, and pinned at both ends. Use ASTM A$992$ Grade $50$ steel.

Using the ASD method, determine the allowable unfactored axial compression load on the column.

$L_x=L_y=20ft$

$K=1\mathrm{.}0,F_y=50$ksi

For $W1265,A_g=19\mathrm{.}1in\mathrm{.}2$

$r_x=5\mathrm{.}28in.,ry=3\mathrm{.}02in.$