A W $15030$ column has a length of $3\mathrm{.}6m$ and the ends are pinned

connected. The steel use is $A36$ with $Fy=250$Mpa and the proportional limit

is assumed to be $230$Mpa with a factor of safety of $3\mathrm{.}0.$ Es $=200,000$Mpa

$(1)$ Determine the allowable compressive stress using Euler's formula

$(2)$ Determine the buckling load

$(3)$ Determine the allowable compressive load