A $300mm300mm$ concrete column which is pin connected at both ends has an unsupported length of $4\mathrm{.}6m.$ The column is carrying a total factored axial load $Pu=300kN$ and a lateral concentrated load of $90kN$ acting at mid $-$ height of the column. Assume f$\text{'}c=21$MPa and ${}_{dns}=0\mathrm{.}15$

Compute the critical buckling load

a$\mathrm{.}1573\mathrm{.}268kN$

b$.2358\mathrm{.}617kN$

c$.3528\mathrm{.}167kN$

d$.3826\mathrm{.}175kN$

Comprte the magnification factor

a$\mathrm{.}1\mathrm{.}204$

b$.1\mathrm{.}305$

c$.1\mathrm{.}406$

d$.1\mathrm{.}507$

Compute the total moment including the secondary moment due to lateral deflection.

a$.421\mathrm{.}464kN-m$

b$.264\mathrm{.}214kN-m$

c$.124\mathrm{.}614kN-m$