Q$\mathrm{.}1)(50$ points$)$ A $300mm400mm$ short column is subjected to an axial dead load and axial live load and no moment. Find the required reinforcement of the column if:

$P_{DL}=100kN$ and $P_{LL}=200kN$

$P_{DL}=500kN$ and $P_{LL}=700kN$

$P_{DL}=1000kN$ and $P_{LL}=2000kN$

$f_c^{\text{'}}=28$MPa, and $f_y=420$MPa, concrete cover $=4cm$