Draw the Moment $($about $x-$axis$)$ and Axial Force Interaction diagram for given box shape RC Column.

Use C$30/$S$420$

$A_{s\text{t}\text{o}\text{p}}=A_{s\text{b}\text{o}\text{t}}=1100m{m}^2$

$d^{\text{'}}=30mm$

Find the point for each $5mm$ increment of c value

Make reasonable assumptions for missing information, if any.

Do a neat work, show all your calculations,