The problem should be solved in Excel as requested, including charts. For the rectangle, $3$ different concrete areas need to be defined. The concrete widths of these $3$ regions, the upper middle and lower regions, need to be calculated separately because they are different. Thanks in advance.Q $2$: $(50$ P$.)$

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

Column.

Use C$30/$S$420$

$A_{s\text{t}\text{o}\text{p}}=A_5$ bot $=1100m{m}^2$

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

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,