Question$-3$: For the column cross$-$section with given material properties as seen in the figure:

Structural Materials: C$40/$ S$420$; Concrete Cover: $d^{\text{'}}=40mm$

a$)$ Obtain and draw $M-N$ interaction diagram:

Consider cases: $($i$)$ simple tension; $($ii$)$ simple bending;

$($iii$)$ balanced reinforcement; $($iv$)$ simple compression.

$A_{s1}=A_{s2}=420$

$A_{\text{s}\text{m}\text{i}\text{d}}=216,(=402m{m}^2)$

b$)$ What are the $N_{\text{m}\text{a}\text{x}}($Axial Force$)$ and $M_{\text{m}\text{i}\text{n}}($Moment$)$ for this column,

allowable in the earthquake region?