Q$6.$ Determine the plastic centroid and also construct the M$-$N interaction diagram for

an non$-$symmetrical rectangular section with the following properties: the width of

web $b=300mm,$ the overall depth $h=550,$ the effective depth $d=500mm,A_s=$

$1470,A_s^{\text{'}}=982,C\frac{28}{35}$ concrete and grade $500$ steel. The interaction diagram

should consist of at least five data points which should include: $(1)$ the data point for

$x_{\text{b}\text{a}\text{l}}=0\mathrm{.}617d,(2)$ the data point for zero moment, and $(3)$ the data point for zero axial

load.