Problem $2(25$ poin$($s$)$

Find the moment capacity of the cross$-$section shown in figure. Consider a concrete cover at the tension steel of $50mm.$

$f_{ck}=25\frac{N}{m}{m}^2$

$f_{9k}=500\frac{N}{m}{m}^2.$

$h=650mm$

$b=250mm$

$d^{\text{'}}=110mm$

$A^{\text{'}}=500m{m}^2$

$A_s=1900m{m}^2$