$1$

$10$ points

Find the practical moment strength $Mn$ of the beam shown in the figure. Assuming a strength reduction factor $()$ of $0\mathrm{.}90.$ The beam is simply supported.

Concrete Compressive Strength $(f^{\text{'}}c)$: $4,000$ psi

Steel Yield Strength $($fy$)$: $60,000$ psi

Reinforcement Area $($As$)$: $4\mathrm{.}00$ in ${?}^2($#$9$ bar$)$

Beam Width $($b$)$: $12$ in