Problem $1-$ Flexure

Below is the framing plan for a floor of a very simple structure. The dead loads acting on this floor include an $8$ inch thick slab of normal weight concrete and $20$ psf of additional dead loads. The floor also needs to carry $75$ psf of live load.

$4$ spaces @$15\text{'}={60}^{\text{'}}$

a$.$ Assume beam $A-B$ can be treated as simply supported. If the beam has the cross$-$section shown below, does beam $A-B$ meet all requirements for flexure?

Jormal weight concrete

${?}^{\text{'}}c=4500$

$t_s=6$#$9$ bars $of$ Grade $60$ steel