$2\mathrm{.}24$ The figures below show the framing plan and section of a reinforced concrete

floor system. The weight of the ceiling and floor finishing is $5$ psf $,$ that of the

mechanical and electrical systems is $5$ psf $,$ and the weight of the partitions is

$20$ psf $.$ The floor live load is $80$ psf $.$ The $6$ in$.-$thick slab exterior bay $($S$-1)$ is

reinforced with #$6$@$9$ in$.$ as the main reinforcement at the midspan and #$4$@

$12in.$ for the shrinkage and temperature reinforcement. Check the adequacy

of the slab. Use the ACI moment coefficients. Use $f_c^{\text{'}}=4,000$ and

$f_y=60,000.$