Problem $1$:

The Figure shows a simply supported beam and the cross$-$section at midspan. The beam

supports a uniform dead load consisting of its own weight plus $1\mathrm{.}5$kip$\frac{s}{f}t$ and a uniform live

load of $1\mathrm{.}2ki\frac{p}{f}t.$ The concrete strength is $4500$ psi $,$ and the yield strength of the reinforcement

is $60,000$ psi. The concrete is normal$-$weight concrete. For the midspan section shown compute

$M_n$ and show that it exceeds $M_u.$

$($i

$($b$)3$ No$.8$ bars

$12$ in$.$