$22\mathrm{.}3.$ A $24$ in $.$ deep, $8$ ft wide, $70$ ft long double T beam carries a girder weight

of $420$ plf$,$ a sustained dead load of $10$ psf $,$ and superimposed live load of

$30$ psf $.$ It is prestressed with twelve $(1)/(2)$in$.$ diameter $270$ ksi low$-$relaxation

strands with a midspan eccentricity of $12\mathrm{.}3$ in $.$ and an end eccentricity of

$5\mathrm{.}0$ in $.$ Section properties are A$\_($c$)=401$in$^(2),$I$\_($g$)=20,985$in$^(4),$y$\_($b$)=17\mathrm{.}15$in$.,$

y$\_($t$)=6\mathrm{.}85$in$.,$ and h$\_($f$)=2$in$.$ Concrete strength is $5000\backslash$psi $,$f$\_($ci$)^(\text{'})=3500\backslash$psi $,$

and R$=0\mathrm{.}80.$ Determine the class of the beam.