$2\mathrm{.}8.$ A pavement structure is comprised of the following layers: $5\mathrm{.}75-$inch asphalt concrete surface, $E=400,000$;$23\mathrm{.}0$ inches of granular base, $E=20,000,$ and a subgrade having an $E=10,000.$ All layers are assumed to have $=0\mathrm{.}5.$ Calculate the horizontal tensile strain at the bottom of the asphalt concrete layer and the vertical compressive strain at the top of the subgrade layer under the centerline of a $40,000-$pound wheel load, $150$ psi pressure.