$(5$ pts$)$ Given the conditions below, determine the layer thicknesses $,$ and $($:$D_3\}$ of flexible pavement according to three suggested ways $($see the instructions below$).$ Show all the tables and diagrams used and assume other conditions if needed. Show all your work. Final answers $($thicknesses$)$ must be reported to the nearest $0\mathrm{.}1.$

Conditions

Design Period $=20$ years

Expected ESALs, $W_{18}=18\mathrm{.}6{10}^6$ ESALS

Reliability $=95\%$;$Z_R=-1\mathrm{.}65$;$So=0\mathrm{.}35$

$\frac{}{P}SI=2\mathrm{.}1(4\mathrm{.}2-2\mathrm{.}1)$

Subgrade $(M_R)=5,700$ psi

Subbase $(M_R)=11,000$ psi

Subbase Coefficient $(a_3)=0\mathrm{.}08$

Subbase Drainage Coefficient $(m_3)=1\mathrm{.}2$

Granular Base $=30,000$ psi

Granular Base Coefficient $(a_2)=0\mathrm{.}14$

Granular Base Drainage Coefficient $(m_2)=1\mathrm{.}2$

Asphalt Surface $(M{R}_R)=400,000$ psi

AC layer coefficient $(a_1)=0\mathrm{.}44$

Instructions

$3-1$ Solve the $1993$ AASHTO flexible pavement design equation for SN of the entire pavement system. Then, estimate $D_3($No need to present $D_1$ and $D_2).$ Hand calculates the thickness $(4$ pts$).$

$3-2$ Using Figure $2($Attached AASHTO Flexible Pavement Design Nomograph$),$ estimate all layer thicknesses $(4$ pts$)$

$3-3$ Using the MS$-$Excel pavement design program, estimate SN and calculate all laver thicknesses. You need to submit your Excel file $($with a file name of your first name initial and last name.xls$)$ to the Test $2$ folder $(3$ pts$)$