Question $1($Deflection$-$based pavement design using Burmister two$-$layer theory$)$

$1/5-$day pavement design method relies on limiting the maximum pavement leflection to within $1\mathrm{.}00$ mm under a selected wheel load. It also involves performing a plate bearing test to determine subgrade soil properties.

A plate bearing test at a construction site performed directly on the subgrade produces a deflection of $2460m.$ The applied load is $30$ kN and the loading plate has a diameter of $305$ mm $.$ The same test performed on a trial section with $300$ mm thick pavement placed on the subgrade gives a deflection of $1080m.$

Given that the selected design wheel load weighs $1\mathrm{.}80$ ton with a tyre pressure of $600k\frac{N}{m^2},$ determine the required pavement thickness using Burmister two$-$layer theory. Assume $=0\mathrm{.}5$ for all materials.

Hints: three steps analyses are required as follows:

Step $1$: Plate Bearing Test on Subgrade $($At the end, you can determine E$2)$

Step $2$: Plate Bearing Test on Trial Pavement Section $($At the end, you can determine $E_1)$

$1$

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Step $3$: Thickness Design of Pavement Layer $($Use the desing wheel loading on tire to determine the radius of circular tire imprint.$)$