Question 4 Use the approximate Odemark approach to determine

Question #4 Use the approximate Odemark approach to determine the surface deflection under the centerli of a tire with a 0.15 m radius, carrying a load of 40 kN resting on a 0.4 m thick asphalt concre layer placed on top of a subgrade of infinite depth. The layer moduli are 1300 MPA and 150 MPA, respectively, and -0.50 for both layers.

Solution

Solution:-

Given

E₁/E₂ =150/1300 = 0.115

A tire radius (a) = 0.15 meter

Thickness of asphalt (h) = 0.4 meter

Load on tire = 40 kN

Tire pressure (p) = 40 *10³/( * (0.15 *10³)²) = 0.707 N/mm²

h/a = 0.4/0.15 = 2.66

by helping of E₁/E₂ and value of h/a , we can calculate value of F from graph

value of F = 0.32

   Surface deflection ( ) = (1.5 * p* a *F)/E₁  

                                             = (1.5 * 0.707 * 0.15 *10³ * 0.32 )/150

                                             = 0.339 mm    Answer