2.6 Figure P2.6 shows a pavement structure composed of the following three layers: 5.75 in. HMA with elastic modulus 400,000 psi, 23 in. granular base with elastic modulus 20,000 psi, and a subgrade with elastic modulus 10,000 psi. All layers are assumed to have a Poisson ratio of 0.5. Calculate the maximum horizontal tensile strain at the bottom of HMA and the maximum vertical compressive strain on the top of subgrade under a 40,000-lb wheel load and 150-psi contact pressure, assuming that the contact area is a cir- cle. [Answer: -7.25 x 10, 1.06 x 10³] FIGURE P2.6 40,000 lb 150 psi E₁ = 400,000 psi e₁ = ? V₁-0.5 5.75 in. E₂ = 20,000 psi => E3 = 10,000 psi V2=0.5 23 in. ? V3-0.5 8