322 Table 8.3 Material Properties and Results of Stress Analysis for US 441 (Columbia County) a) Input Parameters for BISAR Layer Description Thickness Poisson's Modulus (psi) (in.) Ratio Dynaflect FWD 1 Asphalt Concrete 3.0 0.35 1,453,200 * 1,453,200 * 2 Limerock Base 9.0 0.35 85,000 55,000 3 Subbase 12.0 0.35 60,000 35,000 4 Subgrade semi- infinite 0.40 27,500 20,000 * Computed at 23F using log = 6.4167 0.01106T for pavements at incipient failure. b) Pavement Stress Analysis Response Parameters** Dynaflect FWD Maximum Surface Deflection (mils) 10.0 12.4 Radial stress, bottom of AC layer (psi) 208.0 267.0 Radial strain, bottom of AC layer (E-6 in./in.) 93.9 115.0 Vertical stress, top of base layer (psi) -42.0 35.0 Radial stress, top of base layer (psi) -8.0 -7.1 Vertical stress, top of subbase layer (psi) -12.1 -11.4 Radial stress, top of subbase layer (psi) 0.02 -0.5 Vertical stress, top of subgrade (psi) -4.2 -4.8 Vertical strain, top of subgrade (E-6 in./in.) -155.0 -176.0 Deflection in AC layer (%) 1.0 0.8 Deflection in base layer (%) 23.8 25.8 Deflection in subbase layer (%) 17.0 21.6 Deflection in subgrade layer (%) 58.2 51.8 * Computed for single axle with dual wheels (6.0 kips/wheel) NOTE: + = tensile - = compressive