5. (a) For the full depth AC pavement designed in Problem4 (b), calculate the maximum tensile bending strain (EAC) in th

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: 5 A For The Full Depth Ac Pavement Designed In Problem4 B Calculate The Maximum Tensile Bending Strain Eac In Th 1 (33.23 KiB) Viewed 36 times

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5. (a) For the full depth AC pavement designed in Problem4 (b), calculate the maximum tensile bending strain (EAC) in the AC layer under a single tire load P-18,000 lb using the figure provided below and axis symmetry condition of wheel load. Use a circular tire pressure of q-64 psi. Assume the Poisson's ratio as 0.5. If you did not solve Problem 4(b), assume the AC layer thickness as 10". (20 points) 20 200 100 10 $ EE 2 -104 1 Stran actor F 15 02 0.1 0.05 0.02 OL Figure 2.21 Strain factor for single wheel to calculate critical tensile strain (b) Calculate the vertical strain (-) at the top of subgrade using the fact that or = ot for a symmetric loading. (5 points) 9
SN- for 8o4Reliabi tiny, Shandand normal deviali . -6-84 90's Steps from chart SN. 3.9 9,9 +3m +, Sarcoal values og Di BB can be obtained to satisfy SN 3.9 Elastic modules for base Corte 2500 psi, from chart SN - 2.5 5.5 inch . P. 2-3 2.5 0.42 x 6.2.52 9, modulus for Elastic Subbose Couose 150 Psi from chast SN, 2.9 DSN, - SN 27-29 > 3.7 2 + 9, 0.120.9 3.9 - 2 . . 10.10 inch Elastic modules for subgrade 6ooo pai from chart SNS - 3.9 SNE- ams 04 Asphalt Conciela swoice Cranular base Sulobase 6 inch 4 inch 11 inch
4. Using the AASHTO flexible design procedure, design a pavement for a rural principal arterial road by answering the questions below. The expected design ESAL is 1.0 x 104. The pavement structure is to consist of asphalt concrete with an elastic modulus of 400,000 psi, a granular base with an elastic modulus of 25,000 psi, and a granular subbase with an elastic modulus of 15,000 psi. The resilient modulus of the subgrade (Mx) is 6,000 psi during dry season and 3000 psi during wet season (each six months). Material properties of each layer are given in the figure below. Assume that a reliability level of 80 percent is required and the initial serviceability index is 4.0 and the final serviceability index is 2.0. Use a typical value of standard error (So = 0.45). Use the nomograph provided in the next page to get structural numbers of each layer. Neglect minimum thickness requirement. D SN, SN2 SN3 E1 = 400,000 psi a1 = 0.42 Ez = 25,000 psi a2 = 0.14 m2 = 0.8 D2 Ez = 15,000 psi a3 = 0.08 m3 = 0.8 D MR= 6.000 Bhdy) / 31000 SFW (a) What is the required thickness of the asphalt layer (Di), granular base layer (D2), and granular subbase layer (De) to satisfy the above design criteria? (25 points) (b) For a full depth asphalt concrete design (AASHTO method), what is the required thickness of the AC layer for this problem? (5 points)