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ICDP4-361-12

# ICDP4-361-12 - design direction with 400 trucks per day in...

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CE 361 In-Class Design Problem #4: Pavement Design For this exercise, you are to design a roadway that is to carry 100,000 people a day ( excluding truck occupants ) – 50,000 in design direction. The vehicles that carry these people include; (1) personal vehicles (average occupancy of 1.2 people per car) 2-2 kip single axles, and (2) buses with 2-22 kip single axles (assume they are filled with an average of 40 passengers). There are also trucks on the roadway and all trucks have 1-40 kip triple axle, 1-32 kip tandem axle, and 1-8 kip single axle. You know that the soil CBR is 6, the initial PSI is 4.5 and the TSI is 2.5. Other values to be used: All drainage coefficients = 1.0 Reliability = 90% Overall standard deviation of traffic = 0.50 Concrete Modulus of Elasticity = 5.5 million lb/in 2 Concrete Modulus of Rupture = 750 lb/in 2 PCC load transfer coefficient = 3.0 Design a rigid and flexible pavement, to last 15 years, for a four-lane road (four lanes in
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Unformatted text preview: design direction) with 400 trucks per day in the design direction, and 20% of all travelers going by bus (the rest go in personal vehicles). Sketch cross-section of your two pavement designs and show all parameter assumptions. Do not forget to determine the amount of traffic that will be in the “design-lane” before beginning your computations (see Table 4.11). Procedure: • Determine W 18 for rigid and W 18 for flexible (they will not be the same). Assume SN =4 and D =10 to get the axle-load equivalence factors. • Determine design lane W 18 for 4 lanes (design conservatively). See Table 4.11. • For flexible pavement, select layer materials and thicknesses using Eq. 4.9 3 3 3 2 2 2 1 1 SN M D a M D a D a + + = . Assume all but one D , and solve for it (as done in Example 4.2 on page 114)....
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