A rigid pavement is designed with a 11-inch slab, an E_c of 6 million Ib/in^2, a concrete modulus of rupture of 432 Ib/in^2, a load transfer coefficient of 3.0, an initial PSI of 4.50, and a TSI of 2.5. The overall standard deviation is 0.56, the modulus of subgrade reaction is 190 Ib/in^3, and a reliability of 90% is used along with a drainage coefficient of 0.87. The pavement is designed assuming that traffic is composed entirely of trucks (50 per day). Each truck has one 20-kip single axle and one 42-kip tandem axle (the effect of all other vehicles is ignored). A section of this road is to be replaced (due to different subgrade characteristics) with a flexible pavement having a SN of 5 and is expected to last the same number of years as the rigid pavement. What is the assumed soil resilient modulus? (Assume that all other factors are the same as for the rigid pavement). Please report your answer as a decimal in units of Ib/in^2. For example, report 3000.6 Ib/in^2 as 3000.6.

A rigid pavement is designed with a 11-inch slab, an E_c of 6 million Ib/in^2, a concrete modulus of rupture of 432 Ib/in^2, a load transfer coefficient of 3.0, an initial PSI of 4.50, and a TSI of 2.5. The overall standard deviation is 0.56, the modulus of subgrade reaction is 190 Ib/in^3, and a reliability of 90% is used along with a drainage coefficient of 0.87. The pavement is designed assuming that traffic is composed entirely of trucks (50 per day). Each truck has one 20-kip single axle and one 42-kip tandem axle (the effect of all other vehicles is ignored). A section of this road is to be replaced (due to different subgrade characteristics) with a flexible pavement having a SN of 5 and is expected to last the same number of years as the rigid pavement. What is the assumed soil resilient modulus? (Assume that all other factors are the same as for the rigid pavement). Please report your answer as a decimal in units of Ib/in^2. For example, report 3000.6 Ib/in^2 as 3000.6.

Traffic and Highway Engineering

5th Edition

ISBN:9781305156241

Author:Garber, Nicholas J.

Publisher:Garber, Nicholas J.

Chapter20: Design Of Rigid Pavements

Section: Chapter Questions

Problem 17P

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Question 3: A rigid pavement is designed with an 11-inch slab thickness, 95% reliability, E, 4,000,000 lb/in', modulus of rupture of 650 lb/in', modulus of subgrade reaction of 200 lb/in', a 3.2 load transfer coefficient, initial PSI of 4.7, final PSI of 2.5 (A PSI = 2.2), overall standard deviation of 0.40, and a drainage coefficient of 1.0. The pavement has 20 years design life. The pavement has three lanes, with PDL = 0.6 for trucks that have three axles: one 25,000 single axle, one 32,000 lb tandem axle and one 50,000 lb triple axle. What is the daily estimated truck traffic on the three lanes? Solve using AASHTO design Nomographs.
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A six-lane concrete roadway is being designed for a metropolitan area. This roadway will be constructed on a subgrade with an effective modulus of subgrade reaction k of 170 lb/in3. The ESAL used for the design period is 2.5 ? 106. Using the AASHTO design method, determine a suitable thickness of the concrete pavement (to the nearest 1⁄2 inch), provided that the working stress of the concrete to be used is 650 lb/in2 and the modulus of elasticity is 5 ? 106 lb/in2. Assume the initial service- ability is 4.75 and the terminal serviceability is 2.5. Assume the overall standard devi- ation, So, as 0.35, the load transfer coefficient J as 3.2, the drainage coefficient, Cd as 1.15, and R as 95%.
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