Q14: A flexible pavement for a rural principal arterial highway is to be designed using the 1993AASHTO guide procedure to carry a design ESAL of 2 =10^6. It is estimated that it takes about 5 days for the water to be drained from within the pavement and the pavement structure will be exposed to moisture levels approaching saturation for 10% of the time. The following additional information is available: Resilient modulus of asphalt concrete = 40o0,000 lb/in^2, CBR value of base course material =70 CBR value of subbase course material =30 CBR value of subgrade material = 4 Reliability=85%, So=0.45 Initial serviceability=4.5, final serviceability=2.0 a) Determine SN3 value? 3.0 4.1 3.5 2.8

Q14: A flexible pavement for a rural principal arterial highway is to be designed using the 1993AASHTO guide procedure to carry a design ESAL of 2 =10^6. It is estimated that it takes about 5 days for the water to be drained from within the pavement and the pavement structure will be exposed to moisture levels approaching saturation for 10% of the time. The following additional information is available: Resilient modulus of asphalt concrete = 40o0,000 lb/in^2, CBR value of base course material =70 CBR value of subbase course material =30 CBR value of subgrade material = 4 Reliability=85%, So=0.45 Initial serviceability=4.5, final serviceability=2.0 a) Determine SN3 value? 3.0 4.1 3.5 2.8

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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The pavement that need to be constructed is a six-lane divided highway. The present AADT (both directions) of 6000 vehicles is expected to grow at 5% per annum. The percent of traffic on the design lane is 45%. Determine the design ESAL if the design life is 20 years and the vehicle mix is: Passenger cars (1000 lb/axle) 60% 2-axle single-unit trucks (5000 lb/axle) = 30% 3-axle single-unit trucks (7000 lb/axle) 10% %3D Dosign the navement (with the design ESAL calculated in auestion 3a)
12. Refer to Figure II-1 attached. A flexible pavement is to be evaluated according to the AASHTO 1972 design guide. The existing pavement has a weighted structural number=3.4, a regional factor=2.0, and a soil support value=4.5. What would be the approximated number of daily equivalent 18-kip axles to be allowed on this road for a 20-year analysis period?a. 10b. 33c. 100d. 1490
The following figure shows concrete pavement with the layer thickness and elastic modulus as indicated. Assume modulus of rupture of 650 psi, load transfer coefficient of 3.2, serviceability loss from 4.5 to 2.5, and drainage coefficient of 0.9. The bedrock depth and loss of support is not considered for the subgrade. Use the design equation or monograph with 50% reliability to solve the following: 1) Determine the number of ESAL that the pavement can carry before failure. 2) If the daily traffic has 1080 single axles (20-kip), 400 single axles (24-kip), and 680 tandem axles (40-kip), and the annul traffic is the same over the design period, how many years would the concrete pavement last before failure? 8-inch Portland Cement Concrete Ec=4×106 psi 8-inch Granular Subbase Ec=30,000 psi Subgrade Mr = 5000 psi
Problem No. 1A flexible pavement for an urban interstate highway is to be designed using the AASHTOmethod to carry a design ESAL of 3 x 106. It is estimated that it takes about a week for water tobe drained from within the pavement and the pavement structure will be exposed to moisturelevels approaching saturation for 30% of the time. The following additional information is available: Elastic modulus of asphalt concrete = 450,000 psiResilient modulus of base material = 35,000 psiResilient modulus of subbase material = 15,000 psiCBR of subgrade material = 8(a) Consider designing the same pavement with only asphalt concrete and base layer (excluding subbase layer). Use the information provided in Problem 1. (b) Compare strengths and weaknesses of each design.
A rigid pavement is designed with an 11-inch slab thickness, 90% Rellability (ZR = -1.282), Es = 4 million psi, modulus of rupture of 600 psi, modulus of subgrade reaction of 150 lb/in?, a 2.8 load transfer coefficient, initial PSI = 4.8, final PSI of 2.5, overall standard deviation of 0.35, and a drainage coefficient of 0.80. The pavement has a 20-year design life. The pavement has three lanes in one direction (PDL = 0.80) and is conservatively designed for trucks that have one 20,000-lb single axle load (1.58), one 26,000-lb tandem axle (0.619), and one 34,000-b triple axle (0.593). What is the daily estimated truck traffic on the three lanes? logia (APSI) S,C¢(D@7% – 1.132) 3.0 [1.62410x10 |(D + 1)*46 | log10 (W) = Zg5, + 7.35 (log,0( D + 1)) – 0.06 +: +(4.22 - 0.327SI) log10 1+ 18.42 215.63/ De75 - 0.25
2. You are asked to design a new flexible pavement structure for an existing road that will be totally replaced. You are provided with the following borehole results: a) Existing (Old) HMA - 135 mm b) Existing (Old) Granular A Base - 170 mm c) Existing (Old) Granular B Subbase - 340 mm d) Gravelly Silty Sand (Till) Subgrade (25 % 5-75 um) What is the current GBE for the existing pavement structure? What is the GBE for the same pavement structure when it was newly constructed?
1. During the AASHO road test, ONLY flexible pavements were constructed and tested.a. Trueb. False2. The AASHO present serviceability rating (PSR) was considered an objective quantity used to establish the performance of highway pavement in terms of applied traffic.a. Trueb. False3. The AASHTO present serviceability index (PSI) correlates the PSR to actual pavement performance in terms of applied traffic, and select distresses.a. Trueb. False4. There is only one AASHTO PSI equation that applies to both flexible and rigid pavements.a. Trueb. False5. The AASHTO PSI scale ranges from:a. 0-5b. 0-10c. 0-100d. None of the above
Determine the base thickness of plain concrete pavement (PCP) without dowelled joints using the information and charts provided be • Desired project reliability - 85% Subgrade design CBR-6% • Design period -30 years • Design Traffic 5.0*10* HVAG(B) Note: The information obtained from each table or figure must be stated in the examination script to obtain relevant marks. Table 3.1: Minimum subbase requirements for rigid pavements Design traffic (HVAG) Subbase type 125 mm bound Up to 10⁰ Up to 5x10 150 mm bound or 125 mm LCS Up to 1x10 170 mm bound or 125 mm LCS 150 mm LCS Greater than 1x 10 1 Under CRCP, a heavily bound subbase with an asphalt surfacing is an acceptable alternative 75 Maximum permitted value CBR % Effective subgrade strength used in concrete base thickness determinations 60 50 40 35 30 25 20 15 12 10 Concrete Base 200 Thickness 190 (mm) 180 8. Pavement type 7. 6. 5. PCP Dowelled & CRCP 260 250 240 230 220 210 170 160 150 140 150mm LCS 125mm LCS 8 10 Design subgrade…
Q#1 What is the primary function of the pavement structure? Why do we use high quality materials as we go from bottom to top of the pavement structure? Discuss various tests used for the quality of bitumen used in flexible pavements. Discuss various tests used for the quality of aggregate used in flexible pavements.
B. A rigid pavement with a 10-inch slab thickness, 90 percent reliability, E. = 4 million lb/in², 600 lb/in² modulus of rupture, 150 lb/in³ modulus of subgrade reaction, a 2.8 load transfer coefficient, initial PSI of 4.8, final PSI of 2.5, overall standard deviation of 0.35, and a drainage coefficient of 0.8 is designed. The pavement's design life is 20 years. The three-lane road is built for vehicles with one 20,000-pound single axle, one 26,000-pound tandem axle, and one 34,000-pound triple axle. Calculate the projected daily truck traffic on the three lanes.
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 reactionk of 170 Ib/in^3. The ESAL used for the design period is 6.9* 10^6. Using the AASHTO design method, determine a suitable thickness of the concrete pavement (to the nearest 12 inch). provided that the working stress of the concrete to be used is 650 lb/in2 and the modulus of elasticity is 5 *10^6 Ib/in^2. Assume the initial serviceability is 4.75 and the terminal serviceability is 2,5. Assume the overall standard deviation, So, as 0.35, the load transfer coefficient J as 3.2. the drainage coefficient. Cd as 1.15. and R as 95%. Answer: