Repeat Problem 20-19 using the PCA design method, for a pavement containing doweled joints and concrete shoulders. The modulus of rupture of the concrete used is 600 lb/in2.
What will be an ideal response?
First, determine the estimated ESALs:
2-axle (12,000 lb) single unit trucks:
ESAL = 2(0.4)(28.28)(24,000)(365)(0.40)
ESAL = 79.27 × 106
3-axle (16,000 lb) single unit trucks
ESAL = 3(0.1)(28.28)(24,000)(365)(0.40)
ESAL = 29.73 × 106
Subgrade k = 130 lb/in3
For 6 inch untreated subbase, determine effective k from Table 20.22:
k = 140 + [(230 – 140) / 100] × 30 = 167 lb/in3
Assume a slab 7 inches thick with doweled joints and concrete shoulders.
From Table 20.24, obtain equivalent stress values and then interpolate for
effective k,
Equivalent stress = 248 – ((248 – 236) × (17 / 50)) = 243.9
Stress Ratio = 243.9 / 600 = 0.41
From Table 20.27, determine the erosion factor of 2.54
12,000(1.2) = 14,400
16,000(1.2) = 19,200
The 7 inch slab is adequate, check a 6.5 inch slab.
Assume a slab 6.5 inches thick with doweled joints and concrete shoulders. From
Table 20.24, Equivalent stress = 274 – ((274 – 260) × (17 / 50)) = 269.24
Stress Ratio = 269.24 / 600 = 0.45
From Table 20.27, determine the erosion factor of 2.62
12,000(1.2) = 14,400
16,000(1.2) = 19,200
The 6.5 inch slab is inadequate since the allowable ESALs are less than
the expected ESALs.
The 6.5 inch slab is inadequate, use a 7 inch slab depth.
You might also like to view...
The development of the _____ had a revolutionary? effect on agriculture
A) internal combustion engine? B) cotton gin? C) reaper? D) combine
Intermittent sprinklers have been shown to cool swine more effectively than fine mist
foggers. A. True B. False
Technician A says that a leaking head gasket can be checked using a chemical tester. Technician B says that a leaking head gasket can be found using an exhaust gas analyzer. Which technician is correct?
A) Technician A only B) Technician B only C) Both Technicians A and B D) Neither Technician A nor B
The electric fuel pump is usually mounted in which of these locations?
A) Just above the right rear tire well B) Fuel Tank C) In front of the starter motor D) Trunk near the spare tire