Practice Exercise for Lesson 3
3.
What will be the combined thickness of the pavement and base using the Reduced Subgrade
Strength Method, using the following information:
Given:
Design wheel load
= 25,000 lbs
Traffic Area
= Type B
Subgrade Material
= Horizontally uniform clay (CL)
Plasticity Index, 18
Water Content, 25% (avg)
Normal Period, CBR 8
Base
CBR 100 (Normal period, high quality
graded crushed aggregate)
CBR 50 (Remainder of base non-frost-
susceptible sandy gravel (GW)
Any water content after drainage 5%
Highest ground water 3 feet below the
surface or subgrade.
a.
33 inches.
b.
28 inches.
c.
20 inches.
d.
19 inches.
4.
Design the flexible pavement for frost for T/O airfield Problem #2. Assume that the subbase
material is NOT frost susceptible but that the select material is (18% passes the #200 sieve). The
C-130E has a single-tandem landing gear with 400 in2 in each wheel.
75
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