TM 5-850-1
CBR = measure of soil strength as determined
by Test 101 specified in Military
Standard No. MIL-STD-621A,
"Test Methods for Pavement
Subgrade, Subbase, and Base
Course Materials," December 1964.
A = tire contact area, square inches
where
The CBR and thickness requirements for 200 and
t=
total thickness of superior material required
10,000 passes of container handling vehicles operating
above a layer of known strength to prevent
on unsurfaced soils with subgrade strength of four and
shear deformation within this layer of soil,
ten CBR are contained in table B-1. These
inches
requirements may be used as design criteria in
a
1=
load repetitions factor, which varies with
accordance with table B-2.
number of wheels and volume of traffic
b. Soils beneath landing mat.
Strength and
Pe =
SWL or ESWL2 tire pressure, pounds per
thickness requirements for soils beneath landing mat are
square inch. For single-wheel loads, P. =
determined through use of the following equations:
SWL/A. This is an actual tire pressure and
is generally equal to the tire inflation
pressure. For multiple-wheel
configurations, P. = ESWL/A. This is an
artificial tire pressure, consistent with use
of
the contact area of one tire, and has no
relation to actual tire inflation pressure
where
Thickness requirements for various container handling
vehicles were determined for 200 and 10,000 passes
TR =
thickness of flexible pavement structure
through the solution of equation (B-4), and the results of
replaced by landing mat, inches
these computations are shown in figures B-13 through
f=
repetitions factor The soil strength and
thickness requirements for container handling vehicles
are given in table B-4. These requirements may be
1
Discussed in Technical Report S-71-17 by R. G.
used as design criteria in accordance with the
Alhvin.
restrictions set forth in table B-3.
2
ESWL can be determined by methods given in
Miscellaneous Paper 8-73-56 by D. N. Brown and 0.
B-5. Thickness requirements for flexible pavements.
O. Thompson.
Thickness of flexible pavements can be determined
through the use of the following equation:
B-3
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