TM 5-822-13/AFJMAN 32-1018
Table 5-2. Operations Per Coverage Ratio, Rigid Pavements.
(1)
(2)
(4)
(5)
(3)
Contact
Standard
Operations
Load
Width*
Wander*+
Deviation†
per
Range
in.
in.
Configuration
kips
in.
Coverage
Passenger Cars. Trucks. Buses. etc,
Pneumatic tires
5.63
64.37
21.46
9.59
single axle,
0-5
52.86
17.62
5-10
6.29
single wheels
7.14
44.25
2.95
0-10
6.75
Single axle,
14.75
dual wheels
7.20
41.20
13.73
2.64
10-15
20-30
13.20
2.37
7.77
39.60
0-10
Tandem axle,
5.63
54.37
18.13
8.1
single wheels
10-15
7.50
48.50
5.46
16.16
Tandem axle,
10-15
5.63
16.46
3.86
49.38
dual wheels
15-20
8.25
38.75
12.92
2.46
20-50
9.00
37.00
12.34
2.06
Forklift Trucks
Pneumatic tires
Single axle,
5.63
44.88
dual wheels
10-35
14.93
3.52
Solid rubber tires
Single axle.
0-5
5.00
51.00
17.00
8.36
50.00
single tires
5-10
6.00
16.67
7.00
10-20
7.00
49.00
16.34
5.90
Tracked Vehicles††
Solid rubber
grousers
0-20
11.22
56.75
18.92
8.58(1.43)
20-35
12.00
37.00
12.34
5.36(0.89)
35-50
12.00
21.00
7.00
4.38(0.55)
50-70
14.25
17.75
5.92
2.59(0.43)
70-120
17.25
4.75
1.58
2.0 (0.33)
Note:
Traffic lane width (Pw) - 11 ft (except for solid rubber-tired
Spacing between dual wheels(s) - 2 in., Ws - average wheel spacing
from table 3-1.
truck where Cw - Tw).
**Wander (Bw) for single wheels or track - Pw - (Ws + Cw; for dual
wheels, Bw - Pw - (Ws + 1.75 Tw + S).
†Standard deviation (a) - Bw/3.
††The values shown in the parentheses are for conservative type of design.
where
N + 2.665 log10 (E/14.22) + 0.392
A=
5
N = log10(coverage)
E = elastic modulus of the bituminous concrete (psi)
b. Subgrade strain criteria. Failure criteria (fig 5-1) for roads and streets are approximated by the equation
Allowable strain , SUB G = 10-A
(eq 5-4)
where
A = 0.1408 log10 (coverage) + 2.408
Equation 5-5 can also be written as
Allowable coverage = 10-A
(eq 5-5)
where
A = (2.408 + log10 ( , SUBG))/0.1408
5-3
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