TM 5-822-13/AFJMAN 32-1018
e. Example No. 3.
(1) To illustrate the design procedure for tracked vehicles, it is assumed that a concrete pavement is to be
designed for an average of 10 M1 tanks per lane per day. The Ml tank has the following characteristics:
Gross weight
120 kips
Track spacing (c to c)
112 inches
Track width
25 inches
Track contact width
18.75 inches (= 0.75 x 25)
Track length
180 inches
Number of bogies per track
7.0
Operations per coverage ratio
0.33 (from table 5-1)
(2) To use computer codes such as the JULEA computer program, the track load will be converted into
eight uniformly distributed circular loads. Each circle has a diameter of 17.25 inches (the width of the track) and
a load of 7,500 pounds. The distance between bogies is 20.4 inches center to center. The computed maximum
stresses for several concrete thicknesses are tabulated in column 2 of table `7-3. The maximum stress in this case
occurs under the center load. In other cases, the location of the maximum stress needs to be determined. This is
done by computing stresses in many locations and selecting the maximum stress. Following the procedures in
example 2, a plot of concrete thickness (column 1) against damage (column 6) shows that the design concrete
thickness is 13.7 inches. This thickness value would be rounded off to 14.0 inches for design.
Table 7-3. Cumulative Damage Computed for M1 Tank.
Slab Thickness
Maximum Stress
Allowable* Coverage
Damage
Design ** Coverage
ni/Ni
1.33 x
max
max
Ni
(2)
(4)
(3)
(6)
8
347
461.5
329
273,204
830
10
275
365.8
3,124
273,204
87
12
224
297.9
37,137
273,204
7.4
14
185
246.1
615,013
273,204
0.4
*SCI = 80, R = 625 psi.
**Design coverages for 25 years is 25 x 365 x 10/0.33 = 273,204.
f. Example No. 4. To illustrate the procedure for conventional traffic plus forklift trucks and tracked ve-
hicles, design a concrete pavement road for the following traffic:
Passenger cars
300 per
lane
per
day
Panel and pickup trucks
200 per
lane
per
day
Trucks, 2-axle
100 per
lane
per
day
Trucks, 3-axle
40 per
lane
per
day
Track-laying vehicles, 120,000 pounds (Ml tank)
2 per
lane
per
day
Forklift trucks, 25,000 pounds (Pneumatic tires)
20 per
lane
per
day
Table 7-4 shows the design coverages for each wheel or track configuration, and table 7-5 shows the computed
maximum stresses and damage. The cumulative damage for concrete thicknesses of 8, 10 and 12 inches is 34.2,
3.4 and 0.3, respectively. A plot of these values indicates a required concrete thickness of 11.2 inches for a dam-
age of one. This thickness value would be rounded off to 11 inches for design.
7-6. Joints.
The design and construction of joints for plain and roller-compacted concrete, the design and installation of
dowel bars, special provisions for slipform paving, and joint sealing are presented in TM 5-822-5/AFM 88-7,
Chap. 3.
7-7. Design Details.
Typical details for the design and construction of plain concrete pavements are contained in TM 5-822-5/AFM
88-7, Chap. 3.
7-6
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