Load-Carrying
Capacity Calculator
This page calculates the load-carrying
capacity of an ultra-thin whitetopping (UTW) pavement in terms of
the total number of trucks that can be carried during its service
life. The calculations are based on a comprehensive mechanistic
analysis and correlation to UTW performance data. For more information,
see ACPA publication IS100P - Ultra-thin Whitetopping.
|
| Unit
of Measure: |
Select metric or
U.S. Customary Units.
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|
| Axle-Load
Category: |
|
Category A is
for use with low-truck-volume facilities and Category B is
for medium-truck-volume facilities. Select A or B. The table
below is given only to show the axle weights. |
Axle Load
Distributions
|
Axle load,
kips (kN) |
Axles
per 1000 trucks1 |
|
Category A |
Category B |
|
Single axles |
|
4 (18) |
846.15 |
|
|
6 (27) |
369.97 |
|
|
8 (36) |
283.13 |
233.60 |
|
10 (44) |
257.60 |
142.70 |
|
12 (53) |
103.40 |
116.76 |
|
14 (62) |
39.07 |
47.76 |
|
16 (71) |
20.87 |
23.88 |
|
18 (80) |
11.57 |
16.61 |
|
20 (89) |
|
6.63 |
|
22 (98) |
|
2.60 |
|
24 (107) |
|
1.60 |
|
26 (116) |
|
0.07 |
|
Tandem axles |
|
4 (18) |
15.12 |
|
|
8 (36) |
39.21 |
47.01 |
|
12 (53) |
48.34 |
91.15 |
|
16 (71) |
72.69 |
59.25 |
|
20 (89) |
64.33 |
45.00 |
|
24 (107) |
42.24 |
30.74 |
|
28 (125) |
38.55 |
44.43 |
|
32 (142) |
27.82 |
54.76 |
|
36 (160) |
14.22 |
38.79 |
|
40 (178) |
|
7.76 |
|
44 (196) |
|
1.16 |
1
Excludes two-axle, four-tire
trucks. |
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|
| Portland
Cement Concrete Thickness: |
Enter a thickness UTW between
2 and 4 inches (50 and 100 mm).
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|
| Portland
Cement Concrete Joint Spacing: |
|
Enter a joint spacing that
is approximately 12 to 18 times the pavement thickness as
follows:
|
|
Pavement Thickness |
Suggested Joint Spacing
Range |
|
2 in. (50 mm)
3 in. (75 mm)
4 in. (100 mm) |
2 to 3 ft (0.6 to 0.9
m)
3 to 4 ft (0.9 to 1.2
m)
4 to 6 ft (1.2 to 1.8
m) |
|
| [return
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|
| Portland
Cement Concrete Flexural Strength: |
This is the average design
flexural strength (modulus of rupture) as determined by ASTM
C78, Flexural Strength of Concrete (Third-Point Loading).
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|
| Asphalt
Concrete Thickness: |
Enter the thickness of existing
asphalt after milling. Thicknesses between 3 and 6 in.
(75 and 150 mm) are accepted for calculations. If an asphalt
thickness greater than 6 in. (150 mm) is entered, the calculations
will be based on a default value of 6 in. (150 mm).
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|
| K-Value: |
This is the k-value (Westergaard’s
modulus of subgrade reaction) at the top of all layers below
the asphalt surface. Select and enter a k-value from the table
below depending on the subgrade k and combined thickness of
base and subbase (excluding asphalt thickness).
|
Select a
k-Value, pci (MPa/m)
|
Subgrade
|
Combined
thickness of base
and subbase, in. (mm) |
|
Soil |
k, pci
(MPa/m) |
4 (100) |
8 (200) |
12 (300) |
|
Poor |
75 (20) |
90 (24) |
120 (32) |
150 (41) |
|
Fair |
100 (27) |
118 (32) |
152 (41) |
186 (51) |
|
Good |
150 (41) |
168 (46) |
208 (56) |
250 (68) |
|
Excellent |
200 (54) |
217 (59) |
260 (71) |
310 (84) |
|
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|
