1
CEE 462 Fall 2021
HOMEWORK #2
Traffic Calculation (Keys)
Due: September 16, 2021
(Total 57 points)
Calculation: AASHTO 1993 Traffic Input
1. The axle load data are obtained from total 30 vehicles of class 6 type.
Calculate average truck factors for the conditions below.
a) Flexible pavement with SN = 6, Pt = 2.0 (3 points)
b) Flexible pavement with SN = 3, Pt = 2.5 (3 points)
c) Rigid pavement with slab thickness D=6”, Pt = 2.5 (3 points)
d) Rigid pavement with slab thickness D=12”, Pt = 2.5 (3 points)
Keys
a) TF = 3.937 b) TF = 3.618 c) TF = 4.707 d) TF = 5.218
Conditions in the lecture note
Axle Load,
kip
Number of
Daily Axles
10 5
18 10
20 10
30 5
10 2
20 5
30 10
40 10
50 3
Single front axle loads
Tandem rear axle loads
Axle
Load, kip
Number
of Daily
Axles
LEF Daily ESALs
Tandem rear axle loads
Total # of ESALs
Total # of Trucks
Average Truck Factor, TF
Single front axle loads
2
CEE 462 Fall 2021
a) Flexible pavement with SN = 6, Pt = 2.0
Table D1 & D2
Axle
Load, kip
Number
of Daily
Axles
LEF Daily ESALs
10 50.076 0.380
18 10 1.000 10.000
20 10 1.590 15.900
30 59.200 46.000
10 20.006 0.012
20 50.105 0.525
30 10 0.617 6.170
40 10 2.180 21.800
50 35.770 17.310
118.097
30
3.937
Single front axle loads
Tandem rear axle loads
Total # of ESALs
Total # of Trucks
Average Truck Factor, TF
b) Flexible pavement with SN = 3, Pt = 2.5
Table D4 & D5
Axle
Load, kip
Number
of Daily
Axles
LEF Daily ESALs
10 50.118 0.590
18 10 1.000 10.000
20 10 1.490 14.900
30 57.900 39.500
10 20.011 0.022
20 50.162 0.810
30 10 0.703 7.030
40 10 2.060 20.600
50 35.030 15.090
108.542
30
3.618
Total # of Trucks
Average Truck Factor, TF
Single front axle loads
Tandem rear axle loads
Total # of ESALs
c) Rigid pavement with Slab thickness, D = 6“, Pt = 2.5
Table D13 & D14
Axle
Number
of Daily
LEF Daily ESALs
d) Rigid pavement with Slab thickness, D = 12“, Pt = 2.5
Table D13 & D14
Axle
Number