Homework 5

Vehicle Class

Vehicle Count

Flexible LEF

Flexible ESALs

1–2 16302 0.001 16.3 3 3432 0.004 13.7 4 131 0.300 39.3 5 481 0.170 81.8

6–7 515 0.700 360.5 8 824 0.700 576.8

9–13 6915 1.100 7606.5 ADT = 28600 0.304 8695

ESALS =ADT =

f

8695

ESAL 365 ADT T T D L G

1-way ADT 2 lanes 3 lanes 4 lanes

5,000 or less 90% 75% 70%

5,000–10,000 80% 70% 65%

10,000–15,000 75% 65% 60%

15,000–20,000 75% 65% 55%

20,000–30,000 70% 60% 50%

30,000–70,000 65% 60% 50%

52024 2019

5

ADT ADT 1.025

28,600 1.02532,358

1-way ADT 2 lanes 3 lanes 4 lanes

5,000 or less 90% 75% 70%

5,000–10,000 80% 70% 65%

10,000–15,000 75% 65% 60%

15,000–20,000 75% 65% 55%

20,000–30,000 70% 60% 50%

30,000–70,000 65% 60% 50%

Estimating Subgrade MR

1500 RM CBRWARNING: Only for fine-grained soils with soaked CBR < 10.

1993 AASHTO Guide

14

Estimating Subgrade MR

0.642555 RM CBRGood for a wide range of soil types

AASHTO MEPDG

15

1500 7500RM CBR psi

0.642555 7157RM CBR psi

Assume MR = 7300 psi

Asphalt Layer Coefficient

19

0.440.42

400,000440,000

0.30

ATB Layer Coefficients

21

3.5 x 105 psi

0.30

Base Layer Coefficient

23

25,000 psi

30,000 psi

0.30

0.30

Subbase Layer Coefficients

27

10,500 psi