Post on 24-Oct-2021
Characterizing Traffic for Rigid Pavements in IllinoisJeffery Roesler, Ph.D., P.E.Associate ProfessorDepartment of Civil and Environmental EngineeringUniversity of Illinois
North Central M-EPDG User’s Group MeetingAmes, IAFebruary 19-20, 2008
Acknowledgements
ICT R57 – Technical Review Panel
Illinois Department of Transportation
Amy Schutzbach et al.
UIUC Students
Jake Hiller
Dong Wang
Victor Cervantes
Matt Beyer
Amanda Bordelon
Overview
Illinois has existing M-E JPCP method by Zollinger and Barenberg (1989)
ESALs
IDOT has an empirical method to determine CRCP thickness
ESALs
Update/refine existing JPCP procedure and develop M-E CRCP design method
M-EPDG Evaluation
Traffic Objective
Evaluate version 0.91 vs. 1.0
Determine effects of traffic distributions on rigid pavement design
Traffic Questions
How does load spectra affect thickness design of concrete?
Is load spectra necessary over ESALs?
For IDOT, expensive to collect load spectra
Traffic Effects (v. 0.91)
Five different traffic situations
Peoria, IL Control
Standard wheel base distribution
Long Wheelbase
Short Wheelbase
Class 5 – 100% single axles
Class 9 – tandem axles
Traffic Effect –Long Wheelbase
Same inputs as control except for:
Short Medium Long 12 15 18 0% 0% 100%
Wheelbase Truck Tractor
Average Axle Spacing (ft)Percent of trucks
Traffic Effect –Short Wheelbase
Same inputs as control except for:
Short Medium Long 12 15 18 100% 0% 0%
Wheelbase Truck Tractor
Average Axle Spacing (ft)Percent of trucks
Traffic Effect – Inputs Class 5
Same inputs as control except for:
AADTT set to 7,500 to reach 200x106 ESALs
0.0% 100.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Vehicle Class Distribution(Level 3, Default Distribution)
AADTT distribution by vehicle classClass 4Class 5Class 6Class 7Class 8Class 9Class 10Class 11Class 12Class 13
0.00 0.00 0.00 0.00 2.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Number of Axles per Truck
Quad Axle
Class 4Class 5Class 6
Vehicle Class
Single Axle
Tandem Axle
Tridem Axle
Class 7Class 8Class 9Class 10Class 11Class 12Class 13
Short Medium Long 12 15 18 0% 0% 100%
Wheelbase Truck Tractor
Average Axle Spacing (ft)Percent of trucks
Traffic Effect – Inputs Class 9
Same inputs as control except for:
AADTT set to 1,100 to reach 200x106 ESALs
Axle load distribution set to 100% at 3000 lbs
Short Medium Long 12 15 18 0% 0% 100%
Wheelbase Truck Tractor
Average Axle Spacing (ft)Percent of trucks
0.0% 0.0% 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 0.0% 0.0%
Vehicle Class Distribution(Level 3, Default Distribution)
AADTT distribution by vehicle classClass 4Class 5Class 6Class 7Class 8Class 9Class 10Class 11Class 12Class 13
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.00 2.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Number of Axles per Truck
Quad Axle
Class 4Class 5Class 6
Vehicle Class
Single Axle
Tandem Axle
Tridem Axle
Class 7Class 8Class 9Class 10Class 11Class 12Class 13
Traffic Effects
Five traffic conditions produce similar results at ~ 200 million ESALs
Cracking vs. Traffic Condition
0
5
10
15
20
Peoria Control Long Wheelbase Short Wheelbase Class 5 Class 9
Traffic Condition
Crac
king
(%)
V.0.91 MEPDG Summary (Feb. 2007)
Vehicle and axle type changes affected design thickness by 0.5 in. only
ESALs appear to give
All cracking is top-down except Class 5 analysis
ESALs vs. Load Spectra Analysis
Axle load distribution effects
Selected Weigh Scales – Illinois
Bolingbrook (North)
Marion (North)
Marion (South)
Moline West
Weigh Stations
Marion (NB & SB)
Pesotum (NB)
Bolingbrook (NB & SB)Frankfort (EB)Moline (EB & WB)
Maryville (WB)
WIM
Vehicle Class DistributionVehicle Class
Bolingbrook (NB)
Bolingbrook (SB)
Frankfort (EB)
Moline (EB)
Moline (WB)
Marion (NB)
Marion (SB)
Maryville (WB)
Pesotum (NB)
4 1.6 1.6 3.7 0.9 1.1 1.1 1.1 1.0 1.8
5 4.6 4.0 1.5 1.3 1.1 2.4 2.7 1.8 6.7
6 3.7 4.0 1.4 2.9 1.8 2.4 2.8 2.1 1.0
7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
8 6.7 6.2 3.0 2.6 2.2 4.1 3.7 2.3 2.7
99 79.079.0 80.180.1 87.587.5 88.888.8 90.490.4 85.285.2 84.084.0 85.985.9 84.384.3
10 0.9 1.0 1.5 0.8 0.7 0.7 1.1 1.2 0.3
11 3.5 2.9 1.2 2.4 2.6 4.1 3.3 4.9 1.8
12 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.2
13 0.0 0.3 0.1 0.2 0.0 0.1 1.2 0.6 0.1
Vehicle Class distributionClass Illinois* California M-EPDGClass 4 1.4% 1.1% 1.8%Class 5 3.8% 23.0% 24.6%Class 6 2.3% 5.2% 7.6%Class 7 0.0% 0.3% 0.5%Class 8 3.8% 6.7% 5.0%Class 9 84.4% 50.6% 31.3%Class 10 0.5% 0.6% 9.8%Class 11 2.8% 8.8% 0.8%Class 12 0.3% 1.1% 3.3%Class 13 0.3% 0.1% 15.3%
TTC11*Close to MEPDG TTC1
Single Axle Distribution
Bolingbrook
Bolinbrook North - Single
0
20
40
60
80
100
120
Under3,001
3,001-7,000
7,001-8,000
8,001-12,000
12,001-16,000
16,001-18,000
18,001-19,000
19,001-20,000
20,001-22,000
22,001-24,000
24,001-26,000
26,001-30,000
Over30,000
Axle Weight (lbs)
Freq
uenc
y (%
)
Class 4Class 5Class 6Class 7Class 8Class 9Class 10Class 11Class 12Class 13
Comparison - Axle Weight DistributionClass 9 Tandem Axle Weight Distribution
0
2
4
6
8
10
12
14
6000
1000
014
000
1800
022
000
2600
030
000
3400
038
000
4200
046
000
5000
054
000
Axle Weight (lbs)
Freq
uenc
y (%
)
ME-PDGBolingbrook NMation SMarion NMoline WPesotum
Class 5 Axle Weight DistributionClass 5 Single Axle Load Distribution
0
10
20
30
40
50
60
70
80
90
Under
3,001
3,001
-7,00
07,0
01-8,
000
8,001
-12,00
012
,001-1
6,000
16,00
1-18,0
0018
,001-1
9,000
19,00
1-20,0
0020
,001-2
2,000
22,00
1-24,0
0024
,001-2
6,000
26,00
1-30,0
00Ove
r 30,0
00
Axle Weight (lbs)
Freq
uenc
y (%
)
ME-PDGBolingbrookPesotum
Class 9 Single Axle Weight distributionClass 9 Axle Weight Distribution
0
10
20
30
40
50
60
70
80
90
100
Under
3,001
3,001
-7,00
07,0
01-8,
000
8,001
-12,00
0
12,00
1-16,0
00
16,00
1-18,0
00
18,00
1-19,0
00
19,00
1-20,0
00
20,00
1-22,0
00
22,00
1-24,0
00
24,00
1-26,0
00
26,00
1-30,0
00Ove
r 30,0
00
Axle Weight (lbs)
Freq
uenc
y (%
)
ME-PDGBolingbrookPesotum
Traffic Cases Analyzed (v. 1.0)
Analyze thickness’ for weigh stations:
MEPDG and Bolingbrook, Moline, Marion (IL)
Replace MEPDG with Bolingbrook data for:
Single axle replacement only
Tandem axle replacement only
Tridem axle replacement only
All axles replaced
M-EPDG Inputs
Slab thickness = 10-inch
4” Asphalt Concrete Base
A-7-6 soil (7,500 psi)
Joint spacing = 15 ft (1.5” dowels)
AC shoulder
Chicago Midway Climate
MOR = 650 psi
Illinois vehicle class distribution (avg.)
JPCP Traffic Assumptions
AADTT values for MEPDG v1.0
20-year design- MEPDG CONTROL112 million ESALs = 12,000 AADTT
*AADTT = Average Annual Daily Truck Traffic
AADTT vs ESALs
Higher AADTT to reach same ESAL count
Illinois has lighter axle weight distribution
0
5000
10000
15000
20000
25000
ME-PDG Bolingbrook Marion S Marion N Moline
AA
DTT
0
20
40
60
80
100
120
140
ESA
Ls
(mill
ion)
ADDTTESALs
Effect of Axle Load Distribution
Effect of axle weight distribution on ESAL count (constant AADTT)
0
20
40
60
80
100
120
ME-PDG Single Tandem Tridem All
ESA
Ls
(mill
ion)
(Bolingbrook)
Percent Cracking at 112x106 ESALs
0
2
4
6
8
1 0
1 2
M E -P D G B o lin g b ro o k M a r io n S M a r io n N M o lin e
Cra
ckin
g Pe
cent
age
(%)
0
2
4
6
8
1 0
1 2
1 4
Thin
knes
s (in
)
P e rc e n t C ra c k in gC o n c re te T h in k n e s s
Similar cracking percentage at 112 million ESALs
9.4 to 10.6%
Description of Overload Cases
Case 1
Class 9 Tandem axle distribution
10% increase distributed between 36-42 kips
Case 2
Class 9 Tandem axle distribution
30% increase at 44 kips
Case 3
Class 5 single axle distribution
10% increase at 30 kips
Case 4
Class 5 single axle distribution
30% at 30 kips and 10 % at 40 kips
(Bolingbrook)
Overload Case
0
2000
4000
6000
8000
10000
12000
1 2 3 4
Overload Case
AA
DTT
0
5
10
15
20
25
30
Perc
ent C
rack
ing
(%)
AADTTCracking %
Constant ESALs =115 MESALs
Dist. Tan.Cl9 30% 44-k Cl5-10%30k
Cl5-30%30k, 10%40k
Traffic Summary
For existing axle load limits:
ESALs will give reasonable thickness results vs. load spectra for fatigue cracking
Recommend to IDOT to continue with ESALs as traffic input for rigid pavement design.
Load spectra has greater future potential….