8/9/2019 What Is ESA
1/41
The Effects of Overloading on Road Assets
Prepared for the
Mid North
Weight of Loads
Group
8/9/2019 What Is ESA
2/41
Outline
Overview of Operation
Why have a WOL Operation
The Effect of Overloading
How this Effects Our Road Assets
8/9/2019 What Is ESA
3/41
The Role of Weight of LoadsTo improve safety & reduce the costs of maintaining roads
by preventing the damage caused by overloaded vehicles
HOW?
Education ~ through working with the transportindustry to promote an awareness of the negative
impacts of overloading on our roads systems
Regulation ~ through patrolling state &
regional roads monitoring compliance withlegislative requirements
Key Challenges include the prevention of overloading during peak
periods of high intensity freight movements such as harvest periods
8/9/2019 What Is ESA
4/41
NSW Weight of Loads Groupings
8/9/2019 What Is ESA
5/41
Mid North Weight of Loads Member Councils
Armidale / DumaresqGuyra
BellingenNambucca
Coffs Harbour
KempseyGreater Taree
Port Macquarie HastingsGreat LakesGloucester
WalchaUralla
Tamworth RegionalLiverpool PlainsUpper Hunter
Dungog
8/9/2019 What Is ESA
6/41
8/9/2019 What Is ESA
7/41
WhyWhy have ahave a
WEIGHT OF LOADSWEIGHT OF LOADSOPERATION?OPERATION?
8/9/2019 What Is ESA
8/41
Why Do We Need Rules?
8/9/2019 What Is ESA
9/41
How It Used To BeHow It Used To Be
8/9/2019 What Is ESA
10/41
Belltrees Bridge, Scone Shire Council
March 1921
8/9/2019 What Is ESA
11/41
Belltrees Bridge, Scone Shire Council
October 1996
8/9/2019 What Is ESA
12/41
Could a bridge designer of the 1920s have foreseen
a Super-Dog combinationor a B-Double?
8/9/2019 What Is ESA
13/41
NOT JUST BRIDGESNOT JUST BRIDGES..
8/9/2019 What Is ESA
14/41
Age of Australian Road Pavements
8/9/2019 What Is ESA
15/41
IN DAYS GONE BY
8/9/2019 What Is ESA
16/41
TO WHAT THEY NOW HAVE TO CARRY
8/9/2019 What Is ESA
17/41
What Wed Like Our Roads To Be
8/9/2019 What Is ESA
18/41
Pavement Life Curve
8/9/2019 What Is ESA
19/41
WHAT IS THE EFFECT OFWHAT IS THE EFFECT OFOVERLOADING ON THEOVERLOADING ON THE
ROAD ?ROAD ?
T ti P t D bilit
8/9/2019 What Is ESA
20/41
Testing Pavement Durability
Accelerated Load Facility
8/9/2019 What Is ESA
21/41
What is an ESA?
An ESA is an Equivalent Standard Axle
A Standard Axle is defined as a Dual-
tyred, Single Axle transmitting a loadof 80kn (or 8.2 tonne) to the
pavement
8/9/2019 What Is ESA
22/41
Comparison of Axle Groups
Ax le Configurat ionAx le Configurat ion Load (kN)Load (kN)Single Ax le; Single TyresSingle Ax le; Single Tyres 5353
Single Ax le; Dual TyresSingle Ax le; Dual Tyres 8080
Tandem Ax le; Single TyresTandem Ax le; Single Tyres 9090
Tandem Ax le; Dual TyresTandem Ax le; Dual Tyres 135135
TriTr i --AxleAxle 181181
QuadQuad--AxleAxle 221221
8/9/2019 What Is ESA
23/41
The 4th
Power Rule
Load OnAxleGroup
-------StandardLoad For
AxleGroup
4Number ofStandard
AxleRepetitions
=
8/9/2019 What Is ESA
24/41
Application of the 4th Power Rule
The effect of 5% overload
1.05 x 1.05 x 1.05 x 1.05 = 1.22or 22% increase in damage and 18%
reduction in pavement life
The effect of 10% overload
1.10 x 1.10 x 1.10 x 1.10 = 1.46
or 46% increase in damage and 32%
reduction in pavement life
8/9/2019 What Is ESA
25/41
Car vs TruckTo help add contex t
2 tonne car = 1/ 2250th ESAs
Average Articulated Truck = 2.65 ESA
Articulated Truck = 6000 cars
=
8/9/2019 What Is ESA
26/41
Car vs Truc k
82% of traffic on NationalHighways are cars
Cars contribute 0.03% to
pavement loadings basedon ESA-km travelled
8/9/2019 What Is ESA
27/41
Overloading Vs Pavement Life% Overload on
Standard Axle % Increase in Damage
Work ing Life of Twenty
Year PavementReduced to (years)
10 45 13.8
20 105 9.8
30 185 7.0
40 285 5.2
8/9/2019 What Is ESA
28/41
ESAs in Road Pavement Design0
100 MINIMUM THICKNESS BASE MATERIAL CBR
200 >30300
400
500
600
700
800
900
1000
105
20
2 4 6 8 106 2 4 6 8 107 2
15
10
7
5
4
3
2
4 6 8 108
Design Traffic (ESAs)
Thicknesso
fGranularMaterial(mm
)
8/9/2019 What Is ESA
29/41
Pavement LifePavement Life is determined by Number
of Equivalent Standard Axles (ESAs)
Local Rural Road (200 AADT 20% HV)typically 150-200,000 ESAs over 20 yrs
Greater ESAs requires greaterpavement depth and greater initial cost
8/9/2019 What Is ESA
30/41
4th
Power Summary
Pavement Damage is Related to TruckAxle Loads, Not Truck Gross Mass
The 4th Power Rule refers to PavementWear, Not Overload Failure
Even Greater Loads are Imposed by
Dynamic Loads
8/9/2019 What Is ESA
31/41
HOWHOWThis Effects Our RoadThis Effects Our Road
AssetAsset
8/9/2019 What Is ESA
32/41
Gloucesters Road Asset
Local Sealed Roads 174 km
Local Unsealed Roads 464 km
Regional Roads 105 km
TOTAL 743 km
Gl V l
8/9/2019 What Is ESA
33/41
Gloucesters Asset Value
Assest Class CarryingValue Av.DepnExpence ProgramMaint.
Rural Roads 21m 315,000 715,000
Local Seal 26 m 390,000 300,000
LocalUnseal
20 m 200,000 1 m
Total 67 m 905,000 2.015 m
8/9/2019 What Is ESA
34/41
Gloucesters Asset ValueListed Value
$
Annual Depn.
$
Maintenance
$
Regional Roads 21 m 315,000 715,000
Local SealedRoads 26 m 390,000 300,000
Local UnsealedRoads
20 m 200,000 1 m
Total 67 m 905,000 2.015 m
8/9/2019 What Is ESA
35/41
The Cost of MNWOL to Gloucester?
$0.008 m
i.e. 0.1% of Asset Value
or
0.4% of Annual Maintenance Vote
8/9/2019 What Is ESA
36/41
Mid North Weight of Loads Summary
Mid North WOL Group 01/02 02/03 03/04 04/05
No of Vehicles Stopped 1749 1770 2043 2163
No of Vehicles Weighed 739 675 854 932
No of Vehicles Breached 179 143 246 220
Person Hours of Operation 3522.25 3060 3612.5 3710.5
Variation (No. of Breached 36 103 26
Variation (Hrs of Operation 462.25 552.5 98
Group Costs 352570.03 356490.83 424227.27 426894.55
Variation (Costs) 39208.80 67736.44 2667.28
Group Average Costs per Hour 100.09 116.50 117.43 115.05
Variation (Avg. Costs p/hr) +16.41 +0.93 -2.38
8/9/2019 What Is ESA
37/41
Number of Trucks Stopped to Breached
0
500
1000
1500
2000
2500
3000
3500
4000
Number of
Vehicles
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
Calendar Years
Vehicles Intercepted - Vehicles Breached
Intercepts
Breaches
8/9/2019 What Is ESA
38/41
Vehicles Intercepted Vs Vehicles Breached
Vehicles Intercepted vs Vehicles Breached
0
500
1000
1500
2000
2500
3000
3500
4000
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
Calendar Years
No.ofInter
cepts
0
50
100
150
200
250
300
No.ofBreaches
Intercepts Breaches
8/9/2019 What Is ESA
39/41
Compliance Rates
Compliance
95% 94% 95% 95% 96% 95%91% 91%
89% 89%92%
50%
60%
70%
80%
90%
100%
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005%
OfIntercept
edVehicles
WhichCo
mplied
8/9/2019 What Is ESA
40/41
And. like our roads
8/9/2019 What Is ESA
41/41
Thank You
Prepared by
Greg Moran
Director of Technical Services
Inverell Shire CouncilMurray Erbs
Director of Engineer ing Services
Moree P lains Shire Council
Bruce Tester
Weight of Loads Inspector
Mid North Weight of Loads Group