What Is ESA

8/9/2019 What Is ESA

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The Effects of Overloading on Road Assets

Prepared for the

Mid North

Weight of Loads

Group


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Outline

Overview of Operation

Why have a WOL Operation

The Effect of Overloading

How this Effects Our Road Assets


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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


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NSW Weight of Loads Groupings


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Mid North Weight of Loads Member Councils

Armidale / DumaresqGuyra

BellingenNambucca

Coffs Harbour

KempseyGreater Taree

Port Macquarie HastingsGreat LakesGloucester

WalchaUralla

Tamworth RegionalLiverpool PlainsUpper Hunter

Dungog


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WhyWhy have ahave a

WEIGHT OF LOADSWEIGHT OF LOADSOPERATION?OPERATION?


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Why Do We Need Rules?


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How It Used To BeHow It Used To Be


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Belltrees Bridge, Scone Shire Council

March 1921


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Belltrees Bridge, Scone Shire Council

October 1996


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Could a bridge designer of the 1920s have foreseen

a Super-Dog combinationor a B-Double?


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NOT JUST BRIDGESNOT JUST BRIDGES..


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Age of Australian Road Pavements


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IN DAYS GONE BY


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TO WHAT THEY NOW HAVE TO CARRY


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What Wed Like Our Roads To Be


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Pavement Life Curve


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WHAT IS THE EFFECT OFWHAT IS THE EFFECT OFOVERLOADING ON THEOVERLOADING ON THE

ROAD ?ROAD ?

T ti P t D bilit


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Testing Pavement Durability

Accelerated Load Facility


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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


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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


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The 4th

Power Rule

Load OnAxleGroup

-------StandardLoad For

AxleGroup

4Number ofStandard

AxleRepetitions

=


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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


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Car vs TruckTo help add contex t

2 tonne car = 1/ 2250th ESAs

Average Articulated Truck = 2.65 ESA

Articulated Truck = 6000 cars

=


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Car vs Truc k

82% of traffic on NationalHighways are cars

Cars contribute 0.03% to

pavement loadings basedon ESA-km travelled


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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


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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

)


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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


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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


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HOWHOWThis Effects Our RoadThis Effects Our Road

AssetAsset


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Gloucesters Road Asset

Local Sealed Roads 174 km

Local Unsealed Roads 464 km

Regional Roads 105 km

TOTAL 743 km

Gl V l


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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


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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


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The Cost of MNWOL to Gloucester?

$0.008 m

i.e. 0.1% of Asset Value

or

0.4% of Annual Maintenance Vote


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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


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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


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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


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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


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And. like our roads


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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

Documents

What Is ESA