1

Impact of Wide-Base Tires on Pavement and Trucking Operation

Imad L. Al-QadiFounder Professor of EngineeringIllinois Center for Transportation

Outline• Current Knowledge of Wide-base Tire• Impact of “Old” Wide-base Tires on Pavements • Impact of Wide-base Tires on Trucking Operation• New Generation of Wide-base Tires• Analytical Considerations• Three-Dimensional Finite Element Model • Pavement Response Analysis• Summary and Future Research

Tire Development

Bias PlyBias Ply

??Wide Wide Base Base

SinglesSingles

EnergyEnergy

RadialRadial

2

Wide-base TireDual 1980 1982 2000

2002 2000275, 295

385 425 445/455 495445/455: North America, 495: European Union

Tire Dimension

1013427495/45R22.51155340445/65R22.51126308425/65R22.51071285385/65R22.5998329385/55R22.5Wide-base1059235295/80R22.5108520112R22.5105418411R22.5Dual (one tire)(mm)(mm)

Rim-DiameterContact WidthTire SizeTire Type

EUROPE

37.8297.86720455/55R22.537.8291.02720445/50R22.537.8160.07720275/80R22.5(kN)(mm)(kPa)

Axle loadContact WidthTire PressureTire Type

North America

Dual vs. Wide-Base Tires• Wide-base tires have been used in

Europe since the early 1980’s• In 1997, 65% of trailers in Germany

used wide-base tires• Earlier generation of wide-base tires

were proven more detrimental to flexible pavement systems than regular dual tires

3

Impact of Early Wide-Base Tire

• Early generations are 385/65R22.5, 425/65R22.5, and 445/65R22.5:–Required high inflation pressure (790 to

890kPa – smaller contact area).–Significantly increased pavement damage

compared to dual tires:• Damage ratios ranged between 1.31 and 4.30.

Christison et al. (1980)– In-field measured pavement responses– Conventional wide-base tire induces more

damage than dual-tire 1.2~1.8 times more fatigue damage

Akram et al. (1992)• Multi-Depth Deflectometer at a speed of 90km/h• Conventional wide-base tire

Pavement life reduced by a factor of 2.5~2.8 when wide-base tire is used

• Comparison between Dual and Wide-base Tires:• 11R22.5, 245/75R22.5

• 385/65R22.5, 425/65R22.5

• Testing speed: 58 km/hr

• Pavement Damage Evaluation:• 10 and 45% fatigue damage model (Finn et al.1986)

• Wide-base tire induces significantly more damage than dual tire (1.5 times more fatigue damage)

Sebaaly et al. (1989)

4

• Comparison between Dual and Wide-base Tires• 11R22.5, 265/70R19.5• 355/75R22.5, 385/65R22.5, 425/65R22.5• Test speed: 76 km/hr

• Pavement Damage Evaluation• Steering axle is the most detrimental• A drive axle equipped with wide-base tires is more

damaging than dual-tires by a factor of 2.3 ~ 4.0.

Huhtala et al. (1992)

Bonaquist et al. (1993)

• Comparison between dual and wide-base tires• 11R22.5• 425/65R22.5

• Pavement Damage Evaluation:• Wide-base tire induces significantly more damage

than dual tire: 3.5 times more fatigue damage1.9 times more rutting damage

Early Studies on Wide-base Tire

1.9 - 3.5 times more damageWide-base(425/65R22.5)

FHWA (1993)

1.5 times more damageWide-base (385, 425/65R22.5)

Penn State (1989)

Cost 334 (1997-2001)

Huhtala et al. (1992)

1.2 - 1.6 times more damageWide-base (445/65R22.5)

2.3 - 4.0 times more damageWide-base(385, 425/65R22.5)

Damage PotentialsWide-base Tires

•Other studies at Canada, Europe, South Africa, and UC Barkley

•Code: 445/50R22.5Tire width (mm)/ Tire aspect ratio(%)/ Radial ply (R)/ Rim diameter (in)

5

Dual vs. Wide-Base Tires• Earlier generation of wide-base tires were

detrimental to flexible pavement• A new generation of wide-base tires has recently

been introduced:Legalized in all states for 355.8kN GVW trucks16-18% wider than the first generation:

Makes use of a new crown architecture that allows wider widths at low aspect ratiosDesigned based on inch/width principle

More uniform tire-pavement contact stress:Reduced tire pressure (690kPa) at high loads (151kN)

Potential economic advantages to trucking industry

New vs. Old - Design

425/65R22.5 XZY

Unique Infini-CoilTM technology.¼ mile of continuous steel cable to

help eliminate casing growth

New Generation of Wide-Base Tires

0

200

400

600

800

1000

1200

1 2 3 4 5 6 7 8 9 10Rib Number

Stre

ss (k

Pa)

New Wide-base(445/50R22.5)Conventional Wide-base(425/65R22.5)Dual (drive)New wide-base (2nd size) 455/55R22.5

New verses Conventional Wide-base(Footprint width and Tire diameter)

200

220

240

260

280

300

320

340

360

380

400

385/65R22.5 425/65R22.5 445/65/R22.5 445/50R22.5

Tire Size

Con

tact

Pat

ch W

idth

(mm

)

1000

1050

1100

1150

1200

1250

1300

Tire

Dia

met

er(m

m)(New wide-base)(Conventional wide-base)

6

New Generation of Wide-Base TiresMeasured Contact Stress at

Pavement Surface – 445/50R22.5

Measured Contact Stress at Pavement Surface – 275/80R22.5

New Generation of Wide-Base Tires

702.71 730.92 707.55 684.98

896.03 883.29

0

200

400

600

800

1000

Dua

l Driv

e(2

75/8

0R22

.5)

Ste

er(2

75/8

0R22

.5)

New

Gen

erat

ion

Wid

eBas

e(4

45/5

0R22

.5)

New

Gen

erat

ion

Wid

eBas

e(4

55/5

5R22

.5)

Con

vent

iona

lW

ideB

ase

(385

/65R

22.5

)

Con

vent

iona

lW

ideB

ase

(445

/65R

22.5

)

Tire Dimension

Ave

rage

Con

tact

Stre

ss (K

pa)

Average Contact Stress at Pavement Surface

Why Wide-Base Tires NOW?• Substantial savings to truck freight

transportation:– Fuel economy– Increase hauling capacity (increase payload)– Reduced tire cost and repair– Ride and comfort– Reduced emission and noise– Reduced recycling impact of scrap tires– Better handling, braking, and safety

Impact on Road Infrastructure?

7

Unloaded - 8500 lb/axle

Unloaded - 8500 lb/axle

Loaded - 17000 lb/axle

Unloaded - 8500 lb/axle

Loaded - 17000 lb/axle

All footprints done exactly to0.4 : 1 Scale.

Loaded - 17000 lb/axle

At 60 mph (100 kmh), aerodynamic drag consumes approximately 40% of the fuel.Mechanical losses consume approximately 25% of the fuel. Rolling resistance accounts for approximately 35% of the fuel consumed.

aerodynamic drag

Where Does the Fuel Go?

mechanical losses

rolling resistance

Fuel Economy/ Hauling Capacity• Tire rolling resistance accounts for 35% of

truck energy consumption• Using the new generation of wide-base

tires reduces rolling by 12%:– Reduction fuel consumption by an average of

4%– Savings of fuel per year

• A truck that uses 6.5 mpg on duals will be at 6.76 mpg or better with new wide-base generation

• At 120,000 miles/year, the saving is 710 gallons (3230 liters) per vehicle per year

• Reduces truck weight by 410kg:– Increases haling capacity by 2%

8

Tire Cost and Repair, Truck Safety, and Ride Comfort

• Requires only one rim compared to two for dual tires

• Requires half the repair time needed for dual tires• Handling is maintained even when two tires blow

out– Requires regular monitoring of tire pressure

(good practice for all tire types)• Ride quality is improved by 12% compared to dual

tires

Environmental Impact

• Reduced gas emission: Reduction of 1.1 million metric tons of carbon equivalent by 2010 (assuming current market share, 5%)

• Reduce recycling impact of scrap tires:– 72.5kg of residual materials for dual tires vs.

53.6kg for a wide-base tire assembly.

95.6”

71.5”

0” offset

91.9”

74.6”

2” offset

Effect of Tires on Track Width

9

Implementation of Wide-base Tires in Canada!

Areas of Research• Dynamic impact of the tire (25% less

than dual tires?).• Recapping of wide-base tires vs. dual

tires• Impact on road Infrastructure

Cost 334 Action in Europe (1997~2001)• APT and instrumented pavement (17 tire

assemblies)• Intensive research on the effect of wide-base

tires– Tire type, axle load, tire pressure, and pavement

design• Pavement Damage Evaluation:

– Developed Tire Configuration Factor (TCF) by stepwise regression analysis

– Suggested the use of wide-base tires on the steering axle

– Top-down cracking was not considered

10

The COST Action (2001)

-3.1%1.47998380Wide (455/55R22.5)2.7%1.56947380Wide (445/50R22.5)----1.521054368Dual (275/80R22.5)

Wide-base vs. dualTCFD

mmW

mmTire Type

Primary Roads

• Introduced the concept of tire configuration factor (TCF):

81.085.068.1 )ratio.pres()198/length()470/width(TCF −−=

Al-Qadi et al. (2000-)• Heavily Instrumented Virginia Smart Road• Comparison between dual and wide-base tires

• 445/50R22.5, 455/55R22.5• Test parameters: speed, axle load, tire pressure

• Pavement Damage Evaluation:• Various transfer functions• Steering axle is the most detrimental• Wide-base is more fatigue damaging by a factor of 1.35.• Equivalent rutting damage • Wide-base is less damaging than dual in surface initiated

top-down cracking by a factor of 0.45

Prophète et al. (2003)• Instrumented Pavement: Laval University• Comparison between dual and wide-base tires

• 385/65R22.5, 455/55R22.5• 50km/hr, axle load, tire pressure• Wide-base (455) is more fatigue damaging by a factor of 1.54• Wide-base (455) is less rutting damaging by a factor of 0.17• Surface initiated top-down cracking is less damaging by 0.87

times

11

NCAT Experimental Study (2005)• Compared field responses of new generation of

wide-base tires to dual tires• Measurements conducted at 72.4km/h• Used measured strains at the bottom of HMA and

vertical stress on top of subgrade (reported rutting only)

• Both dual and wide-base tires configurations causes the same pavement damage

Current Knowledge of Wide-base Tire

More fatigue damage Similar rutting damage Less top-down cracking

New Gen. Wide-base Tire (445/50R22.5, 455/55R22.5)

Al-Qadi et al. (2003)

Less damage in rutting (0.17) and Top-down cracking (0.87)

New Gen. Wide-base Tire(455/55R22.5)

Prophète et al. (2003)

Cost 334 (1997-2001) 1.2 - 1.6 times more damageWide-base (445/65R22.5)

Damage PotentialsWide-base Tires

• Code: 445/50R22.5Tire width (mm)/ Tire aspect ratio(%)/ Radial ply (R)/ Rim diameter (in)

Impacts on Road Infrastructure• Only a few studies on new wide-base tire• What do we know:

– The steering axle is the most damaging – Significantly less damage than the first wide-base

tire generations– Impact on the subgrade is similar to dual tires– The layered theory can not be used to quantify tire

damage– Focus has been on primary roads

12

• Full-scale pavement testing at the Smart Road

• 12 different flexible pavement sections and a continuously reinforced concrete section.

• The flexible pavement sections were instrumented during construction with a complex array of pressure cells, strain gages, thermocouples, moisture probes, and frost probes.

Field Testing

Smart Road Pavement Design

A B C D E F G H I J K LOGFC

(19mm)SM-9.5D (19mm)

SM-9.5A (50mm)

SM-9.5A (50mm)

SM-9.5A (50mm)

BM-25.0 (225mm)

21B (75mm)

21B (75mm)

21B (75mm)

21A Cement

Stabilized (150mm)

Cement OGDL

(75mm)

21A Cement

Stabilized (150mm)

21A Cement

Stabilized (150mm)

OGDL (75mm)

OGDL (75mm)

21B (150mm)

21A Cement

Stabilized (150mm)

21B (175mm)

Cement OGDL

(75mm)

OGDL (75mm)

OGDL (75mm)

OGDL (75mm)

OGDL (75mm)

21B (175mm)

21B (175mm)

21B (175mm)

SM-12.5D (38mm)

SM-9.5D (38mm)

SM-9.5E (38mm)

SM-9.5A (38mm)

SM-9.5D (38mm)

SM-9.5D (38mm)

SM-9.5D (38mm)

SM-9.5D (38mm)

BM-25.0 (100mm)

SM-9.5A* (38mm)

SM-9.5D (38mm)

SMA-12.5 (38mm)

BM-25.0 (150mm)

BM-25.0 (100mm)

BM-25.0 (225mm)

21B (150mm)

BM-25.0 (100mm)BM-25.0

(150mm)BM-25.0 (150mm)

BM-25.0 (150mm)

BM-25.0 (150mm) BM-25.0

(225mm)

21A Cement

Stabilized (150mm)

21A Cement

Stabilized (150mm)

BM-25.0 (150mm)

21B (75mm)

21A Cement Stabilized (150mm)

21B (150mm)

21A Cement

Stabilized (150mm)

21A Cement

Stabilized (150mm)

21A Cement

Stabilized (150mm)

21B (75mm)

21A Cement

Stabilized (150mm)

CRCP

Concrete (250mm)

Cement OGDL

(75mm)

OGDL (75mm)

21B (150mm)

OGDL (75mm)

Modeled Section

Al-Qadi and Co-Workers• Testing at the Virginia Smart Road

(2000-2002):

13

Four speeds – 2 Load levels – 4 Tire Pressures

Longitudinal Strain

Transverse Strain

-400

-200

0

200

400

600

800

0 1 2 3 4 5

Time (sec)

μstra

in

-50

0

50

100

150

200

0 1 2 3 4 5

Time (sec)

μstra

in

0102030405060708090

100

8.0 24.1 40.2 72.4Speed (km/hr)

μstr

ain

SteeringDualWide Base

Field Evaluation

Tensile Strain under HMA

Vertical Stress under HMA

0

50

100

150

200

250

300

350

A C E F G H K LSection #

Stre

ss (k

Pa)

DualWide-BaseSteering

Conclusions of the Exp. Program• The steering axle is the most detrimental

of all tire configurations (small contact area with respect to the carried load)– Fatigue Failure: slightly greater for the wide-

base tire configuration– Subgrade Rutting: approximately equal for

the wide-base and dual tires configurations• Recommendation: Address a broader

range of failure mechanisms (i.e., HMA rutting, top-down cracking) using FEM.

14

Accelerated Loading Facility Testing

Loading matrix

0Dual, WB-455 & WB-425

80, 100 &1105, 106, 8, 10,

12 & 14

Offset(in)

Tire configuratio

n

Tire pressure(psi)

Speed(mph)

Tire load(kips)

Response testing (20 passes in each case)

Tire-pressure differential in dual tire (20 passes in each case)

0, 6 &-630, 50, 70 & 90110106, 10 & 14

Offset(in)

Variable tire pressure

(psi)

Control tire pressure

(psi)

Speed(mph)

Tire load(kips)

Full Depth HMA Test Sections

ThermocoupleStrain gauge

Section A Section B Section D Section FSMA – 2in

Poly. Binder 2.25in

Poly. Binder 2.25in

Standard Binder 3.5in

Standard Binder 2.5in

Rich Bottom Binder 4in

Lime Modified Subgrade 12in

DG Surface – 2in

Poly. Binder 2.25in

Poly. Binder 2.25in

Standard Binder 3.5in

Standard Binder 2.5in

Standard Binder – 4in

Lime Modified Subgrade 12in

DG Surface 2in

Poly. Binder 2.25in

Poly. Binder 2.25in

Standard Binder 3.5in

DG Surface 2in

Standard Binder 4in

Lime Modified Subgrade 12in

Lime Modified Subgrade 12in

15

Peak Response Ratio

Standard deviation

averageStandard deviation

averageStandard deviation

averageStandard deviation

average

1.19

1.28

Section A

0.05

0.05

1.12

1.19

Section B

0.04

0.05

0.081.180.061.18W455

0.081.310.091.26W445

Section FSection D

The ratio of measured peak longitudinal strain between wide-base tire and dual-tire assembly:

At 16km/h and various load and pressure levels:

dwlRR εε /=

Pavement Thickness Effect

Strain differences between dual-tire assembly and wide-base tire diminish as pavement thickness increases.

10 kips 100 psi at 10 mph

0

100

200

300

400

500

6 10 16HMA thickness (in)

Long

itudi

nal S

trai

n (M

icro

) DualWide base 455Wide base 425

10 kips 100 psi at 5 mph

0

100

200

300

400

500

6 10 16HMA thickness (in)

Long

itudi

nal S

trai

n (M

icro

) DualWide base 455Wide base 425

Load Effect

5 mph, 110 Psi

0

100

200

300

400

500

600

6 kips 8 kips 10 kips 12 kips 14 kips

Long

itudi

nal s

train

( μ)

DualWB455WB425

• Longitudinal strain at bottom of HMA linearly increases with load.

y = 27.284x + 35.423

y = 28.633x + 66.006y = 34.731x + 59.854

0

200

400

600

4 6 8 10 12 14 16

Load (kips)

Long

itudi

nal s

train

(mic

ro)

Dual-tire assemblyWide-base 455Wide-base 425

16

Tire position effect5 mph, 80 Psi

0

100

200

300

400

500

600

6 kips 8 kips 10 kips 12 kips 14 kips

Long

itudi

nal s

train

()

WB425_EdgeWB425

Strain under the low-pressure tire

0

100

200

300

400

30 psi 50 psi 70 psi 90 psi

Long

itudi

nal s

train

()

6 kips10 kips14 kips

Strain beneath the tires

0

100

200

300

400

500

30 psi 50 psi 70 psi 90 psi 110 psi

Long

itudi

nal s

train

()

6 kips10 kips14 kips

Strain under the high-pressure tire

0

100

200

300

400

500

30 psi 50 psi 70 psi 90 psi

Long

itudi

nal s

train

()

6 kips10 kips14 kips Control

tire (110 psi)

Variabletire

Experimental Findings• Ratios of longitudinal strain at bottom of HMA

between W-425 tire and dual-tire: 1.12-1.47; between W-455 tire and dual tires: 1.06-1.35 (at 16km/h).

• Higher strain ratios than smart road study, probably not considering reduction in dynamic forces induced by wide-base tires.

• The strain differences between dual-tire assembly and wide-base tire diminish as pavement thickness increases.

• Fatigue damage ratios between wide-base and dual tires is reduced when wander effect is considered. This effect diminishes for thick pavement.

17

Analytical Model • Uniform Pressure Distribution Model:

–Original models developed by Boussinesq (1885) and Burmister (1954),

–Uniform vertical pressure distribution–Circular areas

• Non-uniform Pressure Distribution Model–Nonuniform tire contact pressure model (Schapery, 1980)

–Distributions are actually non-uniform (Tielking, 1980)–Depends on the size and tire type (Roberts, 1987)

• Tensile strain at the bottom of HMA results in excess of 100% higher than those for uniform pressure

Drawbacks of Current Flexible Pavement Analysis

Vehicular loading:Stationary circularCan not differentiate between wide-base tires or dual tires (i.e., 385/65R22.5 = 455/55R22.5 and 11R22.5 = 12R22.5).

Pressure distribution:Uniform vertical contact stressNo surface tangential contact stresses

Effect of vehicle speed & loading:Pavement response to loading Is time-independent

Finite Element Approaches

Partial

Partial

Middle

Line loadStatic

2D Model

Highest intensityLowestComputational

time and memory

Static/DynamicStatic Loading

YesNoPavement

discontinuity

Interface modeling

Loading area

YesNo

VersatileCircular single

3D ModelAxisymmetric

Major Differences

Effective stiffnessTangent stiffnessStiffness

Equation of motionStatic equilibriumSystem equation

Relatively lowRelatively highResidual error

HighLowComputing intensity

Loading steps intensity

Loading Amplitude

HighLow

Time DependentConstant

Dynamic FEStatic FE

18

FE model for HMA

Layout of the 3-D FE model

Real and FE simulated tire foot prints for wide-base tire and dual tire assembly

Contact Pressure Loading

616k

pa

629k

Pa

703k

Pa

779k

Pa

840k

Pa

779k

Pa

702k

Pa

629k

Pa

616k

Pa

T1 T2 T3 T4 T5 T6 T7 T8 T9

532k

Pa

766k

Pa

867k

Pa

766k

Pa

532k

Pa

T1 T2 T3 T4 T5

532k

Pa

766k

Pa

867k

Pa

766k

Pa

532k

Pa

T5 T4 T3 T2 T1445/50R22.5

Dual Tires

Assigning pressure data to the FE of tire imprint

8kph XDA2- dual 6.9b_6.9bTread A B C D E F G H I J

ELEMENT Weight F for EL 6 Weight F for EL 8 0.641 0.872 0.988 0.858 0.641 0.641 0.872 0.988 0.858 0.64110 0.425 0.371 0.420 0.365 0.371 0.420 0.3659 0.488 0.752 0.313 0.656 0.743 0.645 0.313 0.313 0.656 0.743 0.645 0.3138 0.850 0.935 0.545 0.815 0.924 0.802 0.545 0.545 0.815 0.924 0.802 0.5457 0.975 0.985 0.625 0.859 0.973 0.845 0.625 0.625 0.859 0.973 0.845 0.6256 0.960 0.970 0.615 0.846 0.958 0.832 0.615 0.615 0.846 0.958 0.832 0.6155 0.805 0.898 0.516 0.783 0.887 0.770 0.516 0.516 0.783 0.887 0.770 0.5164 0.405 0.700 0.260 0.610 0.692 0.601 0.260 0.260 0.610 0.692 0.601 0.2603 0.327 0.285 0.323 0.281 0.285 0.323 0.28121

entrance

exit

455_new (7.2bar)_Final Tread A B C D E F G H IELEMENT Weight F for EL 7 Weight F for EL 8 Weight F for EL 9 0.500 0.830 0.884 0.940 0.956 0.940 0.884 0.830 0.500

10 0.500 0.476 0.415 0.442 0.447 0.455 0.447 0.442 0.4159 0.530 0.820 0.790 0.265 0.681 0.725 0.743 0.755 0.743 0.725 0.681 0.2658 0.858 0.940 0.915 0.429 0.780 0.831 0.860 0.875 0.860 0.831 0.780 0.4297 0.962 0.990 0.978 0.481 0.822 0.875 0.919 0.935 0.919 0.875 0.822 0.4816 1.000 0.990 1.000 0.500 0.822 0.875 0.940 0.956 0.940 0.875 0.822 0.5005 0.960 0.935 0.975 0.480 0.776 0.827 0.917 0.932 0.917 0.827 0.776 0.4804 0.845 0.810 0.910 0.423 0.672 0.716 0.855 0.870 0.855 0.716 0.672 0.4233 0.485 0.450 0.770 0.243 0.374 0.398 0.724 0.736 0.724 0.398 0.374 0.2432 0.420 0.395 0.402 0.3951

entrance

exit

• Dual tire

• Wide-base 455

19

Material Characterization• HMA materials: Linear viscoelastic

constitutive model– Indirect resilient modulus and creep

compliance– Prony Series Expansion

• Granular materials: Linear elastic constitutive model

– Nondestructive testing (FWD)

Creep Compliance Test at Different Loading Levels

-80

-40

0

40

80

120

160

0 0.05 0.1 0.15 0.2 0.25 0.3

Time (sec)

Tra

nsve

rse

Stra

in (m

icro

stra

in)

Transversal - T9

Longitudinal - T5

Pavement ResponseRetardation of the response

Asymmetry of the response

-75-50-25

0255075

100125150

0 0.1 0.2 0.3

Time (sec)

Long

itudi

nal S

trai

n ( μ

m/m

) MeasuredCalculated

20

Surface Strain (T=25°C)

-60

-40

-20

0

20

40

60

80

0 200 400 600

Distance(mm)

Tran

sver

se S

urfa

ce S

train

-80

-60

-40

-20

0

20

40

60

80

0.0 200.0 400.0 600.0 800.0

Distance(mm)

Tran

sver

se S

urfa

ce S

trai

n

Combined Relative Damage• Number of cycles till failure spread over

several orders of magnitude:– Rutting of HMA and top-down cracking are the

most critical distresses since they directly affect the pavement surface condition

........,...,)log(/1)log(/1)log(/1)log(/1

)log(/1

432

1

4321

===

+++=

+++=

−−−

−

−−−

aaaNNNN

Na

DRaDRaDRaDRaCombinedDR

fatiguesubgraderuttingdowntopHMArutting

HMArutting

subgraderuttingfatiguedowntopHMArutting

Al-Qadi and Co-Workers

A: Fatigue Cracking, B: Subgrade Rutting, C: HMA Rutting, D: Top-down

0.971.13

C

0.250.76

D

1.071.19

CDR

1.341.43

B

1.832.25

A

445/50R22.5455/55R22.5

DistressTire

• Combined Damage Ratios:

21

New Analysis Approach

Finite Element Modeling

Analysis ParametersMaterial Constitutive ModelsLoading AmplitudeSurface Shear Forces Layer Interface Condition

Validation of FE Models (w/ Field Measurements)

Pavement Damage Analysis

Model A

djustment

Discretization of Tire Imprint

A4

A3

A2

A1

A5

A6

A7

A8

Discretizationinto FE

One of the dual tire imprint

Finite elements

Loading Amplitudes

0.0

0.4

0.8

1.2

1.6

2.0

0 2 4 6Time Step

Am

plitu

de

Entrance Sideof Imprint

0.00.2

0.40.60.8

1.01.2

0 2 4 6Time Step

Am

plitu

de

Exit Side ofImprint

00.20.40.60.8

11.2

1 2 3 4 5Time (sec)

Am

plitu

de

Trapezoidal amplitudeAll tire-pavement contact stresses have same amplitude while moving.

Continuous amplitude for moving loadDifferent amplitudes for the entrance and exit part each rib.

22

Master curve for section “F”

1

10

100

1000

10000

1.E-03 1.E-01 1.E+01 1.E+03 1.E+05 1.E+07

Reduced Frequency, Hz

E*, k

si -10

4

20

Fit

Effect of Tire Loading

Interface FrictionSimple Friction Model: Friction Coefficient Control• Model characterized by the Coulomb friction

coefficient, μ• Resistance to movement is proportional to normal

pressure at interface

Elastic Slip Model: Max. Shear Stress Control• Shear stress and displacement are linearly

dependent until shear stress equals shear strength; then converted to the Coulomb friction condition

23

Measured vs. Calculated• Variation in interface friction coefficients• In case of elastic slip model, results are close to field measurement

5060708090

100110120130140150160170

1 0.7 0.5 0.2 Slip Measured

Friction Coefficient

Stra

in (m

icro

)

TransverseLongitudinal

• Conventional surface tangential pressure distributions(Pierre et al. 2003, Tielking 1987)

Stationary Moving

Surface Tangential Contact Pressures

Moving direction

Measured Tire Contact Stress

-0.20

0.10

0.40

0.70

1.00

0 100 200

Longitudinal Contact Points

Nor

mal

ized

Con

tact

Stre

sses

Vertical StressLongitudinal StressLateral Stress

Data not available

Entrance Aspect of Tire Imprint

Exit Aspect of Tire Imprint

Moving direction

24

Nonuniform Vertical Contact Stress

0

0.2

0.4

0.6

0.8

1

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16Data Points in a Rib

Nor

mal

ized

Ver

tical

Com

pres

sive

Str

ess

Rib 1 Rib 2 Rib 3 Rib 4 Rib 5

0

0.2

0.4

0.6

0.8

1

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28Data Points in a Rib

Nor

mal

ized

Ver

tical

C

ompr

essi

ve S

tres

s

Rib 1 Rib 2 Rib 3 Rib 4 Rib 5Rib 6 Rib 7 Rib 8 Rib 9

1

Asymmetric Transverse Tangential Stress

-1

-0.5

0

0.5

1

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Data Points in a Rib

Nor

mal

ized

Tra

nsve

rse

Tan

gent

ial S

tres

s

Rib 1 Rib 2 Rib 3 Rib 4 Rib 5

-1

-0.5

0

0.5

1

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Data Points in a Rib

Nor

mal

ized

Tra

nsve

rse

Tan

gent

ial S

tres

s

Rib 1 Rib 2 Rib 3 Rib 4 Rib 5 Rib 6 Rib 7 Rib 8 Rib 9

-8.E-04

-6.E-04

-4.E-04

-2.E-04

0.E+00

2.E-04

4.E-04

6.E-04

8.E-04

5000 5010 5020 5030 5040 5050

Tire Element Number

Surfa

ce T

ensi

le S

train

(µ)

Dual tire Widebase 455

-3.E-03

-2.E-03

-1.E-03

0.E+00

1.E-03

2.E-03

3.E-03

5000 5010 5020 5030 5040 5050

Tire Element Number

Sur

face

Ten

sile

Stra

in (µ

)

Dual tire Widebase 455

Without Surface Tangential Stresses

With Surface Tangential Stresses

Surface Tangential Stress Effect at Surface (40 oC)

25

Verification Results

-75

-50

-25

0

25

50

75

100

125

150

0 0.05 0.1 0.15 0.2 0.25

Time (sec)

Long

itudi

nal S

trai

n (µ

)

MeasuredCalculated-With Tangential PressureCalculated-Without Tangential Pressure

20

40

60

80

100

120

140

160

Without Shear With Shear Measured

Stra

in (m

icro

)

TransverseLongitudinal

Effects of Shear Forces

Various Dynamic Analysis ApproachesImplicit Dynamic Analysis

Advantage: Unconditionally Stable/ Very Small Error

Disadvantage: Long Analysis Time

Explicit Dynamic AnalysisAdvantage: Short Analysis Time

Disadvantage: Conditionally Stable/ High Error

Modal/Subspace Dynamic Analysis Only Applicable to the Linear Systems

26

-100

-50

0

50

100

150

200

250

0.000 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045

Time (sec)

Long

itudi

nal S

train

(mic

rost

rain

)

T1

T2

T3

T4

T5

Dynamic Analysis Example with Impulsive Loading

It shows unreasonable strain oscillation at the bottom of HMA

-150

-100

-50

0

50

100

150

200

250

300

350

0.000 0.050 0.100 0.150 0.200 0.250 0.300 0.350 0.400 0.450

Time (sec)

Long

itudi

nal S

train

(mic

rost

rain

)

T1T2T3T4T5T6T7T8T9

Dynamic Analysis Example with Continuous Loading

Reasonable response at the bottom of HMA

Quasi Static vs. Dynamic Analysis

0

50

100

150

200

250

300

350

0.000 0.050 0.100 0.150 0.200 0.250Time(sec)

Tens

ile s

trai

n (μ

)

T1 T2 T3 T4 T5T6 T7 T8 T9

High Initial Strain

0

50

100

150

200

250

300

350

0.000 0.050 0.100 0.150 0.200 0.250Time(sec)

Tens

ile s

trai

n (μ

)

T1 T2 T3 T4 T5T6 T7 T8 T9

Smaller initial Strain

Peak Strain about 260 µ

Higher Peak Strain: 305 µ

Quasi-Static Visco Analysis

Implicit Dynamic Analysis

Interstate Pavement Design: 25v Degree 5 mph

27

Quasi Static vs. Dynamic AnalysisExtreme Case:

10 degree/50 MPH at bottom of 6 inch of HMA: Low Temperature

-60

-20

20

60

100

0 0.05 0.1 0.15

Time (sec)

Long

itudi

nal S

train

(µ)

ElasticQuasi-Static-ViscoImplicit Dynamic

Tensile strain at the bottom of HMA

0

50

100

150

200

250

300

Tens

ile s

train

(mic

ro)

Quasi-static

Dynamic

Tensile strain at thebottom of HMA

263.06 302.73

Quasi-static Dynamic

Quasi Static Response vs. Dynamic ResponseMaximum dynamic strain is higher than that of quasi-static analysis (about 15%)

Summary• Only a few studies on new wide-base tire• What do we know:

– The steering axle is the most damaging of all axles– Significantly less damage than the first generations– Impact on the fatigue is a little higher than dual tires

(depend on pavement structure)– Impact on rutting is similar to dual tires– Impact on surface cracking is less than dual tires– The layered theory with static circular loading is not

appropriate to quantify tire damage– Focus has been given to primary roads

28

??Overall Damage Ratio↑↓Top-Down Cracking↓↑Fatigue Cracking→→Secondary Rutting→→Primary Rutting

Road Infrastructure↑↓Tire Recycling↑↓Noise Reduction↑↓Gas Emission

Environmental Impacts↑↓Ride and Comfort→→Truck Operation and Safety↑↓Tire Cost and Repair↑↓Hauling Capacity↑↓Fuel Economy

Trucking Operations

Wide-base TiresDual TireCriterion