pavement thickness design for canadian 2006...آ  – aging airport pavement infrastructure...

Pavement Thickness DesignPavement Thickness Design for Canadian Airports for Canadian Airports

Leanne Whiteley, B.A.Sc., M.A.Sc.Leanne Whiteley, B.A.Sc., M.A.Sc. Civil EngineeringCivil Engineering

Susan Tighe, Ph.D., P.Eng.Susan Tighe, Ph.D., P.Eng. Canada Research Chair in Pavement & Infrastructure ManagementCanada Research Chair in Pavement & Infrastructure Management

and Associate Professor, Department of Civil Engineeringand Associate Professor, Department of Civil Engineering

University of WaterlooUniversity of Waterloo CPATT SymposiumCPATT Symposium October 13, 2006October 13, 2006

IntroductionIntroduction

Research RationaleResearch Rationale –– Aging airport pavement infrastructureAging airport pavement infrastructure –– Heavier aircraftHeavier aircraft –– International state-of-the-art design programsInternational state-of-the-art design programs

ScopeScope –– Flexible and rigid airport pavement design methodsFlexible and rigid airport pavement design methods –– Canadian airport dataCanadian airport data

ObjectivesObjectives –– To determine the sensitivity of the pavement designTo determine the sensitivity of the pavement design

methods to their input parametersmethods to their input parameters –– To evaluate the Transport Canada design methodTo evaluate the Transport Canada design method

MethodologyMethodology Stage 1

Data Collection

Stage 2 Data Organization

Stage 3 Within Program Sensitivity Analysis

Stage 4 Between Program Data Analysis

Sources of DataData Requirements

Aircraft Traffic & Volumes Climate

Pavement Structure

Climate Sensitivity Analysis

Traffic Sensitivity Analysis

Subgrade Sensitivity Analysis

Design Methods vs.

Transport Canada

Airport Pavement Design MethodsAirport Pavement Design Methods

FlexibleFlexible •• Transport Canada (TC)Transport Canada (TC) •• Federal AviationFederal Aviation

Administration (FAA)Administration (FAA) CBR MethodCBR Method

•• FAA Layered ElasticFAA Layered Elastic Design (LEDFAA)Design (LEDFAA)

•• Asphalt Institute SW-1Asphalt Institute SW-1 •• Australian AirportAustralian Airport

Pavement StructuralPavement Structural Design System (APSDS)Design System (APSDS)

RigidRigid •• Transport Canada (TC)Transport Canada (TC) •• Federal AviationFederal Aviation

Administration (FAA)Administration (FAA) Westergaard MethodWestergaard Method

•• FAA Layered ElasticFAA Layered Elastic Design (LEDFAA)Design (LEDFAA)

•• FAA Finite ElementFAA Finite Element Design (FEDFAA)Design (FEDFAA)

•• American ConcreteAmerican Concrete Pavement AssociationPavement Association AIRPAVE 2000AIRPAVE 2000

Sources of DataSources of Data 20%

0%

13%

20%13%

34% Altantic Quebec Ontario Prairie Pacific Northern

60% 13%

7%

7%

13%

National Airport System Regional/ Local Arctic Remote Unclassified

Airport Region

Airport Type

Within Program Results – FlexibleWithin Program Results – Flexible Equivalent Granular ThicknessEquivalent Granular Thickness

I for all SSI for all SS

VS for all SSVS for all SS

I for all SSI for all SS

M - S for NSBM - S for NSB S for NSBS for NSB M for SBM for SB S for SBS for SB

FAAFAA

W-M for LSSW-M for LSS I for HSSI for HSS

S-VS for HSSS-VS for HSS I for LSSI for LSS

VS for HSSVS for HSS I for LSSI for LSS

S - VS for HVFS - VS for HVF W for MVFW for MVF

I for LVF & XCWI for LVF & XCW

TCTC

N/AN/A

N/AN/A

N/AN/A

S S –– VS for all VS for all LEDFAALEDFAA

N/AN/A

N/AN/A

*W for all*W for all SSSS

VS for allVS for all SW-1SW-1

N/AN/AWheelWheel LoadLoad

N/AN/AMGWMGW

N/AN/AFIFI

VS for allVS for allCBRCBR APSDSAPSDSAnalysisAnalysis

Legend: CBR=California Bearing Ratio FI=Freezing Index MGW=Maximum Gross Weight VS=very strong S=strong M=moderate W=weak I=insignificant HVF=high volume facility MVF=medium volume facility LVF=low volume facility HSS=high subgrade strength MSS=medium subgrade strength LSS=low subgrade strength NSB=non-stabilized base SB=stabilized base XCW=extreme cold weather climates * = Mean Average Air Temperature

Within Program Results – RigidWithin Program Results – Rigid PCC SlabPCC Slab

S for allS for allN/AN/AN/AN/AN/AN/AN/AN/ATire contactTire contact areaarea

L-M for allL-M for allN/AN/AN/AN/AN/AN/AN/AN/AGear LoadGear Load

I for allI for all

S for allS for all I for allI for all

W for XLVFW for XLVF VS for othersVS for others

FAAFAA

S-VS for allS-VS for all

L for HSSL for HSS M for LSSM for LSS

I for allI for all

W for LVFW for LVF S-VS for HFVS-VS for HFV

TCTC

N/AN/A

N/AN/A N/AN/A

NC for XLVFNC for XLVF VS for othersVS for others

LEDFAALEDFAA

N/AN/A

N/AN/A N/AN/A

NC for XLVFNC for XLVF S-VS for othersS-VS for others

FEDFAAFEDFAA

N/AN/AWheel LoadWheel Load

N/AN/AMGWMGW N/AN/AFIFI

VS for allVS for allCBRCBR

AIRPAVEAIRPAVEAnalysisAnalysis

Legend: CBR=California Bearing Ratio FI=Freezing Index MGW=Maximum Gross Weight VS=very strong S=strong M=moderate W=weak I=insignificant HVF=high volume facility MVF=medium volume facility LVF=low volume facility HSS=high subgrade strength MSS=medium subgrade strength LSS=low subgrade strength NSB=non-stabilized base SB=stabilized base XLVF=extreme low volume facility NC=no change

Between Program Flexible ResultsBetween Program Flexible Results

Subgrade strength &Subgrade strength & annual growthannual growth

statistically significant statistically significant

Change in subgradeChange in subgrade strength more significantstrength more significant than an in traffic of upthan an in traffic of up to 10%to 10%

TC with frost protection &TC with frost protection & FAA with stabilized baseFAA with stabilized base

most conservativemost conservative flexible pavement structureflexible pavement structure

LEDFAA and FAA withLEDFAA and FAA with stabilized base moststabilized base most closely relate to TC flexibleclosely relate to TC flexible design outputdesign output

Between Program Rigid ResultsBetween Program Rigid Results

Subgrade strength &Subgrade strength & annual growthannual growth

statistically significant statistically significant

Change in subgradeChange in subgrade strength more significantstrength more significant than an in traffic of upthan an in traffic of up to 10%to 10%

FEDFAA and TC with noFEDFAA and TC with no frost protection = thinnestfrost protection = thinnest PCC slab thicknessesPCC slab thicknesses

TC with frost protectionTC with frost protection and FAA = thickest PCCand FAA = thickest PCC slab thicknessesslab thicknesses

FAA > LEDFAA > FEDFAAFAA > LEDFAA > FEDFAA

FAA & AIRPAVE mostFAA & AIRPAVE most closely relate to Transportclosely relate to Transport Canada rigid design outputCanada rigid design output

Conclusions - FlexibleConclusions - Flexible

Flexible pavement thickness decreases or remainsFlexible pavement thickness decreases or remains unchanged as the subgrade strength increasesunchanged as the subgrade strength increases

The FAA flexible pavement thickness increasesThe FAA flexible pavement thickness increases dramatically once the subgrade is reduced to a CBR of 6dramatically once the subgrade is reduced to a CBR of 6 (weak subgrade strength)(weak subgrade strength)

FAA flexible = FAA flexible = ff (design aircraft maximum gross weight) (design aircraft maximum gross weight)

LEDFAA, FEDFAA, SW-1, APSDS more sensitive toLEDFAA, FEDFAA, SW-1, APSDS more sensitive to subgrade (vs. traffic)subgrade (vs. traffic)

Conclusions - RigidConclusions - Rigid

TC rigid PCC slab thickness = TC rigid PCC slab thickness = ff (design aircraft wheel (design aircraft wheel load)load)

TC rigid TPT = TC rigid TPT = ff (Freezing Index) (Freezing Index)

AIRPAVE = AIRPAVE = ff (tire contact area) (tire contact area)

FEDFAA = thinnest PCC slab thicknessFEDFAA = thinnest PCC slab thickness

FAA > LEDFAA > FEDFAAFAA > LEDFAA > FEDFAA

RecommendationsRecommendations

Geometric design analysisGeometric design analysis –– impact on pavement design and performanceimpact on pavement design and performance

Comparison new design methods (FAARFIELD)Comparison new design methods (FAARFIELD)

New state-of-the art designs do not necessarily accountNew state-of-the art designs do not necessarily account for the climatic conditions experienced in Canadafor the climatic conditions experienced in Canada

Incorporate economic analysis into the design andIncorporate economic analysis into the design and planning stageplanning stage

Pavement Thickness Design for Canadian Airports Introduction Methodology Airport Pavement Design Methods Sources of Data Within Program Results – Flexible Equivalent Granular Thickness Within Program Results – RigidPCC Slab Between Program Flexible Results Between Program Rigi