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 WaterlooCPATT SymposiumCPATT SymposiumOctober 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
MethodologyMethodologyStage 1
Data Collection
Stage 2Data Organization
Stage 3Within Program Sensitivity Analysis
Stage 4Between Program Data Analysis
Sources of DataData Requirements
Aircraft Traffic& Volumes Climate Pavement
Structure
ClimateSensitivityAnalysis
TrafficSensitivityAnalysis
SubgradeSensitivityAnalysis
Design Methodsvs.
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 ElasticDesign (LEDFAA)Design (LEDFAA)
•• Asphalt Institute SW-1Asphalt Institute SW-1•• Australian AirportAustralian Airport
Pavement StructuralPavement StructuralDesign 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 ElasticDesign (LEDFAA)Design (LEDFAA)
•• FAA Finite ElementFAA Finite ElementDesign (FEDFAA)Design (FEDFAA)
•• American ConcreteAmerican ConcretePavement AssociationPavement AssociationAIRPAVE 2000AIRPAVE 2000
Sources of DataSources of Data20%
0%
13%
20%13%
34%AltanticQuebecOntarioPrairiePacificNorthern
60%13%
7%
7%
13%
National Airport SystemRegional/ LocalArcticRemoteUnclassified
Airport Region
Airport Type
Within Program Results – FlexibleWithin Program Results – FlexibleEquivalent 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 NSBS for NSBS for NSBM for SBM for SBS for SBS for SB
FAAFAA
W-M for LSSW-M for LSSI for HSSI for HSS
S-VS for HSSS-VS for HSSI for LSSI for LSS
VS for HSSVS for HSSI for LSSI for LSS
S - VS for HVFS - VS for HVFW 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 allLEDFAALEDFAA
N/AN/A
N/AN/A
*W for all*W for allSSSS
VS for allVS for allSW-1SW-1
N/AN/AWheelWheelLoadLoad
N/AN/AMGWMGW
N/AN/AFIFI
VS for allVS for allCBRCBRAPSDSAPSDSAnalysisAnalysis
Legend:CBR=California Bearing Ratio FI=Freezing Index MGW=Maximum Gross WeightVS=very strong S=strong M=moderate W=weak I=insignificantHVF=high volume facility MVF=medium volume facility LVF=low volume facilityHSS=high subgrade strength MSS=medium subgrade strength LSS=low subgrade strengthNSB=non-stabilized base SB=stabilized baseXCW=extreme cold weather climates * = Mean Average Air Temperature
Within Program Results – RigidWithin Program Results – RigidPCC SlabPCC Slab
S for allS for allN/AN/AN/AN/AN/AN/AN/AN/ATire contactTire contactareaarea
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 allI for allI for all
W for XLVFW for XLVFVS for othersVS for others
FAAFAA
S-VS for allS-VS for all
L for HSSL for HSSM for LSSM for LSS
I for allI for all
W for LVFW for LVFS-VS for HFVS-VS for HFV
TCTC
N/AN/A
N/AN/AN/AN/A
NC for XLVFNC for XLVFVS for othersVS for others
LEDFAALEDFAA
N/AN/A
N/AN/AN/AN/A
NC for XLVFNC for XLVFS-VS for othersS-VS for others
FEDFAAFEDFAA
N/AN/AWheel LoadWheel Load
N/AN/AMGWMGWN/AN/AFIFI
VS for allVS for allCBRCBR
AIRPAVEAIRPAVEAnalysisAnalysis
Legend:CBR=California Bearing Ratio FI=Freezing Index MGW=Maximum Gross WeightVS=very strong S=strong M=moderate W=weak I=insignificantHVF=high volume facility MVF=medium volume facility LVF=low volume facilityHSS=high subgrade strength MSS=medium subgrade strength LSS=low subgrade strengthNSB=non-stabilized base SB=stabilized baseXLVF=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 subgradestrength more significantstrength more significantthan an in traffic of upthan an in traffic of upto 10%to 10%
TC with frost protection &TC with frost protection &FAA with stabilized baseFAA with stabilized base
most conservativemost conservativeflexible pavement structureflexible pavement structure
LEDFAA and FAA withLEDFAA and FAA withstabilized base moststabilized base mostclosely relate to TC flexibleclosely relate to TC flexibledesign outputdesign output
Between Program Rigid ResultsBetween Program Rigid Results
Subgrade strength &Subgrade strength &annual growthannual growth
statistically significant statistically significant
Change in subgradeChange in subgradestrength more significantstrength more significantthan an in traffic of upthan an in traffic of upto 10%to 10%
FEDFAA and TC with noFEDFAA and TC with nofrost protection = thinnestfrost protection = thinnestPCC slab thicknessesPCC slab thicknesses
TC with frost protectionTC with frost protectionand FAA = thickest PCCand FAA = thickest PCCslab thicknessesslab thicknesses
FAA > LEDFAA > FEDFAAFAA > LEDFAA > FEDFAA
FAA & AIRPAVE mostFAA & AIRPAVE mostclosely relate to Transportclosely relate to TransportCanada rigid design outputCanada rigid design output
Conclusions - FlexibleConclusions - Flexible
Flexible pavement thickness decreases or remainsFlexible pavement thickness decreases or remainsunchanged as the subgrade strength increasesunchanged as the subgrade strength increases
The FAA flexible pavement thickness increasesThe FAA flexible pavement thickness increasesdramatically 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 tosubgrade (vs. traffic)subgrade (vs. traffic)
Conclusions - RigidConclusions - Rigid
TC rigid PCC slab thickness = TC rigid PCC slab thickness = ff (design aircraft wheel (design aircraft wheelload)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 accountfor the climatic conditions experienced in Canadafor the climatic conditions experienced in Canada
Incorporate economic analysis into the design andIncorporate economic analysis into the design andplanning stageplanning stage
