Concrete Airfield Pavement Design - Using FAARFIELD for g Rigid ...

Concrete AirfieldPavement Design -Using FAARFIELD forRigid OverlaysFederal AviationAdministrationPresented to: Concrete Airport Pavement WorkshopRight Choice, Right NowAtlanta, GeorgiaPresented by: Navneet Garg, Ph.D.Date: November 4, 2009

2010 FAA WorldwideAirport TechnologyTransfer ConferenceNext Generation ofAirport TechnologySponsored By:-FAA-AAAEConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration2

Information on Disk1. FAA Computer Programsi. FAARFIELD 1.3ii. LEDFAA 1.3iii. FEAFAA 1.4iv. BAKFAAv. COMFAA 2.0 & Equivalent Traffic Spreadsheetvi. ProFAA2. Advisory Circularsi. 150/5320-6E Airport Pavement Design & Evaluationii. 150/5320-6D: Airport Pavement Design & Evaluation (CANCELLED)iii. 150/5335-5A: Standardized Method of Reporting Airport Pavement Strength – PCNiv.150/5370-10D: 10D Standards d for Specifying i Construction ti of Airportsv. 150/5370-11A: Use of Nondestructive Testing in the Evaluation of AirportPavementsvi. 150/5380-9: Guidelines and Procedures for Measuring Airfield PavementRoughness3. Presentations4. Contact ListConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration3

Federal Aviation AdministrationAirport Technology R&D Program• Research conducted at the FAA William J.Hughes Technical Center, Atlantic City, NJ,USA.• Sponsor: FAA Office of Airport Safety andStandards, Washington, DC. (AAS-100)• Provide support for development of FAApavement standards (Advisory Circulars).• http://www.airporttech.tc.faa.gov/h t /Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration4

Location of FAA Technical CenterPhiladelphiaWashingtonNew YorkFAA Technical CenterAtlantic City, New Jersey* Outline map of USA used by permission of the University of Texas Libraries, The University of Texas at Austin.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration5

National Airport Pavement TestFacility (NAPTF)FACTS:• Fully enclosed facility foraccelerated traffic testing ti ofairport pavements.• Full-scale pavement structuresand dlanding gear loads withprogrammed wander.• Opened in 1999.• Total construction contract was$21M.– $14M from FAA– $7M from Boeing Co. underFAA/Boeing CRDA.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration6

NAPTF Test Pavement LayoutConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration7

NAPTF Construction Cycle (CC)Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration8

FAARFIELD – What Is It?FederalAviationAdministrationRigid andFlexibleIterativeeElasticLayeredDesign• FAARFIELD is the newFAA airport pavementthickness designprogram.• FAARFIELDsupersedes LEDFAA1.3 as the standarddesign procedure inFAA Advisory Circular(AC) 150/5320-6E.• Officially releasedSeptember 30, 2009.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration9

FAA Legacy Design Procedures vs.LEDFAA 1.3Traffic ModelStructural ResponseModelsThickness DesignMethodImplementationAC 150/5320-6D(Chapters 3 - 4)All traffic converted toequivalent departures ofdesign aircraft•Westergaard’s solution forrigid pavements•Boussinesq model used tocompute ESWL for flexible•CBR equation with alphafactor (flexible)•Apply percent of thickness tobasic design for 5000coverages (rigid)Design nomographs(spreadsheet implementationalso available)LEDFAA 1.3CDF (Cumulative DamageFactor) accounts for mixedtraffic•Layered elastic analysis(LEAF) for flexible and rigidFailure model relatescoverages to structural failureto a suitable response:subgrade strain (flexible) orconcrete stress (rigid).Desktop computer programConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration10

FAA Legacy Design Procedures vs.FAARFIELDTraffic ModelStructural ResponseModelsThickness DesignMethodImplementationAC 150/5320-6D(Chapters 3 - 4)All traffic converted toequivalent departures ofdesign aircraft•Westergaard’s solution forrigid pavements•Boussinesq model used tocompute ESWL for flexible•CBR equation with alphafactor (flexible)•Apply percent of thickness tobasic design for 5000coverages (rigid)Design nomographs(spreadsheet implementationalso available)FAARFIELD 1.3CDF (Cumulative DamageFactor) accounts for mixedtraffic•Layered elastic analysis(LEAF) for flexible.•3D finite element for rigid.Failure model relatescoverages to structural failureto a suitable response:subgrade strain (flexible) orconcrete stress (rigid).Desktop computer programVisual Studio 2005Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration11

FAARFIELD – Technical Background• Computer program for desktop PCs.• Program preserves the “look and feel”of LEDFAA 1.3.• Major changes are internal.• Main program drives threesubprograms:– LEAF (layered elastic analysis)– NIKE3D (3D finite element analysis)– INGRID (3D mesh generation)• NIKE3D and INGRID information:– Modified for FAARFIELD by the FAA– Distributed in compiled form under asoftware sharing agreement with LawrenceLivermore National Laboratory (LLNL)Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration12

FAARFIELD 1.3Key Differences from LEDFAA 1.3• Rigid Pavements/Overlays– Slab edge stresses are now computed directly using 3D-FEM.– Completely revised rigid pavement failure model.– Rewrote and improved rigid overlay design procedures.• Flexible Pavements/Overlays– Automatic base thickness design.– Improved Pass-to-Coverage ratio computation routine.– Supports HMA overlay design on rubblized PCC base.• General– Upgrade to MS Visual Basic 2005 programming environment.– Aircraft library updated.– New function allows user to export design data to XML.– Improved formatting for Notes.– All user options collected on one “Options” screen.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration13

FAARFIELD 1.3• Pavement thickness is now computed forconstant tire contact area.– Changing the airplane gross weight causes the tirepressure to be adjusted to maintain the contact area.• External aircraft library in XML format.• Displays CDF values graphically.• Enhanced Airplane Data window nowdisplays gear coordinates.• Support for PCC over rubblized base.• Aircraft changed to Airplane(s).Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration14

Cumulative Damage Factor (CDF)• Sums the damage contributed from each aircraft -not from equivalent aircraft.• CDF = Σ (n i /N i ), where:– n i = actual passes of individual aircraft i– N i = allowable passes of individual aircraft i• When CDF = 1, design life is exhausted.• In FAARFIELD (and LEDFAA 1.3):– The gear location and wander are considered separately foreach aircraft in the total mix.– CDF is calculated for each 25.4 cm (10 inch) wide strip over atotal 20.83 m (820 inch) width.– Miner’s rule to sum damage for each strip.• Must input the fleet mix, NOT equivalent departuresof design aircraft.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration15

Cumulative Damage Factor (CDF)Difference in GearLocationCDFDamage fromAirplane ADamage fromAirplane B25.4 cm (10 in.)Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration16

Cumulative Damage Factor (CDF)25.4 cm (10 in.) Total DamageCDFDamage fromAirplane ADamage fromAirplane BConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration17

Large Airplane Traffic Mix GearLocationsnway Cente erline .RuB-777-200B-747-400A330 A-330B-767-200A-300-B2B-757B-727B-737-400MD-83MD-90-30DC-9-50DW 100,000Regional Jet 700Regional Jet 200DW 45,000DW 30,000SW 30,0000000 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400Distance From Centerline (in)Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration18

FAARFIELD – CDF Graphical DisplayConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration19

Remember - in FAARFIELDUse the entire traffic mix!Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration20

FAARFIELD System/SoftwareRequirementsMinimumRecommended• Windows 2000• Windows XP• 600 MHz Pentium III processor • 2 GHz Pentium IV processor• 256 MB memory• 512 MB memory• 200 MB of available space onhard drive.• Users of older operating systemsmay require a one-timeinstallation of the .NETFramework (free download fromMicrosoft).• Users of older operating systemsmay require a one-timeinstallation of the .NETFramework (free download fromMicrosoft).Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration21

Running FAARFIELD:Program Windows and LinkageNOTESAdditional SectionInformation andDetailed Output DataSTARTUPControl andOrganizationOPTIONSSet User Optionsand TolerancesExport XMLSTRUCTUREStructure Data Inputand DesignAIRCRAFTAircraft Load andTraffic Data InputAIRCRAFT DATAView Landing GearGeometry, Load, andTire PressureConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration22

FAARFIELD Input RequirementsStructure WindowAirplane Window• For each structural layer:– Material type (FAA specification)– Layer Thickness– Modulus or R-value (if applicable)• There are built-in restrictions on thelayer types, including relative positionand layer properties.• For subgrade, can enter CBR or k andFAARFIELD will convert to E.• Select airplane from library.• For each airplane in the mix:– Aircraft Name– Gross Taxi Weight– Annual departures and percent annualgrowth if applicable• Enter data for all airplanes in the mix.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration23

FAARFIELD Job Files (JOB.xml)• Job files in FAARFIELD 1.3 are in XMLformat. This is a different format thanprevious job files in LEDFAA.• FAARFIELD looks for old job files in theworking directory and automaticallyconverts them to the new XML format.– After reading, the old job files are moved to asubdirectory of the working directory calledold_job_files.– All subsequent changes are written to the JOB.xmlfiles only. The old job files are not changed.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration24

Structural Models in FAARFIELD 1.3• Both layered elastic (LEAF)and d3DFEM 3D-FEM (NIKE3D) areused in FAARFIELD.• Flexible pavement design– LEAF is used for all structuralcomputations.– For flexible, no advantage tousing 3D-FEM.• Rigid pavement design– LEAF is used to generate apreliminary thickness.– Final iterations are doneusing 3D-FEM.E 1 , ν 12aqh 1h 2E h 2 , ν 22E 3 , ν 3Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration25

3D-FEM Rigid Pavement MeshDisplayed Using NikePlot UtilityModel includes 1 or2 slabs (i.e., basePCC and overlay)Multiple Base LayersNot Visible to theUser During DesignSubgrade(“Infinite” Elements)Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration26

3D-FEM Stress ResponseStress σ yy Contours Displayed Using NikePlot•3D-FEM responses arenot visible to the userduring design.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration27

Traffic Mix for This ExampleNo. Name Gross Wt., lbsAnnualDepartures% AnnualGrowth1 RegionalJet-200 47,450450 1,000 02 RegionalJet-700 72,500 800 03 Canadair-CL-215 33,000 600 04 DC-3 26,900 500 05 Gulfstream-G-V 90,900 200 0Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration28

New Rigid Example Set-UpCreate a new sectionin job PROJECT bydragging sectionNewRigid id in Samplesto PROJECT.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration29

New Rigid Pavement Design Example• Pavement Structure:– PCC Slab, P-501, R = 710 psi– Cement-Treated Base, P-304, 6 inches thick– Crushed Aggregate Base, P-209, 8 inches thick– Subgrade k = 100 pci• Traffic Mix:– 5-Aircraft Mix includes (less than 100,000 lbs)Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration30

Change Pavement StructureIn Structure window,click on ModifyStructureConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration31

Change Pavement StructureClick R to 710 psiChange base layer toCTB, P-304, 6 inChange P-209 layerthickness to 8 inChange subgrade k to100 pciClick “End Modify”Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration32

Change Pavement StructureClick “Save Structure”Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration33

Add Airplane ListClick on “Clear List”to clear the sampleairplanes from thedesign list.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration34

Add Airplane ListConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration35

Run Design•During g the designprocess, the “DesignRunning” clock willappear.•For rigid designs, thedesign will normallytake a few minutes.Don’t interrupt theprocess.•The screen displaywill change with eachiteration.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration36

New Rigid Pavement - Final DesignConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration37

FAARFIELD Overlay Design• HMA Overlays on Flexible Pavement– Same as designing a new flexible pavement, except the designlayer is the HMA overlay.• PCC Overlays on Flexible e Pavemente – Same principle as new rigid design.• HMA Overlays on Rigid Pavement• PCC Overlays on Rigid Pavement– More complex than new rigid pavement design.– Both slabs (base PCC and overlay) deteriorate with appliedtraffic. Stresses are computed for both slabs.– E-modulus of the base slab is a function of reduced SCI.– Subroutines were completely rewritten for FAARFIELD.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration38

FAARFIELD Overlay Design –PCC on Rigid Overlays• Fully bonded overlays– Treat as a new rigid pavement design.– Thickness of overlay slab is h overlay = h design – h exist .• Unbonded d overlay– Bond breaker or leveling course is used.• Partially bonded overlay– No longer a standard design in AC 150/5320-6E.– Default in FAARFIELD is off.– May be enabled from the Options window, butdisplays a “Non Standard Structure” message.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration39

FAARFIELD Overlay DesignRequired Inputs• Existing rigid pavement condition is characterized by theStructural Condition Index (SCI).• SCI derived from PCI as determined by ASTM D 5340 AirportPavement Condition Index Surveys. The new AC givesguidance on SCI.• SCI is computed using only structural t components from thePCI survey.• SCI = 80, FAA definition of structural failure (50% of slabs withstructural crack)• For existing pavements with structural damage (SCI < 100)– The user inputs a value of SCI for the existing pavement. The range ofallowable values depends on the overlay type:• Rigid on Rigid Overlays: SCI 40–100• Flexible on Rigid Overlays: SCI 67–100 (was 50-100)– The Help file gives approximate formulas for relating SCI to Cr and Cbfactors in earlier method.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration40

FAARFIELD – PCC Unbonded OverlayDesign Structural Condition Index (SCI)Rigid Pavement Distress Types Used to Calculate SCIDistressCorner BreakLongitudinal/Transverse/Diagonal CrackingShattered SlabShrinkage Cracks (cracking partial width of slab)*Spalling–JointSpalling–CornerSeverity LevelLow, Medium, HighLow, Medium, HighLow, Medium, HighLowLow, Medium, HighLow, Medium, High* Used only to describe a load-induced crack that extends only part of the way acrossa slab. The SCI does not include conventional shrinkage cracks due to curing orother non load-related problems.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration41

Cumulative Damage Factor Used (CDFU)• For existing pavements where SCI=100(no structural distress):– There is no visible distress contributing to reductionin SCI (no structural distress types). However, somepavement life has been consumed by the appliedtraffic.– The amount of pavement life consumed is thepercent CDF Used (%CDFU).– Need to estimate a value of %CDFU.– The Help file gives guidance on estimating %CDFUusing the Life key.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration42

Cumulative Damage Factor Used (CDFU)– CDFU defines the amount of structural life used.• For structures with aggregate base:• L U = number of years of operation of the existing pavement until overlay• L D = design life of the existing pavement in years– FAARFIELD modifies this relationship for stabilizedsubbases to reflect improved performance.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration43

PCC on Rigid Overlay Example• Existing PCC structure will receive a P-501 PCCoverlay to support additional traffic.– Assume R for new concrete = 700 psi.• Existing Pavement Structure:– PCC Slab, 10 in, R = 710 psiSCI = 100. Estimate %CDFU from traffic history.– Cement Treated Base, P-304, 6 in– Crushed Aggregate Base, P-209, 8 in– Subgrade k = 100 pci• Design Traffic Mix:– Use same traffic mix as in the new rigid pavement designexample.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration44

Estimate %CDFU (Example)•Assume the following traffic mix was applied to theexisting pavement:No.NameGross Wt.,lbsAnnualDepartures% AnnualGrowth1 RegionalJet-200 47,450 1,000 02 RegionalJet-700 72,500 800 03 Canadair-CL-215 33,000 600 04 DC-3 26,900 500 05 Gulfstream-G-V G 90,900900 200 0•Assume that at the time of the overlay the pavement willhave been in operation 12 years.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration45

Procedure to Estimate %CDFU• Input the original pavement structure.• Estimate the annual traffic applied to theexisting pavement up to the time of theoverlay.• Set “Design Life” to the number of years thepavement will have been in operation at thetime of the overlay. Assume that at the timeof the overlay the pavement will have beenin operation 12 years.• Run “Life” to obtain %CDFU.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration46

Estimate %CDFU (Example)In the Structurewindow, change thedesign life to thenumber of years thattthe pavement willhave been in serviceat the time of overlay(12 years in thisexample.)Click End ModifyConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration47

Estimate %CDFU (Example)Click Life to run Life.The calculated%CDFU will appear onthe Structure window,at the lower left of thepavement section.%CDFU = 84.83 (Say85%).Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration48

PCC on Rigid Overlay – ChangeStructureIn the Structurewindow, click ModifyStructure.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration49

PCC on Rigid Overlay – ChangeStructureClick Add/DeleteLayer.Select the PCCsurface layer byclicking on it with themouse. In the dialogbox, select Add andclick OK. A new PCCsurface layer appears.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration50

PCC on Rigid Overlay – ChangeStructureYou must change thetop layer to anoverlay. Click on theLayer Material box.In the Layer TypeSelection Box, select“Overlay FullyUnbonded” and clickOK.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration51

PCC on Rigid Overlay – ChangeStructureIn the upper rightcorner of theStructure window:- Change “Design Life”to 20 years (standard).- Change SCI to 100.- Change %CDFU to 85.Change R (overlay) to700 psi.Click End Modify.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration52

PCC on Rigid Overlay – ChangeStructureClick Save Structure.Click Airplane to go tothe Airplane window.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration53

PCC on Rigid Overlay – ChangeAirplane ListConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration54

PCC on Rigid Overlay – ChangeAirplane ListClick Save ListClick Back to return tothe Structure window.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration55

Run Overlay DesignClick Design Structureto run the overlaydesign.Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration56

Example: PCC on Rigid OverlayFinal DesignConcrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration57

http://www.airporttech.tc.faa.gov/Concrete Airfield Pavement Design Using FAARFIELD for Rigid OverlaysNovember 4, 2009Federal AviationAdministration58