Integrating Structural and Hydrologic Design in Permeable Pavement · Integrating Structural and...
Transcript of Integrating Structural and Hydrologic Design in Permeable Pavement · Integrating Structural and...
2010 Concrete Sustainability Conference 1 © National Ready Mixed Concrete Association
Integrating Structural and Hydrologic Design in Permeable Pavement
David R. SmithTechnical DirectorInterlocking Concrete Pavement Institute
2010 Concrete Sustainability Conference 2 © National Ready Mixed Concrete Association
Pervious, Porous & Permeable Pavements
PerviousPervious PermeablePermeablePerviousPerviousconcreteconcrete
Permeable Permeable interlocking concreteinterlocking concrete
bl f ti
PorousPorous
capable of accepting, finding a way through
PorousPorousasphaltasphalt capable of passing something
(i.e. air/water)
full of pores, capable of being penetrated
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Concrete pavers:
ICP
Concrete pavers:ASTM C 9368,000 psi
PICPPICP Impervious pavement
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No. 8No. 8 Typical bedding, base & subbase stone sizessubbase stone sizes
No. 57No. 57 No. 2No. 2
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PICP for Hydrologic and Structural Design
Structural Analysis HydrologicalAnalysis
Structural Analysis HydrologicalAnalysis
Pavement Structure:Type and thickness of
pavement layers
Drainage Design:Drainage features and characteristic
Pavement Structure:Type and thickness of
pavement layers
Drainage Design:Drainage features and characteristicp y
C id h i
p y
C id h iIs the
drainage adequate?
Consider changing• Drainage characteristics
NoConsider changing
Yes
Is the drainage
adequate?
Consider changing• Drainage characteristics
NoConsider changing
Yes
• Thickness of pavement granular layers
• Thickness of pavement granular layers
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Structural Design - AASHTO
1993 ME PDG 2004
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Structural Design – AASHTO 1993 ⎤⎡ − ti pp
07.8)log(32.2
)1(109440.0
5.1log
20.0)1log(36.9
19.5
0 −×+
++
⎥⎦
⎤⎢⎣
⎡−
+−+×+×= Ri
ti
R M
SN
ppp
SNSZLogW
)1( +SN
W = design traffic load in equivalent single axle loads (ESALs)
Z t d d l d i tZR = standard normal deviateS0 = standard deviationSN = structural number of the pavement
= Σ a * d= Σ ai * diai = structural layer coefficientdi = layer thickness
pi= initial serviceabilitypi initial serviceabilitypt= terminal serviceabilityMR = subgrade resilient modulus (CBR, R-value)
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Truck Volumes and AxleWeights Affect Performance (i.e. rutting)
Traffic loads characterized by Equivalent Single Axle Loadsq g
18,000 lb (80 kN) ESALs
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Truck Factor = ESAL per TruckLEF: Load Equivalency Factor = axle load( )4
5 Axle Truck
LEF: Load Equivalency Factor = axle load80 kN( )
5 Axle Truck
2 x 80kN (18 kips) 2 x 70 kN (15.8 kips) 50 kN (11 kips)
LEF = = 1 (x2) LEF = = 0.15504
80( )80 480( ) LEF = = 0.6 (x2)70
4
80( )
TF (one pass) = 2.00 + 1.2 + 0.15 = 3.35 ESALs
( )
(
80( )80( ) ( )80( )
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AASHTO Typical ESALs by Road ClassAASHTO Typical ESALs by Road Class
Road Class Design ESALsArterial or Major StreetsArterial or Major StreetsUrban 7,500,000Rural 3,600,000Major CollectorsUrban 2,800,000Rural 1,450,000Minor CollectorsUrban 1,250,000Urban 1,250,000Rural 550,000Commercial/Multi-Family LocalsUrban 425,000R l 275 000Rural 275,000
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Porous AsphaltPorous Asphalt Pavements for Stormwater Management, NAPA 2008
Traffic LoadingTraffic LoadingMinimum Compacted Minimum Compacted Thickness, in. (mm)Thickness, in. (mm)
p f g ,
Parking – Little or no trucks 2.5 (65)
Residential street – Some trucks
4.0 (100)
Heavy Trucks 6 (150)
S t d PA l ffi i t 0 40 /i
No Base/subbaseThi k G id li
Suggested PA layer coefficient = 0.40 /in.
Thickness Guidelines
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Pervious ConcreteHydrologic Design of Pervious Concrete, Leming, PCA & NRMCA
Traffic Traffic LoadLoad
Design Design Axle Axle Load, Load, lblb
RepetiRepeti--tionstions
Pervious Pervious Concrete Concrete Thickness, in. Thickness, in. (mm)(mm)
18,000 lb (80 kN) 18,000 lb (80 kN) Equivalent Single Equivalent Single Axle Loads over 20 Axle Loads over 20
(7 200 d )(7 200 d )lbs lbs (kN(kN))
(mm)(mm) years (7,200 days)years (7,200 days)
Low 4,000 (18)
Unlimited 4 (100) Unlimited( )
Moderate 12,000 (53)
<10/day 6 (150) <14,400
High 18,000 (80)
2 to 3/day 8 (200) 14,400 to 21,600 (80)
Minor or collector streets
18,000 (80)
<100/day Consult design professional
<720,000
No Base/subbaseNo Base/subbaseThickness Guidelines
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PICP Typical max. lifetime loads: 600,000 18,000 lb ESALs or TI = 8.5 Permeable Interlocking Concrete Pavements, ICPI 2006g
** Strengthen soil subgrade with crushed stone to full frost depth
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Permeable Design Pro Software
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Moving ahead…• All use empirical structural design methods• PICP – accounts for truck traffic loads and soil
strengths provides base/subbase thicknessesstrengths, provides base/subbase thicknesses• AASHTO method reasonable for PICP• Open-graded subbase/base – more research p g /
needed Load-deformation relationships
i ld d f 200 S O d lField data for 2004 AASHTO modelStructural contribution of pavement layers (elastic modulus/layer coefficients)
Caltrans – theoretical modeling – full scale tests(?)MnRoad – full-scale PC & PA tests
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2 yrs – residential street Oregon
7 -8 yrs container storage New York New construction Minnesota
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Completely clogged surfaces require restorative vacuum cleaning
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• d Inspect & vacuum Inspect & vacuum sweep 2x annuallysweep 2x annuallysweep 2x annuallysweep 2x annuallywith standard with standard
equipmentequipmenttt-- no waterno water
Sweeping only equipmentSweeping only equipmentnot effective in removing not effective in removing
di tdi tsediment sediment
Check infiltration in Check infiltration in small areas with watersmall areas with watersmall areas with water small areas with water --Use ASTM C1701 asUse ASTM C1701 asneededneeded 18
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Sweeper EffectivenessLeast effective
Regenerative air vacuum sweeper - use 1-2 times/year
TTrue vacuum sweeper – very powerful – restores highlyclogged (neglected) surfaces19
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Sediment collects in top ½ - 1 in. (13-25 mm)
True vacuum sweeperpcleans out clogged stone & restores
surface infiltration – refill with clean stone20
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Exposed capUS Army Ft. Stewart, Georgia 21
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Covered cap
Exposed capExposed cap
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Winter Maintenance• Snow melts faster – lower risk of iceSnow melts faster lower risk of ice • Surface does not heave when frozen• Use normal plows - dirty snow piles clog surface• Deicing salts okay• Deicing salts okay• Sand will clog system – use
jointing material for traction
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PICP Inspection ChecklistVacuum surface 1 to 2 times annually, adjust per sediment
loadingloading Replenish aggregate in joints As needed
Inspect vegetation around PICP perimeter for cover & soil stability Annually, repair/replant as needed
Repair all deformationsexceeding 1/2 in. (13 mm) Annually, repair as needed
Repair pavers offset by more than 1/4 in. (6 mm) above/below adjacent units Annually, repair as needed
Replace broken units impairingReplace broken units impairingsurface structural integrity Annually
Check drain outfalls for free flow of water & outflow fromflow of water & outflow from observation well Annually, after a major storm
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PICP MaintenancePICP MaintenancePICP MaintenancePICP MaintenanceWorkshopWorkshop
Friday, June 4Naval PostgraduateSchoolSchoolMonterey, CA
www bae ncsu edu/www.bae.ncsu.edu/stormwater/training.htm
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PICP Installer Technical Certificate CourseResidential & Commercial ConstructionResidential & Commercial Construction
Estimating
Project managementProject management
Maintenance
Include in BMP manuals
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Warrenville, IL