GSI Handbook Details Workshop April 10, 2018 GSI Handbook Details Pervious Pavement Peter Schultze-Allen, EOA / SCVURPPP
Outline of Presentation Pervious pavement basics Types of pervious pavement and location criteria Overview & example details from GSI Handbook Issues for typical details Lessons learned from example project 2
What is Pervious Pavement? Built systems that allow water to pass through the pavement surface to the underlying native soil. 3
Site Design or Treatment? MRP considers pervious pavement differently from other GSI Measures Classified as a site design measure, but considered a treatment measure for the purpose of installation and O&M inspections When integrated into a SWCP, pervious pavement is either a Self-Treating Area or a Self-Retaining Area 4
Self-Treating Area Pervious area that treats rain falling only on itself, via ponding, infiltration and/or ET Pervious pavement must be designed to store and infiltrate the C.3.d amount of runoff in order to qualify as self-treating areas Use a raised underdrain or raised elbow to allow for required infiltration
Self-Retaining Area Pervious area that retains first 1 of rainfall on itself and runoff from adjacent impervious area, up to a 2:1 ratio (impervious:pervious) Must be designed to handle the additional flow Pervious pavement areas are not recommended for treating runoff from other areas that might have excessive sediment Use a raised underdrain or raised elbow to allow for infiltration
Prioritization/Location Criteria Longitudinal slope Geotechnical issues Utility conflicts Utility replacement Flood risk Average Daily Traffic (ADT) levels Soil permeability Pollutant loading Pavement quality Can treat required stormwater volume Complete street plans/multi-modal Political/Visibility 7
Types of Pervious Pavement Permeable Interlocking Concrete Pavers Permeable Pavers Pervious Concrete Porous Asphalt Grid Pavements 8
Generic Cross Section Source: ASCE Permeable Pavements, 2015
Permeable Interlocking Concrete Pavers (PICP) Water flows through the joints Aggregrate for joints and bedding not sand 10
T PICP Full Infiltration 11
T PICP Partial Infiltration * Raised at outlet
Construction Operation Sequencing Installation of Concrete Band and Concrete Swale Photos courtesy of Daniel Apt, Olaunu
Construction Operation Sequencing Installation of Permeable Pavers Photos courtesy of Daniel Apt, Olaunu
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Permeable Pavers Water flows through paver Minimal joint spacing needed 19
Hydro-Flo pavers in San Jose at Fire Station #21 20
Hydro-Flo pavers in Union City 21
Hydro-Flo pavers in Palo Alto 22
Pervious Concrete 23
Pervious Pavement Parking Lot Pervious concrete parking stalls, Bellermine H.S., San Jose
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Pervious Concrete Units Low/no fines concrete For non-freezing climates Install with enlarged joints with permeable aggregate for additional drainage Pedestrian use only
Porous Asphalt 27
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Pervious Pavement Parking Lots Porous asphalt parking lot, Creekside Sports Park, Los Gatos
Grid Pavement Water flows through aggregates, joints or vegetation May have ADA issues Usually used in low volume areas More details in C3 Handbook 30
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Pervious Pavement Design Details 34
Design Process Overview
Pavement Sections and Details San Francisco Public Utilities Commission (SFPUC) District of Columbia Department of Transportation (DDOT or d ) Philadelphia Water Department (PWD) Central Coast Low Impact Development Initiative (LIDI) 36
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PICP Detail 39
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Pervious Pavers for Parking Lane SFPUC LIDI DDOT PWD Paver 3 1/8" 3 1/8" 3 1/8" 3 1/8" Levelling 2" 1.5 2" 2" 1.5" Choker 4 6" 4" 4 6" 8" Reservoir 0 10" Design 6" Design Filter 4" 44
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Pervious Concrete for Sidewalk SFPUC LIDI DDOT PWD Wearing 4.5" 5" 4" 4" 4" Choker 6" Design 4" 1.5" Reservoir Optional Design Optional 8" 46
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Porous Asphalt for Street SFPUC LIDI DDOT PWD Wearing 6 8" 6" 1.5" 2 Binder 3" Design Choker 6" 1 2" 4" 1.5" Reservoir 10 19" Design 6" 8" Filter 4" 48
Edge Control Details SFPUC DDOT PWD 49
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Underdrains: New Approach Raised outlet 54
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Underdrain: Connection to Catch Basin/Utility Structure 56
Observation Well Cap flush with pavement Permeable Surface Open Graded Base Open Graded Subbase Well Cap Subgrade Insert 100 to 150 mm (4 to 6 inches) into subgrade Perforated PVC Pipe
Allston Way: Lessons Learned Double the regular amount of potholing in pre-design Geogrids can reduce aggregate depth needed for structural loading Expect settling of pavers where utility protection changes aggregate depth or type Check 5 feet around perimeter of pavers for vaults and other infrastructure that could have uncompacted base material R value of 5 increased cost (SFPUC: Poor soils-15) ksat - 0.11 - typical for clay soils Expect concerns from utility company O&M 58
59 Slide courtesy of Tom Sweet, AECOM, and the City of Berkeley
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Check Dams for Sloped Subgrades Generally used on 3% or greater subgrade slopes Old school: Concrete, earthen berms, aggregate berms New school: Geomembrane (impermeable liner) only Aggregate berm covered with an impermeable liner Concrete 62
Subsurface Detailing 11 Infiltration Cells w/ Underdrains Slide courtesy of Tom Sweet, AECOM, and the City of Berkeley
Slide courtesy of Tom Sweet, AECOM, and the City of Berkeley 64
Subsurface Detailing Check Dam Configuration Slide courtesy of Tom Sweet, AECOM, and the City of Berkeley
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Additional Resources Caltrans Pervious Pavement Design Manual www.dot.ca.gov/hq/oppd/stormwtr/pervious.htm ICPI Design Guidance www.icpi.org/node/2750 ASCE Design Guidance www.asce.org/templates/publications-bookdetail.aspx?id=15418 FHWA Factsheet www.fhwa.dot.gov/pavement/concrete/pubs/hif1 6004.pdf 68
Questions? Peter Schultze-Allen 510-832-2852, x128 pschultze-allen@eoainc.com 69