HomeMy WebLinkAbout3211721130011-09102014BUILDING DEPARTMENT
SEP - 9 2014
SPECIFICATIONS FOR POROUS
INTERLOCKING CONCRETE PAVEMENT
CITY JF EDINA
CONSTRUCTION OF POROUS PAVEMENT
Proper construction of porous pavement is critical to its long
term performance as a stormwater BMP. Improper or inadequate
erosion and sediment control during construction and immediately
following construction can cause immediate plugging of the
pavement. The construction sequence is also critical to the long
term success of the performance of the pavement and is
described below. Failure to follow the recommendations will likely
cause premature structural failure of the pavement or result in
pavement without the desired infiltration capacity.
EROSION AND SEDIMENT CONTROLS FOR PERMIABLE PAVEMENT
All porous pavement areas should be fully protected from
sediment intrusion by silt fence or construction fencing,
particularly if they are intended to infiltrate runoff. They should
remain outside the limit of disturbance during construction to
prevent soil compaction by heavy equipment. Porous pavement
areas should be clearly marked on all construction documents
and grading plans. To prevent soil compaction, heavy vehicular
and foot traffic should be kept out of porous pavement areas
during and immediately after construction.
During construction, care should be taken to avoid tracking
sediments onto any porous pavement to avoid surface
clogging. Any area of the site intended ultimately to be a
porous pavement area should generally not be used as the
site of a temporary sediment basin. Where locating a
sediment basin on an area intended for porous pavement
is unavoidable, the invert of the sediment basin must be a
minimum of one foot above the final design elevation of
the bottom of the aggregate reservoir course. All sediment
deposits in the excavated area should be carefully removed
prior to installing the sub -base, base, and surface
materials.
INSTALLATION OF INTERLOCKING PAVERS
The basic installation process is described in greater detail by
Smith (Smith 2011). Porous paver job foremen should (not
required) successfully complete the PICP Installer Technician
Course training program offered by the Interlocking Concrete
Pavement Institute (ICPI). The ICPI provides a variety
of technical courses.
The following installation method also applies to clay paving
units. Contact manufacturers of composite units for additional
installation specifications. Guide construction specifications are
available from the Interlocking Concrete Pavement Institute.
• Moisten, place and level the AASHTO No. 2 stone subbase
and compact it in minimum 12 inch thick lifts with four
passes of a 10 -ton steel drum static roller until there is
no visible movement. The first two passes are in vibratory
mode with the final two passes in static mode. The filter
aggregate should be moist to facilitate movement into the
reservoir course.
• Place edge restraints before the base layer, bedding and
pavers are installed. Porous interlocking pavement systems
require edge restraints to prevent vehicle tires from
moving the pavers. Edge restraints may be standard
concrete curbs or curb and gutters.
• Moisten, place and level the AASHTO No. 57 base stone in
a single lift (4 inches thick). Compact it into the
reservoir course beneath with at least four (4) passes of
a 10 -ton steel drum static roller until there is no visible
movement. The first two passes are in vibratory mode,
with the final two passes in static mode.
• Place and screed the bedding course material (typically
AASHTO No. 8 stone (MnDOT 3127 -FA -3), 2 inches thick).
• Pavers may be placed by hand or with mechanical
installation equipment.
• Fill gaps at the edge of the paved areas with cut pavers
or edge units. When cut pavers are needed, cut the
pavers with a paver splitter or masonry saw. Cut pavers
no smaller than one-third (1/3) of the full unit size if
subject to tires.
• Fill the joints and openings with stone. Joint openings
must be filled with AASHTO No. 8 (MnDOT 3127 -FA -3),
89 or 9 (MnDOT 3127 FA-2)stone per the paver
manufacturer's recommendation. Sweep and remove excess
stones from the paver surface.
• Compact and seat the pavers into the bedding course
with a minimum low -amplitude 5,000 Ibf, 75- to 95 Hz
plate compactor. Do not compact within 6 feet of the
unrestrained edges of the pavers.
• Thoroughly sweep the surface after construction to remove
all excess aggregate.
• Inspect the area for settlement. Any paving units that
settle must be reset and inspected.
• The contractor should return to the site within 6 months
to top up the paver joints with stones.
CONSTRUCTION INSPECTION
Inspections before, during and after construction are
recommended to ensure that porous pavement is built in
accordance with these specifications. The following checklist
provides typical inspection observation items:
Pre -construction meeting
1. Walk through site with builder/contractor/subcontractor to
review erosion and sediment control plan/stormwater
pollution prevention plan (SWPPP).
2. Determine when permeable pavement is built in project
construction sequence; before or after building construction
and determine measures for protection and surface
cleaning.
3. Aggregate material locations identified (hard surface or on
geotextile).
Sediment management
4. Access routes for delivery and construction vehicles
identified.
5. Vehicle tire/track washing station location/maintenance (if
specified in the erosion and sediment control plan
(SWPPP)).
6. Ensure that the contributing drainage areas are stabilized
and are not eroding.
Excavation
7. Utilities should be located and marked by local service
provider.
8. The excavated area should be marked with paint and/or
stakes.
9. The excavation size and location should conform to the
plan.
10. Excavation hole as sediment trap: The hole cleaned should
be cleaned immediately before subbase stone placement
and runoff sources with sediment diverted away from the
pavement or all runoff diverted away from the excavated
area.
11. Temporary soil stockpiles should be protected from
run-on, run-off from adjacent areas and from erosion by
wind.
12. Ensure linear sediment barriers (if used) are properly
installed, free of accumulated litter, and built up sediment
less than 1/3 the height of the barrier.
13. No runoff should enter the pavement until soils are
stabilized in the area draining to the pavement.
14. Foundation walls should be waterproofed
15. Soil subgrade: rocks and roots removed, voids should be
refilled with base aggregate.
16. Soil should be compacted to specifications (if required)
and field tested with density measurements per
specifications.
17. No groundwater seepage or standing water. If groundwater
seepage is present, dewatering and possibly a dewatering
permit may be required.
Geotextiles
18. Must meet the design specifications.
19. Sides of excavation should be covered with geotextile prior
to placing aggregate base/subbase.
20. Placement and down slope overlap (minimum of 2 feet)
should conform to specifications and drawings.
21. No tears or holes should be present.
22. No wrinkles should be present and the fabric should be
pulled taught and staked.
23. Impermeable liners (if specified)
24. Must meet the specifications.
25. Placement, field welding, and seals at pipe penetrations
should be completed per the design specifications.
26. Drain pipes/observation wells.
27. Size, perforations, locations, slope, and outfalls must meet
specifications and drawings.
28. Verify the elevation of overflow pipes.
29. Underdrains should be capped at upslope ends.
Aggregates
30. Test results should conform to specifications.
31. Aggregates should be spread (not dumped) with a
front-end loader to avoid aggregate segregation.
32. Storage on hard surface or on geotextile to keep
sediment -free.
33. Thickness, placement, compaction and surface tolerances
should meet specifications and drawings.
Installation
34. See Installation of Interlocking Pavers section.
CONCRETE PAVERS; 3" DEPTH TYPICAL
JOINT FILLER, AASHTO No. 8
BEDDING COURSE; 2" DEPTH, AASHTO No. 8
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 »
°°°°°0°°°°°o°°°0°°°0° 0 0°°°0°0°°°0°0°° BASE COURSE, 4 DEPTH, AASHTO No. 57
SUB -BASE COURSE, AASHTO No. 2, 3, OR 4
10 DEPTH FOR DRIVEWAY
6" DEPTH FOR SIDEWALK OR PATIO
GEOTEXTILE MIRAFI 50OX OR EQUAL
PREPARED SUBGRADE NATIVE SOIL
TYPICAL SECTION
POROUS INTERLOCKING
CONCRETE PAVEMENT
NOTES:
1. ALL STONE IS TO BE WASHED FREE OF FINES.
2. PLACE GEOTEXTIEE ON BOTTOM AND SIDES OF EXCAVATION.
SPECIFICATIONS FOR SOIL
AMENDEMENT BY SOIL RIPPING
SOIL AMENDMENT BY SOIL RIPPING TO RELIEVE COMPACTION:
a)Ripping (Subsoiling) should be performed using a
solid -shank ripper and to a depth of 18 inches as
measured from the top of topsoil.
b)The goal of soil ripping or subsoiling is to fracture
compacted soil without adversely disturbing plant life, topsoil,
and surface residue. Soil compaction occurs most frequently
with soils having a high clay content. Fracturing
compactedsoil promotes root penetration by reducing soil
density and strength, improving moisture infiltration and
retention, and increasing air spaces in the soil. Compacted
layers typically develop 12 to 22 inches below the surface
when heavy equipment is used.
c)Subsoilers (rippers) can break up the compacted layer
without destroying soil aggregate structure, surface
vegetation, or mixing soil layers (Kees, 2008). How
effectively compacted layers are fractured depends on the
soil's moisture, structure, texture, type, composition,
porosity, density, and clay content. Success depends on the
type of equipment selected, its configuration, and the speed
with which it is pulled through the ground. No one piece of
equipment or configuration works best for all situations and
soil conditions, making it difficult to define exact
specifications for subsoiling equipment and operation.
d)Subsoilers are available with a wide variety of shank
designs. Shank design affects subsoiler performance, shank
strength, surface and residue disturbance, effectiveness in
fracturing soil, and the horsepower required to pull the
subsoiler. According to Kees (2008), "Parabolic shanks
require the least amount of horsepower to pull. In some
forest applications, parabolic shanks may lift too many
stumps and rocks, disturb surface materials, or expose
excess subsoil. Swept shanks tend to push materials into
the soil and sever them.
e)Ripping, subsoiling, or scarification of the subsoil should be
performed where subsoil has become compacted by
equipment operation, dried out and crusted, or where
necessary to obliterate erosion rills.
f) Subsoiling should not be performed within the drip line of
any existing trees, over underground utility installations within
30 inches of the surface, where trenching/drainage lines
are installed, where compaction is by design.
g)Subsoiling is only effective when performed on dry soils. If
soils are saturated, the Contractor shall delay operations
until the soil will not hold a ball when squeezed. Only one
pass shall be performed on erodible slopes greater than 1
vertical to 3 horizontal. When only one pass is used, work
should be at right angles to the direction of surface
drainage, whenever practical.
�It .
Liek , 42 vlw m
s�bf
d
CONSTRUCTION SEQUENCE.
a)Subsoil ripping, or scarification of the subsoil will be
required wherever the subsoil has been compacted by
equipment operation or has become dried out and crusted,
and where necessary to obliterate erosion rills. Sub -soiling
shall be completed in areas as indicated on the plan where
plant establishment or grass turf is planned.
b)Install perimeter, and/or down gradient, erosion control
BMP's prior to any upslope land disturbance.
c)Rough grading of the project should be complete and
measured implemented to protect the soil ripping area from
experiencing further compaction by heavy equipment.
d)Existing topsoil shall be stripped from the area of soil
ripping work. Topsoil shall be stockpiled and temporary
erosion control measures shall be implemented as required
for the stockpile.
e)The subsoil shall be in a relatively dry, friable condition to
a depth of 18 inches below final topsoil grade.
f) Ripping channels shall be created by a commercially
available, multi-shanked, parallelogram implement
(solid -shank ripper or equivalent equipment). The
equipment shall be capable of exerting a penetration force
s
necessary for the site. The grid channels shall be paced
a minimum of 12 inches to a maximum of 36 inches
apart. The channel depth shall be a minimum of 18
inches.
g)Sub-soiling shall be completed such that ripping channels
result in a two -directional grid.
h)Topsoil shall be re -spread over the soil ripping subsoil area
at a minimum 6" depth.
i) Final grade of the soil ripping area shall be achieved by
use of light equipment with tracks or turf type tires.
Equipment with high pressure narrow tires or large lugs will
cause excessive compaction.
j) Permanent ground cover turf shall be established by sod or
seed with established growth before perimeter erosion
control BMP's are removed. Erosion control BMP's are to
be removed once final stabilization is achieved.
C*m43tj#P�
ah,`k
GRAPHIC FROM MPCA MINNESOTA STORM WATER MANUAL
SOIL AMENDMENT AREA STORM WATER CALCULATION SUMMARY.
o)Proposed soil amendment area is 1,250 sf.
b)Soil type is Hydrologic Group B per NRCS Web Soil Survey data.
c)Reference MPCA Stormwoter Manual, Comparison of Average Annual Runoff Grouped By Soil Type And
Conditioning, Average Annual Runoff Depth. Average annual runoff depth for compact Group B soils =
5.2 inches. Average annual runoff depth for loose soils = 4.7 inches. Result of soil amendment by
loosing is 0.5 inches. Propose to achieve loose soil condition by soil ripping.
d)Storm water runoff volume reduction due to soil loosening for this project: 1,250 sf x 0.5 inches /
12 in/ft = 52.0 cf.
e)Proposed house and site improvements as noted on Sheet 1 result in increase of 163 sf hard
surface that drains to rear yard area.
f) Proposed soil amendment provides for reduction of stormwater volume control equivalent to 3.9 inch
rainfall event on 163 sf hard surface. 52 cf / 163 sf x 12 in/ft = 3.8 inches
CLIENT:
CORNERSTONE
HOMES, LLC
5609 Warden Avenue
Edina, MN 55436
612-598-5255
d'
4
C
m
CcC
0
0
Z IL
J
m
m
O
m
Q
W
�•-
30♦♦♦
V
`
cc
Z
c
O o
0
NG
9)
to 0
O
W
W
d'
4
.►
0
C,
�
m
m
O
m
Q
W
's
W
W
0
0
0
FILE N0. 00499
�
Q
J
Q
�
Q II
�Z
�I
W .c
�Q
WWW
oo�
W �.,
Q�x
vv0o�
�ONNN
20 II
>
N 4,-
Z _ ^ `
O
O
O
d'
4
.►
0
C,
�
m
m
O
m
W
W
's
W
W
0
0
0
FILE N0. 00499
2/2
Storm Water and
Erosion Control Plan