Strip Drain

PRODUCT DESCRIPTION

Stripdrain is a fully filtered, prefabricated subsoil drainage system widely used around Australia. It consists of a plastic inner core
over-wrapped with a geotextile filter fabric.

SPECIFICATION

For installation of sub-surface drains using Stripdrain for edge road pavement and under road pavement conditions:

SCOPE OF WORKS
The scope of the works includes the installation of a prefabricated sub-surface drainage system (PSD) located at the edge of road pavement and under road pavement conditions. The sub-surface drainage system shall be installed in accordance to this specification and in accordance to all relevant drawings or as specified by the Site Engineer.

MATERIALS
General - The PSD shall be flexible, prefabricated, rectangular shaped geocomposite product. The drain shall consist of a plastic inner core completely wrapped by a geotextile filter fabric.

PSD Core Properties

a) The core shall be manufactured from high density polyethylene plastic (HDPE.) and shall have excellent resistance to both
chemical and microbiological attack.

b)The profile of the HDPE. core shall consist of raised cusps designed to support the geotextile and provide a medium for the
collection and transportation of water.

c)The core material shall have the following minimum properties

Test
Mass
- 1.5 kg/m2

Min. Crush Strength
- 200 kPa
ASTM 1621
Fungus Resistance
- No Growth
AS 1157.11
Creep Resistance:
For HDPE. materials the allowable load limit (limiting stress) is approximately 1/3 of the crush strength at 10
0eflection (ie., approx. 70 kPa).

Geotextile Properties

a)
The geotextile shall be non-woven, thermally-bonded fabric and shall be chemically treated, to reduce the surface tension on the
fabric allowing water to pass quickly through. The geotextile shall be abrasion resistant to resist damage during installation.
b)
The geotextile shall have the following minimum properties:

Properties

Test
Minimum Weight
140 g/m2
AS3706.1
Wide Width Strip Tensile
8 kN/m
AS3706.2
5 percentile strength
7 kN/m
AS3706.2
Elongation
45
AS3706.2
Trapezoidal Tear
320N
AS3706.3
CBR puncture
1300N
AS3706.4
Pore Size
150 micron
AS3706.7
Permeability
1.5/s
AS3706.9
Flow Rate - 10 cm head
50 l/m2/s
AS3706.9

Geocomposite Properties

a)
The geocomposite PSD shall consist of a rectangular configuration to allow for easy installation and minimum trench width
b)
The geocomposite PSD shall be packed in rolls of not less than 50 metres and shall be delivered by the manufacturer in black
plastic bags or other suitable covering to allow easy storage and handling.
c)
The geocomposite PSD shall have the following properties Thickness 25 - 40 mm Width 100 - 900 mm

STORAGE AND HANDLING
The Contractor shall exercise care in storing and placing the PSD to ensure the product remains undamaged. The protective black
wrapping material shall remain in place until the time of placement. The Contractor shall ensure that the product is not torn or
crushed from the time of delivery to the site storage area and up to and including placement.
The PSD, if stripped of its black wrapping shall not be allowed to be exposed to direct sunlight for more than 1 -2 weeks.

CONSTRUCTION METHOD
Excavation - Shall be undertaken by a chain excavator or similar trenching machine. The minimum width shall be 100 mm and the
maximum width of the trench shall be 150 mm. The trench is to be located in accordance with the drawings or as specified by the
Engineer. The trench invert shall be excavated to the gradients as detailed on the drawings or as specified by the Engineer. The
trench invert shall be cleaned of any loose material. The design gradient shall be reinstated in areas where the trench invert has been
over excavated. All excavated material shall be removed and under no circumstances shall be used as backfill material.

Installation - The PSD shall be placed vertically in the trench with the geotextile seam pointing down. The PSD shall be placed in the
centre of the trench and held in the vertical position by locating forks or by some other means during the backfilling operation. Any
PSD which has been damaged by construction plant or equipment shall be cut out and the two ends of PSD shall be jointed in
accordance to the Section Jointing.

Sealing Of Stripdrain Ends - The PSD ends must be covered to ensure soil cannot enter the drain. The ends shall be completely
sealed by cutting back the geotextile for 75 - 100 mm to expose the core. The exposed core shall be cut off and the geotextile folded
back and secured by 50 mm wide PVC adhesive tape.

Jointing Of Stripdrain - The jointing of PSD rolls is undertaken by slitting the geotextile for 75 - 100 mm and pulling back the
geotextile to expose the core on both ends of the rolls. The exposed core is overlapped and the geotextile is then pulled back over the
joint and secured with PVC duct tape to ensure soil is prevented from entering the drain.

Fittings - Suitable fittings for the PSD include, but are not limited to, end outlets flush points, side outlet points and inspection
openings. The fittings shall be of sufficient strength to withstand construction and permanent loadings. The joints shall be sealed in
such a manner as to prevent any foreign material entering the PSD section. The placement of fittings shall be in accordance to the
drawings or as specified by the Engineer.

Flush Points And Inspection Openings - The flush points are to be located at the upstream end of the PSD system as shown on the
drawings or as specified by the Engineer. Inspection openings are to be located between the flush points and the PSD outlet. The
inspection openings should be spaced at approximately the mid point as shown on the drawings or as specified by the Engineer.

End Outlets - The PSD shall be terminated by attaching an end outlet fitting at locations shown on the drawings or specified by the
Engineer. Outlet spacing shall be generally 80 - 100 metres (approx). Shorter outletting distances may be installed at the direction of
the Engineer in areas of high seepage flow. On projects which include an existing or constructed drainage structure, the PSD shall be
outletted to each structure unless otherwise directed by the Engineer.

Side Outlets - Side outlets (tee outlets) shall be used at low points of the PSD system as shown on the drawings or as specified by
the Engineer.

Backfilling And Compaction - Backfilling material shall consist of one of the following:-

a)
coarse washed sand
b)
6 mm minus
c)
no-fines concrete

The trench shall be back filled to the sub-base surface level before the material can be compacted using a vibratory plate compactor
or with other vibratory compaction equipment subject to the approval of the Engineer. The geocomposite PSD must have a
MINIMUM cover of 200 mm before the backfill is compacted by mechanical vibrating equipment weighing up to 15 tonne. For
compacters with mass greater than 15 tonne a cover of 300 mm shall be provided over the Stripdrain. All depressions on the drain
trench shall be refilled and the area compacted to ensure the finished level matches the sub-base surface level. Sub-base backfill or
other materials in or adjacent to the trench shall be compacted to 950f the maximum dry density.

FINAL ACCEPTANCE
The integrity of the installed PSD shall be maintained at all times. The PSD shall be kept free of accumulation of silt, debris, or other
foreign material until the time of final acceptance by the Engineer.

NOTE: The above specification is recommended for general conditions. Design Engineers should modify the specification to
accommodate specific requirements.

GENERAL AREA OF APPLICATION

Stripdrain is used extensively to protect structural elements of roads, railways and building foundations because of its ability to
quickly draw down high water tables.

Similarly, Stripdrain has proven to be highly effective in draining sports fields, golf courses etc. after heavy rain, permitting normal
use much more quickly than would have been the case with traditional drainage methods.

GENERAL CHARACTERISTICS

COMPOSITION

The Stripdrain products are wrapped with TERRAM 1000 S/UV (geotextile ultra-violet stabilised).

DIMENSIONS

Stripdrain is now available in two different configurations:-

1.
Standard double-sided cuspated core. Double-sided Stripdrain is available in 50 m coils in depths of 100-900 mm with a
standard thickness of 40 mm.
2.
New single-sided cuspated core. Single-sided Stripdrain XS is also available in 50 m coils with a depth range of 100-800 mm
and standard thickness of 25 mm.

Stripdrain
Stripdrain XS
Thickness:
40 mm
25 mm
Width:
100 - 900 mm
100 - 800 mm (nominal)
Roll Length:
50 metres
50 metres

WEIGHTS AND DENSITIES

Terram 1000 S/UV (10000B761F0olypropylene) Geotextile Wrap:

Mass per unit area:
AS 3706.1, ASTM D3776
- 140 g/m2
Thickness:
AS 3706.1, ASTM D1777
- 0.5 mm

OTHER GENERAL CHARACTERISTICS

Lightweight, flexible and easy to join, Stripdrain offers significant installation savings with the use of narrow trenches. Overall, the
cost of Stripdrain sub-surface drainage systems is much less than conventional sub-surface drains.

Plastic Core

Stripdrain
Core
Material
HDPE
Mass
1.5 kg/m2 (average)
Crush Strength
200 kPa (min.)
Core Profile
Raised cusps on both sides
Creep Resistance (Limiting stress = 1/3 x ultimate crush strength @ 10 0eflection)
70 kPa (approx.)

Stripdrain XS
Core
Material
HDPE
Mass
2.1 kg/m2 (average)
Crush Strength
300 kPa (min.)
Core Profile
Raised cusps on one side only. Punched circular holes on flat
section of core.
Creep Resistance ( Limiting stress = 1/3 x ultimate crush strength
@ 10 0eflection)
100kPa (approx)

PERFORMANCE AND DURABILITY

STRENGTH

Terram 1000 S/UV (10000B761F0olypropylene) Geotextile Wrap:

Wide width strip tensile AS 3706.2, ASTM D4595
Mean peak strength:
8 kN/m
5 percentile strength:
6.5 kN/m
Modulus:
4 kN/m @ 5
Elongation:
45

Trapezoidal tear AS 3706.3, ASTM D4533
Main peak strength:
320 N
5 percentile strength:
250 N

CBR puncture AS 3706.4, BS 6906: Part 4
Mean peak strength:
1200 N
5 percentile strength:
1000 N

Grab tensile ASTM D4632
Mean peak strength:
550 N

Drop cone AS 3706.5
D/500:
32 mm
H/50:
950 mm

G rating QMRD
G value:
> 1000 Nmm/0.5
G classification:
Mod. robust

MOISTURE BEHAVIOUR

Stripdrain provides a far greater contact area through which water can pass thereby permitting more rapid, efficient drainage
compared to conventional sub-surface drainage systems.

Terram 1000 S/UV (10000B761F0olypropylene) Geotextile Wrap:

Pore size AS 3706.7
EOS 0/95:
130 microns

Permeability AS 3706.0, BS6906: Part 3
Permittivity:
1.3/s
Flow rate-10 cm head:
80 /m2/s

Advantages of Stripdrain'S Unique "Deep Fin" Design
Stripdrain is normally installed vertically in the ground so that it has a deep rectangular cross-section containing a continuous plastic
core. This unique "deep fin" geometry has been designed to provide the maximum hydraulic performance for minimum excavation
thus providing more cost-effective drainage compared with traditional methods. Some of the advantages are as follows:

a)
Complete Interception Seepage Flow - Stripdrain's deep fin geometry means it can achieve full interception by physically
blocking the seepage and then transporting the water away.

b)
Rapid Drainage of High Water Table - Stripdrain has a superior infiltration rate to conventional surface drains, resulting in rapid
drawdown of the water table.

c)
Effective Drainage of Layered Soils - Stripdrain's deep fin geometry means it can directly intercept all the water flow in several
strata of soil. Consequently, effective drainage can be achieved readily and reliably.

d)
Easy Removal of Surface Water Run-off - Stripdrain's deep fin geometry means that larger sizes can be installed deeply enough
to lower the water table and also remove water run-off directly from near the ground surface.

APPLICATION AND MAINTENANCE

PRIMARY AREAS OF APPLICATION

Stripdrain is used extensively to protect structural elements of roads, railways and building foundations because of its ability to
quickly draw down high water tables.

Similarly, Stripdrain has proven to be highly effective in draining sports fields, golf courses etc. after heavy rain, permitting normal
use much more quickly than would have been the case with traditional drainage methods.

OTHER AREAS OF APPLICATION

Larger sizes of Stripdrain can be used as cut-off drains, as the impervious inner core provides a positive intercept for controlling
subterranean flow in cuttings and embankments.

Stripdrain can also be used in the mining industry for stope drainage and for collection of leachates in heap leach operations.

DESIGN CONSIDERATIONS

Fittings
A range of fittings, including End and Tee outlets, is now available for Stripdrain up to 300 mm. These fittings save installation time
and further enhance the performance of the Stripdrain system by maximising flow efficiency.
Backfilling Material
A coarse washed sand with less than 50f fines passing 75 micron sieve should be used as backfill. Alternatively - if no suitable sand
is available - 6 mm minus aggregate or no fines concrete can be used.

LIMITATIONS

Treat with care. Though an engineered product with inherent strength, Stripdrain should not be subjected to abuse. Do not walk on
it, or place heavy materials on it.

INSTALLATION AND USE

The Stripdrain products are wrapped with TERRAM 1000 S/UV (geotextile ultra-violet stabilised). TERRAM 1000 S/UV is strong
and abrasion resistant to withstand damage during installation. It is a non-woven thermally-bonded polypropylene fabric, chemically
treated to reduce surface tension allowing water to pass quickly through the fabric.

A soil filter develops within the first few millimetres of soil against the geotextile. As water passes from the original soil into the drain
it washes a few small particles with it for a short period of time after installation. As the particles are washed through, a bridging
network of slightly larger particles builds up against the geotextile. This network prevents further small particle from being washed
through, stabilising the soil and allowing only water to pass through the system.

Installation
Stripdrain is normally placed vertically in the trench with the geotextile seam pointing down. Stripdrain should be placed in the centre
of the trench and held in a vertical position by locating forks or by some other means during the backfilling operation.

Backfill Compaction
The trench should be backfilled to surface level before the material is compacted, using vibratory equipment or plant in
under-pavement and road edge installation. Stripdrain must have a minimum cover of 200 mm before the backfill is compacted by
mechanical vibrating plant up to 15 tonnes. For compacters with mass greater than 15 tonnes it is recommended 300 mm of cover
be provided above the Stripdrain.

INSTALLATION GUIDE:

1)
Stripdrain can be readily cut with most commonly available cutting blades such as a Stanley knife or NT cutter.
2)
Trenching with a mechanical chain trencher is usually the most efficient and a 100 mm cut is often suitable.
3)
Stripdrain upstream ends must be covered over to ensure that soil cannot enter the drain. This is done simply by cutting back
the geotextile for 75 - 100 mm and pulling back to expose the core. A section of core is removed and the geotextile folded
back and taped.
4)
Stripdrain is joined simply by slitting the filter fabric for 75 - 100 mm and overlapping the core. The filter fabric is then pulled
back over the joint and taped to prevent soil entry. Installation and jointing of single-sided Stripdrain is the same as for
double-sided Stripdrain.
Stripdrain must be terminated in a number of ways:-
A)
Stripdrain end and tee fittings available for sizes up to 300 mm.
B)
100 mm Stripdrain directly into 90/100 mm pipe.
C)
Stripdrain can be terminated into vertical cut-out in a 90/100 mm pipe.
D)
Sizes above 100 mm can be terminated by providing 30 - 35 mm slot at end of pipe.
E)
Cast into a concrete pit (care should be taken to ensure that the outlet is not blocked or fouled during the pour).
5)
Stripdrain must be installed vertically and with the fabric seam pointing down.
6)
Position Stripdrain upright in the middle of the trench during backfilling.
7)
An imported material such as coarse washed sand or small size aggregate should be used as backfill. Backfill with rock or
sharp stones should be avoided.
8)
Compaction - hand held units have no special requirements, although some soil cover to protect the geotextile is desirable.
When compacting beside Stripdrain it is advisable to progressively move a plywood board across the face. For light earth
works with rollers up to 15 tonnes a cover of 200 mm is required, while for heavy earth works a cover of 300 mm should be
provided before compaction.
9)
Cut out and replace any badly damaged core.
10)
It is of critical importance to repair any tears in the geotextile to prevent soil entry. For torn areas, a patch of geotextile should
be placed over the area and taped allowing an overlap of 100 mm.

STORAGE AND HANDLING

Care should be taken in storing and handling Stripdrain to ensure the product remains undamaged. The protective black wrapping
material should remain in place until it is ready to be installed. It is recommended that exposure of Stripdrain to direct sunlight be
kept to a practical minimum (exposure for 1 - 2 weeks being absolute maximum).

OTHER APPLICATION FACTORS

Road-edge Drainage
Stripdrain may be used both as under-pavement and formation drains to protect road structures from almost all sources of water.
Stripdrain (if deep enough) will keep ground water out of the total road structure, completely block and remove any lateral ground
water seepage, assist with removal of surface run-off from the cutting slope, remove surface infiltration of water from shoulders,
medians or verges into the pavement. Different sizes of Stripdrain may be required. Trenches are usually backfilled with material
suitable for compaction, such as small-sized aggregate or coarse washed sand.

Because of its ease of installation, Stripdrain is particularly valuable as a retrofit edge drain to prolong the life of existing roads or in
the reinstatement of water-damaged roads.

Slope Stabilisation
Stripdrain is usually installed just across the contours of the slope to give it some grade, but still take full advantage of its interception
capabilities. Installed correctly, it will assist in stabilising the slope by lowering the water table and reducing erosion caused by
surface water run-off. Typically, the larger Stripdrain sizes will be required.

ESTIMATING AND ORDERING

UNITS OF SUPPLY

Stripdrain is now available in two different configurations:

1.
Standard double-sided cuspated core. Double-sided Stripdrain is available in 50 m coils in depths of 100-900 mm with a
standard thickness of 40 mm.
2.
New single-sided cuspated core. Single-sided Stripdrain XS is also available in 50 m coils with a depth range of 100-800 mm
and standard thickness of 25 mm.