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Brosur Tensar Ground Stabilisation. Stabilisasi Tanah Dasar lunak (CBR Informasi produk dan harga hubungi :ISPARMO (Senior Marketing)PT Multibangun Rekatama Patria Telp/Hp. (021)98907652, 08121083060Email : [email protected] :http://jual-geotextile.blogspot.comhttp://www.multibangunpatria.com
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Tel: +44 (0)1254 262431
Fax: +44 (0)1254 266868
E-mail: [email protected]
www.tensar-international.com
Tensar International Limited
New Wellington Street
Blackburn BB2 4PJ
United Kingdom
Your local distributor is:
Contact Tensar International or your local distributor to receive further
literature covering Tensar products and applications.
Also available on request are product specifications, installation guides
and specification notes.
The complete range of Tensar literature consists of:
• Tensar Geosynthetics in Civil Engineering A guide to the products
and their applications
• Ground Stabilisation Reinforcing unbound layers
in roads and trafficked areas
• Steep Slopes Constructing embankments
with steep slopes
• Retaining Walls Constructing retaining walls in reinforced soil
• Foundations over Piles Constructing over weak ground
without settlement
• Basal Reinforcement Constructing embankments over
weak ground
• Railways Reinforcing ballast under railway track
• Asphalt Pavements Reinforcing asphalt layers
in roads and trafficked areas
• Erosion Controlling erosion on soil and rock slopes
Tensar is a registered trade mark.
©Copyright Tensar International Limited
Printed February 2003 Issue 4, 79010035
The information provided verbally, or in this document or as a Free Application
Suggestion is of an illustrative nature and is supplied without charge. It does not
form any contract or intended contract with the user. No liability in negligence will
arise from the construction of any project based on such information or material.
Final determination of the suitability of any information or material for the use
contemplated and the manner of use is the sole responsibility of the user and the
user must assume all risk and liability in connection therewith.
Tensar geogrids are manufactured under tightly controlled
conditions. The quality assurance procedures covering design and
application and the manufacturing process have been certified by
the British Standards Institution as a Registered Firm in
accordance with BS EN ISO 9001:2000
Q05288
GroundStabilisation
Reinforcing unbound layers in
roads and trafficked areas
Soft sensitive subgrades.
The interlocking between the geogrid and the aggregates particles limits lateral movement when dynamic loading is applied.
Tensar geogrids reduce cost and save timein road construction
Using Tensar biaxial geogrids in road
construction can solve or reduce the
problems described above. Designers
can optimise their pavement design,
especially when conditions are
challenging. Contractors can reduce
cost and save time. Including Tensar
biaxial geogrids in a pavement:
• Reduces granular thickness by up to
40%, thereby conserving valuable
aggregate resources and the
environment
• Reduces excavation, disturbance
and subsequent disposal of
subgrade soils
• Improves fill compaction
• Increases design life and improves
life-cycle management
• Helps control differential settlement
over variable soils and spans voids
or soft spots
3
Tensar biaxial geogrids work by interlockingwith aggregates
Tensar biaxial geogrids can solve
pavement problems because they
interlock very efficiently with
granular materials. When granular
particles are compacted over these
grids, they partially penetrate and
project through the apertures to
create a strong and positive interlock.
The Tensar manufacturing process
produces a unique grid structure,
consisting of full strength junctions
and stiff ribs, which present a thick
square leading edge to the
aggregate. This allows the aggregate
particles to get a good “grip” on the
geogrid, and results in effective
mechanical interlock. Interlock helps
prevent lateral movement and
dilation of aggregate particles, so
that a very high effective angle of
Road construction problemsConstruction of road pavements is
expensive and time consuming.
Difficult access conditions can become
impossible, especially in wet weather.
Soft sensitive subgrades frequently
require large thicknesses of aggregate,
much of which is lost due to deep
rutting. Aggregates are expensive and
scarce, and their extraction damages
the environment. They must be
transported, placed and compacted.
shearing resistance is mobilised.
Vertical load applied through
aggregate particles above the grid
can generate tensile resistance in the
ribs with very small deflection. The
combination of these features
ensures that, in Tensar geogrid
reinforced granular layers:
• Tensile load in the grid is generated
at very small deflections of an
applied vertical load
• Reinforcement benefit is localised
and can be generated within the
loaded area
This mechanism is also referred to as
“confinement”, because interlock
effectively immobilises and confines
the aggregate particles.
Very difficult access.
Wet weather conditions.
Building a pavement over Tensar geogrids (UK).
2
The interlock mechanism.
The unique cross-sectional shape of Tensar ribs provides bearing points for aggregate particles and works like the triangular rack supporting a pyramid of snooker balls.
applied force
Road building aggregates are becoming scarce
and expensive - they must be transported,
placed and compacted.
Tensar. The valueengineeredsolution
In Tensar you’ll find a partner
with the experience and
flexibility to respond to your
project requirements. From
design to completion, we’ll
make sure you always benefit
from a practical, cost-
effective solution to your
specific need.
Tensar SS-G composite.
Installing Tensar biaxial geogrids using an overlap between
adjacent rolls.
4
5
This is a common question when
considering using a geogrid in a road
pavement. The answer is: NO.
Geotextiles cannot interlock with
aggregate particles, so they cannot
generate the same very efficient
interaction and confinement of the
aggregate. Geotextiles are normally
used as separators only, but if they
are designed to reinforce a pavement
by developing tension, then they
must form a “tensioned membrane”
which requires large deformations,
and fixed wheel paths. It is not
suitable for use in the design of
normal surfaced or permanent
pavements. The difference is
illustrated on the diagrams below.
Do geotexiles work in the same way? Designing pavements with Tensar geogrid
Installation of Tensar biaxial grids
This difference in performance is
emphasised by the rut profiles shown
above, measured as part of a detailed
pavement trial carried out by TRL
(Transport Research Laboratory, UK).
These are cross-sections of the trial
pavement, showing both the top of
the sub-base (320 mm thick) and the
top of the subgrade (CBR = 1.5%),
before and after completion of
trafficking. After 5000 passes a deep
rut has formed in the geotextile
reinforced sub-base with a
considerable amount of heave, and
a similar rut has developed at the top
of the subgrade. This results in
remoulding and softening of the
subgrade. For the Tensar SS30 section,
after 10,000 passes the rut in the sub-
base is much smaller with little heave,
and the rut in the subgrade is
negligible with no heave (mainly
consolidation settlement of the clay
subsoil). The strength of the woven
geotextile is slightly higher than that
of Tensar SS30, yet performance is
quite different.
TENSAR GEOGRID REINFORCED
PAVEMENT
• Interlock stiffens the aggregate layer
• Load spread is increased
• Aggregate transfers the load
• Performance is improved
TENSIONED MEMBRANE REINFORCED
PAVEMENT
• Geotextile is anchored at edges
• Load is transferred to geotextile
• Geotextile and subgrade deform
• Negligible performance gain
Designing with Tensar geogrids results in reduced layer thickness.
Designs are carried out using sophisticated software.
Adjacent rolls may be joined together using HDPE braid.
Correct method of placement and spreading of granular
material is important.
Design of road pavements depends on:
• Subgrade strength (CBR)
• The properties of the fill/aggregates
• The number and loading of the axles
• The maximum rut depth or bearing capacity
Tensar International provides a full
design service and has developed
sophisticated computer software based
on a number of different national
pavement design guidelines.
The reinforcing benefit of Tensar
geogrids is incorporated in the design
methods, using data from independent
pavement tests and trafficking trials.
These methods of designing reinforced
pavements are reliable and have been in
use for many years. Detailed test and
trial data are given in “Properties and
Performance of Tensar Biaxial Geogrids”,
available from Tensar International.
Tensar SS biaxial geogrids are
manufactured in three grades (SS20,
SS30 and SS40) with apertures suited to
typical sub-base gradings (75mm
maximum particle size). Tensar SSLA
biaxial geogrids have larger apertures
making them suitable for aggregates of
larger particle size. Two grades are
available SSLA20 and SSLA30. Choice of
grade depends principally on subgrade
condition and strength, but axle load
and service life are also taken into
account. In addition, Tensar SS-G and
SSLA-G are geocomposite products
comprising a Tensar biaxial geogrid
laminated to a non-woven geotextile.
The products are particularly suited for
use with uniformly sized aggregates.
Documents giving detailed
recommendations for choice of grid type
are available from Tensar International.
No responsibility is accepted by
Tensar International for any project
which does not involve the use of
Tensar biaxial geogrids installed
pursuant to Tensar International’s
full design service.
No special plant, equipment or
techniques are required to install
Tensar biaxial geogrids. Site formation
should be prepared in the normal way,
and any large obstructions, tree stumps
and other protrusions should be
removed. On very soft wet subgrades,
biaxial geogrid is often used as a
method of getting access onto the site,
to allow initial layers of fill to be placed.
Rolls of Tensar biaxial geogrid are light
and stiff, and do not require a core.
They can easily be lifted and rolled out
by two workers. Special lifting frames
and cranes are not required. They are
normally held in position by small piles
of fill.
Adjacent rolls are usually overlapped
to give continuity of the reinforcing
function. The required overlap is
between 300 and 600mm depending on
the condition of the underlying material.
The larger overlaps are required over
softer subgrades, whereas minimum
overlap may be used over competent
subgrades or for second layers.
An alternative to a full overlap is to use a
smaller overlap of two to three apertures,
then join the rolls together using
HDPE braid.
It is important that fill is placed correctly
for maximum benefit. It should be tipped
onto stockpiles on top of the existing
placed material, then a mechanical
excavator or bulldozer should lift and
cascade the material onto the grid.
If the material is pushed forwards from a
stockpile, then it can create a bow wave,
and over soft soils it will tend to push the
grid into the subgrade soils. This will
diminish the interlocking effect.
If the fill grading requires a geotextile
separator as well as geogrid
reinforcement, both functions can be
served by a single Tensar SS-G composite.
7
Tensar SS geogrid properties
Versatility of Tensar biaxial geogrids
Road widening, Auckland (New Zealand).
Temporary access road across peat swamp,
Machap (Malaysia).
Construction of major highway (Oman).
New taxiway at Adelaide Airport (Australia).
Wharf area (Latvia).
6
Heavy duty pavements may require two or three geogrid layers.
AIRPORT PAVEMENTS
Loadings on airport pavements are
very high, and frequently lead to
multi-layer reinforced construction.
The US Army Corps of Engineers
carried out some special pavement
trials in the early 1990’s to examine
the benefit of geogrid reinforcement
in aircraft pavements. These well
documented comparative trials
showed that Tensar biaxial geogrids
were the only materials used which
gave a significant improvement in
performance.
HEAVY DUTY HANDLING AREAS
Container yards, logging areas and
fabrication sites frequently require
vehicles with very high track or axle
loads, and the pavements are often
unsurfaced. Tensar biaxial geogrids
have been used in many such
applications, frequently with multiple
layer construction. Performance of
these types of pavement in service has
shown that reinforcement improves
traffickability and reduces
maintenance and regrading.
WHARF AND PORT AREAS
Wharf and port areas are subject to
heavy loads from cranes and transport
vehicles, as well as from the goods
being handled. The subgrades are
frequently poor marginal soils or fills.
Tensar biaxial geogrids improve
bearing capacity and help to create
high quality pavements. Since the early 1980’s several hundred
million square metres of Tensar biaxial
geogrids have been used in tens of
thousands of projects. They have been
used in most countries in the world,
under a wide variety of climates and
soil conditions, and frequently they
have been used to solve difficult
design or construction problems.
ACCESS OVER VERY SOFT SUBGRADE
Some subgrades are so soft or
waterlogged that the main problem is
to get access to place fill or sub-base
material. These include very soft mud,
peat and tailings deposits. Tensar
biaxial geogrids act like a “snow-
shoe”, providing immediate support
to workers and the initial fill layers.
In addition, the interlocking effect
allows some compaction to be
achieved, even in the fill directly
above the soft subgrade.
TEMPORARY ACCESS ROADS
Tensar biaxial geogrids are excellent for
helping to build temporary access
roads, especially when the subgrade is
soft, trucks are heavy and good fill is
scarce. The wide rolls are ideal for a
single track road to carry typical
construction vehicles, and they are
easily transported and deployed.
MAJOR HIGHWAYS
Major highways require large
investment, and the cost of pavement
building materials is normally a
significant proportion. Also, costing of
this type of pavement must take into
account future maintenance, in terms
of overlays and possible reconstruction.
Using Tensar biaxial geogrids can
reduce the cost of capital investment
and future maintenance.
ROAD WIDENING
Widening existing roads is common
due to increasing traffic and
requirements for higher standards.
Generally the existing road must be
kept open, and there are frequently
services already in place. Using Tensar
geogrids can reduce the thickness of
the new pavement, thereby
minimising disruption. This can also
help avoid relocation of existing
services if they are shallow. Linking
the geogrid into the existing
pavement can help minimise
differential settlement between the
old and new sections.
Heavy DutyPavementsWhen axle or vehicle loads become
very heavy, number of axle passes
becomes very great or the subgrade is
very soft, granular layer thickness
increases to an extent where more
than one layer of biaxial geogrid is
required to maintain continuity of the
reinforcing function. In such cases
two or possibly three layers of
geogrid are required.
Getting access over very soft subgrade.
Property Units Tensar geogrid
SS20* SS30* SS40* SS2 SSLA20* SSLA30*
Polymer (1) PP PP PP PP PP PP
Minimum carbon black (2) % 2 2 2 2 2 2
Roll width m 4.0 & 3.8 4.0 & 3.8 4.0 & 3.8 4.0 3.8 3.8
Roll length m 50 50 30 50 50 50
Unit weight kg/m2 0.22 0.33 0.53 0.29 0.22 0.32
Roll weight kg 46 & 44 67 & 64 65 & 62 60 43 65
Dimensions
AL mm 39 39 33 28 65 65
AT mm 39 39 33 40 65 65
WLR mm 2.2 2.3 2.2 3.0 4.0 4.0
WTR mm 2.4 2.8 2.5 3.0 4.0 4.0
tJ mm 4.1 5.0 5.8 3.8 4.4 7.0
tLR mm 1.1 2.2 2.2 1.2 0.8 1.7
tTR mm 0.8 1.3 1.4 0.9 0.8 1.5
Rib shape Rectangular with square edges
Quality Control Strength (longitudinal)
Tult(3) kN/m 20.0 30.0 40.0 17.5 20.0 30.0
Load at 2% strain (3) kN/m 7.0 10.5 14.0 7.0 7.0 11.0
Load at 5% strain (3) kN/m 14.0 21.0 28.0 14.0 14.0 22.0
Approx strain at Tult % 11.0 11.0 11.0 12.0 10.0 9.0
Quality Control Strength (transverse)
Tult (3) kN/m 20.0 30.0 40.0 31.5 20.0 30.0
Load at 2% strain (3) kN/m 7.0 10.5 14.0 12.0 8.0 12.0
Load at 5% strain (3) kN/m 14.0 21.0 28.0 23.0 15.0 25.0
Approx strain at Tult % 10.0 10.0 10.0 10.0 10.0 9.0
Junction strength as % of QC strength (4)
Minimum junction strength % 95 95 95 90 95 95
*SS-G & SSLA-G
Geocomposite properties
All of the geogrids marked * are also available as
a geocomposite. The geocomposite comprises
the geogrid heat bonded to a geotextile
separator. The properties of the geotextile are
given in the following table.
Geotextile component
Puncture resistance (CBR) (5) N >1500
Effective opening size (6) µm 125
Permeability (7) m/s 0.135
Unit weight (8) kg/m2 0.16
(1) PP denotes polypropylene.
(2) Carbon black inhibits attack by UV light. Determined in accordance with BS 2782:Part 4: Method 452B:1993.
(3) Determined in accordance with BS EN ISO 10319:1996 and as a lower 95% confidence limit in accordance
with ISO 2602:1980 (BS 2846:Part 2:1981).
(4) Determined in accordance with GRI GG2-87 and expressed as a percentage of the quality control strength.
(5) Determined in accordance with BS EN ISO 12236:1996.
(6) Mean value of O90 determined in accordance with wet sieving test to BS EN ISO 12596:1999.
(7) Mean value expressed as velocity index VIH50 determined in accordance with BS EN ISO 11058:1999.
(8) Mean value determined in accordance with BS EN 965:1995.
(9) All quoted dimensions and values are typical unless stated otherwise.
Roll Length(Longitudinal)
Roll Width(Transverse)
Ribs
AL
tLR
tJ tTR
Junctions ATWLR
WTR