acigs newsletter 201305
TRANSCRIPT
Newsletter May 2013 Edition
AUS TRALASI AN CHA P TE R
OF TH E IN TERN A TI ON AL
GE OS YN THE TI CS SO C IETY
Corporate IGS Members:
ACIGS in GeoAsia 2012
Invited Lecturers
Malek Bouazza the President,
and Mike Sadlier the Vice Pres-
ident of the Australasian Chap-
ter of the International Geosyn-
thetics Society (ACIGS), were
invited to give separate lectures
at GeoAsia 2012. They were
also invited members in the
conference Technical Commit-
tee.
Case Studies
ACIGS was asked to prepare
some case histories to be pre-
sented at GeoAsia 2012 in
Bangkok, Thailand in Decem-
ber 2012. After announcing this opportunity to its mem-
bers, ACIGS received a paper provided by Amir
Shahkolahi and Jason Crase from Global Synthetics
with the title of ‘Application of Geogrids and Geocompo-
sites in Designing Working Platforms on Cohesive Sub-
grades; Case study: Harvey Norman Bulky Goods De-
velopment Australia’
The paper was accepted by the Technical Committee
and presented by Jason Crase at the conference. The
full paper is attached to this newsletter for public use
with the Author’s permission to the ACIGS. Of course
any further use will require mentioning the paper as a
reference.
Join us on LinkedIn www.linkedin.com (search ACIGS in ‘Groups’)
Geosynthetics Asia 2012 5th Asian Regional
Conference on Geosynthetics
Bangkok, Thailand, 13-15 December 2012 The 5th Asian Regional Conference on Geosyn-
thetics (GA2012) with the theme of Geosynthetics
for Sustainable Adaptation to Climate Change
was successfully held at Centara Grand Lardprao
Hotel in Bangkok, Thailand last 13th to 15th De-
cember 2012.
GA2012 was organised by IGS Thailand Chapter,
Asian Centre for Soil Improvement (ACSI) and
Suranaree University of Technology (SUT) under
the auspices of the International Geosynthetics
Society (IGS). Prof. Dennes T. Bergado and Prof.
Suksun Horpibulsuk served as Chairman and Co-
Chairman of the Organising Committee.
Mike Sadlier
Ribbon Cutting Ceremony during the opening of the exhibition event
The Australasian Chapter of the International Geosynthet-
ics Society (ACIGS) started its activity in 2002. Since then,
several activities such as technical seminars have been or-
ganised by the ACIGS. During these years, the number of the
ACIGS members has increased steadily to reach 68 members
in 2013.
By being an ACIGS member, one will become an International
Geosynthetics Society (IGS) member and get access to all
membership benefits such as free access to Geosynthetics
Journals, Presentations, Lectures, etc. More benefits are pre-
sented in the membership form.
At the same time, ACIGS members will be able to attend
ACIGS meetings and benefit from a registration discount in
ACIGS seminars. The chart above shows the ACIGS mem-
bership increase. It indicates there has been a significant im-
provement (about 240%) in the number of ACIGS individual
members from 2012 to 2013.
More information about IGS and its Chapters around the world
can be found here: www.geosyntheticssociety.org
Membership Growth
ACIGS Individual Memberships
IGS Council Elections Results: Term 2012 to 2016
The IGS, in accordance with its bylaws, held a
mid-term election in 2012. IGS Members
elected eight Council Members from an excel-
lent field of 12 candidates. Each of the elected
members will serve a four-year term, begin-
ning on 11 December 2012.
The successful candidates in the 2012 elec-
tion are (alphabetically by family name):
Dennes T. Bergado, Thailand (2nd term)
Erol Güler, Turkey
Warren Hornsey, Australia
Jiro Kuwano, Japan (2nd term)
Nicola Moraci, Italy
Victor Pimentel, Brazil (2nd term)
Boyd Ramsey, USA
Kent von Maubeuge, Germany
These 8 candidates join the existing council
and elected officers for a total of 22 current
members.
ACIGS Breakfast Gather ing
ACIGS organised a gathering during GeoAsia2012 for ACIGS members to have breakfast and get familiar with each
other as well as IGS Officers and other international geosynthetic experts. The gathering was held on 14th December
2012 at the conference venue. More than 15 members and non-members discussed different ideas and shared their
experiences about geosynthetic products and projects. This was also a good opportunity for ACIGS members to have
a short chat with IGS Officers and international experts in a quiet and private environment.
Contact Us:
Email: [email protected]
Post: C/- Amir Shahkolahi,
44 Telford Street, Virginia QLD 4014
Phone: Amir on 07 3865 7000 .
LinkedIn www.linkedin.com (search ACIGS in ‘Groups’)
3
Seminar Basal Reinforced Embankments
International Guest Speaker Chris Lawson
Sponsors:
Chris Lawson Seminar Basal Reinforced Embankments
Chris Lawson, Managing Director of
TenCate Geosynthetics Asia-Pacific
based in Hong Kong, has worked in
the field of geosynthetics for 30 years
covering Australia, Europe, North
America and Asia. Chris has been in-
volved in developing the geosynthetics
Standards and Codes of Practice, and
is author of over 50 technical papers
on the subject of geosynthetics.
During May/June 2013, Chris will be
touring Australia and New Zealand
presenting along with local Engineers
at 1-day seminars hosted by ACIGS.
Topics include:
Reinforced soil utilising geosyn-
thetics
Geosynthetics for reinforced soil
Design approach to basal rein-
forced embankments
Basal reinforced embankments on
soft foundations
Basal reinforced piled embank-
ments
Basal reinforced embankments
spanning voids
ACIGS is inviting members and non-
members to attend their local 1-day
seminar, being an excellent opportuni-
ty to meet and network with new and
long standing ACIGS peers.
The cost is $100.00AUD. As a special
offer, for non-members the registration
fee includes membership to join the
ACIGS; And for existing members the
registration fee will be considered as a
membership renewal payment.
Sponsorship opportunities available
Please send your interest to
AU ST RAL ASI AN C H APT ER
OF T H E I NT ERN AT I ON AL
GEO SYNT H ET IC S SOCI ET Y
Name:
Position:
Company:
Phone:
Email:
Membership No:
Cheque: Payable to “Geosynthetics Interest Group”
EFT: A/C name: Geosynthetics Interest Group
BSB: 063 142 Account No: 10213604
Credit Card: Mastercard Visa
Account number:
Expiry date:
Name on card:
Authorised signature:
Sydney - 28 May 124 Pacific Hwy, St Leonards NSW
Auckland - 31 May L2, Nielsen Centre, 129 Hurstmere Rd, Auckland NZ
Brisbane - 04 June 147 Coronation Dr, Milton QLD
Adelaide - 12 June 121 King William St, Adelaide SA
Perth - 14 June L3, 1 Havelock St, West Perth WA
Time: 9am - 5pm (morning refreshments and light lunch provided)
Yes, I would like to become an ACIGS member
Please return your form to: Email: [email protected] Fax: (07) 3865 4444
Post: C/- Amir Shahkolahi, 44 Telford St, Virginia QLD 4014
Corporate members:
Venue sponsors:
4
10th International Conference on Geosynthetics 21 - 25 September 2014 Berlin, Germany
Cal l for Abstracts
CALL FOR PAPERS
The deadline for abstract submission is 15 May 2013
For conference themes and submission details visit http://www.10icg-berlin.com
Visit the 10 ICG website http://www.10icg-berlin.com
The German Geotechnical Society (DGGT) and the Interna-
tional Geosyn-thetics Society (IGS) German Chapter, as a
special group within the DGGT, cordially invite you to partici-
pate in the 10th International Conference on Geo-synthetics
(10ICG) in 2014 in Berlin, Germany.
The conference will be held from 21 to 25 September 2014 in
direct connection with the 33rd Baugrundtagung (German
Soil Mechanics Conference) of DGGT (23 to 26 September
2014). As the Baugrundtagung expects 1200 participants,
great synergy and interaction is expected between these
events, especially in the co-organized, co-located exhibition.
The overlapping of lectures from both events will also attract
many additional experts from the geotechnique and geosyn-
thetics professions. The official language of 10ICG will be
English.
Venue
The 10ICG will be held in the south-eastern of Berlin at the
ESTREL convention centre. ESTREL offers about 50 rooms
for lectures and meetings, integrated exhibition halls and a 4-
star hotel. Travelling time from there to the centre of Berlin is
about 20 minutes.
Berlin
Berlin is the capital city of Germany and offers a tremendous
number of interesting cultural events, museums and sightsee-
ing attractions directly in the city. The 10ICG programme for
accompanying persons will cover guided city tours, visits to
museums and galleries.
10ICG Conference Themes
• Green Engineering, Sustainability and Durability with Geo-
synthetics
• Use of Geosynthetics for Renewable Energy
• Mining, Waste Management, Contaminated Sites and Envi-
ronmental Protection
• Roads, Railways and Other Transportation Applications
• Reinforcement in Walls, Slopes, Embankments and Base
Courses
• Flood Control, Levee and Canals, Dams, Reservoirs and
Other Hydraulic Applications
• Drainage and Filtration Properties of Geosynthetics
• Geomembrane and Geosynthetic Clay Liner Barrier Sys-
tems
• Case Histories and Innovative Uses of Geosynthetics
• Quality Control, Quality Assurance and Accreditation
• On-site Installation Technologies and Monitoring Programs
• Soil-Geosynthetic Interaction and Large-Scale Performance
Testing
• Design Approaches
• Regulations and Recommendations
• Looking to the Future with New Geosynthetic Products
Call for Paper
You are invited to send in your abstracts for the conference
dealing with the use of geosynthetics in the topics above
since January 2013. The deadline for the submission is 31
July 2013. The postponement of the abstract submission
deadline is due to avoid direct overlap of the submission peri-
ods with the new established GeoAfrica 2013 conference.
Please find all necessary information in time on the confer-
ence webpage.
Exhibition
The 5000 m² technical exhibition space is directly connected
to the conference rooms, being located half-way be-tween the
hotel and lecture rooms and accessed without having to leave
the centre. The exhibtion space will be used both by 10ICG
and the Baugrundtagung event. The reservation period for
the exhibition will be open through the webpage in June
2013. IGS Corporate Members will have a pre-registration
due the regulations of IGS.
For more information
Please vistit the website that will be updated in due time:
www.10icg-berlin.com
For further information please contact: Gerhard Bräu
([email protected]); or Dr. Kirsten Laackmann
Extended until 21 July 2013!
For the past 35 years, Geofabrics has been striving to be the supplier of choice in the Australian geosynthetics
market. We specialise in the technical marketing and distribution of geosynthetic products, and proudly manufacture a
range of products in our Australian plants, including bidim® nonwoven geotextiles, geosynthetic clay liners, Megaflo®
drainage system and other niche products.
We actively invest in our manufacturing capabilities as well as our R&D activities, whether the research is done
in-house at our customer oriented Geosynthetic Centre of Excellence or through us funding Australian research
students.
Through our range of activities, we provide high-quality, engineered solutions to geotechnical problems. Our use of
highly skilled people, equipped with the leading geosynthetic brands and supported by superior technical tools will
ensure our customers have access to world-class geosynthetic solutions for their infrastructure projects.
Quality, Support and Expertise – the essence of Geofabrics.
GEOSYNTHETICS ASIA 2012
5th Asian Regional Conference on Geosynthetics
13 to 16 December 2012 | Bangkok, Thailand
1
APPLICATION OF GEOGRIDS AND GEOCOMPOSITES IN
DESIGNING WORKING PLATFORMS ON COHESIVE SUBGRADES;
CASE STUDY: HARVEY NORMAN BULKY GOODS DEVELOPMENT,
AUSTRALIA
Amir Shahkolahi1, Jason Crase
2
1Technical Consultant and Applications Engineer/Global Synthetics; Tel: +61-7 3865 7000; Fax: +61-7 3865
4444; Email: [email protected], 2Regional Manager/Global Synthetics; Tel: +61-7 3865 7000; Fax: +61-7 3865 4444; Email:
ABSTRACT
In the construction of heavily trafficked areas such as working platforms, a stable subgrade with sufficient
bearing capacity is required. Economical and environmental advantages of construction methods with
geosynthetics, especially on soft soils are already well known. Soil masses that need to be excavated, transported
and installed can be dramatically reduced by the inclusion of geosynthetics. The best example is the
improvement of soft subgrades with geogrids or geocomposite products. In this paper, the general design
procedure is presented for working platforms using geosynthetics according to Building Research Establishment
(BRE). A project constructed in SE Queensland Australia using a unique geocomposite is then discussed in
further detail. This geocomposite which is a combination of a geogrid with a high secant strength and an integral
nonwoven geotextile, encapsulated between the cross laid welded bars, was successfully installed directly on top
of the subgrade with CBR value as low as 1%, providing not only improvement of the subgrade bearing
capacity, but also a positive separation and filtration layer between fine subgrade materials and imported
granular platform materials. A 350 mm granular platform was then installed on top of the Combigrid®. This
method could make the construction of thin granular platform layer on the soft subgrade possible, reducing
construction costs and construction time for the client and the contractor. Also, the reduced requirement for
imported quarried materials in the working platform had significant additional environmental benefits.
Keywords: working platform, geogrid, geocomposite, cohesive subgrade
INTRODUCTION
The expression, working platform is, restricted to
ground-supported working platforms, for tracked
plant, constructed of granular material. Working
platforms are critical for plant stability, and safety is
a vital issue. Most working platforms perform well,
but overturning of rigs has occurred more frequently
than it should. Experience has shown that it is far
more likely that rigs will overturn owing to localised
problems rather than to a generally inadequate
platform thickness across the whole site. Localised
weaknesses can be associated with the existence of
‘soft spots’ in the subgrade, under the platform, or
with weak areas within the platform formed by
inadequate backfilling of holes that have been
excavated by other contractors working on the site.
Similarly, ‘hard spots’ caused by old foundations or
basements can cause difficulties. Where a weak
subgrade is particularly soft or loose, some form of
stabilisation or ground treatment may be considered
to improve the properties of the ground (BRE 2004).
For a working platform, the soil and groundwater
conditions in the upper 2 m are particularly
important. Where there is a granular subgrade, the
presence of a water-table close to the ground surface
will have a critical effect in reducing bearing
resistance (BRE 2004).
In some situations it may be economic to
incorporate geosynthetics to strengthen the working
platform as an alternative to using a greater
thickness of platform material.
In this paper, the design procedure for working
platforms using geosynthetics has been reviewed
according to the Building Research Establishment
(BRE) design guide published in the United
Kingdom (UK) and was commissioned by the UK
Federation of Piling Specialists, together with a
recently constructed project is presented as a case
history.
APPLICATION OF GEOSYNTHETICS IN
WORKING PLATFORMS
Often the required bearing capacity on subgrades
cannot be achieved, such that additional measures
have to be undertaken. As an economic solution to
GEOSYNTHETICS ASIA 2012
5th Asian Regional Conference on Geosynthetics
10 to 14 December 2012 | Bangkok, Thailand
2
improve the subgrade strength, the installation of
geosynthetics for reinforcement, filtration and
separation may be successfully adopted.
Geosynthetics are generally placed between the
subgrade and the material forming the working
platform. Some designs may require additional
geosynthetic layers to be placed within, but
alternatively may be placed within the platform .to
provide additional support on particularly soft soils
or where the equipment working on the platform is
large.
On cohesive formations, upward migration of
fine material into the working platform may cause it
to degrade, particularly in wet conditions. A granular
filter layer or a geotextile can be used to minimise
the migration of fine material from the subgrade into
the platform material. Geotextiles are normally used
to separate a granular platform from a cohesive
subgrade and to act as a filter (BRE 2004).
Geogrids are normally used to strengthen the
platform. Vehicular loads applied to the road surface
create a lateral spreading motion of the aggregate.
Tensile lateral strains are created at the interface
subgrade/geogrid as the aggregate moves down and
sideways due to the applied load (BRE 2004).
In addition to general strengthening over the
whole area of the platform, localised strengthening
and additional maintenance may be needed at
particular locations. It is important to distinguish
geosynthetics which have been incorporated into the
platform to provide tensile strength from those
intended as separation layers, unless a combined
geosynthetic is used. Owing to the ductile nature of
polymeric reinforcement, ultimate tensile capacity
may occur at very high strain beyond the
serviceability requirements of the reinforced soil,
and design should be based on the strength at a
specified small strain or by applying a factor to the
ultimate strength. Also the likelihood of damage to
geogrids during installation should be taken into
account (BRE 2004).
DESIGNING WORKING PLATFORMS WITH
GEOSYNTHETICS
If the existing soil is not sufficiently strong to
carry the loads of the piling rig, a design of the
geogrid reinforced working platform as an
economic alternative is required to distribute the
loads to an acceptable rate for the in-situ
subgrade. The platform design method follows a
logical sequence from assessment of plant loading
through to platform thickness (BRE 2004).
The bearing resistance Rd of the cohesive in-situ
subgrade underneath the tracks when a load is
applied directly to the subgrade surface can be
calculated as follows (BRE 2004):
uccd cNs=R (1)
where sc is the shape factor, cu is the subgrade
undrained shear strength and Nc is the bearing
capacity factor. The bearing capacity factor for a
cohesive subgrade is Nc = (2 + π), and where the
load is applied at ground surface over a rectangular
area of dimensions W and L, the shape factor is
given by (BS EN 1997-1:2004):
0.2[W/L] + 1 =sc (2)
Where a load is applied to a working platform
with relatively shallow thickness which has been
placed on the weak subgrade, the simple approach
for calculating the bearing resistance of this two-soil
system can be based on the analysis of punching
failure. In this analysis the bearing resistance R is
considered to be the sum of the shear required to
punch through a vertical plane in the granular
platform material and the bearing capacity of the
subgrade (Fig. 1) (BRE 2004).
Fig. 1 Punching failure mechanism
Using the simplified analysis developed by
Meyerhof and his co-workers for a footing punching
through a dense sand layer overlying soft clay, the
following expression is obtained for the bearing
resistance of a platform on a cohesive subgrade
(Meyerhof 1974):
pp
2
pccu s tanK /W)D( +sNc = R (3)
where D is the thickness of the platform material, W
is the track width of the plant, Nc is the bearing
capacity factor for a cohesive subgrade, Kptanδ is the
punching shearing resistance coefficient of the
granular platform material and can be determined
from Fig. 2 as a function of the angle of the shearing
GEOSYNTHETICS ASIA 2012
5th Asian Regional Conference on Geosynthetics
13 to 16 December 2012 | Bangkok, Thailand
3
resistance of the material (φ’), γp is the bulk unit
weight of the platform material and sc and sp are the
shape factors, which are functions of W and L and:
[W/L] + 1 =sp (4)
Where geosynthetic reinforcement is
incorporated at the base of the working platform to
take tensile loads, the required thickness of platform
can be reduced. The design tensile strength of the
reinforcement (Td) should be evaluated by applying
a minimum factor of 2 to the ultimate tensile
strength (Tult) of the reinforcement so that:
Fig. 2 Design values of Kptanδ (BRE 2004)
/2T =T ultd (5)
Where the reinforcement is not stiff, a higher
factor or the strength at 5% strain should be used
(BRE 2004).
The bearing resistance provided by the
reinforcement has to be assessed and it is proposed
that this is calculated in a simplified way based on
the punching failure mechanism, such that the
additional bearing resistance is calculated as 2Td/W.
For a platform on a cohesive subgrade we will have
(BRE 2004):
/W2T +s tanK /W)D( +sNc = R dpp
2
pccu
(6)
The interaction of the base course material
with the geogrid results in a measurably higher
internal friction angle at low lateral compression like
in road constructions (Ziegler and Ruiken 2010).
The tests have shown that internal friction angles
higher than δ = 60° are detectable for the compound
construction (Ziegler and Ruiken 2010). Of course it
should be considered that the punching shear failure
mechanism is only applicable where the working
platform is significantly stronger than the underlying
subgrade. Also the routine design calculation
method based on punching shear is not appropriate
where (D/W) >1.5 and Slopes are greater than 1 in
10 or for ground conditions 20 kPa < cu < 80 kPa
(BRE 2004).
Routine working platform design calculations
with geosynthetics have the following stages:
determine ground conditions, determine design load
cases according to characteristic loads from EN
996:1996 and design load factors (BRE 2004),
derive bearing capacity and shape factors and
punching shear coefficient, check support of
platform material alone, determine required
thickness of platform using geosynthetic
reinforcement and final evaluation of results (BRE
2004). As a final check, the design thickness of
platform should satisfy the following conditions
(BRE 2004): ignoring the effect of the
reinforcement, both load cases q1d and q2d are < Rd
where:
1k1d 1.25q = q (7)
2k2d 1.05q = q (8)
ppd
2
pccudd s tanK )/WD( +sNc = R (9)
where q1d is the design load case 1 (standing,
travelling), q2d is the load case 2 (handling,
penetrating, extracting) and q1k and q2k are
characteristic load cases 1 and 2. If these two
requirements are not met, the thickness of platform
should be increased until they are. As a limitation,
the minimum platform thickness should be the lesser
of 0.5W or 300 mm (BRE 2004).
CASE HISTORY
Project and Problem Description
In 2011, it was planned to build granular piling
rig access platforms to facilitate the installation of
piles for support of the new Harvey Norman bulky
goods project in Maroochydore in Australia to
increase the low subgrade strength and to provide
sufficient bearing capacity for the imposed loads of
the cranes.
After site investigations, the consultant
confirmed that the current condition of the site
surface would not be satisfactory for the safe
operation of the proposed precast piling rig imposed
load of 280 kN/m3. It was also advised that the grey
GEOSYNTHETICS ASIA 2012
5th Asian Regional Conference on Geosynthetics
10 to 14 December 2012 | Bangkok, Thailand
4
clay exposed on the surface of the site had been
badly affected through saturation as a result of the
2010 local flooding. Subsequent continual wet
weather was not allowing the perched groundwater
to drain away, leaving the platform saturated. Three
boreholes were drilled at the site in August 2008
finding a silty sand at the surface in BH1 located
toward the northern end, a clayey silt (low plasticity
with a trace of sand) in BH2, and low plasticity silty
clay in BH3 at the southern end of the site. These
surface soils alone were not capable of supporting
the required 280kPa bearing capacity required for
the pile rig. A further constraint was that the
platform thickness was limited to 350 mm above the
existing subgrade elevation to avoid interference
with the intended levels of the proposed basement
car parking concrete slab on ground.
Geosynthetic Improvement Solution Using
geogrid/geocomposite
The main purpose of the geogrid reinforced
piling platform is to reduce the imposed bearing
pressures of the piling rig to acceptable rates for the
given bearing capacity of the in-situ subgrade. As
the subgrade was a weak subgrade and the thickness
of the platform was limited, the geosynthetic
reinforced platform on existing subgrade was chosen
as the economic alternative solution for the initial
design for providing suitable (i.e. safe and stable)
access for the piling rig, which was 200mm
excavation and 500mm thick platform installation
consisting of good quality unbound pavement
gravel.
With reference to the given information, a
subgrade CBR value of min. 1% (equal to cu > 30
kN/m2) has to be considered for the bearing capacity
of the in-situ soft subgrade. The design was focused
on the specific machine type with the total weight of
77200 kg. The design of the reinforced working
platform was carried out with full consideration of
BRE design manual and design principles defined
in DIN 4017:2006 to reach a sufficiently high
safety factor against bearing failure.
The bearing resistance Rd of the cohesive in-situ
subgrade underneath the tracks can be calculated as
follows (BRE 2004):
2
uccd kN/m 154.2 = cNs = R (10)
with sc equal to 1 (safer value), cu equal to 30 kN/m2
and Nc equal to 5.14 for φ ≥ 0°. The fill material for
the working platform was a well graded crushed
aggregate with an assessed internal angle of friction
of approx. 40°. After consideration of the potentially
variable conditions on site (compaction, grain size
distribution, internal friction angle of fill material)
a relatively conservative internal friction angle
for the compound construction (geogrid + fill
material) of δ = 50° was considered on the safe side
for this design.
In case that a h = 350 mm thick geogrid
reinforced working platform is used, the area of
influence on the in- situ subgrade can be calculated
as follows:
))(h tan 2 +(W ))(h tan 2 + (L 2 =A (11)
A = 22.83 m² with:
L = Length of crawler track, here: 5.75 m
W = Width of crawler track, here: 0.90 m
Considering the required bearing capacity to be
achieved according to the design brief was 280
kN/m2, the net bearing pressure qres imposed on the
subgrade at under side of the 350mm thick geogrid
reinforced crane working pad platform was
calculated as:
kN/m² 63.47 =LW/A kN/m 280 = q 2
res (12)
According to DIN 4017:2006, the safety factor
against bearing failure is taken to η = 2.0. In the
particular case of the above mentioned project, the
safety factor η against bearing failure can be
calculated to:
result. q / q = (13)
Then η = 154.2 kN/m² / 63.47 kN/m² = 2.42. The
calculation shows that the solution adopted satisfies
the minimum required safety factor for bearing
failure of η = 2.0 according to DIN 4017:2006.
To prevent fines from migrating into the base
course a filtration and separation nonwoven
geotextile underneath the geogrid is
recommended. For the selection of the geogrid
reinforcement to be used underneath working
platforms, Rüegger et al (2003) defines an
extensional stiffness of 400 kN/m or 8 kN/m
tensile strength at 2 % strain respectively.
Geogrid/Geocomposite Selection
Upon final approval, some 50000 m2 of
Combigrid® 40/40 Q1 151 GRK 3 was installed
successfully on site under the crane platform directly
GEOSYNTHETICS ASIA 2012
5th Asian Regional Conference on Geosynthetics
13 to 16 December 2012 | Bangkok, Thailand
5
on the soft subgrade, to improve the subgrade
bearing capacity as well as to prevent fines from
migrating into the platform materials. The cross
section is shown in Fig. 3.
Fig. 3 Reinforced working platform
This geocomposite has a min. tensile strength of 16
kN/m at 2% strain which is much more than 8 kN/m
and fulfills the recommendation from Rüegger et al
(2003). This product consists of a Secugrid®
geogrid as the reinforcement component; with a
needle-punched nonwoven geotextile firmly welded
between the reinforcement bars, for soil
stabilisation, separation and filtration. This
geocomposite combines all of these functions into
one single product. It offers the advantages of two
materials with the simplicity of installing a single
product. It is also extremely quick and easy to
install, thus reducing installation costs considerably.
The appropriate strength of the geogrid was selected
according to the stress strain properties required
above and the subgrade bearing capacity. Figs. 4 and
5 show some installation pictures.
Fig. 5 Installation and overlaps
ACKNOWLEDGEMENT
The authors sincerely appreciate the assistance of
colleagues, especially J. Klompmaker and C. Psiorz
from BBG GmbH & Co. KG, and the support from
NAUE GmbH & Co. KG. The authors would also
like to acknowledge Martin Smith for the final
review and the assistance of Chris Carey of ADCO
Constructions Pty Ltd in correspondence and liaison
with the client regarding the development of this
adopted solution.
REFERENCES
British Research Establishment-BRE (2004).
Working platforms for tracked plant: Good
practice guide to the design, installation,
maintenance and repair of ground-supported
working platforms. Report BR470.
BS EN 1997-1 (2004). Eurocode 7: Geotechnical
design – Part 1: General rules.
DIN 4017 (2006). Calculation of design bearing
capacity of soil beneath shallow foundations.
Meyerhof G.G. (1974). Ultimate bearing capacity of
footings on sand layer overlying clay Canadian
Geotechnical Journal, vol. 11, no. 2: 223–-229.
Rüegger R. and Hufenus R. (2003). Building with
Geosynthetics – A Handbook for Geosynthetic
Users. Swiss Association for Geosynthetics.
Ziegler M. and Ruiken A. (2010). Examination of
the Performance of Geogrids with wide-scaled
Triaxial Tests. Project Number 0703, RWTH,
Aachen.
Fig. 4 Installation
C/o Peter Tzelepis
83-93 Canterbury Road Braeside VIC 3195
25 February 2013
MEMBERSHIP FEES FOR AUSTRALIAN CHAPTER OF IGS (ACIGS):
Fee for year 2013 A$ 75.00 per member The cheque is to be made out to Geosynthetics Interest Group. Please note that we are not registered for GST, hence there is no GST component in this fee. Please sign a copy of this invoice and return it with your payment, as a confirmation that you
accept the rules and By-Laws of the ACIGS.
Peter Tzelepis Treasurer
Members Details:
Name: ___________________________________________________________________
Company: ________________________________________________________________
Position: _________________________________________________________________
Email: ___________________________________ Phone No. _______________________
Mode of payment: Cheque enclosed: Payable to “Geosynthetics Interest Group”
Credit card (circle one): Mastercard Visa Bankcard
Account Number: ________________________________
Expiry date: ________________________________ Name on card: ________________________________ Authorised Signature: ________________________________
EFT: Account Name: Geosynthetics Interest Group
BSB: 063 142
Account No.: 10213604
RETURN EMAIL: [email protected]
RETURN FAX No: 07 3865 4444
Australasian Chapter of International Geosynthetic Society
ABN : 27 845 329 614
to collect and disseminate knowledge on all matters relevant to geotextiles, geomembranes and related
products by promoting the development of seminars, conferences, publications, etc.
to promote advancement of the state of the art of geotextiles, geomembranes and related products and of
their applications by encouraging, through its members, the harmonization of test methods, equipment and
criteria , etc.
to improve communication and understanding regarding such products between designers, manufacturers
and users and especially between the geosynthetic manufacturing and engineering communities
The International Geosynthetics Society (IGS) is a non-profit organization which was founded in Paris, on 10
November 1983, by a group of geotechnical engineers and textile specialists. The society brings together
individual and corporate members from all parts of the world, who are involved in the design, manufacture,
sale, use or testing of geotextiles, geomembranes, related products and associated technologies, or who teach
or conduct research about such products.
The IGS has a constantly growing General Membership, currently over 2800 members. In addition, there
are over 230 Student Members worldwide. There are 34 national or regional Chapters of the IGS repre-
senting 90% of the membership. Our growing Corporate Membership has exceeded 137 members from 69
countries.
The IGS is managed by 5 elected officers and 10-16 elected council members— a maximum of 5 co-opted
council members may also serve on the council. Contact information for council and officers is
available on the IGS website under Directories at www.geosyntheticssociety.org.
The IGS Aims
promotes the dissemination of technical information on geosynthetics through its two official journals
Geotextiles & Geomembranes and Geosynthetics International
provides a forum for the exchange of ideas through communications at IGS Conferences and IGS
supported events on local, national, regional and international levels
through work in its Educational and Technical committees, publishes documents which provide guidance to
the users of geosynthetics
through work in its Technical Committees assists in the editing of documents from other agencies,
associations or regulators
publishes The IGS News three times annually
hosts a publicly available web site for members and non-members to search many of the educational
documents created by the IGS
offers multiple awards including the IGS Award for excellence in achievement
A comprehensive listing of the IGS’ 25 years of achievement can be found on the IGS Web Site
on the page titled Milestones
In Order to Achieve These Aims the IGS:
By becoming a member of the IGS you will:
help support the aims of the IGS
contribute to the advancement of the art and science of geotextiles, geomembranes and re-
lated products and of their applications
be exposed to a forum where designers, manufacturers and users are exchanging new ideas
and developing new contacts
become increasingly informed, involved and influential in the field of geotextiles, geomem-
branes, related products and associated technologies
on-line access to the IGS Membership Directory which is updated in real-time, with full
addresses, telephone, email and fax numbers of all members
complete access to the on-line version of Journal Geosynthetics International.
complete access to the on-line version of the Journal Geotextiles & Geomembranes
electronic access to the IGS NEWS, published three times annually
on-line access to the 19 IGS Mini Lecture Series for the use of the membership
Opportunity to join open committees to contribute to topics of common interest
on-line access to the growing library of multilingual IGS Educational Leaflets
discount rates
on any document published by the IGS
at all international, regional or national conferences organized by the IGS or under
its auspices
preferential treatment at conferences organized by the IGS or under its auspices
eligibility for various IGS awards
IGS membership card and IGS lapel pin
Benefits to All Members
Chapters of the IGS
Contact information for all Chapters of the IGS may be found on our website:
Argentina
Indonesia Poland
Australasian Italy Portugal
Belgium Japan Romania
Brazil Korea Russia
Chile Mexico Slovakia
China Netherlands South Africa
Czech North American Spain
Finland Norway Thailand
France Pakistan Turkey
Germany Peru United Kingdom
Greece Philippines West Pacific Regional
India