GABIONS -MESH FACED RETAINING STRUCTURES .pptx

REINFORCED SOIL SYSTEMS
Prof. Samirsinh P Parmar
Asst. Prof. Department of Civil Engineering
Dharmsinh Desai University, Nadiad, Gujarat, India
Mail: samirddu@gmail.com

• Part 1: Types of Retaining Structures Relating to Woven Mesh
• Part 2: The Engineering Behind These Systems
• Part 3: Different Applications
• Part 4: Individual System Components and Construction Procedures
• Part 5: Why Consider these Systems as an Option
• Part 6: Experienced Gained – Product and Design Issues
• Part 7: Ensuring Expectation and Performance
• Part 8: Demonstrating Long Term Durability
• Part 9: Various (Impressive) Local Projects
Content of the Presentation:
M.Tech (Geo)- Prof.S.P.Parmar, DoCL, DDUniversity, Nadiad,
Gujarat, India
2

Types of Retaining Structures
• Mass gravity structures e.g. Gabions
H
± 0.7 x H
As per Wikipedia.org
A gabion (from Italian gabbione meaning
"big cage"; from Italian gabbia and
Latin cavea meaning "cage") is
a cage, cylinder or box filled with rocks,
concrete, or sometimes sand and soil for use
in civil engineering, road building, military
applications and landscaping.
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• Reinforced soil systems e.g.
Terramesh
(walls greater than 70°)
H
± 0.8 x H
Gabion Facing Reinforced Earth Wall
Soil Reinforcement
Gabion Facing
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Gabions
Gabions are flexible cages made of hexagonal
double twist heavily galvanized mild steel woven
wire and mesh with additional polymer coating
if required. These units are laced together,
packed with selected stone and act as building
blocks. They are used in the construction
of retaining walls, weirs, culvert
inlet/outlet and other civil structures.
Galvanized
Steel wire
mesh cage
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Applications of Gabions
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Applications of Gabions
Applications of Gabion Walls are found in following cases:
•Retaining wall structures
•River and canal training
•Road protection
•Soil protection
•Bridge protection
•Architectural cladding for walls and buildings
Gujarat, India
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Drainage Structure in Gabions
Can they only be used for low height walls/slopes and non-critical structures?

Terramesh is a mechanically stabilized earth
system comprising of a Gabion facing with
woven steel mesh or high strength geogrid
soil reinforcement.
The Gabion facing prevents erosion on the
front face and the soil reinforcement
increases the shear parameters of the backfill
material.
Gabion Facing
Woven Mesh and/or Geogrid Soil Reinforcement
Geotextile
Terramesh
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Green Terramesh
Green Terramesh is a reinforced soil system
(reinforced slope at 45°, 50°, 60° or 70°)
comprising of a preformed woven mesh+ECB
facing with integral woven steel mesh
and/or high strength geogrid soil
reinforcement. The facing can either be vegetated
or packed with a rock veneer.
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• Anchored or tied-back systems e.g. Gabion faced soil
nailed structure
H
Soil Reinforcement: As
soil Nailing
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Gabion Faced Anchored Structures
Gabions are commonly used as a flexible
facing to soil nailed/anchored structures. They
offer all the inherent benefits of a traditional
Gabion /Terramesh structure
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COMPONENT PARTS OF
GABION STRUCTURES
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COMPONENT PARTS OF GABION STRUCTURES
1. Woven Mesh
2. Fill Material
3. Geotextile ( Basal reinforcement or Drainage application)
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Individual System Components
1. Woven Mesh
Gabions and Terramesh:
Mesh Type 80 (80 x 100 nominal) 2,7mm mesh
wire (3.7mm o/d with polymer coating). Double
twist for stress transfer around a wire breakage
80mm
Gujarat, India
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Mesh body wire, lacing wire and selvedge wire
Pneumatic closing tool for
installing “C” ring connectors
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Woven Mesh
Mesh selection tools are available
depending on the required working life:
BBA certificate, EN 10233-3, ASNZS
4534 technical specification, HITEC
report and independent test certificates
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2. Rock Fill
Rock must be clean, sufficiently durable, non
friable and not show any signs of weathering (AS
2758.4 – 2000)
The rock should be evenly graded between 1.5D
to 3D (Between 100mm and 250mm normally
suffices) and be angular to provide interlock
Type of rock kg/m3 Suitability
Basalt 2900 Considered
Acceptable
Granite 2600
Hard Limestone 2600
Calcareous Pebbles 2500
Dolerite 2400
Hard Sandstone 2300 Needs further
checks
Soft Limestone 2200
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2. Gabion Fill Material
Unit weight of gabion rock infill
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Geotextile Separator
A geotextile will not perform its function if it is
damaged during installation.
If they can withstand installation damage, they
generally withstand the in service stresses.
We recommend a minimum strength class C (e.g.
Bidim A34) be used with mesh systems. It has the
required energy absorption (installation damage
resistance), permeability and is sufficiently
abrasion resistant
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Foundation
The foundation should be:
• Stripped of topsoil/organic material
• Level and compacted
• Sloped if constructing an angled wall
• If on smooth bedrock or concrete,
advisable to incorporate shear keys to
minimize sliding issues
We want to ensure:
• Uniform foundation pressure
• Minimal differential settlement
Gujarat, India
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Backfill
Compacted in lifts to the required effort as per
the specification
• Heavy compaction equipment not closer
than 1-1.5m to back of structure
• Walk behind compaction equipment
directly adjacent to structure
• Take care not to damage the mesh or
geotextile
• Backfill immediately after completing one
layer of Gabions.
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Why Consider Gabion Systems?
• Flexible – Unlike welded mesh, concrete blocks, concrete mats or reinforced concrete, double
twist woven mesh Gabions & Terramesh systems are able to accommodate substantial differential
settlement
• Monolithic – the fastening (lacing) procedure ensure the units act as one homogeneous
structure
• Permeable – pore water pressures are easily dissipated through the structure
• Durable – Double twist mesh and heavily galvanized (can have an additional polymer coating)
with 45 year old local installations disprove the fallacy that Gabion type structures are temporary
solutions
• Adaptable – Gabion systems can be stepped, vertical or angled to suit specific project
requirements. They can be filled in-situ or prefilled depending on site conditions using various
mechanical means to assist with the packing process
• Economical – Generally, Gabion installation does not require any special equipment (pliers,
temporary formwork, lacing tool etc.)
• Environmentally friendly – Vegetation easily establishes, eventually re-creating the pre-existing
environment. The added use of bio-degradable coir logs and Jute blankets will accelerate the
vegetative process if required
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Why Consider Gabion Systems?
Speed of installation Foundation issues
Bad access Energy Absorption
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Design Criteria : Gabions
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Types of Gabion face
Different gabion wall face configuration, stepped face
(left side) and smoothed face (right side)
stepped face
smoothed face
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Failure Criterion (No. RE wall)
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Failure Criteria for Gabion facing reinforced earth wall
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Gabion Wall base width relative to wall height
• Base width of a gabion gravity
retaining wall is related to height
of wall so as the wall height
increases the base of the wall
becomes wider to ensure
structural stability.
• Terra Aqua has provided the
diagram here to illustrate a
starting point for design analysis
to determine the base width
relative to wall height. Terra Aqua
recommends a conservative
value of base width = 2/3 wall
height.
• The stability analysis may
determine that the gabion gravity
retaining wall base width be less
than or greater than ½ - 2/3 wall
height.
GABION GRAVITY WALL SIZES & DIMENSIONS
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Calculation of coefficient of active thrust on rear of Link
Gabion gravity walls
Front sloped wall
Rear sloped wall
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Stability against bearing failure
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Stability against sliding
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Stability against overturning
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Introduction
Experience peace of mind with professionally designed gabion structures as part of our quotation process
Give us a call and make sure that your installation starts with a well adapted, cost-effective technical structure design undertaken by our team.
Gabion structure design
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GEO5- Gabion Software Interface
For further design please refer above software*
* I am not involved in any kind of marketing agency, its just to support design of structure @ academic level.
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Tests on Gabion’s
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The Compression Test on Gabion
Reference: UNICAMP
, Brazil
Load P
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• Fixed elongation speed: 6mm/min
• 4000 N preload to tension the wire
Tensile Strength Test As Per EN 10223-3:2013
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Durability Test of wire mesh
Before salt spray test (ISO 9227) Test
temperature 35°
Test solution 5% NaCl
After 6000 h exposure in salt spray
No sign of Dark Brown Rust (EN10223- 3:2013)
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Full scale Monitoring and Soil Interaction test
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Full scale deformation analysis
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Full scale deformation analysis
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H = 37 m
We now have the parameters and ability to design massive
structures
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We now have the parameters and ability to design
massive structures
Sikkim Airport – International Project of the Year 2012 60m High Reinforced Soil Structures
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We now have the parameters and ability to design massive
structures
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Learning from Failure …!
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Experienced Gained
Failures happen, HOWEVER the majority
of them are avoidable
Failures are typically as a result of:
• Incorrect products/materials
• Poor designs & inadequate design
information
• Sub-standard installation /construction
techniques
• Inexperienced supervision
• System misconceptions
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Issues With System Components
Welded Mesh

Structure designed using the parameters associated with this mesh
Poor Quality Woven Mesh
Broken Wire’s of mesh
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Wrong grade / type of geotextile
Puncture in geotextiles

Incorrect Rock Fill Grading – too small and too big

Inadequate scour protection
Issues With Design Details

Outflanking

Insufficient embedment

No geotextile separator

Poor foundation preparation

Drainage behind the reinforced block

Poor construction techniques and lack of experienced site supervision
Make sure the tender specification states that the contractor must have
the necessary experience to carry out the installation
Gujarat, India
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Ensuring Expectation & Performance
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Check all Possible Failure Modes
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Take Drainage Seriously
•Water = Reduction of cohesion
•Water = Increase in pore water pressure
•Water = Possible scour/erosion at the toe
The AS4678 (Appendix G) states:
As drainage is perhaps the most important consideration in
the design of earth-retaining structures, it is very important
that the drainage systems are carefully designed and
specified with sufficient detail to ensure that the system
can be correctly constructed
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Quality Control – Sample Units
A series of Gabions (quantity and location to be
determined by the Engineer) are to be constructed on
the site close to the proposed structure.
These units will be used for quality control purposes
throughout the duration of the Gabion works.
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Performance Based Specifications
Rather than:
2x1x1 Galvanised Gabions with PVC and 2.7mm mesh wire
Ideally:
Gabions shall be manufactured according to EN 10223-3:2013 from double twisted,
hexagonally woven wire mesh of nominal 80x100 mesh, with 3.4mm o/d frame wire
and 2.7mm o/d mesh wire, complete with diaphragms at 1m centres. The nominal
tensile strength of the wire mesh shall be 50kN/m; test done as per EN 10223-3:2013.
The punch strength of the wire mesh shall be 67kN; test done as per UNI 11437. All
wire is mild steel, Galmac coated (Zinc-Al5% alloy) to the requirements of EN 10244-2
(Table 2 – Class A) and heat bonded through extrusion with an additional 0.5mm
heavy duty grey PVC coating. Gabions must have a valid British Board of Agrément
(BBA) certificate for zinc-aluminium alloy & polymer woven mesh. The Gabions must
be manufactured in a ISO 9001 certified factory. The BBA, ISO 9001 and tensile
strength certificates must be provided by the contractor for the materials they intend
using.
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2015– 41 Years Later
Demonstrating Long Term Durability
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Gujarat, India
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Great Ocean Road Galvanised + PVC Coated Terramesh Installed 1988
27 Years Old – in Excellent
Condition
Gujarat, India
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Before 27 Years
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Cobbler Creek Adelaide Galvanized +PVC Coated Terramesh 1989
Gujarat, India
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Gujarat, India
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Bilgola Beach, NSW Galvanized+ PVC Coated Rockfall Netting Installed 1997
Gujarat, India
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Inspected 2015 – 18 years After
Installation
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Rowville Weir, VIC
Installed 1971
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Rowville Weir, VIC Inspected in
2015 Structure is 44 years old
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Examples
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Examples
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Examples
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Examples
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Gabions and River Mattresses
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Gabions Rocks
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Hexagonal woven mesh
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Geotextiles
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• Combination pliers
• Crow bars
• Gabion tensioner
• Gabion frame
• Tensioning frame
• Heavy duty hammer
• Leather gloves
• Stanley knife
• Fencing standards
Gabion Tool Sets
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Biodegradable soil blankets
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Applications
All gabion water structures requiring additional protection from fast hydraulic flows.
Impermeable liners
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Introduction
Gabion Baskets offer training to
personnel on site to help local
possibly unskilled communities
participate in infrastructure
development projects, even when
experienced construction skills are
not available nearby.
Give back to the community by
utilising the local talent to perform
great gabion structure installations.
Practical Site Training
Gujarat, India
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Introduction
Our professional technical
consultants are available to
advise you on the best product
range and purchases with
installation methods and advice
to follow, ensuring that your
final solution is cost effective
and long lasting.
Consultation
Gujarat, India
87

Introduction
Take advantage of the
Gabion Basket turnkey
installation service.
We provide the full
advisory, design, product
range required,
installation services(by
specialised installers) and
peace of mind.
Complete Installation
Gujarat, India
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References:
• Wikipedia.org
• Google Images
• Google search engine docs.
Use for Forces
acting/generated and
design calculations
Use for material Specification and
Erosion control in Hydro structures
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Questions… ?
Thank You
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90

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