Segmental Block Retaining Walls

Transcription

Masonry Design Guide
BOOK
South Australia
4
4 Segmental Block Retaining Walls
Updated September 2007
PAGE
A2
PAGE
4
PAGE
BOOK
Contents
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A2
Products @ a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A4
Fast Find Product and Application Guide . . . . . . . . . . . . . . . A3
About This Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A6
A
B
Introduction
Planning and Design
An Introduction to
Segmental Block Retaining Walls . . . . . . . . . . . . . . . . . . . . . B2
C
Site Investigation — Preliminary Design . . . . . . . . . . . . . . . . B6
Gardenwall®
Gardenwall Product Information . . . . . . . . . . . . . . . . . . . . . . C2
Curved Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C4
Selection and Construction Guidelines . . . . . . . . . . . . . . . . . C3
D
Heathstone®
Heathstone Product Information . . . . . . . . . . . . . . . . . . . . . . D2
Step Tread and Cap Unit Installation. . . . . . . . . . . . . . . . . . . D5
Gravel Fill Construction Guidelines . . . . . . . . . . . . . . . . . . . . D3
Corner Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D6
Curved Wall Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . D4
No-Fines Concrete Wall Construction . . . . . . . . . . . . . . . . . . D7
Step Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D4
E
Keystone® and Pyrmont®
Keystone Product Information . . . . . . . . . . . . . . . . . . . . . . . E4
No-Fines Concrete Wall Selection
Construction Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . E11
Pyrmont Product Information . . . . . . . . . . . . . . . . . . . . . . . . E5
Gravity Wall Selection and Construction Guidelines . . . . . . . E6
Typical Installation Detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . E8
F
Geogrid Soil-Reinforced
Wall Selection Construction Guidelines . . . . . . . . . . . . . . . E13
Typical Specification for
Keystone/Pyrmont Block Retaining Walls . . . . . . . . . . . . . . E15
Custom Engineered Wall Systems
Engineered Retaining Walls . . . . . . . . . . . . . . . . . . . . . . . . . F2
Typical Terraced Wall Application . . . . . . . . . . . . . . . . . . . . . F9
Keysteel Product Information . . . . . . . . . . . . . . . . . . . . . . . . F4
Typical Fencing Application . . . . . . . . . . . . . . . . . . . . . . . . . F10
Typical Soil-Anchor Application . . . . . . . . . . . . . . . . . . . . . . . F6
Typical Railing and Barrier Application. . . . . . . . . . . . . . . . . F11
Typical Rock-Anchor Application . . . . . . . . . . . . . . . . . . . . . . F7
Typical Seawall Application . . . . . . . . . . . . . . . . . . . . . . . . . . F8
The information presented herein is supplied in good faith and to the best of our knowledge was accurate at the time of preparation. No responsibility can be accepted by
Boral or its staff for any errors or omissions. Users are advised to make their own determination as to the suitability of this information in relation to their particular purpose
and specific circumstances. Since the information contained in this document may be applied under conditions beyond our control, no responsibility can be accepted by us
for any loss or damage caused by any person acting or refraining from action as a result of this information.
PAGE
BOOK
Fast Find Guide
4
A3
The quickest way to find a Boral Masonry Segmental Block Retaining Wall Solution.
Simply follow the FAST FIND guide on the right hand side of the table.
Surcharge
Loading
Wall Height
(mm)
Nil
≤ 1125
PR
O
D
U
G
CT
ar
de
nw
H
al
ea
l
th
st
on
Py
e
rm
on
t
Ke
ys
to
ne
Ke
ys
te
el
Co
re
Fi
lle
d
Bl
oc
k
BORAL
MASONRY
SEGMENTAL
BLOCK
RETAINING
WALLS
Wall
Type
Set Back
≤ 5kPa
≤ 1600
D
Vertical
C
Vertical
D E
Set Back
≤ 5kPa
or
≤ 1:4
Sloped
Backfill
≤ 3000
≤ 25kPa
> 3000
,
,
,
,
E
E
E
E
Property
Boundary
E# E#
Vertical
E# E#
E#
Vertical
> 6000
Set Back
1 Select your application
criteria from the left
hand columns
2 Go straight to the book
section indicated by the
letter at the intersection of
application rows and
product columns (e.g.
Section E in this example)
,
Not
Boundary
Set Back
> 25kPa
E
,
F
F
Fast Find
a Boral
Solution
Requires ‘No-fines Concrete
Backfill ’ or ‘Geogrid’ systems
#
Requiring ‘Geogrid’ systems
,
Please refer to Book 1, Boral
Masonry Design Guide and Book 2,
Boral Masonry Blocks & Bricks Guide
For technical support and sales office details please refer to the outside back cover
Max. wall heights disclaimer:
The gravity wall heights are maximum heights calculated in accordance with CMAA MA-53 Appendix D guidelines and a qualified engineer should confirm the suitability of the product
for each intended application. As such, due consideration must be given to but not limited to:
• Cohesion,
• Dry backfill: no ingress of any water into the soil behind the retaining wall,
• All retaining walls are designed for zero surcharge.
These walls are intended for structure Classification A walls only as defined in AS4678 Earth Retaining Structures as being where failure would result in minimal damage and loss of access.
4
PAGE
BOOK
Products @ a Glance
A4
Landscape
Retaining Wall Systems
for low-height domestic and commercial
garden beds and retaining wall applications
• Gardenwall®
Boral Gardenwall is ideal for gravity wall installations
of less than 1125mm wall height. The blocks are laid
with a slight set-back, and are located by a lug along
the back edge. Gardenwall can also be used curved
wall applications.
• Heathstone® and Heathstone® Grande
Boral Heathstone retaining wall systems combine
the attractive impression of natural hewn stone,
the elegance of a vertical wall and the simplicity of
mortarless installation. Various installation formats
cater for walls up to 0.97m height. Heathstone Grande
double-length blocks are particularly effective in larger
installations.
Engineered
for domestic and commercial landscaping, roadside
and custom engineered retaining wall applications
• Keystone®
Boral Keystone walls have been proven time-andtime-again, by engineers, architects, councils, road
authorities and landscapers throughout Australia.
Keystone walls can cater for a wide range of
applications from low height gravity walls to geogrid
soil reinforced applications up to 12m wall height.
Keystone walls can be constructed as near vertical
with curves as tight as 1m radius, or set-back. Blocks
are available in a wide selection of colours.
4
PAGE
BOOK
Products @ a Glance
A5
• Pyrmont®
Boral Pyrmont retaining walls are a modern-day link
to our pioneer heritage. Pyrmont combines modern
engineering versatility with the elegance of a vertical
wall and the style of hand-finished natural stone.
Pyrmont gravity or soil reinforced retaining wall
systems can be engineered for applications up to 6m
height and can accommodate gentle curves and step
installations.
• Keysteel™ Custom Engineered Retaining
Wall Systems
Boral Keysteel is a high performance engineered
retaining wall system for applications requiring wall
heights in excess of 6m and/or where critical surcharge
loadings are present. Boral Keysteel is an internationally
proven system that integrates the superior strength
and durability of Keysteel blocks with steel-ladder soilreinforcement to provide engineered solutions for the
most demanding retaining structures.
4
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BOOK
About This Guide
A6
Boral Masonry Product Range
Boral Masonry offers a comprehensive range of proven products
and systems including Segmental Block Retaining Wall
Systems, Segmental Paving Products, Masonry Blocks, Masonry
Bricks, Masonry Fire and Acoustic Wall Systems.
What’s in this Guide
The Boral Masonry Segmental Block Retaining Walls Guide,
(this book), details a comprehensive selection of retaining wall
options ranging from low height gravity landscaping walls to
critically loaded reinforced-soil retaining structures.
This guide has been prepared as a comprehensive Boral
Product Reference Guide. It does not attempt to cover all the
requirements of the Codes and Standards which apply to
retaining wall construction. All structural detailing should
be checked and approved by a structural engineer before
construction. Boral reserves the right to change the contents
of this guide without notice.
Please note that this guide is based on products available at
the time of publication from the Boral Masonry South Australia
sales region. Different products and specifications may apply
to Boral products sourced from other regions.
Additional Assistance and Information
• Contact Details: Please refer to the outside back cover
of this publication for Boral Masonry contact details.
• Colour and Texture Variation: The supply of raw
materials can vary over time. In addition, variation can
occur between product types and production batches.
Also please recognise that the printed colours in this
brochure are only a guide. Please, always ask to see a
sample of your colour/texture choice before specifying
or ordering.
• Terms and Conditions of Sale: For a full set of Terms
and Conditions of Sale please contact your nearest Boral
Masonry sales office.
A Guided Tour of a Typical Product Information Page
Product pages are laid out in a consistent manner to assist with easy selection and specification
of Boral Masonry products.
PAGE
Keystone® & Pyrmont®
BOOK
Product Range, Book and
Page Identification
4
E4
315
200
455
455
Standard Unit
Product Icons
with dimensions
for products
available in your
region/state
Product Name and other
identifying features
315
200
275
275
100
100
455
455
Flushface Straight
Sided Cap
(made to order)
275
300
100
50
300
455
D-Cap
Straight Sided Cap
(made to order)
the tail to 300mm width.
INTRODUCTION
Flushface Unit
(Made to order)
Standard Cap
(made to order)
Keystone®
Boral Keystone is an advanced,
highly versatile and thoroughly
proven high performance segmental
block retaining wall system which
can be used as a gravity structure
or it can incorporate geogrid soilreinforcement to cater for greater
heights and surcharge loading
situations.
DESIGN CONSIDERATIONS
• Suitable for straight and curved
wall installations with a minimum
convex curve radius of 1800mm
without trimming the tail width,
or 970mm radius by trimming
• Can be installed as near vertical,
or for straight walls without
curves or corners it can be
installed with a 1-in-8 setback.
COLOURS
Keystone is offered in a range of
colours to suit decorative and
engineering applications. Please
refer to colour swatch information
for an indication of current colours.
To reduce the possibility of staining
and to enable easier cleaning, a
masonry sealer can be applied to all
visible surfaces after installation.
Product information
relating to features,
applications, and
accessories
Pins
Lifting Bars
Keygrid Geogrid Soil Reinforcement
Colour and
Availability
information
for products
distributed
in your
region/state
Specifications
Description
Availability & Colours
• No minimum order quantities apply.
• Lead time 0-4 weeks.
Almond
Paperbark
Tuscan
HxLxDmm
Wt kg
N°/m2
Standard Unit
200x455x315
41
11
Straight Sided Cap
100x455x275
25
2.2/lin mtr
Standard Half High Unit
100x455x275
20
22
Standard Cap
100x455x275
20
2.2/lin mtr
Flushface Unit
200x455x315
41
11
100x455x275
26.3
2.2/lin mtr
Flushface Straight Sided Cap
Pins
2 pins per full unit
(high strength pultruded fibreglass)
Lifting Bars
(Keystone units should be lifted by
two people using the Keystone lifting bars)
Product
Specifications
BOOK
South Australia
4
4B
SECTION
SEGMENTAL BLOCK RETAINING WALLS
Planning and Design
4
PAGE
BOOK
Planning and Design
B2
An Introduction to Segmental
Block Retaining Walls
Background
Segmental block gravity
retaining structure, drystacked against a soil
slope
For many years cantilever retaining walls have been constructed
with reinforced concrete masonry stems (steel reinforcement
grouted into hollow concrete block work) and reinforced
concrete footings. (Refer to Fig B1).
Segmental block gravity retaining structures, consisting
of dry-stacked concrete units which resist overturning by
virtue of their own weight and setback, were introduced into
Australia in the early 1990’s, and rapidly became popular. This
system provides an attractive and cost effective solution, but
its stability is limited by the geometry of the units and wall
heights. (Refer to Fig B2).
In order to achieve greater heights, reinforced-soil walls
(such as Boral Keystone) were introduced. These walls
typically consist of geosynthetic materials, which are
placed in horizontal layers in the compacted backfill and
mechanically connected to the blocks. Such systems can
be constructed several metres high, and accommodate
significant loads.
A further development of this system is the Boral Keysteel
system which utilises steel-ladder reinforcement. Here the
steel-ladder reinforcement is placed in horizontal layers in
the compacted backfill and mechanically connected to the
blocks. These systems are individually engineer designed,
and are suitable for walls in excess of 6m high and for critical
surcharge loadings. (Refer to Fig B3).
Fig B2 — Typical Segmental Block
Gravity Retaining Wall
Segmental
concrete
gravity
retaining
structure, with
reinforced soil
Steel reinforced
and concrete
grout filled
hollow concrete
block wall
Fig B3 — Typical Reinforced-Soil
Segmental Block Retaining Wall
Reinforced
concrete
footings
Fig B1 — Typical Reinforced Concrete Masonry
Cantilever Retaining Wall
Behaviour of Segmental Block
Reinforced-Soil Retaining Walls
If unrestrained, a soil embankment will slump to its angle of
repose. Some soils, such as clays, have cohesion that enables
vertical and near-vertical faces to remain partially intact, but
even these may slump under the softening influence of ground
water. When an earth retaining structure is constructed, it
restricts this slumping. The soil exerts an active pressure on
the structure, which deflects a little and is then restrained by
the friction and adhesion between the base and soil beneath,
passive soil pressures in front of the structure and bearing
capacity of the soil beneath the toe of the structure.
4
PAGE
BOOK
Planning and Design
B3
• Adequate connection to the facing to provide local stability;
• A drainage system that will relieve hydro static pressures
for the life of the structure.
Importance of a Geotechnical Report
The design of a reinforced soil retaining wall includes two
essential parts:
• Analysis of the proposed reinforced soil structure and
the adjacent ground for global slip, settlement, drainage
and similar global considerations; and
• Analysis and design of the reinforced soil structure itself.
If water is trapped behind the retaining structure, it exerts an
additional hydraulic pressure. This ground water also reduces
the adhesion and bearing resistance.
These analyses must be based on an accurate and complete
knowledge of the soil properties, slope stability, potential slip
problems and ground water.
If massive rock formations are present immediately behind the
structure, these will restrict the volume of soil which can be
mobilised and thus reduce the pressure.
Except in the case of simple structures, a geotechnical report
by a qualified and experienced geotechnical engineer should
be obtained.
Reinforced-soil systems consist of a series of horizontal
geogrids that have been positioned and pulled tight within
a compacted soil mass, thus strengthening it and restricting
its slump. The geogrids are strategically placed to intersect
potential failure planes that are inclined from near the base of
the wall, up at an angle (depending on the soil properties), to
the top of the fill. The function of the geogrids is to ‘strengthen’
the soil mass and they are ‘anchored’ by compacted backfill
beyond the potential failure planes.
Such a report must address the following considerations, as
well as any other pertinent points not listed.
Local collapse and erosion of the front face is eliminated by
fixing concrete segmental facing units to the exposed ends of
the geogrids. However, the segmental concrete facing is not
designed to ‘retain’ the strengthened soil mass, which should
be able to stand independently of the facing except for local
effects. The connection spacing (and the geogrid spacing) must
account for the local stability of the facing, including bulging
and rotation above the top geogrid. The top capping course
is normally bonded to the course below using a concrete to
concrete adhesive.
A surface sealing layer and surface drainage system minimise
the quantity of rainwater entering the soil mass. A sub-surface
drainage system behind the segmental concrete facing and
(sometimes) beneath the wall reduce pore water pressures and
thus reduce the tendency for local or global slip.
Thus, the essential features of a properly designed and
constructed segmental block reinforced soil retaining wall
are:
• Geogrids with adequate length and strength;
• Soil properties;
• Extent and quality of any rock, including floaters and
bedrock;
• Global slip and other stability problems;
• Bedding plane slope, particularly if they slope towards
the cut;
• Effect of prolonged wet weather and the consequence of
the excavation remaining open for extended periods;
• Effect of ground water;
• Steep back slopes and the effect of terracing;
• Effect of any structures founded within zone of influence.
Safety and Protection of Existing
Structures
Whenever soil is excavated or embankments are constructed,
there is a danger of collapse. This may occur through movement
of the soil and any associated structures by:
• Rotation around an external failure plane that encompasses
the structure;
• Slipping down an inclined plane;
• Sliding forward, or
• Local bearing failure or settlement.
4
PAGE
BOOK
Planning and Design
B4
These problems may be exacerbated by the intrusion of surface
water or disruption of the water table, which increase pore
water pressures and thus diminish the soil’s ability to stand
without collapse.
The safety of workers and protection of existing structures
during construction must be of prime concern and should be
considered by both designers and installers. All excavations
should be carried out in a safe manner and in accordance with
the relevant regulations, to prevent collapse that may endanger
life or property. Adjacent structures must be founded either
beyond or below the zone of influence of the excavation. Where
there is risk of global slip, for example around a slip plane
encompassing the proposed retaining wall or other structures,
or where there is risk of inundation by ground water or surface
water, construction should not proceed until the advice of a
qualified and experienced Geotechnical Engineer has been
obtained and remedial action has been carried out.
Global slip failure
Soil retaining structures must be checked for global slip failure
around all potential slip surfaces or circles.
Designers often reduce the heights of retaining walls by
splitting a single wall into two (or more) walls, thus terracing
the site. Whilst this may assist in the design of the individual
walls, it will not necessarily reduce the tendency for global
slip failure around surfaces encompassing all or some of the
retaining walls.
Analysis for global slip is not included in this guide, but it is
recommended that designers carry out a separate check using
commercially available software.
Differential Settlement
The Concrete Masonry Association of Australia (CMAA)
recommends that for dry stacked mortarless retaining
walls employing masonry units (i.e. units with an area
less than 0.2m2) on an aggregate levelling pad, the
differential settlement should be limited to 1% of the
length. Whilst it is permissible for the retaining wall to
undergo differential settlement up to 1% of the length,
it may be preferable to limit settlement to a lower
figure giving consideration to aesthetics (i.e. keeping
the bedding planes level), in addition to the structural
considerations.
Techniques to reduce or control the effects of differential
settlement include:
• Articulation of the wall (in discontinuing the normal
stretcher bond) at convenient intervals along the length,
• Excavating, replacing and compacting areas of soft soil,
• Limiting the stepping of the foundation and bottom course
to a maximum of 200mm.
Unit Cracking/Gapping — Settlement
Keystone modular retaining wall structures can tolerate a
certain amount of settlement due to the flexible nature of the
system and small individual unit size.
Observation of a number of completed structures that have
undergone settlement indicates that the wall’s tolerance
for settlement without cracking is inversely proportional to
the wall height. Lower height walls (H<5m) appear to have
considerably more facial flexibility than taller walls (H>5m).
This increased flexibility is due to lower confining forces and
load transfer taking place on each block, which permits small
individual movements to occur, accommodating the settlement
experienced without facial distress. Taller walls place the lower
wall units under considerable confining pressure, restricting
unit movement and permitting shear and flexural stresses
to build up to the point where a block cracks as a means of
stress relief.
Low wall settlement problems are typically observed in
residential projects where soils adjacent to houses are
uncompacted and the walls settle differentially over a short
distance. Usually gapping or offset joints are visually noted
and the settlement is obvious.
Gapping and offset joints
Downward
movement
Fig B4 — Typical Low Wall
Settlement
Tall wall settlement is not as obvious but occasional facial
cracks can be observed in areas of flexural stress concentration,
typically in small groupings in the bottom 1/3 of the wall.
Settlement induced cracks are usually not structurally
significant and are just a means of facial stress relief for the
unreinforced dry-stack facing system. However, cracked units
can be a symptom of other types of problems, so a review by
an engineer is always recommended.
Downward
movement
High confining
pressure
Flexural stress
Facial cracks
Fig B5 — Typical Tall Wall
Settlement
Importance of Drainage
This guide assumes that a properly functioning drainage
system is effective in removing hydraulic pressure. If this is
not the case, the designer will be required to design for an
appropriate hydraulic load.
Based on an effective drainage system, it is common to use
drained soil properties. For other situations, the designer
must determine whether drained or undrained properties are
appropriate. In particular, sea walls that may be subject to
rapid drawdown (not covered in this guide) require design
using undrained soil properties.
4
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BOOK
Planning and Design
B5
4
PAGE
BOOK
Planning and Design
B6
Site Investigation: Preliminary Design
Date: _______________________
Report prepared by: _______________________
Client: __________________________________________________________________________
Project: _________________________________________________________________________
Location: ________________________________________________________________________
Use for which retaining wall is intended: _____________________________________________
Proximity of other structures to the face of the retaining wall:
Structure or load
Distance (m)
Distance of live loads from top of wall (Dqi)
_______________________
Distance of dead loads from top of wall (Dqd)
_______________________
Distance of point loads from top of wall (Di)
_______________________
Distance of other structures from base of wall (Ds)
_______________________
Structure classification: _________________________________________________
For guidance refer AS4678, Table 1.1
Structure Classification
Examples
2.
3.
4.
Where failure would result in significant damage or risk to life
Where failure would result in moderate damage and loss of services
Where failure would result in minimal damage and loss of access
Required design life: _____________________________________________________
For guidance refer AS4678, Table 3.1
Type of Structure
Design life (years)
Type of Structure
Design life (years)
Temporary site works
Mine structures
Industrial structures
River and marine structures
5
10
30
60
Residential dwellings
Minor public works
Major public works
60
90
120
Wall geometry:
Wall height above GL (H’)
Retained soil data:
___________ m
Soil density (gr)
___________ kN/m3
Internal friction angle (fr) peak
___________ °
___________ kPa
Embedment depth (Hemb)
H/20 or 200mm
___________ m
Cohesion (C*i)
Wall slope (v)
___________ °
Loading data:
Angle of backfill slope (b)
___________ °
Height of backfill (h)
___________ m
Foundation material:
Allowable bearing pressure
Under reinforced soil block
___________ kPa
Water profile:
Water table depth within wall fill
___________ m
Dead load surcharge (qd)
___________ kPa
Live load surcharge (ql)
___________ kPa
Horizontal line load (F)
___________ kN/m
Vertical line load (P)
___________ m
Width of bearing (b)
___________ m
BOOK
South Australia
4
4C
SECTION
Gardenwall®
PAGE
BOOK
Gardenwall®
4
C2
228
228
125
125
300
300
Standard Unit
Straight Sided Unit
Gardenwall®
Retaining Wall System
INTRODUCTION
Boral Gardenwall is ideal for low
landscaping walls and edgings
in garden and communal areas.
Gardenwall’s rockface texture, multifaceted face and setback construction
produces an aesthetically pleasing
feature for landscaped areas.
Gardenwall is often used for garden
edges and raised beds, terraces and
to create decorative features such as
around pools.
Depending on the foundation
and retained soil characteristics,
Gardenwall is effective as a gravity
retaining wall structure up to
1125mm (maximum 9 courses).
Never install where loads (e.g.
buildings, driveways) will be located
within 1125mm of the wall. For
engineered walls (to AS4678) higher
than 1125mm, or where a surcharge
is present, Boral Keystone or Pyrmont
walls should be considered.
Availability and Colours
ADVANTAGES
• Gardenwall does not require
concrete foundations.
• Easy installation of straight walls
and curved walls.
• Durable, low maintenance, longterm landscaping.
• Solid units — eliminates the need
for capping and corner units.
COLOURS
Gardenwall is offered in a range
of colours to suit traditional and
contemporary settings. Please refer
to colour swatch information for an
indication of current colours.
Light Sands
Tuscan
Paperbark
Hawkesbury Yellow
Specifications
Product Description
Finish
HxLxDmm
Approx Wt kg
No. per m2
Standard Unit
Rockfaced
125x300x228
15.5
26.7
Straight Sided Unit
Rockfaced
125x300x228
15.5
26.7
4
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BOOK
Gardenwall®
C3
Selection and Construction Guidelines
IMPORTANT: Please consult with the regulating council for
local design requirements prior to the design and construction
of a retaining wall. Councils in general require that retaining
walls be designed and certified by a suitably qualified engineer
where the wall is over 0.5m in height and/or where there is
surcharge loading such as a roadway, house, or other structure
near the wall.
• Boral Gardenwall is only suitable for walls up to 1125mm
in height and where no loads or surcharge exists within
1125mm behind the wall.
Installation
• Remove the retaining lug on the base of the unit on
those Gardenwall blocks being used on the base course
only (this makes levelling the first course much easier).
To remove the lip, place at an angle on the ground and
strike the lug firmly with a hammer (safety glasses should
be worn).
• As a safety precaution to avoid lifting or movement of the
top units, it is recommended that the top course units
are secured using a construction adhesive. This is also
recommended in areas of possible vandalism.
• Standard units can also be used to construct convex curves.
Dish drain to direct surface
run-off (if required)
Gardenwall Unit
No loads to be located within 1125mm behind wall
Backfill should be no higher than the top of the wall
Backfill placed and
compacted in 250mm layers
150mm width of 12-20mmØ
free draining granular
material eg. blue metal
Filter fabric to stop silt
clogging drainage material
1 in 5 set-back
H
Drainage pipe (if required)
First course to be buried below
final ground level (to engineer's
specification - 100mm min.)
Native soil
100mm min.
350mm
min.
Compacted road base levelling
pad on undisturbed inorganic soil
Fig C1 — Typical Gravity Wall Construction Detail — Gardenwall
Note: Refer to max. wall heights disclaimer on page A3 of this guide.
The gravity wall heights are maximum heights calculated in accordance with CMAA MA-53 Appendix D guidelines and a qualified engineer should confirm
the suitability of the product for each intended application.
4
PAGE
BOOK
Gardenwall®
C4
Curved Walls
m
0m
um 10 0 e
s
im =
in s
ur
M diu t co
a
s
R
r1
fo
Fig C2 — Construction of Curved Walls
• When designing Gardenwall for convex curves to the
maximum height of 8 courses, it is necessary to begin
with a minimum radius of 1000mm. It may also be
necessary to remove the outer portions of the retaining
lug from each unit to maintain a consistent setback. It is
important that the entire lug is not removed.
• When building curves, some blocks may also require
trimming of the length to maintain a half bond pattern.
BOOK
South Australia
4
4D
SECTION
Heathstone®
PAGE
BOOK
Heathstone®
4
D2
280
Heathstone®
Retaining Wall System
162
162
380
270
220
Standard Unit
INTRODUCTION
Standard Corner Unit
280
162
440
Grand Unit
300
300
50
50
300
300
Bullnose Cap
Stoneworks® Cap
Boral Heathstone is ideal for low,
vertical landscaping walls in garden
and communal areas. The rockface
texture and bevelled edges add a
formal and elegant element to
a landscaped area. Heathstone is
often used to separate and highlight
entertaining areas, BBQ areas, paths,
garden beds, hedges, or to create and
differentiate levels. Heathstone is
also suitable for constructing steps,
planter boxes and for curved walls.
Tuscan
Almond
Charcoal
Paperbark
Limestone
Stoneworks Cap ONLY
(made to order)
Sandstone
Stoneworks Cap ONLY
(made to order)
Convex curves as tight as 900mm
radius can be constructed using the
standard unit. The Curved Cap can
be used to form curves of 1800mm
outside radius and 1500mm inside
radius.
COLOURS
The range of Heathstone components
is designed to optimise space, and
includes a ready-to-install corner unit
and a series of caps to accommodate
single or double sided applications
and curved installations.
Depending on the foundation
and retained soil characteristics,
Heathstone is effective as a gravity
structure up to 972mm, or up to
1600mm when installed with nofines concrete backfill. Heathstone
should not be used where the base
soil or backfill is not firm, or is of
expansive clay. Never install where
loads (e.g. buildings, driveways) will
be located within 1000mm of the
wall. For walls higher than this, or
where a surcharge is present, Boral
Keystone or Pyrmont walls should
be considered.
Heathstone is offered in colours
which emulate natural hewn stone,
and which contrast beautifully with
soil, mulch, shrubbery and grassed
areas. Please refer to colour swatch
information for an indication of
current colours.
Specifications
Product Description
Finish
HxLxDmm
Approx Wt kg
No. per m2
Standard Unit
Rockfaced/Smoothfaced
162x220x280
11.9
28.1 units/m2
Rockfaced x 2 Faces
162x380x270
23
1/course/corner
Grand Unit
Rockfaced
162x440x280
26.2
14.05 units/m2
Bullnose Cap
Smooth
50x300x300
9.4
3.3/linear metre
Stoneworks Cap
Rockfaced
50x300x300
22
3.3/linear metre
Note: Refer to max. wall heights disclaimer on page A3 of this guide.
4
PAGE
BOOK
Heathstone®
D3
Heathstone® Gravel-Fill Construction
IMPORTANT: Please consult with
the regulating council for local design
requirements prior to the design and
construction of a retaining wall. Councils
in general require that retaining walls
be designed and certified by a suitably
qualified engineer where the wall is over
0.5m in height and/or where there is
surcharge loading such as a roadway,
house, or other structure near the wall.
Dish drain to direct surface water
or filter fabric to stop silt filling
drainage layer
No loads to be located
within 1.0m of the wall
150mm min. of 12-20mmØ
free draining granular
material eg. blue metal
Voids in and around Heathstone
blocks to be filled (if required)
with 12-20mmØ free draining
granular material eg. blue metal
Refer to Heathstone
Gravel-Fill Selection
Table for maximum
number of courses
Backfill (eg. excavated soil)
to be placed and
compacted as each course
of blocks is laid
Agricultural drainage line 100mmØ
Blocks to be embedded
a minimum of 100mm
Native soil
Compacted
roadbase
100mm min.
350mm
min.
Fig D1 — Typical Construction Detail — Heathstone Gravel-Fill
Table D1 - Maximum Wall Height — Heathstone Gravel-Fill
Maximum Courses
For walls without gravel fills
to all voids and cores
Maximum Courses
For walls with gravel fills
to all voids and cores
Poor soils — including sands, gravelly
clays, sandy clays and silt clays
2 (324mm)
4 (648mm)
Average soils — including well graded
sands and gravelly sands
3 (486mm)
5 (810mm)
Good soils — including gravels, sandy
gravels and crushed sandstone
4 (648mm)
5 (810mm)
NOTES: Backfill retained by a retaining wall should be no higher than the top of the retaining wall.
For engineered retaining walls to AS4678, refer to the Heathstone No-Fines Concrete Wall Guidelines.
Refer to max. wall heights disclaimer on page A3 of this guide.
The gravity wall heights are maximum heights calculated in accordance with CMAA MA-53 Appendix D guidelines
and a qualified engineer should confirm the suitability of the product for each intended application.
4
PAGE
BOOK
Heathstone®
D4
Curved Wall Construction
Curves as small as 900mm in radius can be constructed with
Heathstone Standard Units.
Concave (Internal) Curves
• For concave curves use Standard Units spaced evenly to
a scribed arc.
Heathstone
Standard Unit
Convex (External) Curves
• For convex curves, the tails of the blocks must be
trimmed to suit the desired radius. Use a hammer and
bolster on the back, top and bottom of the tail. Use light
hammer blows first to trace the area to be removed, then
a heavier blow on top. Repeat the tracing and final blow
if necessary.
C
M onc
in
a
im ve
um Cu
ra rve
di
us Rad
90 ius
0m
m
Bolster back
of blocks to
form convex
curves
Fig D3 — Forming Concave Curve
NOTE: Premium Curved
Caps have an outside
radius of 1800mm
Step Construction
Fig D2 — Forming Convex Curve
Bullnose Cap
Fix cap units with
construction adhesive
Remove locating
lugs before laying
255
162
25
45
Heathstone
Units
1:10
Cement : Sand
Native soil
Fig D4 — Construction of Heathstone Steps
Step Treads and Cap Unit Installation
• Splitface Cap (225mm long) has a recess in the underside
to allow for the lug on the Heathstone Unit. Removal of
the lug is not required in this case
• To allow for installation of the Double-sided Rockface Cap
units and step treads, it is necessary to bolster locating
lugs from the blocks.
• Push the Heathstone split-face into sand for support.
Trace along the back of the lug with a bolster and
hammer, increasing the force of hammer blows until
the lug splits off. All blows must be from the back of
the block, with the bolster blade nearly parallel to the
top of the Heathstone unit. Refer to the illustration. Any
remaining high spots should be removed with a scutch
hammer or an old screwdriver and hammer.
Fig D5 — Bolstering Lug from Heathstone Units
4
PAGE
BOOK
Heathstone®
D5
4
PAGE
BOOK
Heathstone®
D6
Corner Construction
Constructing Internal and External Corners
• Corners are constructed using Corner Units and Standard
Units or Grand Units and Corner Units.
• Continue this step until the desired height of the wall is
achieved.
• Use a construction adhesive to secure corner blocks and
caps.
• Lay the Corner Units’ largest splitface in alternate
directions in adjacent courses (see illustrations).
Grand Unit cut
to 330mm on site
Grand Unit
330mm
Grand Unit
Corner Unit
Corner Unit
Fig D6 — Heathstone Standard External Corner (270°)
110mm
Fig D8 — Heathstone Grand External Corner (270°)
220mm
Grand Unit
Corner Unit
Standard Unit
Grand Unit cut
to 330mm on site
Bolster lug to
fit next course
Bolster lug to
fit next course
Corner Unit
Grand Unit
NOTE: Internal 90º corners using Grand
Units do not require corner units
Fig D7 — Heathstone Standard Internal Corner (90°)
Fig D9 — Heathstone Grand Internal Corner (90°)
4
PAGE
BOOK
Heathstone®
D7
Heathstone® No-Fines Concrete Wall Construction
No-Fines Concrete shall consist of cement, water and coarse
aggregate. Cement will comply with the definitions for cement
per AS3972-1991 — ‘Portland and Blended Cements’. The
quantity of cement is specified as 210kg/m3 with a total
water/cement ratio of between 0.45 and 0.55.
The particle size distribution of the aggregate shall comply with
the limitations for the nominal single sized 20mm aggregate
specified in AS2758.1.
NOTES:
• Table D2 is based on AS4678 : 2002, Earth Retaining
Structures. The code assumes a surcharge of 5kPa is
applied to all retaining wall structures.
• Global stability and all design considerations should be
checked by an engineer in poor clay conditions.
• Design assumes a dry excavation (i.e. water table is
below bottom of footing level). If ground water exists in
the excavation the wall is to be re-designed by a suitably
qualified engineer.
• These tables are supplied free of charge and do not form
any part of any contract with the user.
• 15MPa No-Fines concrete with a 6:1 ratio (Gravel : Cement).
• Remove tail fins to allow “no fines” to connect block fill
to back fill.
T
No loads above 5kPa to be
located within 1.0m of the wall
Cap unit
Filter fabric or dish drain
15MPa ‘No Fines’ concrete.
All voids within and around
units to be completely filled.
Retained soil
Sub-soil drain
connected to
stormwater system
or flood pit. Place
loose aggregate
around subsoil drain
before pouring
no-fines concrete.
clogging drainage of
‘no-fines’ material
H
(Refer to Heathstone
No-Fines Concrete
Selection Table)
Pour no-fines concrete
directly onto prepared
foundation material
Blocks to be embedded to
engineer‘s detail (1 course min.)
25MPa concrete
footing on 150kPa
allowable bearing
capacity material
150mm min.
600mm min.
Fig D10 — Typical Construction Detail — Heathstone No-Fines Concrete Wall
Table D2 — Heathstone Maximum Wall Heights — No-Fines Concrete Construction
φ
Wall Height
‘H’ (mm)
Retained Soil
CLAY φ = 26° (POOR)
‘T’ (mm)
972
670
570
570
1296
730
770
670
1620
1170
970
770
Denotes the internal angle of friction of the retained material
SAND
Retained Soil
φ = 30° (AVERAGE)
‘T’ (mm)
Retained Soil
GRAVEL φ = 34° (GOOD)
‘T’ (mm)
4
PAGE
BOOK
Heathstone®
D8
• The density of this product will vary with the density
of the aggregate used. The density range may be from
1650kg/m3 to 2100kg/m3.
• The void ratio of the mix is expected to be between 20%
and 30% and should be free draining.
• The compressive strength should generally exceed
10MPa for design purposes.
• This product has no slump and exerts similar pressures
on the soil and formwork, as does loosely poured
aggregate.
No-Fines Construction Steps
Special purpose construction such as waterside walls, post
fixing, earthquake zones, and terraces will require additional
engineer’s design.
STEP 2:
Installing the First Course
Lay the first course of Heathstone units side by side over the
prepared base. Bolster off the tails so that ‘No-Fines’ concrete
connects backfill to core-fill areas.
STEP 3:
No-Fines Concrete Backfill
Backfill the first 21Ú2 courses of the wall with ‘No Fines’
concrete. All voids inside and between the units must also be
filled. The vertical height of any pour of ‘No Fines’ concrete is
limited to 400mm. For walls greater in height, each pour must
be allowed to harden prior to pouring the next lift. Alternatively
the wall may be propped to support the lateral load from the
wet concrete.
STEP 4:
Installing Capping Units
STEP 1:
Excavation/Preparation of Levelling Pad
Excavate a trench 600mm wide and sufficiently deep to allow
a 150mm levelling base plus 1 course below ground.
Install capping units and fix with construction adhesive.
BOOK
South Australia
4
4E
SECTION
4
PAGE
BOOK
E2
Keystone® and Pyrmont Retaining Wall Systems
The Keystone Retaining Wall System is a world-wide
success story, and since its introduction by Boral into
Australia in 1992, hundreds of thousands of square
metres have been installed along our highways, roads
and transport corridors, and around our sports facilities,
buildings, foreshores and open spaces.
Boral Keystone retaining wall systems combine proven
engineering capabilities with design versatility, cost
effectiveness, lasting durability and an attractive dynamic
appearance to provide total solutions for retained earth
structures.
Keystone®
Boral Keystone systems provide infinite flexibility
for design variation and individuality. The range of
components and installation methods cater for straight,
curved and terraced walls, level or stepped foundations
and capping, and a near vertical or set-back face. Then
there is a choice of standard or flushface, and a selection
of popular standard colours or custom colours can be
ordered for larger projects.
Pyrmont®
Boral Pyrmont retaining wall system retains all of the
engineering characteristics of the Keystone system
and combines them with a more traditional appeal of a
bevelled-edge splitface block, and vertical construction to
emulate walls built during Australia’s pioneering era.
The range of components and installation methods
cater for straight and gently curved walls as well as
crisp 90º corners, while the rock-faced caps provide a
finishing touch that completes the transformation into a
masterpiece from the colonial era.
4
PAGE
BOOK
E3
Proven Engineering
Ease of Construction
Various installation methods cater for simple gravity walls
through to geogrid soil-reinforced retaining structures.
Boral Keystone and Pyrmont systems can also cater
for critical surcharge loads, enabling the construction of
buildings or roadways close to the wall to optimise land
usage.
Boral Keystone and Pyrmont systems are designed to
reduce construction time and cater for all locations. The
modular blocks can be moved and installed without the
need for heavy lifting machinery, and the dry stacked,
mortarless installation provides less complex, more rapid
construction.
For high performance retaining walls, please refer to the
section on Boral Keysteel Custom Engineered Retaining
Wall Systems later in this guide.
Durability
Boral Keystone and Pyrmont systems combine the
durability of concrete units and interlocking fibreglass pins
to produce maintenance free walls with life expectancies
of up to 120 years.
PAGE
BOOK
4
E4
315
315
200
200
455
455
Standard Unit
275
275
100
100
455
Flushface Straight
Sided Cap
(made to order)
Standard Cap
(made to order)
275
300
100
50
300
455
Standard Cap
Straight Sided Cap
(made to order)
the tail to 300mm width.
INTRODUCTION
Flushface Unit
(Made to order)
455
Keystone®
Boral Keystone is an advanced,
highly versatile and thoroughly
proven high performance segmental
block retaining wall system which
can be used as a gravity structure
or it can incorporate geogrid soilreinforcement to cater for greater
heights and surcharge loading
situations.
• Suitable for straight and curved
wall installations with a minimum
convex curve radius of 1800mm
without trimming the tail width,
or 970mm radius by trimming
• Can be installed as near vertical,
or for straight walls without
curves or corners it can be
installed with a 1-in-8 setback.
COLOURS
Keystone is offered in a range of
colours to suit decorative and
engineering applications. Please
refer to colour swatch information
for an indication of current colours.
Pins
Lifting Bars
Almond
Paperbark
Tuscan
Specifications
Description
HxLxDmm
Wt kg
N°/m2
Standard Unit
200x455x315
41
11
Straight Sided Cap
100x455x275
25
2.2/lin mtr
Standard Half High Unit
100x455x275
20
22
Standard Cap
100x455x275
20
2.2/lin mtr
Flushface Unit
200x455x315
41
11
100x455x275
26.3
2.2/lin mtr
Pins
Lifting Bars
(Keystone units should be lifted by
PAGE
BOOK
4
E5
275
305
100
20 0
455
455
Pyrmont®
Vertical Retaining Wall System
INTRODUCTION
Standard Unit
Straight Sided Cap
(made to order)
275
100
455
Pyrmont Cap
(made to order)
Boral Pyrmont retaining wall systems
integrate the engineering capabilities
of the Keystone system with the
versatility and pleasing aesthetics of
a vertical wall. The Pyrmont unit is a
split-face block with four chamfered
edges, emulating the care, skill and
determination of stone masons from
Australia’s early settler period.
Boral Pyrmont retaining wall system
is also suitable for constructing steps,
planter boxes, gently curved walls
and crisp 90° corners.
Suitable for curved wall installations
with a suggested minimum convex
curve radius of 5m (resulting in
a 5mm lip).
COLOURS
Please refer to colour swatch
current colours.
Lifting Bars
Pins
Almond
Paperbark
Tuscan
Specifications
Description
HxLxDmm
Wt kg
N°/m2
Standard Unit
200x455x305
42
11
Pyrmont™ Cap
100x455x275
20
2.2/lin mtr
Straight Sided Cap
100x455x275
21
2.2/lin mtr
Pins
Lifting Bars
(Pyrmont units should be lifted by
E6
Table E1 — Maximum Wall Height for Gravel-Fill Walls
Retained Soil Descriptions
Poor Soils
Average Soils
Good Soils
Include fine sands, gravelly
clays, sandy clays, silty sands.
Angle of internal friction ≥ 25°
Include well graded sands,
gravelly sands.
Include gravels, sandy gravels,
crushed sandstone
NOTES: Pyrmont walls can only be constructed in near vertical
format, and must be selected on the basis of data in the near
vertical column from Table E1.
Table E1: Refer to max. wall heights disclaimer on page A3
of this guide. The gravity wall heights are maximum heights
calculated in accordance with CMAA MA-53 Appendix D
guidelines and a qualified engineer should confirm the
suitability of the product for each intended application.
Surcharge Loading
SETBACK
No Surcharge Loading
For low, non-critical walls, (i.e.. walls covered in the adjacent
table) the Keystone and Pyrmont Retaining Wall Systems are
effective as a gravity wall structure, utilising their weight and
interaction of the units to resist earth pressures.
15° Sloped Backfill
Gravel-Fill Wall Selection
Driveway/Carpark Loading (5kPa)
4
PAGE
BOOK
Backfill
Type
Wall Height H(mm)
Near
1 in 8
Vertical
Setback
Poor
800
900
Average
900
1000
Good
1000
1200
Poor
600
900
Average
700
900
Good
800
1100
Poor
400
500
Average
500
600
Good
600
800
Gravel-Fill Wall Construction Guidelines
IMPORTANT: Please consult with the regulating council for
local design requirements prior to the design and construction of
a retaining wall. Councils in general require that retaining walls be
designed and certified by a suitably qualified engineer where the
wall is over 0.5m in height and/or where there is surcharge loading
such as a roadway, house, or other structure near the wall.
• Near vertical installation must be used when designing
walls with curves or corners.
Refer to Keystone and Pyrmont ‘No-Fines Concrete’ Guidelines
for engineered retaining walls to AS4678.
• Two sets of pin holes are provided in Keystone units.
• For near vertical construction, install pins in the front holes.
• For 1 in 8 setback construction, install pins in the back holes.
Fig E1 — Installation of Pins
• For curved installations, leave a small gap between units
for convex curves. Concave curves will require a small
overlap of adjacent units. Refer to curve installation
details on Page E9 of this guide.
• If backfill is required behind the drainage zone, place
and compact existing site soils in 200mm maximum lifts.
Heavy clays and organic soils are not recommended due
to water holding problems.
4
PAGE
BOOK
E7
backfill if the type of backfill is likely to wash into the
drainage layer and clog it.
• Use only walk-behind compaction equipment within
1000mm of the wall face to prevent movement of the
Keystone units.
• In areas of possible vandalism, it is recommended that
capping units be secured using a masonry adhesive.
• Provide a filter fabric between the drainage layer and the
Compacted backfill
soil (if required)
Drainage pipe
Free draining
granular material
Compacted footing
Native soil
Fig E2 — Typical Installation Detail — Keystone Gravity Wall
Granular material
for drainage
300mm
Cap Unit
Keystone or Pyrmont
units
Optional 1:8 wall setback
with Keystone units
Backfill
12-20mm free draining
granular material, fill all
voids in and around units
from clogging drainage material
Drainage pipe (if required)
First course to be buried below
final ground level (to engineer's
specification - 100mm min.)
150mm min
600mm min.
Compacted roadbase,
crushed stone or gravel
levelling pad
Fig E3 — Typical Construction Detail — Keystone Gravity Wall
H
4
PAGE
BOOK
E8
Typical Installation Details
FIRST COURSE
SECOND COURSE
Align centre of unit
with face of
adjoining wall
No pin in
overlapping
unit
No pin in
overlapping
unit
Fig E4 — 90° Internal Corner — Standard Keystone Units
FIRST COURSE
SECOND COURSE
Align face of unit with the
centre line of adjacent unit
Cut to suit on site
Cut to suit on site
Omit one
pin only
Omit one
pin only
Align face of unit with the
centre line of adjacent unit
Fig E5 — 90° Internal Corner — Pyrmont Units
Adhesive fix
corner units.
Liquid Nails or
similar
Full mitre-cut
Pyrmont unit
4
PAGE
BOOK
E9
Half mitre-cut
Pyrmont unit
Half mitre-cut
Pyrmont unit
Full mitre-cut
Pyrmont unit
FIRST COURSE
SECOND COURSE
Fig E6 — 270° External Corner Detail
— Pyrmont Units
Use front pin holes for curves.
Maintain a small overlap
between units.
Fig E7 — Concave Curve
Use front pin holes for curves. Maintain a
small gap between units.
3 unit 90 corner : r = 900mm
Bolster
backs as
required
Radius ‘r’
Fig E8 — Convex Curve
4
PAGE
BOOK
E10
Drill and
install fixing
pin
Keystone cap unit
225˚ corner unit – to be cut
and bolstered on site from
Keystone/Pyrmont Unit
Next course is a mirror image.
Keystone unit
Fig E9 — 225° External Corner
Flushface Keystone/Pyrmont Units
Fig E10 — Stepped Capping Units
Bolster backs as
required
290mm Treads
Fig E11 — Plan view of step through Keystone
Tread approx. 290mm
for 40mm pavers (30˚)
Compacted bedding sand
40mm Boral Pavers
160mm riser
40mm
10mm mortar joint
Keystone Flushface Caps
10mm
100mm
10mm
Sand : cement = 6 : 1
Bedding sand –
compact before laying treads
Fig E12 — Keystone section through steps
4
PAGE
BOOK
E11
‘No-Fines Concrete’ Wall Construction Guidelines
The ‘No-Fines Concrete’ backfill system increases the mass of
Keystone/Pyrmont allowing the maximum heights in Table E1
to be exceeded without using geogrids.
The particle size distribution of the aggregate shall comply with
the limitations for the nominal single sized 20mm aggregate
specified in AS2758.1.
This is ideal for boundary walls where the geogrids would
otherwise cross the boundary line.
NOTES:
No-Fines Concrete shall consist of cement, water and coarse
aggregate. Cement will comply with the definitions for cement
per AS3972 : 1991 — ‘Portland and Blended Cements’. The
quantity of cement is specified as 210kg/m3 with a total
water/cement ratio of between 0.45 and 0.55.
• The density of this product will vary with the density
of the aggregate used. The density range may be from
1650kg/m3 to 2100kg/m3. Table based on density of
2100kg/m3.
• 15MPa No-Fines concrete with a 6:1 ratio (Gravel : Cement).
• The void ratio of the mix is expected to be between 20%
and 30% and should be free draining.
T
Cap unit
Filter Fabric to stop
clogging ‘No Fines’ material
15MPa ‘No-Fines’ concrete.
All voids within and around
units to be completely filled.
Retained soil
Keystone or Pyrmont unit
Sub-soil drain
connected to
stormwater system
or flood pit
H
Pour no-fines concrete
directly onto prepared
foundation material
Blocks embedded to
engineer's detail
(10 0mm min)
25MPa concrete
footing on 150kPa
allowable bearing
capacity material
(see note below
Table E2)
150mm min
60 0mm min.
Fig E13 — Typical Construction Detail — Keystone No-Fines Concrete Mass Gravity Wall
Table E2 — Maximum Wall Heights for No-Fines Concrete Wall Construction
Wall Height
‘H’ (mm)
Retained Soil
CLAY φ = 26° (POOR)
‘T’ (mm)
1000
550
500
450
1400
750
700
650
1800
NA
1000
850
2200
NA
1250
1000
2600
NA
1350
1200
SAND
Retained Soil
φ = 30° (AVERAGE)
‘T’ (mm)
Retained Soil
GRAVEL φ = 34° (GOOD)
‘T’ (mm)
φ Denotes the internal angle of friction of the retained material
Non-shaded Area = Compacted Roadbase Footing Shaded Area = Concrete Footing as per Fig E12
If material below no fines concrete is of poor quality, then the material must be replaced with a 150mm thick layer of crushed sandstone.
4
PAGE
BOOK
E12
• The compressive strength should generally exceed
15MPa for design purposes.
• This product has no slump and exerts similar pressures
on the soil and formwork, as does loosely poured
aggregate.
Table E2 is prepared as per AS4678 : 2002, and is based
on a 5kPa surcharge loading at the top of the wall. This
table is supplied as a guide, and does not form any part
of any contract with the user.
• The maximum slope of the backfill behind the wall is to
be 5% (1 vertical to 20 horizontal).
• The vertical height of any pour of ‘No Fines’ concrete is
limited to 600mm. Each pour must be allowed to harden
prior to pouring the next lift. Alternatively the wall may
be propped to support the lateral load from the wet
concrete.
• For higher walls or walls with a greater surcharge loading,
Geogrid soil reinforced construction is required.
• For walls founded on clay with a height greater than
2.0m, Geogrid reinforcement is required.
• Global stability considerations should be checked by an
engineer in poor clay conditions.
• Design assumes a dry excavation (i.e. water table is below
bottom of footing level). If ground water appears in the
excavation, the wall is to be re-designed by a suitably
qualified engineer.
Construction Steps
Special purpose construction such as waterside walls, post
fixing, earthquake zones, and terraces will require additional
engineer’s design.
STEP 1:
Excavation/Preparation of Levelling Pad
For walls less than 900mm high, excavate a trench 600mm
wide and sufficiently deep to allow a levelling base of 150mm
+25mm height for each course. Spread coarse sand or 12-20mm
gravel for the levelling base and compact.
For higher walls or in poor foundation material, a footing as
shown in Fig E12 may be necessary. Refer to Table E2.
STEP 2:
Installing the First Course
Lay the first course of units side to side over the prepared
base, with the 12mm pinholes on top and kidney holes on the
underside. Maintain the required distance between pinhole
centres of adjacent units. In straight walls, units will touch.
In concave or convex curves, the units will overlap or require
spacing respectively. Refer to Figs E7 and E8 for curve
installation details.
STEP 3:
Installing the Pins
Place the high strength fibreglass connecting pins into each
unit. Use the front holes for a near vertical setback (corners
and curved walls). Use the rear holes for a 1 in 8 setback
(i.e. for every course the wall will set back 25mm for straight
walls only).
STEP 4:
Additional Courses
Sweep the top of the previous course of units clean of any loose
gravel. Place the next course of units so that the kidney holes
fit over the pins of the two units below. Pull the unit towards
the face of the wall until it locks with the pins on both sides.
Repeat steps 3 and 4.
STEP 5:
No-Fines Concrete Backfill
Backfill the wall with ‘No Fines’ concrete. All voids inside
and between the units must also be filled. The vertical height
of any pour of ‘No Fines’ concrete is limited to 600mm. Each
pour must be allowed to harden prior to pouring the next lift.
Alternatively the wall may be propped.
STEP 6:
Installing Capping Units
Lay capping units, backfill and compact to required grade. In
areas accessible to public vandalism, it is recommended that
the capping units be secured using masonry construction
adhesive or epoxy cement.
4
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BOOK
E13
Geogrid Soil-Reinforced Wall Construction Guidelines
to a qualified professional engineer. These tables are
supplied as a guide, and do not form any part of any
contract with the user.
For taller, more critical walls, the combination of Keystone units
with geogrid soil reinforcement allows walls to be built to heights
of 12m and greater, without costly structural footings. When placed
between layers of compacted soil, geogrids create a reinforced soil
mass, which essentially acts as a larger gravity wall structure.
• Table E3 is based on foundation material with minimum
200kPa bearing capacity.
Geogrids can be used with most existing site-soils and are not
affected by water, micro organisms, alkali or acidic soils. Consult
your engineer for design requirements of Keystone walls using
geogrid soil reinforcement.
• Where site conditions and loadings vary from those in the
table, professional engineering advice should be obtained.
• The minimum embedment of wall below ground level is
assumed to be H/20, or 100mm, whichever is greater.
NOTES:
• The length of the 15° backfill slope is assumed to be equal
to the height of wall, H.
• Table E3 is prepared as per AS4678 : 2002. Suitability of
the information contained in the table must be referred
Table E3 — Maximum Wall Heights for Geogrid Soil-Reinforced Walls
Surcharge
Wall
Geogrid
Geogrid Height Above
Geogrid Length
Height
Layers
Levelling Pad
L (m)
Layers
Soil Type (phi)
H (m)
1
2
3
4
5
6
7
25
30
35
15 Degree
1.1
2
0.2
0.8
—
—
—
—
—
2.2
2.0
2.0
Backfill Slope
1.5
3
0.2
0.6
1.2
—
—
—
—
2.5
2.0
2.0
1.9
4
0.2
0.6
1.0
1.6
—
—
—
2.4
2.0
2.0
2.3
5
0.2
0.6
1.0
1.4
2.0
—
—
2.8
2.4
2.0
2.7
6
0.2
0.6
1.0
1.4
1.8
2.4
—
3.6
2.7
2.4
3.1
7
0.2
0.6
1.0
1.4
1.8
2.2
2.8
4.3
3.0
2.7
5kPa
1.1
2
0.2
0.8
—
—
—
—
—
2.4
2.0
2.0
Driveway
1.5
3
0.2
0.6
1.2
—
—
—
—
2.7
2.1
2.0
1.9
4
0.2
0.6
1.0
1.6
—
—
—
3.0
2.4
2.0
2.3
4
0.2
0.8
1.4
2.0
—
—
—
3.3
2.7
2.3
2.7
5
0.2
0.6
1.2
1.8
2.4
—
—
3.6
3.0
2.5
3.1
6
0.2
0.6
1.0
1.6
2.2
2.6
—
4.0
3.3
2.8
*Geogrid with Tul=55kN/m2
4
PAGE
BOOK
E14
Native soil
Geogrid sections are
located over pins at the
front, pulled taught and
staked at the back
Compacted
backfill soil
Drainage pipe
Free draining
granular material
Native soil
Compacted
roadbase footing
Fig E14 — Typical Installation Detail — Keystone/Pyrmont Geogrid Reinforced-Soil Wall
L
Granular
material
30 0mm
Cap Unit
Keystone or Pyrmont unit
12-20mm free draining
granular material, fill all
voids in and around units
Compacted backfill material
Reinforced Soil Zone
Geogrid soil reinforcement
to engineer's specification
Drainage pipe (as required)
First course to be embedded
below final ground level to
engineer's detail (10 0mm min.)
Compacted roadbase or
concrete footing
150mm min.
60 0mm min.
Fig E15 — Typical Construction Detail — Keystone/Pyrmont Geogrid Reinforced-Soil Wall
H
Typical Specification for
Keystone or Pyrmont
Retaining Walls
1. Scope of Work
1.1 Extent
This specification covers the works for construction of segmental,
reinforced-soil retaining structures. The works include footing
excavation, foundation preparation, drainage, backfill and
compaction and related items necessary to complete the work
indicated on drawings and as further specified.
All retaining wall construction is to be carried out in accordance
with the levels, distances and details as shown on the drawings
and in accordance with this specification.
The Keystone reinforced retaining wall system shall also
be constructed in accordance with the manufacturers
installation guidelines by a suitably qualified and experienced
contractor.
1.2 Responsibilities
The Contractor shall be responsible for carrying out the
installation of all retaining walls in accordance with this
specification and the associated contract documents.
2. Standard Specification
Wherever reference is made to Standards Association
of Australia (SAA) the requirements of the editions and
amendments, shall apply to the relevant materials or operations
and be deemed to be incorporated in this specification.
In the case of a conflict between the referenced standard
specification and code and this specification, the more stringent
provisions shall apply.
The following is a summary of standard specifications applicable
to this subsection of the work:
AS1012
AS4456
AS3600
AS4456.4
AS4678
AS1289
Methods of Testing Concrete
Concrete Masonry Units
Concrete Structures
Masonry Units — Compressive Strength
Earth Retaining Structures
Methods of Testing Soils
Materials or operations not covered by the above standard
codes shall conform to the appropriate Australian Standard.
4
PAGE
BOOK
E15
3. General Requirements
3.1 General
Terms used in this specification shall have the meanings
assigned to them as follows:
‘Approved’ shall mean approved in writing by the Engineer.
‘Or equal approved’ shall mean equivalent in performance,
quality and price to that specified and approved by the
Engineer.
Where limits to the properties of soils are defined elsewhere
herein these properties shall be determined by the methods
laid down in AS1289.
The term ‘construction area’ in this Part shall be defined as an
area to be excavated or an area to be cleared and filled.
3.2 Regulations
The Contractor shall comply with all relevant Acts, Regulations
and By-Laws in respect of all work specified herein, including
temporary timbering, strutting, guard rails and all safety
measures to be adopted.
3.3 Certification
The Contractor’s Geotechnical Engineer shall certify that the
bearing capacity of the foundation is as per the foundation
requirements specified on the drawings. The Geotechnical
Engineer shall also inspect and certify that the Reinforced
Soil Block material is as specified on drawings with regard to
friction angle, and bulk density.
4. Materials
4.1 Masonry Units
The retaining wall units shall be manufactured in accordance
with AS4456 Concrete Masonry Units. Block types and sizes
for Keystone retaining walls shall be as shown on the drawings
or specified herein.
4.1.1 Tolerance
Permissible tolerance in the manufacture of retaining wall units
shall comply with AS4456.3 - 1997. In the case of Keystone
units, the tolerance of ± 2mm shall not apply to profiled or
textured faces. Non conforming concave distortions shall be
rejected.
4
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E16
4.1.2 Strength
Retaining wall units shall be manufactured with a minimum
compressive strength of 10MPa. A minimum of ten (10) samples
must be tested to obtain a mean compressive strength, tested
to failure as per AS4456.4 — 1997 under normal compressive
and laboratory conditions.
4.1.3 Colour
The colour and texture of masonry units shall be as specified
and shall remain consistent with the ‘sample range’ approved
by the project Superintendent.
4.1.4 Handling/Storage/Delivery
Keystone units shall be delivered on pallets to minimise
damage during transportation. The Contractor shall store
and handle units so as to prevent units from damage, which
may affect the aesthetic quality or structural integrity of the
finished wall.
4.2 Connecting Pins
High strength pultruded fibreglass pins shall be used to
interlock and align all Keystone units in a running bond pattern.
Pins shall also provide an integral connection between the
Keystone units and the geogrid.
4.3 Geogrids
The reinforcing elements for the reinforced soil structure shall
be as shown on the drawings.
If required, each consignment of geogrids delivered to site shall
be accompanied by a Quality Control Tensile Test Certificate
from the manufacturer.
4.4 Approved Reinforced Soil Block Backfill
Material for backfilling between geogrids for the Keystone
retaining wall shall be ‘Approved Backfill’ defined as sand,
crushed sandstone or broken rock obtained from excavations
or approved borrow areas. Such material shall be
•
•
•
•
Free of rock fragments greater than 75mm in size.
Free of clay lumps retained on a 75mm sieve.
Free of organic matter.
Within the following grading requirements;
Sieve Size
% Passing by Weight
75mm
26.5mm
4.75mm
0.425mm
0.075mm
100
50 - 100
25 - 75
10 - 50
0 - 20
• Non-plastic in that the fraction passing 0.425mm has a
Plasticity Index of not greater than 15.
• Capable of being brought to a moisture content suitable
for compaction as specified elsewhere herein, under the
weather conditions prevailing on site.
The ‘Approved Backfill’ shall be stockpiled on site, and
inspected and approved by the Geotechnical Engineer that the
material satisfies the specification above the design friction
angle and dry density values as specified on drawings. Testing
for dry density and friction angle shall be in accordance with
section 6 herein.
4.5 Drainage
All retaining walls are to contain drainage systems that prevent
the build up of hydrostatic pressure behind walls. This is to
include a 12-20mm free draining clean hard aggregate, used
to fill all voids within the retaining wall units and to extend
300mm behind the units.
Drainage is to be installed as per the drawings and as per the
manufacturers recommendations.
4.6 Concrete Works
All concrete for use in footings for retaining walls shall have a
compressive strength after 28 days of 25MPa unless specified
otherwise.
The supply, placement, finishing and curing of reinforcement
and insitu concrete shall comply in every respect with
AS3600.
4.7 Hold and Witness Points
The following shall be deemed a Hold Point:
• Submission of test results and samples of all retaining
wall components.
The following shall be deemed a Witness Point:
• On-site slump and strength testing of concrete.
5. Construction of Keystone/Pyrmont
Retaining Walls
5.1 Foundations
Excavation is to be to the lines and grades shown on the
drawings. The reinforced soil block foundation size shall be
constructed as per drawings unless alterations are made by
the Geotechnical Engineer, who may require tests on the
sub-grade material, to be carried out by a registered N.A.T.A.
Testing Laboratory.
The reinforced soil block foundation subgrade shall be proof
rolled with a heavy steel drum roller (minimum applied
intensity of 4t/m width of drum with at least 8 passes)
without vibration. Any material which is soft, visibly deformed,
unstable or deemed unsuitable by the Contractor’s geotechnical
consultant shall be excavated and replaced with approved fill
and compacted to achieve dry densities of between 98% and
103% of Standard Maximum Dry Density at moisture content
of ±2% of Standard Optimum Moisture Content.
The foundation shall be inspected and approved by the
Geotechnical Engineer, who shall verify that the foundation
bearing capacity exceeds the required bearing capacity as
specified on drawings. The approval of the reinforced soil block
foundation shall be deemed a HOLD POINT.
Detailed excavation for the mass concrete footing shall proceed
following acceptance of the foundation. The footing subgrade
shall be inspected by the Contractor’s Geotechnical Engineer
and any areas deemed soft, unstable or unsuitable by the
Geotechnical Engineer shall be excavated and replaced as
described above.
The footing shall be constructed as shown on the drawings.
It could be shown as compacted roadbase or concrete. For
concrete, the footing shall be poured to the correct level
using formwork edge boards, or other methods which ensure
the correct level of the footing. The concrete footing shall
be screeded flat. The level of the footing or first course of
blocks shall be verified by survey methods, and approved by
the Contractors QA representative. This shall be deemed a
WITNESS POINT.
5.2 Unit Installation
Foundations and all courses are laid level. Batters are achieved
by inserting the fibreglass connecting pins into the appropriate
holes. The Keystone retaining walls shall be constructed with
batters as shown on the drawings.
First course of units shall be placed side by side on the base
levelling pad. Units shall be levelled side to side and front
to back and checked for alignment. The accurate placement
4
PAGE
BOOK
E17
of the first course is most important, to ensure acceptable
horizontal and vertical tolerances. Two fibreglass connecting
pins shall be inserted into the appropriate holes to interlock
and align units.
The front set of pin holes shall be used for near vertical
setback.
The rear pair of holes shall be used for 25mm (1:8) setback.
All voids in units and between units shall be filled with
drainage fill as specified in section 4.5. Drainage fill shall
extend to 300mm behind units.
Units shall be placed in a running bond pattern. Top of units
shall be swept clean of excess material. Kidney holes of units
above shall be positioned over pins in units below. Units shall
be pulled toward the face of the wall to interlock the pins
with units on either side. Levels and alignment of each course
shall be checked. Each course shall be filled, backfilled and
compacted prior to placement of the next course. The Keystone
wall shall be surveyed for vertical level tolerance every 3
courses. This shall be deemed a HOLD POINT.
5.3 Drainage Installation
The drainage measures shall be installed as shown on drawings.
100mm diameter agricultural pipe shall be used for subsoil
drainage behind the first course of Keystone units. The subsoil
drain shall be placed with a minimum 1% fall as shown on
drawings.
‘T’ piece connection fittings shall be used at all outflow points
to connect the subsoil drainage to a 100mm diameter pipe
stub which extends 300mm past the face of the Keystone wall.
The pipe stub material shall be UPVC or HDPE and shall be
approved by the project Superintendent.
The outflow points shall be at a maximum of 60m centres.
The locations of the outflow points shall be determined by the
Superintendent. The outflow pipe stub shall be supported on
the concrete footing, and shall pass between two Keystone
units with 60mm of the facing removed by sawcutting. The
gap above the pipe in the first course shall be neatly patched
with cement mortar.
The drainage measures shall be inspected by the QA
representative after the installation of the first and second
course is complete. Inspection and approval of the drainage
installation shall be deemed a HOLD POINT.
4
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BOOK
E18
5.4 Placement of Geogrid
The Geogrid shall be placed between Keystone units as
specified on the drawings. Geogrids shall be cut to the required
length. Geogrids may be longer than required, but shall not be
shorter than the specified length shown on the drawings.
The Geogrids shall be placed with the roll direction perpendicular
to the face of the Keystone wall. Correct orientation of the
geogrids shall be verified by the Contractor.
After compaction, the layer of select backfill below each
geogrid, shall be raked to a depth of 25mm to ensure good
interlock between the geogrid and the select backfill. The
Geogrid shall be laid horizontally on compacted backfill and
connected to the Keystone units by hooking geogrid over the
fibreglass pins. The geogrid shall be pulled taut against pins
to eliminate slack from connections and loose folds. The back
edge shall be staked or secured prior to backfilling to maintain
tension in the geogrid. Each block shall be checked for level
accuracy, as out of position transverse bars will lead to sloping
blocks. If the course above a layer of geogrid is found to be
not level, then the blocks shall be removed, and the geogrid
repositioned to ensure levelness.
For a straight length of wall, the geogrids shall be laid side
by side without joints or overlaps. Where the wall is convex,
the geogrids shall not be cut, but shall be overlapped with
a minimum of 75mm of compacted fill between them. For a
concave wall the position of the layers of grid shall be alternated
between consecutive geogrid layers to cover the triangular gaps
between strips of geogrid. Refer to Fig 5.4.
The QA Representative shall inspect and keep records of the
position of grid and the type of grid placed for each layer of
geogrid. The number of courses between each successive layer
of geogrid shall be noted. The QA Representative shall also
check this. This shall be deemed a WITNESS POINT.
5.5 Placement of Reinforced Soil Backfill
Prior to placement of ‘Approved Backfill’ in the reinforced soil
block, the Geotechnical Engineer shall approve the material and
confirm that the friction angle and dry density of the material
is in accordance with the drawings for that particular section
of the project. This shall be deemed a HOLD POINT.
All backfill imported or otherwise shall be as specified on the
drawings. Backfill shall be spread in a maximum of 200mm
layers, in such a manner that minimises the voids directly
underneath the geogrid. Fill should be deposited using suitable
plant which causes fill to cascade onto geogrids. Placement of
fill on top of the geogrids shall start from the wall face and
work back from the wall face in order to minimise slack or loss
of pretension from the grid. Care should be taken to not mix
the reinforced soil block backfill material with the drainage
material. If backfill material mixes with the drainage material,
then the drainage material is to be removed and replaced with
clean material.
Compaction shall be to 98% of Standard Maximum Dry Density.
Compaction shall start at the wall face and work back from
the wall face. Compaction testing shall be in accordance with
section 6 specified herein. Compaction testing shall be deemed
a WITNESS POINT.
Tracked construction equipment shall not be operated directly
on the geogrid. A minimum thickness of 150mm of backfill
material shall be placed prior to the operation of tracked
construction equipment. Rubber tyred equipment may pass
over the geogrids at very slow speeds. Sudden braking or
sharp turning shall be avoided to prevent displacement of
geogrids.
Geogrid
Construction plant and all other vehicles having a mass
exceeding 1000kg shall be kept at least 1m from the back of
the Keystone units. Compaction of the 1m zone behind the
Keystone units shall be restricted to:
• Vibrating rollers with a mass < 1000kg
• Vibrating plate compacters with a mass < 1000kg
Wall Face
Fig 5.4 — Typical Geogrid Layout
• Vibro tampers having a mass < 75kg
Surface drainage during and after construction of the wall shall
be provided to minimise water infiltration in the reinforced
soil zone.
5.6 Hold and Witness Points
The following shall be deemed a HOLD POINT:
• Approval of foundation material by the Geotechnical
Engineer.
• Inspection and approval of ‘Approved Backfill’ for use in
reinforced soil block by the Geotechnical Engineer.
• Survey of the Keystone Wall every 3 courses.
• Inspection and approval of the drainage installation by
the QA Representative.
The following shall be deemed a WITNESS POINT:
• Survey verification that the first course is installed at the
correct level, and inspection and approval of footing by
• Inspection of level and type of geogrid at each layer by
• Compaction Testing by the Geotechnical Engineer.
6. Material Testing
6.1 Testing of ‘Approved Backfill’
Each source of ‘Approved Backfill’ shall be pretreated by 5
cycles of repeated compaction, and then tested for dry density
and friction angle. Material for use as ‘approved backfill’
shall be inspected and approved for use by the Geotechnical
Engineer. A stockpile at least equivalent to 5 days reinforced
soil wall construction shall be maintained on site at all times.
This will allow time for friction angle testing of the approved
backfill should visual inspection of the material when it is
received on site indicate that testing is required.
Notwithstanding the above the following minimum testing
shall be carried out:
• Dry Density shall be tested at a frequency of 1 test per
400m3 of approved backfill.
• Friction angle shall be tested at a frequency of 1 test per
2000m3 of approved backfill.
If the dry density results are not within ±5% of the specified
design value, then the Engineer shall be notified, and the
material not approved for use until the design has been
verified.
4
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E19
6.2 Testing for Compaction
Compaction will be checked by standard maximum dry density
test and field density test for materials other than sand or by
the density index and field density tests for sands as specified
on drawings and herein.
Tests will be carried out in groups of at least three, and
compaction of the layer concerned will be considered to be
satisfactory if no single result falls outside the specified
density range. Should the results not reach this standard the
Sub-Contractor shall again roll the area, if necessary after
scarifying, adding water, blading to reduce the moisture content
and/or removing and replacing excessively moist fill as may
be required.
Should the Geotechnical Engineer consider that the depth
of insufficiently compacted material is greater than can be
effectively compacted from the surface, material shall be
removed to a depth at which compaction is satisfactory and
replaced and compacted in 200mm maximum layers.
The standard maximum dry density referred to herein for
materials other than sand shall be maximum standard dry
density as determined in accordance with AS1289 - Test
numbers 5.1.1.
The modified maximum dry density referred to herein for
materials other than sand shall be the maximum modified dry
density as determined in accordance with AS1289 - Test 5.2.1.
The field density referred to herein for all materials shall be the
dry density of the material in place as determined in accordance
with AS1289 - Test 5.3.1.
The percentage of the standard maximum dry density (Dry
Density Ratio) elsewhere herein for materials other than sand
shall be calculated from the formula given in AS1289.5.4.1.
The maximum and minimum densities of cohesionless materials
shall be determined in accordance with AS1289 - Test E5.1.
The Density Index specified elsewhere herein for sands shall
be calculated from the formula given in AS1289.E6.1.
6.3 Frequency of Testing
The following testing frequencies relate to acceptance on a
‘not-one-to-fail’ basis. The testing should be carried out in
essentially randomly chosen locations and at the frequencies
as given below. However, it may be appropriate to undertake
testing in specific locations, based on visual appearance or
past experience.
4
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BOOK
E20
Where a test or group of tests is carried out on an area which
has been subjected to essentially the same preparation and
compaction procedures, the whole of this area is considered
to be represented by this test or group of tests. The uniform
area is generally known as a work lot. On this basis, if one
or more tests indicate compliance with the specification has
not been achieved, the whole of the area which has been
submitted for testing is deemed not to comply, unless it can
be demonstrated that the area in which the non-complying
test result(s) can reasonably be separated from the whole. It
should not be assumed a test result applies only to the area
immediately surrounding it.
Required frequency of testing, is not less than 1 test per layer of
200 mm thickness per material type per 400m3 which is 1 test
per layer per 100 linear metres of wall construction. If different
sources of ‘approved backfill’ are used within the 100 linear
metre work lot, then 1 test per type of material is required. If
the work is staged in sections of less than 100 linear metres,
then 1 test per section is required.
The testing frequency may be re-assessed to the approval of
the Engineer, if a high degree of uniformity becomes evident
during construction.
BOOK
South Australia
4
4F
SECTION
Custom Engineered Walls
4
PAGE
BOOK
F2
Engineered
for domestic and commercial landscaping, roadside
and custom engineered retaining wall applications
Boral Keystone, Pyrmont and Keysteel Retaining Wall
Systems provide a proven and versatile platform for the
development of custom engineered high performance
retained earth structures.
Boral has developed alliances with a number of suitably
experienced engineering companies that can provide
professional assistance with the custom design and
installation of Keystone, Pyrmont and Keysteel retaining
structures.
Please contact Boral Masonry in your region for assistance
with your high performance, engineered retaining wall
projects.
Keysteel Custom Engineered
• Gravity Retaining Walls
• Mass Gravity Retaining Walls
• Geogrid Reinforced-Soil Retaining Walls
• Steel-Ladder Reinforced-Soil Retaining Structures
• Bridge Abutments
• Stream or Drainage Channels
• Erosion Prevention
• Tunnel Access Walls
• Wing Walls
• Embankment Stabilisation
• Terraced Walls
• Seawall Applications
• Soil-Anchor and Rock-Anchor Walls
• Fencing, Railings and Barriers
4
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BOOK
F3
• Keysteel™ Custom Engineered Retaining
Wall Systems
Boral Keysteel is a high performance engineered
retaining wall system for applications requiring wall
heights in excess of 6m and/or where critical surcharge
loadings are present. Boral Keysteel is an internationally
proven system that integrates the superior strength
and durability of Keysteel blocks with steel-ladder soilreinforcement to provide engineered solutions for the
most demanding retaining structures.
PAGE
BOOK
4
F4
305
305
200
200
455
455
Standard Unit
275
100
100
455
455
Standard
Straight Sided Cap
(made to order)
Steel Pins
(hot-dip galvanised)
Keysteel retaining structures.
INTRODUCTION
Flushface Unit
275
Keysteel®
High Performance Engineered
Flushface
Straight Sided Cap
(made to order)
Lifting Bars
Boral Keysteel is an internationally
proven, high performance retaining
wall system that integrates the
superior strength of Keysteel blocks
with steel-ladder soil-reinforcement,
and is ideally suited to retaining
structures in excess of 6m high and
for critical surcharge loadings.
Boral Keysteel installations are
individually engineered to match
the application criteria.
Please contact Boral Masonry
Technical Services in your region for
assistance with Keysteel projects.
COLOURS
Boral Keysteel is made-to-order
in the same range of colours as
Keystone, allowing integration of
the two products within the one
project. Please refer to colour swatch
current colours.
Boral has developed alliances with
a number of suitably experienced
engineering companies which can
provide professional assistance
with the design and installation of
• All Keysteel products are made-to-order.
• Lead times apply Please consult with the Boral Masonry
sales office in your region.
Specifications
Tuscan
Antique Copper
Desert Sand
Description
HxLxDmm
Wt kg
N°/m2
Standard Unit
200x455x305
36
11
Standard Straight Sided Cap
100x455x275
25
2.2/lin mtr
Flushface Unit
200x455x305
39
11
100x455x275
26.3
2.2/lin mtr
Pins (steel)
hot-dip galvanised steel
Lifting Bars
(Keysteel units should be lifted by
two people using the Keysteel lifting bars)
4
PAGE
BOOK
F5
Typical Keysteel® Application Layout
Keystone unit
Cut ladder around pylon
Where piles prevent installation of
ladders refer to engineers detail.
Pylon
Fig F1 — Typical Construction Detail — Keysteel wall
Wall face
Keysteel unit
Keysteel unit
Soil reinforcing
ladder
Soil
reinforcement
ladder
Keysteel unit
Fig F2 — Typical Curved Wall Detail — Keysteel
Fig F3 — Typical Straight Wall Detail — Keysteel
PAGE
BOOK
4
F6
Typical Soil-Anchor Application
Soil anchors
Granular backfill
Geogrid (if
required)
Stiff firm soil
Galvanised
steel pipe
1200mm cts nominal
Galvanised pipe
loop connector
Keystone unit
TYPICAL PLAN VIEW
Top of wall stepped (optional)
Galvanised pipe
Galvanised pipe,
loop connector and
soil anchors
(staggered installation)
Footing step
(optional)
Finished grade
TYPICAL WALL ELEVATION
Threaded pipe
coupling
300mm
nominal
Stiff firm soil
Cap unit
See connection detail
5˚
Keystone units
Soil failure plane
Keystone unit
Geogrid
1
Galvanised steel pipe
8
Loop connector
Soil anchors to site
specific design
Granular fill
Drainage pipe
Leveling pad to
engineer's detail
Finished grade
Soil anchor to
design details
TYPICAL CONNECTION DETAIL
TYPICAL SIDE ELEVATION
Fig F4 — Typical Soil-Anchor Detail
4
PAGE
BOOK
F7
Typical Rock-Anchor Application Layout
Rock anchors
Reinforcing bar to
project specifications
Drainage net
Geogrid to project
specifications
Expansion joint material
to design details
Temporary face
support and drainage
system
Concrete backfill
Keystone unit
TYPICAL PLAN VIEW
Top of wall stepped (optional)
Reinforcing bar
to design details
Geogrid
Finished grade
Soil Anchor to
design details
TYPICAL WALL ELEVATION
Footing step
300mm
nominal
Drainage net
to design details
Keystone cap
See anchorage detail
Keystone unit
Horizontal reinforcing
bar to design details
Temporary concrete and
mesh facing support
system with drainage to
design details
Vertical reinforcing bar
to design details
1
8
Rock anchor
system
to design
details
Rock anchor
to design detail
1500mm
typical
Keystone unit
Concrete backfill to
design detail
Geogrid
Geogrid at 600mm
vertical centres extended
to wall face between
reinforcing bar
Thread bar to
design details
Reinforcing bar
to design detail
Drainage pipe
Concrete
backfill
Levelling pad
Finished grade
Steel plate and securing
nuts to design detail
Granular material
wrapped in geotextile
TYPICAL SIDE ELEVATION
Fig F5 — Typical Rock-Anchor Detail
TYPICAL ANCHORAGE DETAIL
4
PAGE
BOOK
F8
Typical Seawall Application Layout
Engineering
Undermining of Foundation Wall
All water application projects should be designed by a suitably
qualified engineer. The Keystone Retaining Wall System has
been used in numerous international projects where the blocks
are subjected to high velocity flood water, wave action and
tidal action.
Greater embedment of units, concrete footings (piered or
otherwise), Keystone units keyed to a concrete foundation are
all means of preventing undermining of the wall foundation.
Rip-Rap in front of the wall will also help to prevent erosion.
Spacing of Geogrid
Filter fabric used behind the 300mm drainage layer will prevent
loss of retained soils during fluctuation in water level.
As with all geogrid soil reinforced Keystone walls, the spacing
of the geogrid should not exceed 600mm, to prevent bulging
between the grid layers.
Suitability of Keystone Blocks in a Seawall
Application
It is recommended that if the Keystone units are submerged
in salt water, then marine grade Keystone units should be
used. Minimum order quantities apply to these units.
NOTE: Product colours will be different due to the use of
marine grade cement.
Loss of Material through Wall Face
Differential Water Pressures
Fluctuations in water levels and rapid draw down may induce
differential water pressures across the face of the wall and
need to be addressed.
Test Reports
Tests have been carried out on the high velocity flow effects,
wave action and sudden draw down and Manning’s ‘n’
determination. These test results are available on request.
300mm
Impermeable soil layer
Filter Fabric
Keystone
Cap Unit
10-20mm crushed rock,
fill cores and voids of
Keystone units
Free draining granular
material (less than 10%
passing the #200 sieve,
no organic material)
Keystone
block
Typical
1900mm
Geogrid as per
design
Nonwoven
filter fabric
Native soil
Water level
150 - 200mm
rip-rap
150mm min.
Compacted
aggregate or
crushed rock
600mm min.
Fig F6 — Typical Construction Detail — Keystone Seawall Application
PAGE
BOOK
4
F9
Typical Terraced Wall Application Layout
When terracing walls, they are effectively being split into
sections. This is done for a number of reasons. For example, to
level off a sloping front or backyard, to increase the aesthetic
appeal of the garden and in some instances to reduce the single
wall heights where by they still act as gravity walls and thus
minimise the need for geogrid. In such instances, however,
the upper terrace wall can put pressure on the lower terrace if
the walls are too close together. Multiple terrace walls in close
proximity to each other, can have structural stability issues
related to the lower walls not having the capacity to carry the
loads developed by the upper walls.
Question:
How far apart do the terrace walls have to be to perform as
individual gravity walls?
Answer:
As a rule of thumb, the minimum distance between the wall
terraces must be at least 1.5 times the height of the lower wall.
Example:
If the lower gravity wall is 1.2m tall, then the minimum
recommended spacing between terraces is 1.8m. This rule
also applies to walls with more than two terraces. The
distance between any two terraces must be at least twice
the height of the lower adjacent terrace wall for multiple
terraces.
NOTE: This simple rule of thumb does not address global
stability issues where walls are built on steep slopes or over
poor soils of low friction strength. If these conditions exist,
then contact your engineer.
Question:
What if there isn’t enough room to space the terraces
according to this rule (1.5 x H1 minimum)?
Answer:
The wall can still be built, but the effect of the upper terrace
on the lower terrace and overall stability must be taken into
account when designing the walls. When the terraces are
close together, the design analysis may model the structure
as a single taller wall to account for the added load from the
upper terrace wall on the lower walls.
Keystone or Pyrmont wall
H2
Cap unit
Keystone or
Pyrmont wall
L = 1.5 x (H1)
L = minimum distance between terraces
H1
Fig F7 — Typical Construction Detail — Terraced Wall Application
4
PAGE
BOOK
F10
Typical Fencing Application Layout
Fences can be incorporated into the Keystone Retaining Wall
System by placing fence posts into the Keystone cores or
behind the wall.
NOTE: The following recommendations are suitable for
fences with no wind loadings.
Fence posts should be embedded through a minimum of three
courses (600mm minimum) and then core filled with concrete.
Only those units with the fence posts need to be core filled with
concrete, the remaining filled with drainage material.
Fence posts positioned behind the wall should be embedded
700mm minimum and encased in concrete.
When constructing a soil reinforced wall, the Geogrid may be
cut to allow for placement of fence posts as per the Geogrid
manufacturer specifications.
It is important that these walls be designed to accommodate any
additional wind loads from fencing (eg. extra embedment).
1824mm max.
900mm
700mm
Fig F8 — Typical Fencing Detail
PAGE
BOOK
4
F11
Typical Railing and Barrier Application Layout
Railing, guard rail, and traffic barrier requirements for retaining
walls are not clearly defined in design codes nor are they
properly addressed in many site plans. Many times railings
and barriers are added as an afterthought which can become
a costly and logistical issue when no provisions are made
in the original retaining wall layout and site design. Guards
and barriers require a common sense approach by the site
designer considering the proximity of a wall structure to
people and traffic. Sufficient space must be reserved for such
installations.
It is important that these walls be designed to accomodate any
additional loading these guards and barriers may impose on
the Keystone wall.
Load
Load
Typical
900mm
Typical
900mm
900mm min.
150mm
Additional Geogrid
layer turned upwards
and wrapped around
void former at 400mm
below ground level
Railing – offset
Railing – offset
Load
Load
1000mm min.
Typical
800mm
Guardrail
Traffic Barrier
Fig F9 — Railing and Barrier Details
Customer support
South Australia
1. Stock colours Colours other than stock colours are made to
6. Important notice Please consult with your local council for
order. Not all colours displayed in this brochure are available in all
design regulations prior to the construction of your wall. Councils
states. (Contact your nearest Boral Masonry office for your area’s
in general require those walls over 1m in height and/or where
stock colours.) A surcharge applies to orders less than the set
there is loading such as a car or house near the wall be designed
minimum quantity.
and certified by a suitably qualified engineer.
2. Brochure colours The printed colours in this Masonry Design
® — Heathstone and Pyrmont are registered trademarks of Boral
Guide are only a guide. Please ask to see a sample of your
Masonry Limited.
colour/texture before specifying or ordering.
® — Keystone and Gardenwall are each registered trademarks
3. Colour and texture variation The supply of raw materials can
of Keystone Retaining Wall Systems, Inc. under licence by Boral
vary over time. In addition, variation can occur between product
Masonry Limited. ABN 13 000 223 718
types and production batches.
© Boral Masonry - all rights reserved 2007.
4. We reserve the right to change the details in this publication
without notice.
5. For a full set of Terms and Conditions of Sale please contact
your nearest Boral Masonry sales office.
Orders, product samples and sales enquiries
Other regional sales offices
SA
NSW
NQ
Main North Road,
Clunies Ross Street,
Cairns
Pooraka,
Prospect, NSW 2148
8 Palmer Street,
SA 5095
Tel (02) 9840 2333
Portsmith,
Tel (08) 8262 3529
Fax (02) 9840 2344
QLD 4870
Tel (07) 4035 1888
VIC
Fax (07) 4035 1208
Level 1
Townsville
17-47 Turner Street,
360 Bayswater Road,
Port Melbourne,
Garbutt,
VIC 3207
QLD 4814
Tel (03) 9681 9722
Tel (07) 4725 6285
Fax (03) 9681 9766
Fax (07) 4725 6043
QLD
Mackay
62 Industrial Ave,
Wacol,
QLD 4076
Tel (07) 3271 9292
Fax (07) 3271 1581
For technical assistance:
Call Specifier Line on 1300 360 255
Visit www.boral.com.au/masonry
David Muir Street,
Slade Point,
QLD 4740
Tel (07) 4955 1155
Fax (07) 4955 4130
V260907 eBC 03119 Sep 07
Fax (08) 8260 3011

Segmental Block Retaining Walls

Transcription

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