Specifications

STANDARD SPECIFICATION - BUILDINGS
DPI REFERENCE TEXT - APRIL 2009
PAGE 8
A.S. METRIC SIEVE PERCENTAGE
PASSING BY WEIGHT
75.0 mm 100
9.50 mm 30 - 100
2.36 mm 15 - 65
0.075 mm 5 - 25
Liquid Limit Maximum 35%
Plasticity Index Maximum 12%
Linear Shrinkage
(Passing 04.25 mm) 6% Maximum
C.B.R. - 4 day soaked Minimum 40
at 95% MMDD at
2.5 mm penetration
Locations
Use select ll under concrete building slabs and
paving and general ll in other areas.
Placing ll
Place ll in layers less than 200 mm and compact
each layer to achieve the required density.
Maximum depth of sand ll: 400 mm.
Moisture content
If necessary to achieve the required density or
moisture content, adjust the moisture content of the
ll before compaction.
Required Density
Minimum density table
SITE PREPARATION
Location Minimum
dry density
ratio (standard
compaction)
to AS 1289.5.1.1
Residential: Lot ll 90
Footings and non
spanning slabs on
ground areas of
buildings 98
Embankments and
paved areas: >0.15 m
below subgrade
surface <0.15 m below 90
subgrade surface 95
All other areas:
>0.3 m below nished 90
surface
<0.3 m below nished
surface 95
Tests - Witness Point
Witness Point: Provide proof that the required
compaction has been achieved.
2.8 SANDLAYER
Material
Clean sharp sand free from deleterious material,
well graded with at least 90% by weight passing the
4.75 mm sieve, and not more than 10% passing the
0.075 mm sieve.
Extent: Place a layer of sand to the area of the
building under concrete slabs.
Nominal thickness: 50 mm.
Wet down before laying vapour barrier.
2.9 PILING
Bored piers
After excavating bored piers, remove loose material
and water from the base and conrm the bearing
capacity. Do not allow loose material to fall down
the hole before or during concreting; provide a liner
if necessary.
Screw-in foundations
Provide a proprietary system designed to AS 2159.
2.10 SERVICE TRENCHES
Excavation
If practicable, make trenches straight between per-
sonnel access ways, inspection points and junc-
tions, with vertical sides and uniform grades.
Trench widths
Keep trench widths to the minimum consistent with
the laying and bedding of the relevant service and
construction of personnel access ways and pits.
Backlling
General: Backll service trenches as soon as
possible after laying the service. Place backll in
layers. Compact each layer to a density sufcient to
minimise settlement.
Backll material: Excavated spoil or well graded in-
organic material with maximum particle size of 75
mm.
• Next to services: Do not place any particles
greater in size than 25 mm within 150 mm of
services.
• Under paved areas: Coarse sand, controlled low
strength material or ne crushed rock.
• In reactive clay sites classied M, M-D, H, H-D or
E to AS 2870: Impervious material.
Specifications March 2009.indd 8 11/03/2009 11:47:09 AM