110 / 140
110
|
design
mag
It’s said to be Sydney’s last CBD waterfront
development.A derelict 22 hectare site in
the former dockside suburb of Barangaroo
is being transformed into a $6 billion blend
of residential, commercial and recreational
precincts.
Barangaroo Headland Park, a six hectare
headland fronting Sydney Cove, will be open
for public and community use, with unique
tidal rock pools, lookouts, and walking and
cycling tracks.
Extensive retaining walls are being
constructed at Barangaroo using Austral
Masonry’s unique Magnumstone system, to
help bring form and order to the landscape
while maintaining an environment of 75,000
plants native to Sydney.
(Austral Masonry’s sister company Austral
Precast is also supplying product into the
Barangaroo project.Their precast panels are
being used in the construction of the first two
residential towers.)
The Magnumstone retaining wall system is
appropriately named, as the standard unit
weighs in at a mighty 621 kilograms! It’s the
basic component of what engineers call a
passive retaining wall.This means the wall is
engineered to use its mass to resist the lateral
forces of the soil it retains.
Sydney-based commercial landscaping
contractor, Regal Innovations, is carrying out
the installation of almost two kilometres of
Magnumstone retaining walls at Barangaroo
Headland Park.
The retaining walls curve gently across the
landscape, some carrying elevated walkways
and others providing a bed for the wide
range of flora being planted.
The process of constructing such a large
retaining wall is simple and surprisingly
speedy.The project has been broken down
into six runs of walling, each about 300
metres long.A blinding slab – a level pad of
unreinforced concrete – is formed to support
the retaining wall.
The base blocks are then lifted and lowered
into position using an excavator.The higher
courses require a slightly different block, one
with a double lug in its base that keys into the
unit below.Austral Masonry calls this the
SecureLug system which allow interlocking
between units without mortar.
Each level is tied back to the retained soil
using a geogrid soil-reinforcement material.
Drainage also needs to be installed at the
base of the wall.
At each stage the Magnumstone blocks,
which are hollow, can be filled with
aggregate to increase their weight and thus
their retaining capacity.When the wall
reaches its design height, it can be finished
with top units (full or half height) or step/cap
units.
The Barangaroo Magnumstone retaining
walls are two units high and comprise a base
unit and a standard-height top unit. Each
course is offset from the underlying course by
half, identical to a stretcher bond in brickwork.