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The rear of the wall is drained by slotted pipe
in a layer of free-draining aggregate wrapped
in a geotextile material.All blocks are also
filled with aggregate.A layer of geogrid
material is inserted between courses. Finally,
the area behind the walling is back filled with
selected subsoil material and capped with
top soil.
Constructing a Magnumstone retaining wall
is a straightforward process, according to
Daniel De Chellis, Regal Innovations foreman
who led the onsite construction team.
Although the blocks are heavy, his team
members found them easy to lift and
manoeuvre using an excavator boom.Two
chains are attached to lifting points cast into
the units which are then elevated about half
a metre off the ground and transported into
position.
The Magnumstone system offers a range of
advantages over competitive methods. Each
unit is manufactured using nearly half the
amount of concrete required in a traditional
solid concrete retaining wall blocks.
Magnumstone blocks have low absorption
and excellent freeze/thaw characteristics,
ensuring enhanced durability in challenging
environments.
As shown in the Barangaroo project, standard
units can be laid in gentle curves. Special
units are available for tighter curves.
But the greatest advantages are on site.
Blocks can be unloaded two at a time.There
is no mortar to mix, no formwork, no stream of
concrete trucks coming onto the site.
And it’s quick. Daniel De Chellis reports they
are laying up to 130 blocks per day.That’s up
to 80 metres of 1.2 metre high walling per day.
Not bad for just two men and an excavator.
Barangaroo Headland Park is scheduled for
completion in 2015.While the flora settles into
the new landscape, the overall site will evolve
over the following decade into what promises
to be a dynamic and attractive harbourside
precinct.
previous opening.
The new
Magnumstone retaining walls
curve sinuously through
Barangaroo Headland Park, a
six-hectare site fronting Sydney
Harbour.The walls carry
elevated walkways and beds
that are being planted with a
wide range of local flora.
this opening.
The
Magnumstone blocks each
weigh 621 kilograms but are
quickly manoeuvred into
position using an excavator
boom. Lifting lugs are built into
each block.The Magnumstone
block keys into the unit below
and doesn’t require mortaring.