Basement Support Sydney

1. CASESTUDY
the project the problem the solution www.coateshire.com.au
Brace for the future

2. THEPROJECT To install an
internal bracing
system in the
basement
levels of a major
residential
development
in Homebush,
Sydney,
constructed by
Coates Hire
customer
Citybuilt Group.

3. When construction companies build multi-
level projects with basement levels, they
must support the walls of the basement
levels during construction to stop them
subsiding. The traditional method of
basement wall retention has been to
‘anchor’ the walls of the basement by
drilling through the retaining wall into the
soil on the other side, and ‘anchoring’ the
wall with injected grouting, usually at a 45
degree angle to the wall. The problem for
Citybuilt Group was that it faced a lengthy
compliance process with Roads and
Maritime Services (RMS) which owns the
M4 motorway on one wall of the project,
while on another wall, another developer
was beginning construction. The need for
certainty on a start-date for the project
meant Citybuilt Group wanted a method
of bracing the basement walls that did not
entail the potential delays of obtaining
permission from third parties.
THEPROBLEM

4. THESOLUTION
Citybuilt Group asked Coates Hire to tender for the contract to ‘internally brace’
the basement walls and the Coates Hire Engineering and Technical Services team
at Ingleburn delivered on a bracing design that allowed the builder certainty of
timelines on the project.
Internal bracing means the retaining walls of the basement are pushed back from
the middle, rather than ‘pulling’ from anchor points outside the basement area. To
achieve a safe working environment in the basement level, Coates Hire designed
a bracing system consisting of 200 metres of ‘Mega Brace’ (steel waler beams
laid against the inside of the retaining wall) and 11 hydraulic struts that push back
against the mega bracing, holding the walls in place. The struts were a mix of
150-tonne (MP150) and 250-tonne (MP250) capacity struts.
The Coates Hire internal bracing solution was designed and specified by engineers
at the Ingleburn office, installed by the Coates Hire installation team and certified
by Coates Hire engineers. It is unique hardware in the Australian market and is also
a unique turn-key product in which Coates Hire designs, installs and certifies the
system.
“The customers like the product because it has engineers designing, installing
and certifying it,” says Darren Browne, engineer at Coates Hire Engineering and
Technical Services. “It’s a turn-key product and one less thing to worry about for
the customer.”
Browne says the internal bracing system features significant time advantages for
the construction company.

5. “The Coates Hire engineers do the design and certify it. For us,
the Mega Brace solution was a chance to make sure of our start
dates and our schedule. If you can remove a layer of permits
and compliance, you can be more certain about your project.”
- Toriq Isaac, Director, Citybuilt Group
“We spend less time in the set-up of our system,” says Browne, “and we are also faster in the dismantling because the system is fully pre-
fabricated and modular, minimising the amount of work on-site.”
He says the major advantage of the Coates Hire internal bracing system is that the builder does not face delays and uncertainty around
permissions from neighbours to use an anchoring system in the basement levels.
Browne says the internal bracing system is re-useable which is proving an advantage in government projects, where environmental and
recycling initiatives are required in construction.
“This hydraulic system of bracing has been used in Europe for fifteen years,” says Browne. “We’re the first and only organisation to use it in
Australia.”
Citybuilt Group
Toriq Isaac, Director of Citybuilt Group, says his projects have to start on time to make them viable and the process of gaining permission to
anchor his basement walls under the M4, would have proved too long and uncertain.
“We needed a way to shore the basement walls, without spending time and money getting permissions for our anchors. It wasn’t clear that
the RMS would allow us to put anchors under the M4 – we couldn’t afford to enter into that process only to be told ‘no’.”
He says the system designed by Coates Hire’s engineers consist of 11 hydraulic struts which hold-up the seven metre basement walls of the
38-unit development.
“The Coates Hire engineers do the design and certify it,” says Isaac. “For us, the Mega Brace solution was a chance to make sure of our start
dates and our schedule. If you can remove a layer of permits and compliance, you can be more certain about your project.”
THESOLUTION