2004 Case Earth
Awards - SA Winner - Category 2
2004 SA Case Earth Awards – Liberty Towers
Development
Construction Excellence: Category 2, $2 million
to $10 million
South Australian winner: Liberty Towers Development
Contractor: McMahon Services Australia Pty Ltd
Principal: Baulderstone Hornibrook and Urban Construct
The Case Earth Award for Construction Excellence
To reward companies performing at the highest standards of civil
construction, the Case Earth Awards recognise advancements in construction
practices as well as the impact on the environment.
The selection criteria are:
1. Innovative methods
2. Industry best practice and use of new technology
3. Overcoming construction constraints and client satisfaction
4. Quality, OH&S and environmental management
5. Interface with other project parties and/or components
6. Completion within timing deadlines and cost budgets
7. Technical complexity
8. Workplace training
Judges’ comments on the winning Liberty
Towers project
…a well-managed and coordinated project in very restricted
conditions, addressing difficult problems such as ventilation, space
limitations and a shallow groundwater table as well as delivering
a cost and time efficient result…
Overview
McMahon Services’ Case Earth Award-winning task was to complete
bulk earthworks for a four-level basement car park for almost 400
cars in the Liberty Towers Development in Glenelg. Liberty Towers
is a 12 level residential apartment building with a total floor
area of 43,500m2, making it the largest single building ever constructed
in Adelaide.
The job of excavating 26,000m3 of material presented
a major de-watering challenge, with the water table lying just two
metres below the surface. McMahon installed a series of 6m-deep
de-watering spears at the north and south elevations to lower the
water table within the construction area and several holes were
sunk at lift shaft locations to further lower the water table at
the centre of the building. Foot valve pumps were installed to extract
groundwater.
The contractors also needed to find a way to
safely remove excavated material. McMahon Services used purpose-built
conveyors to allow the safe transportation of materials through
areas occupied by other trades. They also worked on each basement
level in two halves, saving time by allowing one side to be concreted
while the other was still being excavated.
Low headroom – just 2.1m – meant
conventional plant and equipment could not be used, so purpose-built
or modified equipment was purchased.
McMahon Services also adopted a “top down”
construction method to reduce construction time. This meant installing
wall panels from the existing ground level and then casting-in columns
extending to the underside of the first above-ground structural
floor slab. The ramp to the next level was then excavated and poured
and the process repeated. The technique allowed excavation to take
place under the slab at the same time as construction above it commenced.
The project budget was $1.7 million and overall
completion is scheduled for September 2004.
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