Clients Special Requirements
Environmental considerations were of extreme importance. Piling had to be installed directly opposite and below the hospitals existing operating theatre and patient recovery rooms. Noise and vibration reduction factors were critical.

Site Logistical Problems
Access to the areas to be piled was limited to 2.4 metre headroom in a lower car park level and roof access to the upper level. The installing machine, a Hitachi EX220 excavator, was trafficked to the upper level and the roof was prop supported. The majority of installation had to be conducted through holes cut-out in both the suspended roof waffle pod slab and the lower level ground slab.

Other difficulties included; limited machine boom height access where piles were required next to and below the existing building overhangs, installation of piles at differing levels which included the machine operator to work blind as walls and level drops obstructed vision and access.

Piling and Installation
A total of 22 piles with a SWL capacity of up to 35 tonnes SWL were required.  Site soil conditions varied throughout the site therefore an allowance was made for pile extensions to cater for these variations.  Piling depths varied from 4 to 9 metres.  Installation was completed in 4 days which included pre-drilling at 7 locations due to concrete construction rubble encountered at a depth of 2.0m and large limestone rock floaters at footing bases in 2 other locations. 

Pile Testing
A test procedure was carried out to confirm the pile design criteria and the installing torque/pile capacity relationship in accordance with the design methodology. The results supported the projected design performance.

Summary
The project presented various challenges during construction.  Performance projections and associated projected costs were achieved demonstrating that the versatility and reliability of the Screwpile Australia's Screwpiling System can overcome difficult site conditions with relative ease.