Wodonga Rail Bypass

Wodonga Rail Bypass
JMJ V (joint venture John Holland & MVM Rail)
Techniques Used: 
Large diameter concrete injected CFA piles

Project Brief: The Wodonga Rail Bypass project involved the construction of a five kilometre dual track rail bypass, comprising some 12 bridges over the local waterway areas and a new passenger station.

The project was one of the first infrastructure projects in Victoria to adopt the CFA construction technique for the piled foundations of permanent structures. This provided a cost effective solution with regards to the speed of construction, environmental issues and material costs compared with the conforming foundation options.

Geological Conditions: The bridge locations were situated in the Murray River floodplain, with subsurface conditions comprising Quaternary Age fluvial deposits. Founding conditions typically comprised gravelly sands / sandy gravels, with varying degrees of silt content and occasional clay bands.

Scope of Work: The supply and construction of approximately 300 concrete injected Continuous Flight Auger (CFA) piles, 900mm and 1200mm diameters, to depths of up to 24m. All piles were installed with full computer instrumentation to ensure pile quality and integrity.

The use of Vibropile's Fundex F3500 rotary piling rig with 47Tm torque (the largest CFA piling rigs in the world), made the project possible providing the available torque and line pull to install large diameter piles in the given soils without the risk of loosening of the surrounding soils.

Due to the potential variability within the fluvial deposits, an Engineer was on site to access the drilling characteristics returned from the onboard piling computer and undertake visual assessment of the
auger cuttings returned for assessment of potential pile performance against the design intent. By installing column reinforcing steel directly into the piles, columns were constructed directly on top of the piles, thus eliminating pile caps and saving the client considerable time and money. A thorough testing program comprising 60 lateral load tests and 80 dynamic load tests ensured piles met specification requirements.
Conclusion: The adoption of concrete injected CFA piles enabled a cost effective solution with significant time and cost saving to the client through the speed of construction plus environmental benefits compared to the original piled solutions.