In order to service the new Perth Football Stadium, Belmont Park Station on the Perth to Armadale railway line is being expanded to provide dedicated platforms for event goers. This involves increasing the number of railway lines that pass through the station from two to six. In order to do this, the bridge that carries Victoria Park Drive above the station has to be expanded to accommodate the additional tracks. In addition, a pedestrian underpass is being constructed beneath Victoria Park Drive to provide access to the stadium from the station.
Scope of Works
Avopiling was required to install a total of 247 piles forming five contiguous pile retaining walls for the new bridge abutments. In addition a further 11 piles were installed beneath load bearing piers. Pile diameters varied from 600mm to 900mm and they were installed to various depths, some exceeding 35m.
Temporary casing was vibrated through the fill materials from which the existing bridge approach embankments had been constructed. Beneath the engineered fill forming the embankment lay uncontrolled fill comprising medium to high plasticity sandy clay interbedded with layers of sand. High plasticity clayey silt known as Swan River Alluvium lay beneath the fill materials, which in turn was underlain by medium dense silty sand. The deeper piles were founded in very dense Kings Park Formation sand.
To support the pile bore in the deeper natural materials, Avopiling used a polymeric drilling fluid.
All this took place in a very confined site with live traffic running alongside the piling works and passenger trains passing beneath the existing bridge. Close collaboration with Lend Lease ensured that traffic switches between the westbound and eastbound carriageways took place with minimum disruption and maximum efficiency to the piling operations. To meet the programme constraints of the northernmost part of the bridge expansion Avopiling worked seven days per week to ensure that Lend Lease was able to meet its contractual obligations.