Victoria’s Level Crossing Removal Project team says it’s the first to use an innovative ‘monopiling’ technique to lay foundations for a new rail bridge, as part of its Reservoir project.
The level crossing at High Street in Reservoir is one of many being eliminated by the Andrews Government’s program. Under a $232 million contract, an elevated rail bridge is being built over High Street, and a new Reservoir train station is being built.
Traditional rail bridge foundations typically consist of a cluster of smaller-diameter piles below ground, topped with a large concrete ‘pile cap’ to support each bridge column.
Under a monopiling method, a single large pile is created instead.
“At Reservoir, we’re doing the traditional grouped piles, but we’re also doing monopiles which are these giant 2.1-metre diameter single piles,” site engineer Andrew explains, “and these single piles sit underneath each bridge pier.”
He says the benefits of the method are twofold.
“We save space, it saves time, and particularly when we’re working in this live rail traffic environment we need as much space as possible.”
In total, 32 bridge columns, known as piers, will be erected during the Reservoir project, using a mixture of monopiling and traditional methods.
Some monopiles are being dug as far as 28 metres deep. Once that foundation is created, a cylindrical steel reinforcement cage is inserted into the hole, then filled with concrete to form a pile. The pier is then erected above that, again using a cylindrical steel cage which is fitted with a steel mould, then filled with cement.