Biggest Oz box jack19 August 2011
Thiess has successfully jacked a box the size of a rugby field as part of Brisbane’s Airport Link project in Queensland, Australia. It was the largest box jacking project undertaken in Australia.
“Traditional methods of tunnelling would have required up to 30 weekend track closures, affecting freight, city network and AirTrain customers,” said a Thiess spokesman.
“However, the box jacking operation during which two purpose-built concrete boxes were pushed and pulled beneath the rail embankment in Kalinga Park was successfully completed without any disruption to rail services.”
The spokesman added, “As one of the most complex engineering aspects of Airport Link's construction, the jacking of the giant boxes was required to form part of the project's road tunnel.
“Before jacking work could begin, 48 canopy tubes were pushed through the embankment to form a platform providing stability to the North Coast Railway Line. The concrete boxes were then constructed beside the railway line, before hydraulic jacks and steel strands were used to push and pull the boxes through the rail embankment.”
The boxes were 65m long, 12.5m high and had a combined span of approximately 38m. They were pushed 55m into position beneath the railway embankment. Thiess announced the success on 10 August.