Burdekin Bridge

The Burdekin Bridge spans the Burdekin River between the towns of Ayr and Home Hill, Queensland, Australia. Located on the Bruce Highway which is part of Highway 1, it is an important link in the national road network. It is a road-rail bridge which provides high flood immunity link between north and south Queensland.The Bridge was completed in 1957. Construction began 10 years earlier in 1947. At 1097 metres in length, it is one of the longest multi-span bridges in Australia and longer than Brisbane's Story Bridge or New South Wales's Hawkesbury River Railway Bridge. It is 46 metres shorter than Sydney's Harbour Bridge.HistoryOriginally, it was thought that the bridge could not be built in its present location. No trace of rock could be found on which to build the bridge foundations. In 1946, two high-ranking Government engineers visited India to inspect a number of bridges built on sand foundations. The same technique was used for the Burdekin Bridge and it is the only bridge in Australia not built with a firm foothold.The bridge rests on 11 huge, hollow, concrete caissons sunk into the river bed. The caissons are 17 metres across the top (measured parallel to the stream) and vary in width from 5.5 to 7.6 metres. The caissons were sunk into the river bed to a depth of about 30 metres. Add to that the approximately 20 metres that the caissons rise above the bed and the end result is some very massive pieces of concrete. Each weighs about 4,000 tons. The caissons were fitted with steel "cutting edges" to help them sink. The steel used in the cutting edges weighed 238 tons.