Sydney Harbour Bridge, the steel-arch bridge across Sydney Harbour (Port Jackson), Australia
was formally opened on 19 March 1932. The bridge serves as the primary
transportation link between Sydney and its suburbs on the northern
side of the harbour. It spans about 500 metres (1,650 feet), making it one of
the longest steel-arch bridges in the world. Along its length, it features four
railroad tracks, a highway, and two pedestrian walkways.
In 1912 John Bradfield, a civil engineer with
the New South Wales Department of Public Works, presented plans to Australia’s
parliament for the construction of a bridge over Sydney Harbour, with options
for either a suspension bridge or a cantilever bridge design. He envisioned the
structure as part of an electric railway system for Sydney and its suburbs. The
year after Bradfield submitted his plans, his
cantilever design was accepted, and he was appointed to lead the project. Work
on the bridge was delayed by World War I,
however, and it was not until 1922, with the passage of the Sydney Harbour
Bridge Act, that funding for the project became available. By that time too,
progress in steelmaking had made possible the construction of an arch bridge.
The building contract was awarded to the English
enterprise Dorman Long & Co., which hired Sir Ralph Freeman to perform
detailed design work. The final, approved plan called for a steel-arch bridge
linking Dawes Point on the south with Milsons Point on the north. An arch
bridge was chosen because it was less expensive than a cantilever design and
capable of handling heavier loads. Construction began in 1924 under Bradfield’s
supervision. The deep waters of Sydney Harbour made temporary supports
impractical, so the steel arch was assembled by building out from each bank.
The two sides met in the middle in 1930, and the bridge was officially opened
with an elaborate ceremony on 19 March 1932.
Despite Bradfield’s submission of proposals for the bridge
design, Freeman considered himself to be the bridge’s true designer. The claim
was supported by some authorities, though the controversy was never fully
resolved.
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