Bradfield oversaw the construction, which began in 1924. Because temporary supports were impracticable in Sydney Harbour's deep waters, the steel arch was built out from each shore. The two sides met in the center in 1930, and the bridge was officially inaugurated on March 19, 1932, with an extravagant ceremony. Bradfield died a few months later on June 8, 1932.
The harbor bridge is an example of a braced beam or truss bridge, which uses vertical members called "beams" to support its deck. The beams are held up by horizontal members called "trusses." Bridges of this type were used extensively before the advent of the suspension bridge in 1867.
Other notable bridges designed by Bradfield include the Glebe Island Road Bridge (1926), the Cahill Expressway Bridge (1928), and the Old Windsor Bridge (1929).
After Bradfield's death, the job of completing his work went to his son Arthur, who completed the last section of the bridge not done by his father - a span over the entrance to Darling Harbor. He also redesigned some parts of the original structure to make it safer for drivers. This new version of the bridge was opened on March 19, 1937. It was named after its designer, who had been killed in an automobile crash a few months earlier on February 9, 1937.
An arch bridge was selected because it was less costly than a cantilever design and could handle larger weights. On the Australian continent, arches are common instead of tunnels because they are less expensive and less disruptive to traffic.
The choice of material for the new bridge was important because it had to be strong enough to carry vehicles and heavy rail traffic but also have a reasonable life span. The decision was made to use rolled homogeneous steel because it was light and easy to work with, had good strength properties, and was durable over time.
The main feature of an arch bridge is its support structure. An arch has two parallel vertical members called trusses that cross each other at right angles like the legs of an 'X'. The horizontal member, or deck, hangs between the ends of the trusses. When a vehicle drives under an arch, its weight causes the trusses to bend. But because the trusses are tied together at their center, they do not collapse. Instead, they spread the weight evenly across a large area.
This type of bridge is most efficient at carrying heavy loads because the pressure per square inch on the bridge is lower than it would be if it were made out of one solid piece of metal.
Eighteen years The Sydney Harbour Bridge began construction on July 28, 1923, employing 1,400 employees and taking more than eight years to complete at a cost of more than PS10 million. The bridge was opened by the New South Wales governor, Sir Philip Game, on October 29, 1930.
It was an immediate success. The first vehicle crossed the bridge just after it opened, and within a few weeks, there were more than 100,000 cars driving across it every day. In its first year, it carried more than half a million vehicles. Today, it carries more than one billion people a year who work, play, or study near the city center.
The main idea for the design of the bridge came from a drawing made by English civil engineer Francis Petter Smithson (1863-1943). He proposed that instead of crossing beams like a traditional suspension bridge, vehicles would be driven over a vertical tube with horizontal rails attached. This would allow the traffic to pass smoothly above large ships in the river while keeping the height clear of buildings for safe pedestrian access below. His plan was adopted by the Australian government which hired him to design their version of the bridge.
Smithson started working on his project but died before he could finish.
The Australian Historic Council determined that the Sydney Harbour Bridge is of exceptional national heritage value. Its building was a significant event in Australian history. Its inauguration in 1932 was essential in the building of contemporary Sydney and served as a focal point for national optimism throughout the Great Depression. The design and construction of this iconic bridge were innovative solutions to practical problems related to connecting Australia's largest city with its harbour. These problems included overcoming geological obstacles such as deep valleys between North Shore City and New South Wales, and establishing a route over the Barrington Tops/Great Dividing Range mountain range.
The decision by the government to fund the project through tolls rather than taxes helped to make it possible for many people not only from Sydney but from all over Australia to visit and experience what has become known as the "Sydney Spirit". Free access to the site during construction allowed for a more general participation in the development of Sydney than would have been the case if it had been funded by the state government. This factor, combined with the fact that the bridge was designed by an independent body, led to it being viewed as superior in quality to other bridges built at the time across Australia.
Being the first major work of architecture by a female architect makes Anne Geddes' contribution to Australian culture and society important. She is also regarded as one of the leading architects of her time in the United Kingdom. Her expertise in structural engineering was crucial to the success of the project.