Australian
Screen

Teacher’s notes

provided by

This clip shows the final stages in the construction of the Sydney Harbour Bridge in 1931 – the completion and sealing of the Bridge deck. The clip opens with the asphalt road surface being prepared. The next scene shows the appearance of the deck before concreting and asphalting, followed by scenes of concrete being made onsite, moved, poured and finished off. The last two scenes show the ironbark sleepers for the railway tracks being prepared and a view of the unfinished pedestrian walkway. Intertitles are used to explain what is shown to the audience.

Educational value points

• The Sydney Harbour Bridge was one of the greatest bridge-building projects undertaken anywhere in the world in the late 1920s and early 1930s. With a deck 1,149 m long and 48.8 m wide, it remained the widest long-span bridge until the 2012 opening of the Port Mann Bridge in Canada. About 1,400 men worked on constructing the Bridge and, within nine months of closing the arch, the workforce had finished the immense deck, ready for laying the roadway and the railway and tramway tracks.

• Progress in bridge-building technology combined with advances in Australian manufacture of reinforced concrete and prefabricated steel turned the idea of a bridge across Sydney Harbour from a dream into a reality. The New South Wales Government first began to consider building the bridge at the beginning of the 20th century and finally decided to proceed in 1922. Construction commenced in 1924 and the completed Bridge opened on 19 March 1932.

• High levels of innovation were required for this technically demanding project and the deck was no exception. Originally developed by Dr JJC Bradfield (1867–1943), the design of the Bridge called for 42 hangers to be erected on either side of the arch to carry the deck. Lifting the prefabricated hangers, which ranged in height from 7.3 m to 58.8 m, called for the construction of a specially designed cradle.

• As the Bridge neared completion in 1931 popular excitement grew, fuelled by almost daily newspaper reports, photographs and films such as this one explaining how the Bridge fitted together, piece by piece. The public learnt how the arch held the hangers, which in turn held huge steel beams across the width of the Bridge. The beams held the trimmers, narrow lengthwise beams that formed the base for the concrete of the deck and the asphalt of the road.

• The 1924 tender for the Bridge was one of the first issued for a major infrastructure project in Australia that specified that materials had to be sourced and manufactured locally where possible. Kandos Cement Ltd in central NSW was one company that benefited. The 1924 contract to supply the Bridge with concrete ensured the company’s survival and expansion of its technical capacity. Some 95,000 cubic m of concrete was used in the Bridge.

• There were relatively few machines on the Bridge and its deck was built by hard physical labour, starting at the centre and moving outwards. The clip shows almost every stage of asphalting and concreting being done by hand. There were just two 1-cubic-yard- (0.76-cubic-m-) capacity concrete mixers in use, one for the north gang and one for the south, with 12 concreters working in each gang – six would mix and push the loaded wagons and six would concrete.

• The Bridge reflects the major changes in transport that occurred from the 1920s onwards. Originally conceived as more of a rail bridge than a road bridge, at first it had two rail tracks on each side, with trains running on the western side and trams on the eastern side. With the demise of the city’s tram system in the 1950s, the tram tracks were converted for road traffic, which has since grown from 10,900 vehicles a day in 1932 to about 160,000 in 2007.

• The scenes in this clip are typical of the silent industrial documentary film genre in which the intertitles briefly introduce a particular process but the images carry the weight of description. In the clip, panning and medium-distance shots set the scale and show the process as a whole. These are interspersed with close-ups of tools in use and machines in operation, including a rare tracking shot achieved by mounting the heavy camera on one of the concrete wagons.

This clip is silent, interspersed with intertitles. Workers shovel hot asphalt onto a concrete bed to begin laying the roadway for the bridge. The asphalt is smoothed and compressed, rolled and pummelled.

Intertitle Main arch decking and troughing.

Intertitle Concreting the main arch roadway which is 57-feet wide.

Intertitle Preparing sleepers for laying tracks.

Intertitle Arch footways before concreting.