Australian
Screen

Teacher’s notes

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This clip shows construction of one of the last panels in the arch of the Sydney Harbour Bridge in mid-1930. It opens with a panning shot of the two cantilevered half-arches, showing how close they are to being joined. Next, a piece of the bottom curve of the arch, the 'bottom chord’, is lifted from a barge and placed in position. A sequence of a riveting team at work follows. The clip closes with a shot of one of the creeper cranes on top of the arch lifting a section of the bottom chord. Four intertitles describe the action shown on screen and supply the technical terms.

Educational value points

• The Sydney Harbour Bridge took 1,400 men eight years to build and was one of the greatest bridge-building projects undertaken anywhere in the world in the late 1920s and early 1930s. Although not the longest it remains the largest steel arch bridge ever built. The arch consists of 28 panels with a total span of 503 m, weighing 39,000 t. The summit of the arch is 134 m above sea level and it was Sydney’s tallest structure for 35 years.

• Construction of the Bridge across Sydney Harbour was the culmination of an idea first proposed in 1815 and regularly revived as Sydney grew. The New South Wales Government first began to consider actually building the bridge at the beginning of the 20th century and finally decided to proceed in 1922. The first sod in the project was turned on 28 July 1923, the arch was joined on 19 August 1930 and the completed Bridge opened on 19 March 1932.

• High levels of engineering design were required for this technically difficult project. By 1922 Dr JJC Bradfield (1867–1943), the chief engineer for metropolitan railway construction and original designer of the Bridge, had decided that a double-hinged steel arch bridge would best suit the location. Footage at the beginning of the clip shows one of the huge hinges designed to cope with the expansions and contractions of the arch caused by temperature changes.

• Public interest in the Bridge’s construction was relatively subdued at first but as the half-arches anchored by huge wire cables began to rise, the popular imagination was captured by frequent newspaper reports, photographs and films, in which the technical details of erecting the Bridge, particularly its arch, were explained and illustrated in great detail. Although some feared that it might collapse, most members of the public had faith in its science and technology.

• The Bridge was constructed of huge prefabricated steel components, as the clip illustrates, and used the best bridge-building technology available at the time. The steel pieces were fabricated in workshops on the Harbour’s North Shore, placed on barges, moved into position beneath the Bridge and lifted by one of two 580-t electrically operated creeper cranes, each with a lifting capacity of 122 t, that operated at the edge of the half-arches.

• About 6 million rivets hold the Bridge together and all stages in the riveting process involved the manual labour of a team of men. As seen in the clip, the process began with the 'cooker’ heating the rivet until it was white-hot, transferring it, often by throwing, to the 'catcher’ who passed it to the 'holder-up’ and the boilermaker, who worked in tandem. One held the rivet head firm with a pneumatic anvil or dolly while the other drove the rivet in with a pneumatic hammer.

• Examples of unsafe work practices can be seen throughout the clip and were common in the 1930s when occupational health and safety was not a high priority. While workers may have realised that conditions on the Bridge were unsafe, it was the time of the Great Depression and jobs were scarce. Nine men died during construction. Most were riggers or crane workers, such as the man seen here riding a steel piece up from a barge to the arch with no safety harness.

• The cinematographer used a range of shot types to emphasise the heroic nature of the construction and those who undertook it. The pan at the start of the clip was shot from underneath to show the great extent of the span. The raising of the piece of bottom chord, shot from locations at water level and up on the arch, gives a dramatic sense of the weight and distance involved, while the close-up of the 'holder-up’ at work using the pneumatic dolly reveals his concentration and effort.

This footage is silent, interspersed with intertitles. It shows the joining together of two sides of the arch of the Sydney Harbour Bridge. A view of the main bearing and arch ribs shows the two sides of the cantilever arches almost meeting.

Intertitle Erection of bottom chord 13th panel. Weight of piece 61 tons.

Intertitle The panel is lifted by crane and a worker can be seen standing on it. A boat passes under.

Intertitle Outer end of bottom chord 13th panel.

Intertitle Riveting a chord joint and holding up by a pneumatic dolly.

intertitle Lifting bottom chord section 13th panel.