Challenges & Solutions
A bridge for this site had been talked about at least since 1815. By 1890 cross harbour ferry traffic and congestion at transfer stations on each shore were getting unmanageable, and a Royal Commission determined that a bridge was needed.
A world-wide competition was announced in 1900, but no entry was declared the winner (specifications had to be revised). The new competition in the following year was won by a Sydney-based engineer Norman Selfe. But by 1904 nothing had happened, and when the government changed the project went nowhere.
Eventually a new proposal was accepted in 1911 and in 1912, Bradfield was appointed chief engineer on the project. He completed a single arch design in 1916, but the project was deferred because of the World War.
Building had already begun on the approaches when in 1924, Bradfield recommended that the tender of Dorman Long & Co be accepted.
It was the second cheapest, but it most closely resembled the plan created by Bradfield, a. two-hinged arch (at each end of the arch) which included decorative granite faced pylons. These pylons don't support the arch itself, just the approaches. Bradfield argued they were essential to the idea of "humanizing our landscape in simplicity, strength and sincerity".
With new lighter steel available, Dorman Long devised a method of building the bridge arch in two sections, starting from each side of the harbour and building out over the water in virtual unison — work on the southern end of the bridge was just ahead of that on the northern end, in order to detect any errors and before they occurred in both locations.
On each section a 580-tonne creeper crane moved slowly out along the top of the arch as it was constructed, lifting steel sections into place from barges on the water below. Large steel cables helped support each half of the arch during construction, and these went from the partly constructed arches back to anchor points behind the pylons.
Eventually, the two sections met in the middle on the afternoon of 19 August 1930. Following a parting that occurred due to the contracting of metal in the evening, the ends were rejoined at 10 pm, and have remained thus ever since.
Once the arch (the main supporting structure) was complete, the vertical hangers were appended to the arch, and it is from these hangers in turn that the actual roadway is suspended.
One of the challenges of many major projects is to create the actual space for the project to proceed. The two sides of the harbour were at the time extremely busy locations with many existing structures on location.
The first stage of the project included building two worksheds at Milson's Point (the light and heavy workshops), and demolishing 800 homes. The owners of these homes received compensation, but their occupants did not.
Safety was always a challenge — and totally inadequate by today's standards. Sixteen workers died during construction (mainly falling off the bridge). Others were injured in various circumstances, such as handling the hot rivets… the rivet cooker would throw red-hot rivets to the rivet catchers, who caught them in buckets while balancing on structural steelwork high above the harbour, and then hammered them into place. Deafness experienced by many of the workers in later years was also blamed on the project.
Over 1500 workers were employed on average each year over the eight-year building period.