Originally the ANZAC Bridge was to have been a conventional concrete box girder construction with support piers in the water. However consideration of the effects of a large ship hitting a pier precluded that design and the cable stayed option with support towers on the land was adopted.
The bridge deck was constructed in 10 metre concrete segments. The first three segments were initially supported by scaffolding.
When tower construction was completed, the first stay cables were installed.
The cables connect to the deck segment at its furthest edge from the tower.
Construction over the water used a recent innovation - the formtraveller - which is, in effect, travelling formwork.
Supported by the leading edge cables of the previous segment, the formtraveller provided support for the next 10m concrete segment to be cast.
The formtraveller was of substantial construction being 30m long and 32m wide, and weighing 280 tonnes. 8.
Deck segments weigh in the order of 460 tonnes. As a deck segment is cast on one side of the tower it must be balanced by one on the other side. The land side segments were cast first.
After the western half of the water span was completed the formtraveller was lowered onto a barge using Austress Freyssinet's L180 heavy lift system.
The rising tide was used to gradually take up the weight of the formtraveller before it was moved across to the eastern tower to start work there. 8
The approach deck is supported by concrete box girders which were cast in situ.
The People
The client for the bridge was The Road and Traffic Authority of NSW (RTA). Peter Wellings was the RTA's on-site project engineer. Leighton Contractors built the protective embankments and placed the piles to the bedrock and bridge footings for the two towers starting in 1989.
Baulderstone Hornibrook Engineering Pty Ltd was the major contractor for the bridge. Their project director was Sandy Buchan and Hugh Bishop the engineering manager.
Austress Freyssinet Pty Ltd was the sub contractor responsible for the cable stays and other specialist engineering technologies.