ANZAC Bridge Maintenance Project, Sydney
The ANZAC Bridge is one of a small number of large cable stay bridges around the world. Opened in 1995 it is a dramatic Sydney landmark and vital connection for Sydney. Like many of the early cable stay bridges it suffered from instability in the cables as a result of low wind conditions with rain. A rivulet of water under the cables created a wing-like effect that caused uplift and movement – an undesirable outcome reducing the durability of the bridge.
The strengthening project fixed this condition securing the bridge for the future. Using a robotic system, a helix was welded to the cable covering to ensure the drips and rivulets do not collect in a line. Damping systems were attached to the base of the cables to absorb any movement damaging the footings. Improved pedestrian fencing, access for maintenance and routine cable replacement work was also carried out.
The success of this project was dependent on how well the work was designed so that the bridge remained a high quality Sydney icon. Engineers and urban designers worked together to design and select the best options that were in keeping with the character of the bridge. Photomontages were produced to demonstrate the proposed work to the local community. The new fence is an example of this attention to detail with tapered posts and ends, and an infill mesh coloured and designed to allow unimpeded views of the harbour.