Maintenance of the ANZAC Bridge - a large-scale project and a world first
The ANZAC Bridge in Sydney provides a link
between the central business district and the city's western suburbs. Carrying
2 x 4 lanes, the ANZAC road bridge is the longest cable-stayed bridge in
Australia with a main span of 345 m. When the bridge was opened in 1995,
abnormal vibrations were detected in the stay cables. Faced with the prospect
of the vibrations ultimately causing deep-down damage to the bridge, Roads
and Maritime Services (RMS) of New South Wales launched a maintenance program
From November 2010 to December 2011, the Technical Division delivered effective
support to the on-site team, especially in spearheading a solution to overcome
the problem of the vibrations. Since the cause of the vibrations was known
(combined effect of the wind and rain), the problem was solved by fitting
helical contour ridges to the existing HDPE sheaths. The ridges were fitted
using Freyssilix, a welding robot created in partnership with Alpin Technik.
In addition to the contour ridges that will reduce vibrations by 80%, Freyssinet's
IRDs (Internal Radial Dampers) will neutralise any residual vibrations.
The Technical Division also helped design the "new-generation"
The Technical Division also masterminded a world first at the ANZAC Bridge,
by finalising a ground-breaking method for replacing the protective wax
coating on the stay cable anchorages. The process was verified in Australia
and specifically adapted for the ANZAC Bridge. The replacement process
will start in the next few months and will significantly extend the durability
of the cable-stayed structures.
A project with the focus on safety and quality
Throughout the maintenance program, the bridge's eight lanes remained open
to traffic. To ensure the complete safety of the teams working on the bridge,
two 80 cm-wide fixed platforms have been fitted on each side of the bridge.
At the same time, the decision was taken to improve the permanent access
systems, which involved installing a lift in each tower and providing access
to all of the bridge's deck-level anchorages.
Furthermore, the eight largest stay cables on each tower were be fire-protected
in case of a road traffic accident using an intumescent epoxy resin system
applied by Mecatiss (Nuvia subsidiary). In the event of a fire, this process
has the special property of swelling as a result of exposure to high temperatures,
thereby acting as a thermal shield to protect the strands of the stay cable.
For this particular project, Freyssinet's local office applied the quality
standards required by NSW Roads and Maritime Services.
Furthermore, as part of its strong determination to ensure the safety and
well-being of the teams, Freyssinet and its three partners developed a
highly advanced safety policy. For example, the policy allows workers to
stop work if they feel that the working environment has not been made sufficiently
The project was completed in October 2013.