A significant milestone has been achieved in the Rawdon Island Bridge rehabilitation project with the specialist underwater repairs now complete.
The project, managed by council's contractor Duratec, has involved highly specialised underwater work to repair the critically damaged concrete piles that support the bridge.
Over the past few months, crews have been accessing the bridge foundations via a platform stationed on the water enabling them to transport and install customised fabricated steel jackets to act as 'sleeves' to wrap around the damaged piles.
Once the steel jackets were secured in place, specially formulated grout was injected into the compromised points and concrete poured into the sleeves to encase and strengthen the existing piles.
Group manager community infrastructure planning and design Blayne West says it has been an incredible effort to get the project to this point.
"The work completed to date is a critical stage in the overall bridge rehabilitation project, and workers are now progressing with the above-water components of the project," she said.
"Everyone has worked really hard to get this stage of the project. This is such a unique repair, and what has been achieved in such a short time is quite phenomenal."
Specialist divers have been working up to eight hours each day in challenging conditions - with muddy water, strong river currents and the ever-present threat of bull sharks.
To ensure safety for those traversing the bridge, and those working under the bridge, Maritime NSW established a waterways exclusion zone under Rawdon Island Bridge, in effect, closing the waterway to boating vessels. It's important to note, this waterway closure remains in place while the bridge repair work continues.
Typically projects like the Rawdon Island Bridge rehabilitation may take up to two years to come to fruition, with extensive research and design, environmental assessments and approvals, contract tenders, sourcing materials and scheduling operational works.
In the case of the Rawdon Island Bridge project, this has been achieved in six months. The complexities of this project were further compounded by the unique situation with the bridge providing the sole access on and off the island for Rawdon Island residents.
"We understand this has placed a strain on the local community, and we've made concerted efforts to fast-track the project where possible. This also involved working in close collaboration with various third parties and government agencies to ensure we had their support to remove or reduce the red tape," Ms West said.
"This repair project is technically challenging, and it's been a huge effort by the team within council and our contractors to achieve this major milestone. We're lucky to have such impressive and experienced talent on staff at council, and within our local area, to deliver this unique bridge project."
The repairs completed to date means council can lift some of the temporary traffic restrictions. The load limit of the bridge was increased to 42.5T GVM just before Christmas, and this week two-lane access will be reinstated, and an increase in the speed limit to 40km per hour when travelling across the bridge.
The team are now transitioning into the next stages of the repair project which will include repairing the concrete on the bridge piers above the water line, repairing and strengthening the blade walls, installing corrosion protection and completing the project with improvements to the bridge deck. The project is expected to be completed by June this year.
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