The upgraded Pacific Highway and Wyong Road Intersection opened in November 2017, one year ahead of schedule. Aurecon, NSW Roads and Maritime Services, and contractor Seymour Whyte delivered the upgrade, reducing congestion and improving safety for the 55 000 motorists that use it daily.
The $84 million Pacific Highway and Wyong Road Intersection project, funded by the NSW Government, addressed a history of congestion and incidents by replacing the existing roundabout with traffic lights. Other significant works included duplicating an existing bridge over the Main North Rail Line and improving the shared path network. Digital engineering tools helped to identify and address issues, and communicate project details to stakeholders.
A major feature of the project was the new four-span road over rail bridge. Construction of the new bridge was extremely complex due to the interface with the Main North Line below, and the proximity to road traffic on the existing structure, both needing to remain operational during construction. There was a 45-degree skew between the bridge and rail line below and this presented a unique design challenge compared to a conventional bridge.
Aurecon developed an innovative solution to safely and efficiently duplicate the bridge so close to a live rail corridor. The solution included the use of cast in-situ and precast concrete for the central pier. This isolated the work site from the live rail corridor and was a contributing factor to the project finishing ahead of schedule.
The first 3.6 metres was constructed with cast in-situ formed concrete to reduce the safety risks associated with construction of the central pier. The pier was then extended to full height using precast concrete segments installed during a scheduled track possession. The lower in-situ section of the pier was constructed behind the trackside shutter, which doubled as an isolation screen. This innovative pier formwork system allowed construction to progress adjacent to live rail, and outside of track possessions.
The precast concrete pier segments for the central pier included:
• 59 stress bars (each 40 mm in diameter) to support and secure the upper precast segments.
• 10 precast concrete segments to form the upper section of the pier, each approximately 3 m long x 3.88 m high x 1.8 m wide.
• Each precast segment weighed up to 34 tonnes.
• After erection each precast segment was stressed, and the ducts and joints grouted.
• Horizontal and transverse shear keys assisted in the transfer of lateral loads, including rail collision loads.
To facilitate the widening of the approaches to the intersection and bridge, more than 1 km of retaining structures up to 11 m high were constructed, together with the relocation of above and underground utilities.
Aurecon used digital engineering tools to make a substantial difference across all phases of the project, from planning to design and throughout delivery.
3D modelling was carried out to gain an appreciation of the geometry for the new and existing bridges. The modelling was extremely beneficial for assessing the complex geometry and clearances.
The 3D models were used to create a real time interactive visualisations for the whole project. This enabled stakeholders to explore and interrogate a virtual environment showing the completed project. This environment captured all aspects of the project including road works and roadside furniture, structural elements, stormwater drainage, and above and underground utilities. In addition to this, an animation of the proposed construction sequence was also created. Both outputs proved extremely useful in briefing and working through issues (and risks) with stakeholders, Transport for NSW and Sydney Trains.
Construction of more than 2 km of extended shared path has provided safe, off-road connections for commuters and recreational cyclists between community spaces, train stations and shopping precincts.
This project is an excellent example of client, designer, contractor and stakeholders working together to achieve a safe and economical outcome.
The once congested Pacific Highway and Wyong Road Intersection has now been transformed into a safer and more reliable link for the New South Wales Central Coast.
“Considering the complexity and very high-risk nature of the project, the team should be commended for delivering the project 12 months ahead of the Contractual Completion Date whilst achieving excellent safety, quality and environmental outcomes,” said Chris Dransfield, Senior Project Manager, NSW Roads and Maritime Services.
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