Congratulations to the Yandhai Nepean Crossing and Green Square Stormwater Drain projects on being recognised as Australian Engineering Excellence Award finalists.

Both projects, delivered by Seymour Whyte, represent the outstanding achievement in engineering and demonstrate the invaluable contribution engineering makes to the economy, community and the environment.

Yandhai Nepean Crossing – an Australian first

The landmark Yandhai Nepean Crossing over the Nepean River in Penrith, west of Sydney, reflects creativity and ingenuity. It serves as a benchmark to inspire future generations, where the function is expanded to be more than just a utilitarian crossing, but rather a destination-in-itself.

Measuring 284m long with a 200m main span, the crossing incorporates a straight triangular Warren truss (8m wide x 13.5m high) with a gentle vertical curved bridge supported by two abutments and two piers. It’s construction required a simplified methodology to:

  • reduce bridge self-weight loads
  • manage the longitudinal thermal expansion and bowing effects on the truss.

The main feature of the bridge, which has the longest unsupported span for a shared-path bridge in the southern hemisphere, is the 200-metre long Warren truss. This truss was built by assembling prefabricated sections on one side of the river and then progressively launching them over temporary piers in the Nepean River using an innovative ‘node-by-node’ incremental launching technique used for first time in Australia.

Photo (above): Yandhai Nepean Crossing, Penrith, NSW

Green Square

Sydney’s Green Square is one of Australia’s largest urban renewal developments that is setting a benchmark for the future of sustainable communities.

Once an industrial heartland on a floodplain, Green Square will be transformed into a vibrant, sustainable and connected hub for 61,000 people by 2030.

To achieve this, one of the first major infrastructure projects was to build a stormwater drain – using microtunnelling technology to install twin and triple 1800mm diameter pipes over 2km in length – to carry floodwaters from south Sydney into Botany Bay, and significantly reduce the risk of flooding.

The Green Square Stormwater Drain project was delivered by the Drying Green Alliance comprising of the City of Sydney and Sydney Water with Seymour Whyte, UGL Engineering, WSP and RPS. Rob Carr, a VINCI company, provided the specialist microtunnelling services required to deliver the project.

Photo: Emily Rose, the microtunnelling boring machine, being lowered into position to start work on the Green Square Stormwater Drain project.