Built for Watagan Park’s expansion, this 50m twin-tower cable-stay bridge complements the historic...
- Client
- Wyndham City Council
- State
- Victoria
Delivering connection with cost-efficiencies at Allura Estate
Following a highly competitive tender, FORGE was appointed as lead contractor by Wyndham City Council to deliver three pedestrian bridges and connecting boardwalks at Allura Estate, 25km west of Melbourne. Surrounded by nature reserves, walking tracks and wetlands, the new bridges form critical access links across Dohertys Drain allowing local residents and families to safely walk and cycle around the growing estate whilst also providing direct access to public transport.
While the original tender drawings from Council nominated a truss design, a thorough review of the project brief also saw us explore a second option based on our proprietary BALMORALTM girder bridge system - an 18-metre clear span design that drove significant budget savings while providing greater protection against potential flooding events.
Offering the ideal balance of aesthetics, safety and cost, the girder option was approved by Council, with FORGE subsequently chosen to lead the design, engineering certification, fabrication and installation for each of the bridges and approach boardwalks.
Our involvement.
Guided by design and methodology insights gained from similar successful bridge projects in Victoria, we were confident in our ability to meet Wyndham City Council’s requirements. Our initial tender submission included preliminary engineering reviews and a concept drawing package that presented a family of bridge structures aligned with the project’s aesthetic and structural requirements.
While we explored a truss design as nominated in the tender drawings, we also proposed an alternative solution that was ultimately selected by Council. Following approval of the design, FORGE was appointed as Lead Contractor to deliver all three bridges and associated approach boardwalks.
The first step was to refine the final designs in close collaboration with key project stakeholders. FORGE then managed all engineering certification, detailed design, fabrication, pre-assembly and on-site installation, successfully delivering the structures in accordance with the project requirements.
Design Challenge
It was essential for the design of the Allura Estate bridges to be functional and economical, yet also able to contribute positively to the wider aesthetic of the fast-growing community. To achieve this we recommended a modified version of our proprietary BALMORALTM steel girder bridge system. In addition to being highly cost-effective and ideal for use in flood impact zones, BALMORALTM also offered the flexibility to add several custom design embellishments for Council.
Another key consideration for our design team was working within strict Melbourne Water guidelines to meet the necessary freeboard requirements. For all three bridge structures the design needed to achieve a soffit height above the 1% flood level.
Construction Challenge
Given the sensitive wetlands habitats at Allura Estate and adjacent land managed by Parks Victoria, all preparation and installation work needed to follow a strict Environmental Management Plan. Site access was heavily restricted with designated environmental zones unable to be disturbed in any way – something that required crews and contractors to use tight residential streets for two of the main installations and a busy main road for another.
During the construction window, FORGE also needed to navigate minor flooding, a complex network of underground services and even the curious local pelican and kangaroo populations.
Features
- 3 x BALMORALTM steel girder bridges - all spans 18 metres
- 6 x WATERSIDETM approach boardwalks - ranging from 3-22 metres in length
- 100+ metres of shared use concrete path
Materials
- Hot dip galvanised steel
- Fibre-Reinforced polymer (FRP) joists
- FRP minimesh decking
- Stainless steel handrails
- Powder coated steel bollards
- Concrete piers
Safety & Risk Considerations
Allura Estate was already home to more than 40,000 people making the safe management of adjacent traffic and pedestrians absolutely critical in the bustling residential community. Another potential project risk, and a key objective identified in a Dilapidation Report prepared by Wyndham City Council, was the need to carefully preserve the existing network of paths and flora and fauna habitats at Allura Estate during every stage of site works.
