Saltwater Creek on the shores of Tuggerah Lake is one of the Central Coast’s favourite tourist spots. The creek is a natural obstable in the busy walking track that connects Killarney Vale and Long Jetty, making a pedestrian bridge a much needed piece of infrastructure. When we installed the shared walkway and cycle bridge across the creek we provided an essential link in the track, giving local residents and visitors continuous access around the lake.
Because of the natural beauty and cultural significance of this site, our brief called for the design of the new pedestrian and cycle bridge to blend into its surroundings, without spoiling the views of the Creek. It needed to have minimal impact on the environment and, during the build, cause as little disruption for the local residents as feasibly possible.
The key challenge here was environmental: the sensitivity of the ecosystem in this region required very careful handling of the operations. It was essential that we didn’t disturb the acid sulfate soils in the surrounding mangroves. Also, with the bridge footings at water level, it was essential to prevent any corrosion from damaging the structure.
With DE2, we’ve refined over 20 years of client engagement into a collaborative, end-to-end process that’s founded on the principles of trust and certainty. And there’s never a more important time to apply these principles than when we’re approaching a project of such environmental sensitivity.
Consultation with the local council gave us the information we required to assess the local ecosystem and understand the limitations and considerations we were working with.
Our first step was to match the Council’s specifications with products that had already been developed through our DE2 methodology for similar projects. We call these our ‘off-the-shelf’ options.
These ‘off-the-shelf’ products are ideal for our partners who want a tried and tested solution, that has already been previously imagined and designed by our team of specialist Design-Led Engineers at our Hub. These proprietary solutions are easily adapted and customised to meet a specific need, making them a fast-track to a great outcome.
The options chosen were a twin tower cable-stayed Stirling™ bridge, a single tower cable-stayed Stirling™, and a cantilevered arch Sandford™. Each option we reviewed and presented to the Central Coast Council.
In making their decision, the Council referred to our recently installed pedestrian bridge at Tumbi Creek, Berkeley Vale.
The Sandford™ pedestrian bridge was chosen because it features rolled main girders, custom arcing central support columns and approaches at both ends. This ensured the pathway was code compliant.
The bridge also incorporated FRP mini-mesh joists and decking, galvanised balustrade and a stainless steel handrail.
Following collaboration with Council on the chosen bridge design, our visualisation and drafting team assembled photomontage. This delivered the detail and realism to allow the Council to see how the reworked design would look and work once it had been evolved to meet their specific requirements.
Once the Council was happy with the visualisation, we could move on to developing the detail. Every aspect of the engineering designs, materials selection, construction process was thoroughly documented and presented to the Council in preparation for construction.
At each stage of development, our DE2 model allowed us to revert back to the Council and gather feedback. This allowed us to make changes to the design, which with this project were only minor.
The great thing about using and adapting one of our existing tried and true bridge designs is that the client experience is smooth and uncomplicated.
Anyone who’s visited our Wetherill Park Workshop will know the size of the space and the scale of the pre-assembled construction we’re able to complete there. This enabled us to manufacture and pre-assemble the bridge and approaches in three main sections at our Workshop.
To prevent corrosion and increase the durability of the metal frame and components, we applied Marine Gel coating.
Once prepared, we transported the bridge sections to the site for easy installation by our Onsite Construction Crew. Moving from in-house to on-site, our installation team used an overhead crane to minimise the impact on creek banks.
As we explained the introduction, our methodology is underpinned by principles of trust and certainty, and no-one is more in tune with these than our Onsite Crew. Because they’re so experienced working within fragile or preservation areas they could confidently prevent any disturbance to the mangroves, or the release of acid-sulfate during excavation.
Once complete, the local residents could enjoy uninterrupted access all along the Tuggerah Lake foreshore. They have commented to us that they’re happy (and relieved!) that no elements of the new structure have obstructed their existing views of the creek and the surrounding reserve.
With all Australian Standards met, the bridge introduces a beautiful structure to the landscape that complements the natural surroundings. We’re very proud to say, that for such a complex geometrical shape, this was quite an achievement!
You can clearly see the curve in the bridge. So not only is there the arced elevation over the creek, there’s also this single curve which needed to be included in the plan. This made it a more complex structure than the original Sandford™ pedestrian bridge, so the design and detail had to be amended to ensure it worked structurally, and still met the relevant Australian Standards for a shared cycle and pedestrian path and bridge.
Beautiful smooth and elegant lines along the large span allowed us to meet the objective in the design brief from the client: i.e. to “keep the structure as slimline as possible.” By designing curved superstructure support that reduced the actual clear span, we reduced the size of the main beams. We then used screw piles and concrete footings to support the structure.
What sets Fleetwood Urban apart is the overall value for money-the product and the price combined. They do both very well. For Council, It’s good to be able to hand over the whole package-Fleetwood do the design and then follow through with quality construction.Doug Marchant Senior Project Manager, Wyong Shire Council