AUSTRALIA’S FIRST TRUE DIAGONAL ARCH BRIDGE

By Tess Macallan, Journalist, Infrastructure Magazine

As the first true diagonal arch bridge to be designed and constructed in Australia, the Alfred Street Bridge has been a complex undertaking for the City of Parramatta. But once complete, this new urban gateway will provide a convenient, safe and scenic walking and cycling link over the Parramatta River, connecting locals directly to the Parramatta Light Rail.

As the bustling suburb of Parramatta grows, so does its infrastructure – with the Alfred Street Bridge showcasing a focus on active transport and innovative engineering.

The Alfred Street Bridge is located over the Parramatta River between James Ruse Drive and Gasworks Bridge, with the 4.5m-wide, 200m-long active transport link in its final stages of construction – as bridge ramps and decks were installed in late March 2023.

A true diagonal arch bridge is designed so the arches are arranged diagonally in relation to the bridge’s horizontal axis. The $19 million project has been funded by the City of Parramatta Council and the New South Wales Government – which has provided a $11.5 million funding contribution through grants from Transport for New South Wales and the Department of Planning and Environment.

City of Parramatta Lord Mayor, Cr Sameer Pandey, said, “Alfred Street Bridge will be a great new landmark that will benefit so many people as they travel through Parramatta.

“The bridge acts as a river gateway to our city, creating better active transport links. We live in a beautiful city and we want to make it easier for people to walk, run, cycle, skate or wheel across the LGA and connect to public transport.

“For those who live north of the Parramatta River, this bridge will cut the trip into the CBD by up to 20 minutes,” Mayor Pandey said.

A spokesperson for Council said the project would provide many benefits for the growing Parramatta community, creating an essential connection to open green space, the future light rail stop, restaurants, urban services and would create easy access to the Parramatta River.

“The bridge will connect our community to the great outdoors and allow users to explore more than 20km of offroad paths along the Parramatta River. It also establishes two new recreational loops based on the two bridges either side of Alfred Street,” the spokesperson said.

The project is a key element within a network of planned pedestrian and cyclist networks centred on the Parramatta River and Alfred Street. Council has worked in collaboration with the New South Wales Government to plan and deliver this network, which is expected to be completed within 12 months.

Design And Construction

As an important gateway in and out of the Parramatta CBD, the Alfred Street Bridge design has had to meet high expectations.

“The design team for the bridge was selected in the tender not just on their experience, but through demonstrating how the architectural and engineering teams would work together to deliver an exceptional result,” the spokesperson said.

“The design team was challenged by Council to prepare a number of simple yet elegant solutions for the review of an expert Design Review Panel. Ultimately, the diagonal arch was recommended by the Panel as not only the most appropriate response to the setting, but it also meant people travelling on the river over the bridge would pass ‘through’ the arch.”

The spokesperson also explained that strong coordination between Council, the New South Wales Government and local stakeholders – throughout the design and construction phases – has been key to the success of this project.

Council's State Government partners will also be involved in the official launch scheduled for July 2023.

“The bridge was very complex to design and deliver. The design was tested to withstand both high-velocity winds and floodwaters,” the spokesperson said.

Off-site in Western Sydney more than 30 workers fabricated the deck and arch using 280t of Australian BlueScope steel, with transporting these assets to the site proving to be a challenge.

“Each was fabricated in three pieces, then trucked from Western Sydney to the site on oversized prime movers in the night. The deck pieces, then the arch, were assembled on site and each lifted into position using a 750t crane. The steel cables that support the deck had to be manufactured in Italy. A specialist team flew in to oversee the installation,” the spokesperson said.

The final piece of the puzzle will be positioning the steel cables that support the deck from the arch.

Widespread Community Support

“There has been growing enthusiasm especially as we get closer to the public opening,” the spokesperson said.

“Residents in nearby apartments have been eagerly watching the bridge being built. We have a lot of cyclists, riding groups, and keen pedestrians who are very excited about the opening during winter this year.”

The project has been trending on social media, with members of the community expressing enthusiasm and curiosity about the bridge, as well as sharing pictures as it progresses.

“Our community is excited about the progress of the Alfred Street Bridge, affectionately known as “Alfie” for now,” Mayor Pandey said.

Long-time Parramatta resident, Greg Temme, has lived in the area since 1985. He has been watching the bridge come to life from his apartment window, and said the Alfred Street Bridge will cut down his travel times by up to 20 minutes.

“We’re really looking forward to the opening of the Alfred Street Bridge. It will be a life-changing addition for us, it’s going to make it so much quicker to visit the town centre and the local shops,” Mr Temme said.

“We’ll be able to cross the bridge and connect to the future Parramatta Light Rail stop at Tramway Avenue where we can travel straight to Western Sydney University, Westmead Hospital, Eat Street and Parramatta CBD.”

Ready For Alfie

The bridge is in its final stages with civil works and landscaping underway. In addition to the works, a new urban plaza on the southern approach to the bridge is being established.

The Alfred Street Bridge is expected to open in the coming months.

Once formally opened, the City of Parramatta will work with the community on naming the bridge. A proposed name will then be submitted to the Geographical Names Board of New South Wales for formal exhibition and determination.

Mayor Pandey said, “Now that the arch has been lifted into place, landscaping and civil works are underway. Our $19 million Alfred Street bridge will make it safer and faster to move in and out of the Parramatta CBD.”