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The $440 million Elizabeth Quay was officially unveiled to the public in January 2016.
Part of a bold plan by the Western Australian Government to revitalise central Perth, Elizabeth Quay features a stunning 2.7ha inlet and 1.5ha promenade with bars and restaurants and will eventually be surrounded by a vibrant mix of offices, apartments, hotels and shops.
The event also marked the opening of the spectacular new $20 million pedestrian and cyclist bridge, which stands out as the jewel in the crown of the precinct.
The 22m high cable-stayed bridge spans the inlet and offers impressive 360 degree views across the Swan River and the Perth CBD and allows for continuous movement around the Quay.
Arup was engaged by the Metropolitan Redevelopment Authority (MRA) and novated to managing contractor CPB Contractors (formerly Leighton Contractors) and Broad as the lead design consultant for the bridge, and worked closely with stakeholders to deliver multi-disciplinary services from concept design through to completion.
The design process
A bridge as a primary element is a very simple structure; however the Elizabeth Quay bridge presented three core challenges. Firstly, the bridge was to be simple and transparent despite being positioned in constrained location. Secondly, the deck needed to be raised up to a certain level to provide clearance and allow vessels to safely pass underneath it. And thirdly, from a functional point of view the bridge had to have a minimum width of 5m to offer easy access for pedestrians and cyclists to move smoothly across it, including disabled users.
Given these challenges, Arup's team of designers knew that the bridge's design needed to be more complex than a simple 'straight line' bridge.
The solution was two leaning arches with 45m spans, connecting in the middle, and sweeping down towards the water to rest on concrete piers supported on piles socketed into the rock bed.
To ensure that existing views across the river to South Perth were not obstructed, elements’ of transparency were added to the bridge’s balustrades. However, the bridge still needed some level of solidity in order to reduce wind-induced vibrations. Arup’s wind engineers reviewed the bridge to mitigate vibration and overcome potential vortex shedding issues.
Bridge materials
Presented with a windy riverside location and the at-times harsh Western Australian climate, in-depth consideration was given to the materials selected for use in the new bridge. Jarrah was selected for the bridge decking, not only because it wears well but because it is native to Western Australia and therefore familiar to many of the people using the bridge. The Jarrah was sourced from the south-west of Western Australia.
Because of its durability and in particular its resistance to salt and wind corrosion, stainless steel was selected for the architectural elements such as balustrading. Similarly, concrete was adopted for the foundations and piers.
Bringing it all together
The delivery of the design for the Elizabeth Quay pedestrian and cyclist bridge took a multi-disciplinary approach, which included Arup’s structural, civil, geotechnical, electrical, wind, materials, maritime and vibration engineering teams and Arup Associates.
Arup’s design solution overcame every technical challenge whilst ensuring the bridge’s visual appeal was at the forefront of the design.
The final bridge design has delivered everything the MRA and Arup sought to achieve in terms of simple and pure structural forms, complemented by rationalised modular architecture. The bridge is an iconic structure and a key element in the transformation of Perth’s Swan River waterfront.
