Arup was the design lead consultant for the Elizabeth Quay pedestrian and cyclist bridge and delivered a lot more than just structural engineering for the feature arch and suspension bridge.
The bridge spans from the western Williams Landing and the new island in the east, providing increased opportunities for people to interact with the Swan River. It is 22m high, 5m wide and suspended over the inlet with a 5.2m current mean clearance. Two 45m spans connect in the middle, with the bridge’s arches sweeping down towards the water to rest on concrete piers supported on piles socketed into the rock bed.
Arup’s engineers and architects worked together to calculate everything from how to balance the dramatic impact of the bridge’s leaning arches with its structural function, to how to minimise wind vibration.
Using parametric modelling, Arup optimised the geometry of the pedestrian pathway to overcome design constraints, including the range of different heights required at different sections of the walkway.
120m long pedestrian and cyclist bridge
3600views across the Swan River
22m highcable-stayed bridge
Vessels needed enough space to travel under one section of the bridge, while pedestrians needed smooth access across to the island at the end of the bridge. Arup’s architectural solution was a curved form for the bridge deck allowing the creation of extended ramps to clear the navigation channel.
Arup’s end design of the Elizabeth Quay pedestrian bridge is everything the Metropolitan Redevelopment Authority sought to achieve in terms of simple and pure structural forms, complemented by a rationalised modular architecture.
Artfully structuring complex curves
The digital design workflow was a highly collaborative process that proved to be pivotal in the successful delivery of the project. The architect used Rhino and Grasshopper as parametric tools to converge quickly on the architecturally-desired, ‘S’-shaped bridge concept. Preferred sculptural forms of the bridge were developed parametrically with the architect using Grasshopper, opening up the opportunity for Arup’s engineers to link into the architect’s parametric scripts to integrate the design workflow.
Working from the same shared Grasshopper canvas, the engineering team were able to generate analysis models to assess the structural performance of bridge form as it developed in concept. 1D finite element models were parametrically generated directly from Grasshopper to GSA using Arup’s very own Salamander plug-in. These direct digital links provided the design team with the ability to optimise and rationalise the complex bridge form in a very short time-frame.
As an outcome of the digital workflow, complete coordination and alignment of design between architect and engineer was maintained throughout.