Landmark new bridge twists, turns and connects

Jennifer Shand Jennifer Shand Australasia Press Office,Sydney
9 June 2020

A striking new pedestrian and cycle bridge across one of Sydney’s busiest motorway intersections, is believed to be world-first design. 

Arup and KI Studio architects designed the bright blue Lachlan’s Line bridge with its unique double-helix shape to connect a new residential/mixed-use development, a major business precinct and a metro station. It is now open to the public.

Lachlans Line Bridge is a striking new pedestrian and cycle bridge Lachlans Line Bridge is a striking new pedestrian and cycle bridge

The eye-catching bridge twists and turns over the motorway

More than 3,600 steel plates make up the 178m long structure, but no two pieces are alike – every piece of steel has a different curvature, and the helix varies 2.3m in its diameter in relation to the structural demand.


Image © Landcom

The curved, fabricated box section construction elevates helix design and fabrication to a new level combining sharper surfaces with fluid geometry, enabled by Arup’s digital approach through both design and delivery phases. ”

Andrew Johnson Andrew Johnson Project Director

Image © Landcom

The eye-catching bridge was built and installed in four separate spans. The entire workflow was digitised, connected by computational code, which allowed the team to accommodate changes more quickly than traditionally – updating in minutes, not weeks – and continuously innovate during the design process.

The digital design also enabled more interactive engagement with the client Landcom, and community stakeholders, positive and timely outcomes around updates for the adjoining road widening, and minimal impact on the adjacent forest of native Turpentine trees. 

Arup also provided civil, lighting and landscape architecture services to ensure this is a liveable and well-connected part of the city. 

Landcom finalised the landscaping and pavement upgrades and installed bridge features such as handrails and lighting. Some 5,000 people are expected to take up residence in Lachlan’s Line.