Bridges

The West Gate Tunnel Project provides a second freeway link between the western suburbs of Melbourne and the city, including a much-needed alternative to the West Gate Bridge. 14km of new walking and cycling paths are being constructed to improve commuter accessibility, including a new cable stay bridge which traverses the intersection of Footscray Road and Waterfront Way. The bridge comprises two 46m approach spans and a 121m central span over the intersection. The central span of the bridge is set on a vertical crest curve whilst the horizontal alignment comprises back-to-back reverse curves of radii 135m and -127.5m. Five backstays and seven forestays tie the steel box girder superstructure to each steel pylon. The stays are arranged in a semi-fan configuration and asymmetrically support the steel box along its length. Tie-down systems are provided at each of the abutments to resist torsional uplift of the bridge. This paper outlines the key constraints, discusses the construction stage methodology and analysis and describes important considerations in the fabrication and detailing of the bridge steelwork to accommodate the complex geometry. The paper also discusses the extensive wind tunnel testing undertaken throughout the design stage to determine key wind parameters and identify the bridge's susceptibility to wind-induced excitation and aerodynamic instability. The paper also presents the assessment methodology and outcomes relating to dynamic effects of pedestrians traversing the bridge.