Bridges

As part of the Northern Beaches Hospital Connectivity and Network Enhancement Project, Warringah Road is being upgraded and widened to accommodate grade separation. The upgrade includes two new shared path bridges, at Forest Way and Hilmer Street, to link the shared path system and provide for hospital, school and local access across Warringah Road.

The bridges’ curvilinear superstructure will have a striking visual appearance and consists of long span, continuous steel box girder with a composite reinforced concrete deck slab. The structure is slender and elegant; the sloped safety screen accentuates the elegant cresting wave form of the aluminium panels on the curve outer, and will provide a pronounced gateway to the Northern Beaches.

The design of the shared path bridges was developed with the following aims:

• Safety during construction.
• Cost-effective design.
• Minimal disruption to Warringah Road traffic during construction.
• Accessibility provisions are to be achieved in accordance with AS 1428.1 (3).
• Minimal future maintenance requirements with the elimination of tuned mass dampers and drainage scuppers on the deck. Hand railing and safety screens elements are detailed to enable removal and replacement from the bridge deck.
• Acceptable vertical and lateral dynamic performance for human induced vibrations.

The vertical and lateral dynamic performance was assessed using the provisions of Eurocode BS EN 1991-2 (4) together with the JRC Technical Report - Design of Lightweight Footbridges for Human Induced Vibrations, Heinemeyer (6) which are more comprehensive than the criteria in AS 5100.2 (1). The delivery of the shared path bridges is the result of a strong working relationship between Ferrovial York Joint Venture, AECOM and Roads and Maritime Services. The project has demonstrated the successful outcome of close collaboration between the designers, the client and stakeholders throughout the design and construction.