Sydney's revolutionary urban link, connecting Wynyard - CBD - BarangarooOpened to the public in late 2016, Wynyard Walk is a major transport infrastructure designed to provide pedestrians with a safe, swift, and efficient method of movement between Wynyard Train Station and the new and expanding areas of the Barangaroo waterfront precinct and Sydney CBD western corridor. Wynyard Walk components consist of a new civic entry building for Wynyard Station, a 180m long pedestrian tunnel (110m of driven tunnel plus 70m cut and cover), a western tunnel portal, a plaza and a bridge spanning Sussex Street.
This project is an essential upgrade for Sydney and one that involves the comfort and safety of Sydney's population. It is anticipated that the new Barangaroo development will accommodate up to 23,000 office workers and attract around 33,000 additional visitors per day. A primary focus for the design was to enhance the customer journey and experience. Embracing the concept of flow', the tunnel's smooth lines and curved forms add aesthetic appeal to functionality - enabling pedestrians to move safely and comfortably from Wynyard Station to Barangaroo, avoiding steep inclines and congested road crossings to arrive at their destination in only six minutes.
The engineering design was a result of the collaboration between PSM (geotechnical and tunneling experts) and TTW (experts in building structures) working in close consultation with CPB Contractors, Transport for NSW, Woods Bagot, NDY and other stakeholders to deliver optimal outcomes for this extremely complex design and construct project. Located just beneath the surface of Sydney's Central Business District, the project's challenges encompassed design and construction within a major city hub, surrounded by critical services, heritage concerns, and situated in an area of constant activity.
Highly-constrained environments were inherent throughout the project - particularly for the Wynyard Station Connection and Wynyard Walk Pedestrian Tunnel components, which pass directly under heritage-listed Railway House, commercial high-rise One Margaret Street, and adjacent to the busy Wynyard Station. Creative engineering solutions, in conjunction with advanced construction methods, were employed to navigate this complex web of heritage elements and contemporary services.
Through this approach, we have demonstrated that outstanding D&C outcomes can be achieved on a complex site by challenging the design through collaboration across disciplines. Moreover, we were able to demonstrate our ability to improve on the precedence set by the reference design and offer the client time and value savings through an integrated approach between structures, geotechnical, and construction engineering.
The key features of the project include:
- Western entry to Wynyard Station - a new entry building off Clarence Street with a deep excavation and transfers spanning over a future railway corridor
- Railway House transfer and underpinning - a complex underpinning and transfer of an existing 12 level 1920's heritage building in an extremely confined basement adjacent the operating trains. This element required extensive high tech surveying monitoring systems and a network of multi-stage jacking ensure zero settlement of the existing building
- One Margaret Street transfer - structural transfer beam system within the basement of an existing 20 storey tower to support the building and allow the new tunnel to pass under
- Western Tunnel Portal - excavation and bridging works within a confined worksite with a landmark steel and glass canopy
- Sussex Street Pedestrian Bridge - connects Wynyard Walk to Barangaroo with a bold concrete structure consisting of precast Super-T girders for the main span connecting to a unique cantilevering west abutment via a continuous integral joint. This bridge was designed to RMS standards and specifications in consultation with RMS review engineers.
- Pedestrian Tunnel - a new 120m long tunnel constructed below both Clarence and Margaret Street