Parramatta Escarpment Boardwalk and Stewart Street Stairs
The award-winning Parramatta Escarpment Boardwalk is a 3.5m wide pedestrian and cyclist path along the northern foreshore of the Parramatta River.
It serves as the final link in the Parramatta Valley Cycleway and initiates the transformation of Parramatta Quay, the riverside gateway to Parramatta CBD. The Project also includes a new set of stairs linking the river level to Stewart Street at a higher level enhancing accessibility and connectivity in the area.
Location: Parramatta River foreshore, between Charles Street Weir and Rangihou Reserve, Parramatta, Sydney
Client: City of Parramatta Council
Project Completion: March 2021
Project Type: Community Infrastructure (Active Transport, Shared Paths)
Technical Challenges and Solutions
The project required carefully monitored and staged excavation into the steep Ashfield Shale escarpment up to 800 cuts. Maintaining the natural appearance of the shale, with no visible stabilization measures was a key objective of the design brief.
In 2015, Douglas Partners was engaged by Council to peer review the geotechnical information and advice at the time. Leveraging extensive field experience and literature research, Douglas Partners proposed an innovative solution based on the behaviour of shale under varying moisture conditions.
The key insights were:
- Shale frets (crumbles) upon drying and wetting but remains intact in a constant moisture environment.
- A layer of fretted shale on the face acts as a protective barrier, preventing regression.
- If fretted fragments are removed, the faces regress by 5-25mm/year.
Experimental Trial and Implementation
Douglas Partners assessed the proposed shotcrete and rock-bolt stabilisation of the cuttings and proposed an alternative methodology. This apwas tested through an experimental trial excavation, using rock-hammer and milling head techniques. Adversely oriented rock-wedges were pinned using hidden fiberglass dowels, ensuring stability without compromising the natural appearance.
Collaboration and Outcomes
Douglas Partners worked closely with urban design architects (Hill Thalis) and structural engineers (Tonkin) to prepare the tender specification, design the hidden cliff face supports and oversee the excavation. The project was successfully completed, with Parramatta City Council acknowledging Douglas Partners’ solutions and advice as significant to the feasibility and success of the project.
Awards and Recognition
The Parramatta Escarpment Boardwalk has been recognised for its innovative design and successful integration into the natural landscape.
