Lennox Bridge Portals

NSW
Parramatta City Council
2015

Abergeldie was engaged by City of Parramatta to deliver the construction of the Lennox Bridge portals. The works included the excavation and construction of two portals within the outer abutments of the historic bridge that spans Church Street over the Parramatta River. The works were carried out to provide seamless riverside access for pedestrians and cyclists on both sides of the river, eliminating the need for users to ascend steps or ramps from the riverbank to the street-level bridge deck.   

Scope of works

The works involved excavation through the bridge deck, roadway, and abutments to install structural in situ culverts to form the two cycleway portals. 

The scope of work included:  

  • Contiguous piling, excavation, and disposal of excess material. 
  • Construction of structural in situ culverts. 
  • Removal and replacement of significant heritage sandstone masonry blocks. 
  • Relocation and adjustment of multiple service lines buried within the brick deck. 
  • Internal fit-out, including lighting and essential services. 
  • Road realignment including kerb and gutter and road pavement work. 
  • Footpath and cycleway paving. 
  • Installation of a new sandstone balustrade. 
  • Landscaping. 
  • Management of archaeological preservation. 

Mitigating community impact through staged construction

To prevent congestion on the road and pedestrian paths during bridge work, the project team utilised temporary scaffolding and walkways spanning the river’s full width. The staged approach to construction and traffic management ensured minimal disruptions of the road bridge which carries busy Church Street over the river.


Complexity of historic infrastructure 

The bridge, built in 1839 and later reinforced in 1902 and widened in 1934, holds significant heritage importance. Given the absence of construction drawings from 1839, assumptions were necessary for structures within the existing abutments. Method flexibility was allowed to ensure stability during open-cut excavation, considering potential revisions as work progressed. 

Construction was paused after uncovering archaeological remnants of Australia’s oldest known bridge, the Gaol Bridge, believed to be built in 1810. An archaeological team documented findings and provided guidance for modifying the tunnel’s interior fit-out to incorporate a display of discovered elements. 


Improved access for pedestrians and cyclists

The project has improved access for pedestrians and cyclists, preserved historical elements including the Gaol Bridge remnants, and minimised disruptions for users of the Church Street bridge.