Rehabilitation
Kirribilli Aqueduct Rehabilitation
Kirribilli Aqueduct occupies a prominent position on the Sydney Harbour foreshore and is used to service a number of nearby residents. The existing aqueduct, which was built in 1968, was in poor condition due to the harsh environmental conditions experienced during its life which has resulted in barnacle encrustation and increased levels of corrosion. Failure of the structure would result in sewage discharging into the harbour waters.
Due to our extensive experience and reputation for providing innovative solutions to challenging problems SASTTI JV was engaged by Sydney Water to complete the design for the rehabilitation of Kirribilli Aqueduct. This included an initial condition assessment to assist in determining the scope of repairs, site survey of the alignment, preparation of technical specifications and repair requirements, detailed construction drawings and construction support.
Given the location of the work, there were several key challenges that needed to be addressed. Some of these included:
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Limited access for inspection and construction as the aqueduct lies within the tidal zone and is inundated during high tide. This was particularly problematic for the downstream areas which have a very small window for completing work.
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Challenges associated with the harbour environment including wave impact, increased corrosion rates and barnacle encrustation.
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Limiting any impacts that the work may have on the community and customers, in particular those residents whose properties were immediately adjacent the aqueduct.
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Oddities within the existing arrangement that would not meet current best practice such as horizontal deflections in the alignment (not at MHs) and in-pipe junctions.
Our extensive experience with condition assessment meant SASTTI JV was able to identify those components of the aqueduct, such as the concrete piers and MHs, whose condition did not warrant replacement. This allowed substantial time and cost savings as minor repairs were sufficient rather than more costly replacement.
SASTTI JV worked collaboratively with the Delivery Contractor to develop a repair solution that minimised the amount and complexity of onsite work and allowed much of the work to be completed from the water. This was the first stainless steel aqueduct renewal Sydney Water completed on a foreshore and the pipe wrapping system was a first for this type of application known to the supplier. The strong relationship shared between SASTTI JV, Sydney Water and the Delivery Contractor was key to successfully delivering these works.
