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Port Macquarie stormwater pipe repaired using Expanda liner

The stormwater pipe, which drains into a waterway in Port Macquarie, was significantly deteriorated with heavy infiltration through open joints and shellfish encrustation along the pipe walls.

This deterioration was causing a reduction to the pipe’s flow capacity, contribution to regular upstream flooding.

Expanda Pipe liner was selected to complete the project as it would restore the pipe’s structural capacity and eliminate infiltration.

The material was also preferred as it was suitable for the challenging project conditions; two key challenges being the short working hours limited by changing tides, and the variable pipe diameter which ranged from 800 mm to 950 mm.

Ahead of installing the liner a heavy cleaning operation was necessary to remove internal oyster encrustation.

To complete the project, Interflow installed the line from the downstream end, avoiding disruption to the Port Macquarie CBD.

As the downstream end of the pipe was submerged most of the time, work crews constructed a coffer dam where dewatering was carried out using Interflow’s Super 2000, which is ordinarily used as a combination recycling jetter.

The liner was then installed starting from the dewatered coffer dam.

As Expanda Pipe is mechanically expanded during the installation process, it was able to efficiently handle the variations in diameter along the pipe length.

Installation does not block the pipe and heating is not part of the process, so work could be undertaken in working hours limited by low tide with the liner partially submerged.

Following lining, a duck bill flap was installed at the the pipe outlet to limit backflow.

These works resulted in long-term pipe restoration, restoring its flow capacity and minimising the chance of flooding in the CBD.

For further information visit on Expanda Pipe liner visit the Interflow website.

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