The locals enjoy their area and outlook over Sydney Harbour, so when the existing 2.5 m deep, 150 mm sewer at Ithaca Road needed to be rehabilitated, Trenchless Technology was the first requirement and guaranteed success in upsizing the sewer to 250 mm PE was the second.

The Grundoburst 800G was the first choice by Veolia Water Network Services to satisfy both the job and client requirements. Veolia also own two Grundoburst 400Gs with which they normally install thousands of metres of new mains each week, and have recently purchased a 1250G.

The locals were impressed that the disruption caused while the works took place was temporary, and were blissfully unaware of the obstacles encountered by Veolia Water Network Services staff on this job.

Controlling the pedestrians and traffic above ground was an important issue, but finding suitable space in amongst all the underground services to fit in the relatively small machine and to pull in the new pipe, and keeping the tidal water flow out of the excavations was much more challenging.

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The excavations were kept relatively dry using de-watering spears, set up around each of the excavations, with the machine pit only 15 metres away from the Elizabeth Bay foreshore and 2.8 m deep to the base. Extensive shoring was required to support all the utilities in the area as well as provide a safe work environment for the Veolia Water Network Services crew. To add a further complication, the old 150 mm cast iron main had been lined with a PVC slip lining so special accessories were incorporated to be able to cut the PVC, burst the cast iron mains and joints and then expand these fragments with the 300 mm expander to install the new 250 mm PE with minimum tension during the pulling-in phase.

The first 38 m burst was completed in less than half an hour and through the extensive quantity and quality of job planning and preparation, resulted in another successful pipe upsize exercise by the team at Veolia Water Network Services and their GrundoBurst 800G. Ultimately, a very challenging project became a relatively straight forward pipe bursting project.

The highly sensitive job was completed to the total satisfaction of the client, Sydney Water, the contractor Veolia Water Network Services and the local residents.

Overall a positive environmental outcome was achieved utilising a long term, larger replacement pipe installed with TT Grundoburst Trenchless Technology.