Completed in April 2011, the over 100 year-old sewer presented numerous challenges due to its location. Running in close proximity to key Sydney city structures and infrastructure, including the Powerhouse Museum, the light rail corridor, and UTS, the project required a great level of skill for safe and successful completion.

Several major requirements underpinned the project:

  • Design, supply and installation of a self-supporting structural liner consisting of a GRP DN600 pipe with a minimum stiffness requirement of SN32,000.
  • Hydraulic jacking of pipes in both directions from a centrally-located 6 m deep launching pit.
  • Jointing of GRP pipes with a flush rubber ring and collar system.
  • Watertight connection of the live junctions, despite a total prohibition of any man access into the 600 mm diameter GRP liner.
  • Injection of a specifically designed grout between the oviform and new GRP liner to ensure it wouldn’t ‘float’.

Sewer access

Entry access over the full sewer length was crucial for the detailed survey and clean-up required, however the restrictive 1,220 mm high by 810 mm wide oviform sewer made access difficult.

Eptec overcame this access restriction by designing and constructing of a series of trolleys to travel along the oviform. The company also designed a hydraulic pipe-launching system capable of jacking GRP pipe in a continuous line of up to 180 m within the sewer.

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Minimising impacts

Minimising environmental impacts required careful planning and management, and saw the company install a failsafe continuous flow bypass system along the 370 m section of pipe lined. A ventilation system compliant with stringent noise limitations was also installed. Excavation and removal of highly unsuitable soil from the launching pit excavation, and de-silting and removal of hazardous and malodorous material from the sewer was also required.

Eptec liaised closely with key stakeholders over the course of the project, with the most affected stakeholder, the Powerhouse Museum, commending Eptec for creating ‘minimal impact’ and maintaining the surrounding area to the highest safety and environmental standards.

Sydney Water’s performance appraisals and audits on safety, quality, environmental and community relations confirmed that Eptec demonstrated a very high level of technical expertise throughout the course of this successful project.