Record pipe renewal in Adelaide Road in Wellington, New Zealand

05.04.17 - In Wellington, the capital of New Zealand, an existing 152 mm (6 inch) section of earthenware sewer had to be renewed in Adelaide Road. Contractor GP Friel Ltd. were engaged by Wellington Water to do this challenging job. Engineering consultancy CH2M Beca designed a pipe cracking solution that minimised the hazards associated with open trenching and reduced the length of traffic disruption. This design solution was ideal for the location in a residential area. 180 m SEWER REHABILITATION IN ONE GO
Upon inspection of the site and the design G.P. Friel realised that there was only one intermediate manhole with no significant change in grade and alignment. Therefore, in order to capitalise on a smart design, a plan was put in place to break out in the intermediate manhole and pull the new 160mm OD HDPE pipe in one continuous length applying the dynamic pipe cracking method. This further reduced the number of excavations needed and the amount of time that would be required to work in traffic management. It also turned the pipe cracking into a massive 180m long renewal – the longest G.P Friel had ever attempted with their GRUNDOCRACKPCG 130 and maybe even a record for New Zealand. The air-driven pipe cracking machine shatters the old pipe while advancing through the old pipe and radially displaces the fragments into the surrounding soil. The bore hole for the new pipe is extended at the same time. The pulling force of a winch supports the pipe cracker,guaranteeing safe guidance through the given pipe path.
After consulting with TRACTO-TECHNIK Australia’s product specialist Daniel Toms, G.P. Friel were confident that their new state of the art GRUNDOCRACKPCG 130 pipe bursting tool and 5 tonne GRUNDOWINCH constant tension winch (both supplied through TRACTO-TECHNIK Australia in Brisbane) were more than capable of safely completing a burst of this magnitude. But that was only half the story.

In order to pull a 180 m length of HDPE pipe you need to have somewhere to weld it into one length. G.P Friel liaised with Wellington City Council Parks & Gardens and secured a section of the nearby McAlister Park for that purpose. A launch pit was prepared the day before the burst which used compliant skid resistant plates to protect it overnight. G.P. Friel also ensured that the receiving manhole and intermediate manhole were prepared and ready to go.

G.P. Friel’s supply chain partner ATMS provided traffic management for the pipe cracking. The work site needed to be over 360 m long in order to encompass the receiving pit, launch pit and the 180m of welded pipe all in one line. It also included a busy signalised intersection between Adelaide Road and Luxford Street so it was imperative for the team at G.P. Friel to liaise with the residents of the nearby Village Park care home to ensure that no accesses were blocked in such a long worksite.

The preparation work really paid off and the burst was completed in a little under 3 hours as planned. There were no incidents and only minimal disruption to the travelling public was encountered.. At the time of writing G.P. Friel had a few more days of reinstatement to do in Adelaide Road and a new manhole to construct which once completed will improve maintenance access in the future, and leave the residents with a new robust sewer.

G.P. Friel look forward to continued success utilising trenchless technology techniques and further strengthening their relationship with Wellington water.



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