UEA Trenchless has recently completed a pipe bursting contract for Dubbo City Council for the renewal of 357 metres of 100mm water main with PN16 125mm polyethylene pipe.
Pipe bursting technology was necessary for the successful completion of this project for two key reasons. Large, established trees were situated above the existing main and could not be removed for visual and heritage reasons. In addition, existing utilities were situated along either side of the existing water main, leaving the existing 100mm water main as the only possible location for the new 125mm PE pipe.
Pipe bursting replaces the existing host pipe by displacing its fragments into the surrounding soil while simultaneously pulling in the new product pipe of the same or larger diameter into the void created. This method is what made pipe bursting the best possible solution for this environmentally sensitive project.
UEA Trenchless worked closely with Dubbo City Council staff to complete the project which encompassed the installation of 357 metres of PE pipe, completed in five runs, the installation of five fire hydrants, 34 house service main cocks and connections onto the existing main including anchor details. Once the main was renewed and main cocks installed council staff performed the connections back to boundaries before UEA backfilled and restored each area.
Careful planning and consideration was required to address two primary areas of concern:
Firstly, the depth of the existing water main under the large, heritage listed trees meant the root system came into close proximity of the main. As these trees were protected, damage to the root system was not acceptable; therefore a non-destructive unit was used to locate and expose the root system to avoid damage.
The projects rural location was another potential risk factor. This was overcome with careful pre-planning to ensure suppliers from out of town were able to transport fittings to site on time, and local suppliers were used wherever possible.