We supported the Porirua Wastewater Treatment Tank project, supplying PE gravity wastewater pipe and manholes using our proprietary EF welded socket system. The project required careful planning thanks to challenging ground conditions – hillside runoff to the east, coastal groundwater to the west, and a high water table throughout the site.
To ensure the pipeline and manholes remained secure, the design incorporated detailed flotation calculations, trench-strengthening improvements and approval of an SN16 pipe structure capable of meeting both HNHO72 load and seismic uplift requirements.
Supply included in-house training for the team ahead of installation, followed by trench-side support once pipe arrived on site. The project featured high-vis yellow internal spiral PKS pipe from DN800 to DN1500, including around 400m of DN1200, along with 24 PE manholes up to DN2500. Concrete ballast bases and on-site benching ensured stability across the network.
Welding support spanned more than 15 days, covering spool fabrication, flow meter brackets, flange transitions and multiple connection types into manholes, structures and weirs. Technical oversight included PS1 and CM checks, third-party engineering review, and peer review.
We were integral in connecting Wellington to the growing economy centres of the Kapiti Coast/ Horowhenua regions and the wider North Island.
Over 12km of PKS Civil Culverts, ranging from DN300 to DN2500, were supplied to the Transmission Gully Project to be installed as culverts under the main highway alignment. The contractor found that the long lengths resulted in less joints and less risk posed to the culverts under the main alignment.
On the project, there were six major culverts that were designed to the NZTA Bridge Manual and required an FEA (Finite Element Analysis) modelling to be carried out on each individual pipe section to determine selection of the correct Stiffness Nominal (SN) class for pipes that were installed. The culverts are installed near many earthquake fault lines, and at varying depths, the culverts are required to support the earth structure and State Highway constructed directly above.
