Roleystone DN760 Pipe Replacement

February 2023

Perth Region Alliance (PRA – now PRFS) was the infrastructure operations arm of Water Corporation of WA and is responsible for the water and wastewater network maintenance and operating asset upgrades across the Perth Metropolitan area. The nearly 100 year old pipe had reached its service life and was in the process of gradual replacement with the priority of work being critical supply destinations and the number of failures over time. A 150m section on the western slope of Butcher Road in Roleystone was identified as a critical section requiring immediate replacement.

To accelerate delivery of the project, DM Civil was approached to price a design and construct package to reach practical completion prior to the peak demand. This required a fast-track design and approval process as well as procurement of approved MSCL pipes.

An aspect of the project that was identified as one that would require DM Civil to move beyond the ‘business as usual’ approach was re-sequencing and redesign. The project was AS4000 construct only but still needed assistance from the contractor to realise the design on the ground. The series of challenges beyond IFC documentation included anchorage details for the DN400 PE bypass to counter the hill section thrust, the refurbishment of the existing RC pedestals, extension of the bypass for the full route and detailing and sequencing the Soldiers Road tie-ins. This required the contractor to assume control of additional procurement, a partial design role and a degree of management of the project, not normally experienced on a construct only project.

The eastern slope was the most critical section of the pipeline and the contract to replace this was awarded to DM Civil in 2021. The site constraints presented by this project were such that PRFS would be very selective in their choice of contractor.

The measure of successful delivery for the project was demonstrated in the project and construction management overcoming the difficulties that arose as pipeline water supply system operational and other issues became apparent. Although the RFIs relating to these challenges were numerous, significantly, it was the site management team who ultimately developed the solutions for success.

Another measure of success for the project was a clear record for health, safety and environmental incidents. The site was constantly subjected to housekeeping inspections and internal and external safety and environmental audits. The one in three slope section of the pipeline presented as a high risk activity and this was addressed in the controls implemented in the safety plans.  One of DM Civil’s best plant operators was tasked with operating his excavator along the slope, challenged daily by environmental constraints yet achieving results with no negative impact or damage to assets or the environment.

The experienced project team was exceptional in their project management and delivery.  The already varied length of the bypass pipeline was a critical service while the MSCL pipeline was out of commission.  Two additional PE welding technicians were trained from DM Civil’s permanent staff from theoretical and onsite training during the course of the contract.

Our project manager for this contract was Tessa. Tessa fulfilled the role of project engineer on the previous section of pipeline on the other side of Butcher Road, a mirror of this project’s sloped section, but built as a buried pipeline. Tessa’s performance on that project and subsequent works gained her a promotion into a Project Manager role which she seamlessly took on. Her previous experience undoubtedly set her up to take on the stage 2 works.

Tessa was awarded 2021 Project Engineer of the Year, in recognition of her technical skills, people skills and project results. This calibre of management produces successful outcomes for the project and all stakeholders. Tessa is now a mentor for junior engineering and project staff.

Overall, DM Civil successfully traversed this challenging project to deliver their objectives and high standards within the strict project’s safety, environmental and quality requirements.