Multi-disciplinary experience to deliver a complex water infrastructure upgrade

July 2019

DM Civil were contracted to provide complex construction services to re-locate existing major water systems, with new replacement water mains, as well as removal, or grout fill abandoned water pipes, under Armadale Road near the intersection of Armadale and Nicholson Roads. These projects were critical stages to the delivery of a main roundabout and fly-over bridge development.  

As these pipeline works incorporated some of Perth’s main water supplies, Serpentine & Armadale Trunk Water Mains, it was crucial to have early contractor involvement. DM Civil, collaborated closely with key stakeholders to develop extensive constructibility methodologies and establish clear planning, staging, sequencing and co-ordination for the roll-out of all services, including:

  • Comprehensive stakeholder management – a staged process to minimise disruption to local businesses, scheduling of works during peak water demand times, hazard prevention with high voltage power lines, high pressure gas mains and water reticulation mains to maintain the integrity of the water supply during construction.

  • Pipeline design, replacement and construction logistics – a re-iterative process to establish the best suited alignment, pipe materials for the location, environmental sustainability and to minimise the disruption of existing infrastructure.    

Our scope of works expanded as the project evolved and DM Civil were awarded:

  • The replacement of 90m of the DN1220 & DN1370 Serpentine trunk mains, replaced with DMN 1400 Sintakote® MSCL, under Armadale Road. This involved the removal of each main, then installing new pipeline. Weekend shut downs and traffic diversions were required of Armadale Road for each main.
  • The installation of 2 x DN900 section butterfly valves on the existing Serpentine Trunk Mains;
  • Installation and removal of temporary DN600 MS PRV pipeline with 2 x DN600 butterfly isolating valves, off the existing Serpentine mains, into the existing PRV (Pressure regulating Valve) station;
  • The installation of 125m of DN315 PE and 230m of DN250 PVC, to replace existing Cast iron water reticulation mains.  This included HDD (Horizontal Directional Drilling) under Nicholson road for the DN315 PE.
  • The laying of 1,050m of DN800 MSCL pipe. This included:
    • 4 Air & scour valves
    • 21m of DN1500 MS casing pilot auger bored under Nicholson Road with DN1200 MSCL pipe sleeved and grouted inside, in ground water at 4m depth, with 12 metres of the bore requiring use of manual pipe jacking techniques through hard rock;
    • 24m of DN1000 MS casing pilot auger bored under twin live DN1400 Serpentine Trunk Water Mains, with the DN800 MSCL Armadale Main sleeved and grouted inside, in groundwater at 4.8m depth.
    • 18m of DN1000 MS casing pilot auger bored under high pressure gas main.
    • DM Civil’s Trenchless Technology Division provided the pilot auger boring, sleeving & grouting for the DN1500 & DN1000 MS bores to achieve the relocation, disinfection, hydrostatic testing, connection and replacement of this DN800 Armadale Trunk Water Main pipeline section.  By using our trenchless techniques, this mitigated safety issues with working in groundwater, at depth with large diameter mains and it also provided added protection to existing live services, whilst maintaining traffic flow.
    • 556m3 Aerated Foam Grout to abandoned remaining sections of DN1370mm & DN800 water pipe;
    • Removal and disposal of redundant existing DN1370, DN1200 and DN800 coal tar epoxy enamel coated MSCL trunk water main pipes, which had ACM (Asbestos Containing Material) in the wrapping.
    • Demolition, removal and disposal of existing redundant steel reinforced concrete valve pits, valves and interconnecting pipework.

DM Civil ensured the successful delivery of these projects through meticulous engineering, project and operational management. There were no service strikes, or safety incidents, even when unknown services were encountered. It is a testament of our multi-disciplinary experience and capabilities that prove DM Civil can build a pipeline, anywhere and guarantee our performance.