Pipeline Construction

We specialise in comprehensive pipeline construction, supporting trenchless methods in the water sector to achieve optimal project outcomes. Our network of expert suppliers enhances our capabilities in micro-tunnelling open cut pipelines, and pipe repair. We handle deep pipeline construction in challenging geotechnical and groundwater conditions, using advanced ground support techniques.

Our services include building manholes, detention ponds, and related civil works, with expertise in both new and existing areas. We integrate trenchless and conventional methods to efficiently manage projects and reduce risks. Our pipeline construction services cover main sewer, retic sewer, drainage, water, gas pipelines, pressure mains, MSCL, GRP, and PVC pipelines, utilising trenchless tunnelling with jacking or casing pipes.

In addition to new pipeline installations, Digga Civil has proficiently removed existing pipelines, which were in deteriorating condition, and replaced them with new mainlines.

Our comprehensive pipeline services include:

• Development of Work Plans and Job Safety Analyses (JSA)

• Surveying and setting out

• Clearing and earthworks

• Rock breaking

• Traffic and rail management

• Installation of scour, gate, and isolation valves, along with associated off-takes

• Anchor block and thrust block installation

• Directional boring, pipe sleeving, and grouting

• Disposal of decommissioned pipes, valves, and pits

• Accredited asbestos removal, including Asbestos Cement (AC) pipe removal and disposal

• Pressure testing, flushing, and disinfection of pipelines

• Site restoration, including the removal of excess or contaminated material

• Preparation of as-constructed drawings.
  

Over the past three decades, Digga Civil has successfully installed and removed hundreds of kilometres of various types of pipes and fittings. Commonly installed pipes include PE, Steel, PVC, and Ductile Iron, each selected based on the specific design, pressure requirements, and location of the pipeline project.

Examples of pipeline installations utilising different pipe types:

PE PIPE

Replacement of 1,000 meters of existing 100 mm AC main pipe with new DN 125 PE 100 PN16, and substitution of 400 meters of DN 125 GI pipe with new DN 125 PE 100 PN16 pipe and associated fittings, including bends and gate valves. Installation of a new below-ground scour valve arrangement, additional gate valve, marker posts, and anchor/thrust blocks. Removal and disposal of AC pipe in compliance with current legislation, with road crossings and driveways sleeved and grouted. Conduct pressure testing, disinfection, and provision of As-Constructed Drawings.

STEEL PIPE

1. Replacement of existing steel pipe with new DN 300 and DN 250 MSCL pipe, including associated fittings, anchor/thrust blocks, and services. Road crossings to utilize 560 mm PE sleeve pipe. Reconnection to existing assets, followed by a 2-hour pressure test and disinfection. Provision of As-Constructed Drawings.

2. Replacement of 391 OD MS pipe with DN 400 MSCL, including associated fittings and valves, site drainage, trenching, backfilling, reconnection to assets, pressure testing, and disinfection of the pipeline. Provision of As-Constructed Drawings.

PVC PIPE

1. Replacement of 1,700 meters of 100 mm galvanized steel with DN 100 PVC class 20 RRJ pipe. Excavation along the existing pipe and installation according to Water Corporation Standard 63, including link-ins and associated fittings. Pressure testing and disinfection upon installation. Provision of As-Constructed Drawings.

2. Trenching and laying of approximately 1,400 meters of DN 150 MPVC PN 16 RRJ, including take-offs, CI fittings, and valves, with two links to existing assets. Pressure testing and disinfection. Installation of 2,000 meters of DN 100 MPVC PN 12 RRJ with two road crossings in DN 125 PN12.5, plus two water services, two air valves, a 100 mm scour valve and pit, and an inline 100 mm valve. Linking to existing assets, conducting a 2-hour pressure test, and disinfection. Provision of As-Constructed Drawings.

DUCTILE IRON PIPE

Replacement of 1,580 meters of existing 178 OD S Main with DN 150 DICL RRJ Pipe and associated bends and fittings, including two air valve arrangements, two scour valve arrangements, thrust blocks, and concrete overhead. Reconnection of two existing services and removal of a portion of asbestos bitumen-wrapped MSCL pipe.