Projects

Project Overview:

The Bonds Creek Carrier Extension project is a 1.4-kilometre extension to the previously completed wastewater network delivered by the Austral Leppington Wastewater Stage 3 Phase 1 project. It forms part of a number of critical water and wastewater assets to enable growth and development in the Austral Leppington catchment area.

Project Description:

The Bonds Creek Carrier extension connects the Bringelly Creek Carrier, to the existing Bonds Creek Carrier which was installed as part of the Austral Leppington Phase 1 works. Quickway were engaged by Sydney Water as the Principal Contractor to undertake the works. Scope includes:

• Constructability review of all designs.
• Conducting Service investigations to identify all services and confirm or adjust the proposed design. We also completed Geospatial modelling and space proofing to ensure avoidance of clashes during construction works between existing services/obstacles and the proposed pipelines.
• Establishing compounds, laydowns and access tracks to all launch/receival sites maintenance holes.
• Construction of circa 1.4 kilometres of DN750mm Gravity Mains between MH3 (located opposite 242 Eleventh Ave, Austral) to SP1183. The entire pipeline is being constructed via Trenchless Micro-tunnelling technology, with the nine tunnel drives ranging from 112 to 185 metres in length.
• Due to the alignment being adjacent to, and crossing under the existing Bonds Creek waterway, and the tunnelling and shaft construction works being located within water-charged ground, employing temporary works measures that limited the ingress of water was important. Quickway were responsible for all Temporary Works Design and assessed the best and most cost-effective solution for each specific shaft. The final design solution included the following two methods:
• Secant Piles: 750mm diameter piles drilled in a 7.5m diameter circular configuration, into the shale strata.
• Segmental Shafts: Sinking of precast concrete caisson rings to the required depth sufficient for bi-directional tunnel drives.
• Construction of ten (10) no. DN1800-DN2000 diameter Maintenance Holes (combination of In-situ and Fibreglass Reinforced Plastic) along the alignment, which ranged between 8 – 11 metres in depth. The scope also included the supply and install of 18m high Vent Stacks at several locations.
• Pre & Post Condition Surveys
• Traffic Planning/Management
• Progressive testing and commissioning of the pipelines
• Permanent Restorations including landscaping and rehabilitation of effect grassland areas.

Key Challenges/Highlights:

• Design: The designer (WSP; our nominated design partner for the Icon Water NPDP) was engaged directly by Sydney Water, however as we are working with WSP on Kemps Creek Dual Pressure Mains D&C project also, and as Quickway were engaged in an ECI (Early Contractor Involvement) process to finalise the designs, Quickway provided bespoke design solutions to reduce the cost on several elements of the project, including shafts (secant pile/segmental shafts) and bore lengths.
• Scope: the project was mainly constructed via trenchless technology, however also included some open trenching and deep shaft construction. The works would be required on the Icon Water NPDP.
• Value: the value of the project (circa $27 Million) is similar or larger than that expected for under the Panel. The project was completed successfully and within budget.
• Complexity: this project had similar (or higher) complexity to that expected for the NPDP, which included construction of pipelines around existing assets, working in close proximity to properties, required constructability reviews of all designs, and technical solutions to the project challenges.
• Program: Despite a short timeframe to design, construct and commission the pipeline, Quickway completed the project ahead of program, and to the satisfaction of the client. This was achieved not only through self-performance of site investigations, survey and 3D modelling, access tracks and enabling works, open trenching excavation, excavation of launch & receival shafts for the trenchless works, concrete structures, etc., but also through collaboration with our key partners on the project – namely WSP (Design), TTC and Bothar Boring (Micro-tunnelling) and Citilink Piling (Piling works).
• Community Management: Quickway’s Community Manager for the project led the engagement with the community, business owners, and other stakeholders on the project.
• Additional works: Based on our excellent working relationship and performance on the delivery of this project, and Kemps Creek Dual Pressure Main D&C, Quickway were successfully shortlisted on to both Sydney Water’s Pipeline Panel and Pump Station Panel.