Barrow Link Bulk Supply Point – DN500 connection
Key Achievements
- Delivered under-pressure connections onto live treated water trunk mains & aqueduct
- Maintained the integrity of operational water network assets throughout a complex excavation and connection programme
- Installed DN500 ductile iron pipework and associated fittings within challenging ground conditions
- Completed pressure testing, chlorination and commissioning
- Managed rock-bound excavation conditions and significant groundwater ingress
Project Overview
GDB Civils Ltd were engaged to install DN500 ductile iron pipework and associated connections onto existing live trunk mains as part of the Barrow Link BSP (Bulk Supply Point) works.
Focus
To install DN500 ductile iron pipework and associated connections onto existing live trunk mains as part of the Barrow Link BSP (Bulk Supply Point) works.
The works
The works were carried out on/around existing aqueduct infrastructure, requiring careful planning and coordination to protect the integrity of the asset throughout construction & commissioning.
Key Challenges
- Deep excavations adjacent to live water trunk mains and aqueduct infrastructure
Works were undertaken in close proximity to operational trunk mains requiring stringent controls to prevent disturbance to either asset. - Bespoke temporary works required to support excavations approximately 4m deep
Trench support required a bespoke temporary works design, developed to suit excavation depths of approximately four metres and the specific ground conditions encountered. - Difficult excavation conditions including heavily rock-bound ground
Excavation progress was affected by heavily rock-bound ground, requiring an adapted excavation methodology. - Significant groundwater ingress into excavations
Significant groundwater ingress required continuous pumping throughout the works to maintain safe working conditions. - Under pressure connection works onto live assets
Connections were made onto live trunk mains under pressure, requiring careful sequencing and control to avoid interruption to supply. - Maintaining integrity of operational infrastructure throughout the works
All activities were planned and executed to safeguard the continued operation and structural integrity of the surrounding network. - All this was delivered ensuring the strict water hygiene and quality standards were adhered to.
Our Delivery Approach
Key activities included:
- Installation of DN500 ductile iron pipework and associated fittings
- Excavation and support using bespoke temporary works systems, including trench boxes and sheets & frames
- Installation of fabricated under-pressure tee
- Coordination of under-pressure connection activities
- Commissioning activities including pressure testing, chlorination and flushing
- Connection works onto a secondary live main via a welded saddle arrangement
Outcome
GDB Civils successfully delivered complex live asset works within a high-risk operational environment, maintaining network integrity throughout.
Feedback from United Utilities Senior Project Manager
This was an exceptionally challenging and highly complex connection project. The works involved numerous technically demanding elements and were delivered within a complex operational environment.
GDB Civils successfully completed the trunk main connection, overcoming challenging ground conditions, deep excavations, and significant groundwater ingress. Throughout the project, the management and construction teams demonstrated excellent planning, effective stakeholder engagement, and robust risk management practices.
The works were delivered safely, ensuring uninterrupted customer supplies and full compliance with all water quality standards.
A key factor in the successful delivery of this project was the strong and continuous collaboration between United Utilities and GDB. This partnership approach enabled challenges to be addressed proactively and ensured the project objectives were achieved safely, efficiently, and to a high standard.