MGF has supported United Utilities and VJ Donegan on the Carr Mill Better Rivers Project in St Helens, a £4.3 million scheme that forms part of United Utilities’ ongoing commitment to improving river water quality across the region. The project is designed to reduce the environmental impact of storm overflows by upgrading key sections of the wastewater network, installing new connecting pipework and constructing a new combined sewer overflow (CSO) structure. Â
These works require several deep excavations, each with its own set of ground conditions and structural demands. Ensuring these excavations could be carried out safely and efficiently was critical to maintaining progress across the wider programme.
Carr Mill Better Rivers Project, St Helens
VJ Donegan
Provided a deep excavation support solution that allowed for major water infrastructure improvements
MGF was initially brought into the project during the early contractor involvement stage to develop a temporary shoring concept for the new CSO structure. As the design progressed, this early concept was refined into a full detailed solution that could support the various deep excavations needed for pipework connections, manhole installations and the main CSO structure. Â
To achieve this, MGF supplied modular 406/305 Bracing systems paired with pre-driven Larssen interlocking sheet piles. This combination offered the strength, flexibility and stability required for the deeper excavations while remaining adaptable to the differing excavation footprints across the site. The use of pre-driven piles helped secure the excavation boundaries in advance, preventing ground movement and supporting safe excavation throughout the project. Â
One specific requirement from the customer was the need for a clear top frame opening during the second stage of works to allow the installation of the CSO screening unit. MGF adapted the temporary works to accommodate this requirement, ensuring the contractor maintained the necessary access without compromising the integrity of the excavation support system. Â
MGF’s involvement continued throughout the project, providing design development, equipment and ongoing technical support to help the contractor manage the challenges associated with deep excavations and complex wastewater infrastructure installations. Â
MGF delivered a robust and dependable temporary works solution that enabled VJ Donegan to carry out the deep excavations safely and in line with United Utilities’ programme requirements. By engaging early and working closely with the contractor, MGF ensured that the shoring system supported all phases of construction, from initial excavation through to the installation of the new CSO and associated pipework. Â
The modular bracing system design, combined with the stability of pre-driven sheet piles, provided a practical and effective approach for deep excavation support. The tailored top frame arrangement ensured that the contractor retained essential access for mechanical installation, allowing the works to proceed smoothly and efficiently. The project highlights MGF’s commitment to delivering safe, practical and well-engineered temporary works solutions for major water infrastructure improvements. Â
Our 406UC Brace has been designed to brace large and deep cofferdams, these are frequently used on major basement and …
Designed to brace large/deep cofferdams for the safe installation of underground structures, deep drive/thrust pits or basements. Double acting hydraulic …
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