Envolve Infrastructure Ltd were engaged to deliver additional stormwater storage capacity at Holdenhurst Water Recycling Centre in Dorset via construction of a new reinforced concrete below-ground storm tank; their long-standing relationship with MGF meant we were appointed to support with temporary works requirements.
Early engagement was key to the success of this project. Communication began around 18 months before our equipment was sent to site, and thanks to a long-standing record of successful project delivery, there was already a clear understanding of how MGF and Envolve Infrastructure collaborate. This proved invaluable, as the project required a large-scale excavation to accommodate the proposed tank, presenting significant engineering challenges due to its size and complexity.
Holdenhurst – Storm Tank
Envolve Infrastructure Ltd
Christopher Atherton, Design Team Leader and Jack Hooper, Key Accounts Manager – South West
In-house engineering team provides tailored solutions for complex excavations, ensuring safety and efficiency.
The key challenge was delivering a detailed design for a large-spanning cofferdam that accounted for pile positions while minimising deflections. The scale of the excavation and integration of multiple elements required precise engineering and coordination with other contractors, including JIG Consulting Engineers for the cofferdam & full temporary works integration and Ritcher Associates for the Dewatering design & CAT3 check.
MGF was engaged to provide a frame-only design for the cofferdam, working closely with Envolve Infrastructure. Through clear communication between the contractor, our Design Team and other consultants, we developed a solution for a propped cantilever using a single-frame system for the main excavation. This included a 406UC Tank Brace Frame, complete with four 400 series knee braces, four 600 series knee braces and three 1000 series cross struts.
A deeper section of excavation necessitated, a two-frame arrangement using 305UC Tank Brace Frames with additional knee braces for support. MGF also supplied the sheet piles based on JIG’s wall design and collaborated on the lifting design for installing the three large struts. MGF’s Lifting & Safety team was on hand to provide our T33 Lifting Tray, helping to safely move machinery in and out of the excavation.
Our 400 series strut is a highly versatile, heavy duty modular bracing strut system designed primarily for use with hydraulic …
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