Mabey Hire has announced its work with BAM Nuttall to help enable the installation of a new flood barrier in the River Haven. Due for completion in early 2021, the floodgate will better protect over 14,000 homes and businesses from tidal flooding in Boston, Lincolnshire.
The £100m Boston Barrier project, led by contractors BAM Nuttall and Mott Macdonald Joint Venture (BMM JV) on behalf of the Environment Agency, follows floods in 2013 where a tidal surge overtopped banks of the River Haven and damaged over 800 properties in the area. Mabey Hire, contracted by BMM JV, has provided a series of struts and frames to support the walls of the water tight excavation area, known as a cofferdam, in which the new floodgate is being built. Mabey Hire’s structural supports are coping with differing load of 0kN/m up to approximately 500kN/m, coming from the varying currents and tide levels of the water surrounding three of the cofferdam’s four walls. The fourth is bordered by the river embankment resulting in an eccentrically loaded structure.
Mabey Hire designed the struts with these different load cases in mind, to ensure the cofferdam remains stable and watertight as works progress. The engineering experts supplied a Supershaft Plus hydraulic frame, alongsideSuper Bracing struts made up of 600 box sections and a 350T ram unit. To stabilise the structure, bespoke box sections were created and welded to the rear of the frame, which sit in the pan of the sheet pile wall to ensure the eccentric loads are distributed around the cofferdam walls.
Mabey Hire’s on-site advisor worked with BAM to install the frames in December 2018, which will be used until the end of May.
Steve Lowder, Project Director, BAM Nuttall comments:“Working with a cofferdam is always tricky, let alone with the added challenge of varying and significant loads due to the tide range and the depth of excavation. Mabey Hire’s rapid strut design enabled us to secure the cofferdam as quickly as possible, so excavation work could progress quickly, safely and efficiently. We look forward to delivering this vital flood prevention scheme, which will protect thousands of homes and businesses from further flood damage.”
Gordon MacDonald, CEO, Mabey Hire, comments: “This project is a prime example of our ability to provide bespoke, engineered solutions to unique challenges within a short period of time. Since the frames were installed, we’re on 24-7 call to support as needed. We’re proud to be working with BAM Nuttall to support this crucial work that will give peace of mind to both local residents and business owners.”
