Groundforce Shorco’s Premier Trench Boxes proved to be the ideal solution to support the installation of a floodwater attenuation tank on a new housing development in East Sussex.
Groundworks specialist J Devine Civil Engineering, based in Cheam, is the groundworks contractor on a development of luxury homes for a consortium comprising Bellway, Devine Homes and Persimmon.
The development, known as Amblehurst Green, is part of a major scheme comprising nine separate parcels of land to the east of Billingshurst.
The latest phase of the project, which got underway about four years ago, required the installation of an attenuation tank that will temporarily store run off during periods of heavy rainfall. This is a key part of a sustainable drainage system designed to avoid the risk of flooding and groundwater pollution.
A large excavation, measuring 4.5m wide by 4m deep and 45m long was required to accommodate the tank. J Devine contacted Groundforce Shorco to provide a support solution for the sides of the excavation.
“The Premier Trench Box was the ideal solution for this excavation because it provided J Devine with the space necessary for the assembly of the attenuation tank,” explains Groundforce regional manager Matt Hughes.
Whereas the Groundforce standard trench box has a nominal clearance of 1.44m under the strut, the Premier Trench Box offers a clearance of 2.45m. “This clearance was essential for the safe installation of the attenuation tank on site,” says Matt.
The Premier Trench Box is suitable for trenches up to 6.6m deep, using a base plus two top extension units. Capable of supporting trenches up to 4.7m wide, the Premier Trench Box was used almost to its maximum width on this project.
To ensure maximum site safety, J Devine also specified Groundforce’s Edgesafe and Endsafe systems to complement the Premier Trench Box. Endsfafe was installed at either end of the 45m-long excavation. This safely retained the backfill and prevented accidental dislodgement of loose material into the excavation.
“Groundforce was the only supplier capable of guaranteeing delivery of this volume of specialist equipment in the timescale required,” comments J Devine’s contracts manager Darren Clark.
The Premier Trench Box is designed specifically for deep pipe laying activities with its clearance of almost 2.5m under the lower strut allowing the installation of large-diameter pipes or, as in this case, large attenuation tanks.
Endsafe, a structural steel panel designed to close-off the end of trench boxes and manhole boxes. Edgesafe is a lightweight mesh barrier system designed to provide light duty edge protection to help prevent falls around trench boxes and sheeted excavations.
Components for the 13 trench boxes, plus ancillary equipment, was delivered to site in November 2021 and remained on-hire for four weeks.