HMP Belmarsh West – Prison Groundworks

OVERVIEW

Skanska, working with Serco, undertook the design and construction of a new prison at Belmarsh West.  The new prison centres around a 600-cell, four-storey house block, supported by associated buildings that provide education, rehabilitation, training, healthcare, sports, worship, kitchens, recycling, storage, visiting facilities, administration, horticulture, and security. The Natta contract was the prison groundworks package, including all enabling, associated ground and external works for the new 900-inmate prison.

SCOPE OF WORKS

The project remediated the site using the ‘Conform’ remediation system, addressing its former use as a munitions works for Woolwich Arsenal. This remediated platform became the working platform for all the following site works. The Natta groundworks package included surface & foul drainage, including a large diameter precast concrete attenuating surface water system, and diversion of the existing prison’s foul pumping main. Ground beams, lift pits, pile caps, ground floor slabs and general foundation works following the installation of the piling.

The site demanded extensive and complex service installation, including gas, water, communications, and security installed in a very large number of ducts, closely coordinated between the shallow and deep drainage. A high water table combined with poor ground conditions (underlying peat) required extensive use of temporary works, together with complex drainage design solutions. Natta also partnered with Buchan Precast Ltd to carry out the Perimeter Wall works.

A fast cyclic programme was required to enable Buchans to rotate their temporary propping equipment, while keeping their propping equipment to a minimum and maintaining a fast erect/cast cycle. Natta trialled and purchased a machine laser from Scan Laser to ensure the 360º machine could be kept digging at full capacity to aid programme requirements. The ‘externals’ outside the wall works include ‘Bodpave’ access road system to the wall perimeter, visitor and main car park, access roads, extensive landscape bunding and surface water ‘Swale’, underground fuel tanks, Grease and Petrol Interceptors. A buried asbestos treatment programme formed part of the project, with specialist contractor Metro Ltd undertaking the works on our behalf.

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