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St Christopher's House & Annex, London SE1

Client : The City of London Real Property Co. Ltd
Value : 4.5 M

Overview

Duration:  29 weeks

Amongst the largest of demolition contracts carried out in London.

Built in 1960 the structure consisted of 3 main blocks, their construction using 26,800 cubic metres of concrete and 3,050 tonnes of steel. The central block was 14 storeys high, standing 43m above the pavement with two eleven storey towers and a lift lobby projecting northwards from it. The west wing was 11 storeys and joined to the centre block by a further tower; the south easterly 6 floor section containing retail and commercial units on the ground floor. The car parking was both above and below ground providing spaces for 260 vehicles.

  • Following the soft strip, erection of scaffolding, Mono-flex and 2.4m high hoardings, two super long reach excavators began work from ground level, as did the variety of plant that was lifted onto the roof by a 150 tonne crawler crane. The cranes were also used to lift the plant down through the building; sections of concrete down to the processing area and lift purposely designed skips from the work area and back
  • Demolition commenced in four separate areas simultaneously, with eight Hitachi EX60 excavators equipped with breakers and concrete crackers bringing the building down one floor at a time.
  • Due to the 60,000 tonnes of concrete generated by this project, a processing area was set up where a larger hydraulic excavator fitted with a pulverisor was sited. The high standard concrete was crushed to manageable sizes then taken away in tipper lorries to a crushing plant for reuse within the construction industry. The reinforcing rods filled 40 yard bins and were also taken away for recycling.
  • Once the building heights were suitably reduced, Caterpillar 350 and Liebherr 954 Super Long Reach excavators were employed to complete the demolition of the lower levels.
  • Strict rules were enforced for the control of noise pollution whereby machines were unable to start their engines until 8am and were terminated at 6pm. Ten noise level monitoring points were set up around the perimeter site as agreed with The London Borough of Southwark and were checked every day at various times.
  • All of the high reach excavators were equipped with dust suppression water jets to minimise air pollution and a sprinkler system installed at each of the process loading areas.
  • Operatives were constantly employed to wash and sweep the roadway, keeping the areas as clean as possible.
  • The demolition of the various structures was completed within the 29 week programme and within the contract sum.

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