This landmark project comprised the demolition of the former Headquarters of the Department of the Environment and is purported to be the largest ever City Centre Demolition Contract to be undertaken in the UK.
The 17 month contract involved the demolition of 3 no. reinforced concrete 20 storey office tower blocks and 3 “bomb proof” bunker structures with reinforced concrete walls up to 3m thick. The contract also included extensive internal asbestos removal and temporary works to the existing, 2 storey deep, basement retaining walls.
Equipment introduced on this project varied from 1.5 tonne mini excavators to a goliath 110 tonnes base-weight 360° excavator equipped with a concrete crusher attachment with jaws extendable to 2.6m. Brown and Mason were able to recycle 90% of the 200,000 tonnes of masonry arisings comprising concrete and brickwork from the site.
The site’s location in central London presented particular problems – to resolve these:
- Each tower was allocated its own tower crane which was used to lift the plant and machinery necessary to carry out the demolition of the roof and each floor, as well as assisting with the removal of arisings from each level. Every floor had to be back-propped to enable the safe utilisation of mini demolition plant.
- A detailed stakeholder liaison plan was developed with Westminster City Council which, among other things, ensured levels of noise, dust and vibration were kept to a minimum.
- Brown and Mason established full time monitoring equipment on and around the site. Data was downloaded daily by a full time, site based technician who monitored trends and variations so that if a problem was to arise it could be dealt with efficiently and immediately.