Bringing the house down

FEW sights are as impressive as a tall building neatly collapsing onto its own footprint after being rigged with explosives by demolition experts. The spectacle attracts large crowds and lots of cameras. The levelling earlier this year of AfE Turm, a 32-storey skyscraper in Frankfurt (pictured), showed how it is possible to reduce thousands of tonnes of masonry, concrete and steel to a pile of rubble without damaging surrounding buildings. Using explosives might be quick, but with ever more development in crowded cities, more discreet ways of demolishing old buildings are having to be found.

Bringing down a building with explosives is a carefully orchestrated event. The “blasters”, as contractors who specialise in such work are known, position charges to tear apart critical sections of supporting structures. The detonations are staggered, so that material from above collapses into voids created a moment earlier. This helps to protect underground infrastructure in the vicinity, such as sewers and fibre-optic cables, which might be broken if everything hits the ground at once.