DEMOLITION OF CONCRETE STRUCTURES-A FINE ART.

The demolition of structures and buildings by the use of explosives is a relatively new innovation in South Africa. There are five basic techniques that can be used to bring down a building: Deliberate telescopic collapse such as used on cooling towers; Toppling as used on chimneys; Shattering for massive concrete structures; Deliberate controlled collapse by implosion where the outer walls are left explosive free in order to fall inwards; Progressive collapse for diaphragm wall slipformed blocks of flats. For the demolition of any major structure a comprehensive planning exercise must be carried out, firstly to determine which elements such as walls or columns are to be removed by explosives, secondly to determine in which sequence they are to be removed and, finally and very important, to plan the placing of the charges.