Blasting techniques

The quality of life and the deterioration of buildings from the 1950s have led building owners to remodel their estates by demolishing all or part of buildings constructed in diverse and often highly urbanized sites.

These demolitions are carried out mechanically or using explosives.

The difficulty of blasting decreases as the difficulty of mechanical dismantling increases.

With building heights in excess of 20 m, demolition using explosives becomes more appropriate and less dangerous than uncontrolled felling such as "dismantling with a ball, nibbling with concrete tongs or any other device often used without regard for the safety circulars in force".

However, demolition using explosives, which only presents a danger the minute the shot is fired (unlike mechanical dismantling, where the risks are continuous throughout the worksite), is no simple matter. And the contractor who carries it out needs to know :

• general explosives ;

• physical laws related to the dynamics of falls;

• mechanical strength of materials.

In what follows, we will only cover the technical aspects of demolition using explosives. The aim is to provide contractors and project owners with a basic understanding of 20th-century demolition techniques:

• to homes ;

• chimneys ;

• air coolers ;

• water towers;

• blockhouses;

• industrial (including nuclear) buildings.