How Building Demolition Works
Demolition is simply the tearing down of existing structures. These can be anything from small homes to high-rise buildings or whole apartment complexes. When we think of demolition most of us imagine tall buildings falling in on themselves as explosive charges go off. The sight of such demolitions is violent, destructive—but also beautiful in a way. In nature the old must be destroyed to make way for the new, and construction is no different.
Modern building demolition is a choreographed and complicated effort, and requires a demolition expert with extensive engineering knowledge. You might think the demolition team could just set off a bunch of charges and call it a day, but demolishing a building without causing damage to other structures or people in the area can be a challenge, especially when explosives are being used.
Types of Demolition
Though explosive demolition is the first thing that comes to mind when we think about a building being torn down, it is certainly not the only method being used. Some structures are demolished using only cranes with wrecking balls and jackhammers. Numerous factors are taken into consideration when determining which demolition methods are appropriate for a given structure. Every demolition project starts with an engineering survey during which the entire building is assessed. The age, integrity, building materials used, and surrounding area are all evaluated during this process.
When dynamite is used in demolition the technique is referred to as implosion. The explosives are placed and set off in such a way as to cause the building to fall neatly in on itself like a house of cards. The sight of implosions is so captivating that there are actually “demolition junkies” who travel around just to view these occurrences. When the towers collapsed after the tragedy on 911 they imploded in this way—which actually became fodder for the conspiracy theorists.
The tricky thing about implosion is not blowing up the building, but doing so in a way that prevents damage to any adjacent structures. This is where the expertise of the engineers comes into play. It is their job to cause many tons of steel and cement to violently crash to the ground without devastating the surrounding area—not an easy task.
How Blasting Works
Explosive demolition experts are colloquially called “blasters.” The process of blasting is quite complex, and involves a variety of steps.
First the building is divided into vertical columns. Thousands of holes are then drilled in the weight-bearing supports and stuffed with explosives. The supports are then wrapped in thick plastic and metal fencing so that the debris is contained during the explosion. The individual sticks of dynamite are all plugged with blasting caps to control the timing of the explosions.
The result of a well planned implosion is a veritable symphony of coordinated downward movement. The columns collapse in a smooth motion resembling a wave—which minimizes the shockwaves produced by the impact. When it is all said in done there is a neat pile of rubble contained in the original footprint of the structure.