Building implosions are spectacular feats of scientific planning. They are also rare. Most buildings slated for destruction are short enough for high-reach excavators and other ground-based equipment to do the job. Taller buildings are generally taken down via induced collapse, in which the building is loaded with explosives in such a way that it collapses off to one side, like a felled tree. A vacant parking lot or worthless structure receives the falling building. Building implosion, however, is required when no vacant area exists to receive the force of an induced collapse. An imploded building falls neatly down into its own footprint, preventing damage to nearby structures. The carefully choreographed series of explosions in an implosion is one of the most jaw-dropping scenes in industrial demolition.
Colorado to Timbuktu, gravity is what actually brings a building down in an implosion. Explosive loads are placed in lower stories, causing upper stories to collapse down. This utterly destroys the building without harming nearby structures. Explosives are also placed in higher stories, to break the building into several parts and thereby accelerate demolition cleanup.
However, this description greatly simplifies what implosion experts must do. Long before the day of the implosion, demolition scientists must study blueprints, tour each floor to understand structural supports, and input data into predictive computer programs, to understand how the building could fall with various explosion arrangements. One possible arrangement is to blow up the building’s central support columns first, followed by the outer columns. Done right, this causes the outer sections to fall inward, toward the middle of the building. Each building demands its own meticulous approach, and implosions are so complex that three different firms would have three completely different load arrangements for the same project. Implosions are so tricky that they are only done by a tiny fraction of companies offering industrial demolition.
Arizona to Azerbaijan, special safety precautions must be taken to protect workers as well as members of the public near an implosion, as expanded on below.
Implosion Precautions for Industrial Demolition Services
Reduce projectile debris by using the minimum possible amount of explosives.
Wrap each support column with chain link fencing and geotextile fabric. This further reduces the amount of detritus sent flying.
Cover nearby buildings to protect them from debris and pressure.
Erect pedestrian barriers to prevent implosion enthusiasts from getting dangerously close to the blast. Industrial demolition services take special care to calculate where to place the safety perimeter.
Because implosion is so complicated, only a handful of long-established demolition firms take on true implosion projects.
[photo by: dwrichards on Flickr via CC License]