Having a Blast

Destruction in Construction

By Joel Nelson on Sep 6, 2022 in News

Before a majestic skyscraper, sleek office building or sturdy apartment complex takes its place on a city’s skyline, a structure currently occupying the space might have to be cleared out. In many cases that requires an explosive sequence that looks like an exercise in disarray but actually is a carefully calculated, prepared and controlled event.

An old building is a candidate for demolition when it requires too much maintenance, contains dangerous materials or is otherwise unsafe. It’s fairly easy to level a five-story building using excavators and wrecking balls, but bringing down something on the scale of a 20-story skyscraper safely and efficiently requires an exquisite, fully planned explosive demolition involving “highly trained experts working with debris, weather conditions, materials, mass and physics,” says Irvine, Calif.-based BigRentz, the U.S.’s largest online construction equipment rental network.

“Today’s technology can see skyscrapers fall from their stance in a matter of seconds, transforming the aesthetic of a landscape and allowing for new features to be constructed,” adds information source Live Science.

Explosives comprise a compound or mixture of compounds that releases tremendous amounts of energy in the form of heat and gas when ignited. They include molecular explosives such as trinitrotoluene (TNT) and nitroglycerin, chemical explosives like dynamite (which includes nitroglycerin) and composite explosives that contain fuel, oxidizers and other self-explosive ingredients.

When a building is surrounded by other structures, implosion – a collapse into the structure’s own footprint using explosive materials in a pre-determined, detailed sequence and detonating them at a pre-arranged time – is the method of choice. A series of small explosions, strategically placed within a structure, encourages a collapse by weakening or removing critical supports. Explosives on the lower floors then initiate a controlled collapse and the building fails under its own weight, creating a pile of rubble without damaging nearby buildings.

The event is preceded by pre-blast structure surveys, blueprint examinations, 3D modeling, clearing of debris and hazardous materials, planning for vibration and blast control measures, weakening of the supporting columns with sledgehammers or steel-cutters, removal of non-load bearing walls, blast area security and warning methods for the safety of nearby people and structures, and the loading of the columns with explosives.

Some demolitions take out the entire structure whereas selective demolition removes specific sections of a building while retaining the structure. This approach is favored for remodels, upgrades and extensions where recycling, reusing and a reduced environmental impact from demolition are a priority.

“The violent blasts and billowing dust clouds may look chaotic, but a building implosion is actually one of the most precisely planned, delicately balanced engineering feats you’ll ever see,” says HowStuffWorks, another science information resource.

In November 2020, the 540-foot Mina Plaza building in Abu Dhabi, United Arab Emirates, became the tallest building to be demolished using explosives, taking all of 10 seconds. 

Construction is the fastest-growing segment for the explosives market in the U.S., which also encompasses transportation projects and other infrastructure activities. Mining interests favor explosives as a more versatile, time-saving and less expensive alternative to mechanical drills.

The global industrial explosives market was valued at $7.1 billion in 2019 and is projected to reach $10.9 billion by 2027, according to Allied Market Research. “Demolitions are important to the growth a revitalization of our communities and are continually evolving to become more cost-effective, safe and environmentally friendly,” says BigRentz.

Property owners can use Yardi Construction Manager to stay on time and on budget through every phase of a commercial real estate construction project – including demolition.