Constructing a building from the ground up can take years to complete. Even with crews working around the clock, creating a habitable building with dozens of floors is a tremendous task. But to bring it down? That can take as few as six seconds.
Thanks to building implosion techniques, demolition teams can save property owners major time and money by using gravity—along with powerful explosives—to bring structures crumbling in on themselves.
In the late 1940s, Baltimore forestry worker Jack Loizeaux discovered that dead tree roots could be easily removed with a stick of dynamite. Fast-forward to today, and his tree-felling technique is now used on buildings of staggering height. He created the art of building implosion.
“My father blasted his first structure in 1947. I started going out on jobs with him when I was 6 years old, so I’ve been doing this all my life,” says Mark Loizeaux, president of Controlled Demolition, Inc. “We get to change skylines. My father was once referred to as the ‘dentist of urban decay.’”
Taking down a major, long-standing structure isn’t as simple as strapping on some dynamite and hitting a button.
But taking down a major, long-standing structure isn’t as simple as strapping on some dynamite and hitting a button. In order for the building to have a controlled fall, the team must look at the building through a scientific lens, an engineering lens and an historic lens.
Loizeaux notes that there are no college courses on building implosions, nowhere to go to learn how exactly to set each structure so that it’ll fall the same way each time. Loizeaux’s team, which includes his family, adult children and a family-like corporate team, relies on a deep trove of historic data from prior implosions, some of which hold world records. The tallest building they’ve ever imploded was the 439-foot J.L. Hudson Department Store building in Detroit, in 1998. The tallest concrete building they’ve ever imploded was the 379-foot Ocean Tower building on South Padre Island in Texas.
But perhaps their most notable implosion to date is the Seattle Kingdome, the largest structure, by volume, ever demolished, which came down in 2000. That project posed a specific set of problems, as the circular nature of the stadium meant that the 25,000-ton concrete dome would fall directly onto the field, creating enough vibration to cause widespread damage to the area. Instead, Controlled Demolition, Inc. used small explosives to crush the roof before it hit the ground, greatly minimizing the impact.
“When we look at a new demo project, I’ll look at the blueprints and go walk the structure. As I’m walking around, I’ll identify different points of that structure that might remind me of another structure we imploded,” he explains. “Then we’ll pull videos on those projects and look through to see what level of control I had and try to find similarities to the new building.”
The number of explosives differ for each building, as every structure is unique, but the team will place explosives in specific spots throughout a building so that the columns, which are connected to the beams and the foundations, sever, causing the building to collapse in on itself. Ideally, the building will collapse into its own basement—bonus points if it’s several stories deep—but the team can also incline buildings toward an open area to catch debris.
But what if there’s a subway tunnel running under the building, or there are adjacent buildings on each side? Implosion is no longer an option.
“What you’d do in a city like New York, where there are typically structures touching both sides, is dismantling: using small equipment and workers to remove a building from the top down. It’s like reverse construction,” Loizeaux notes.
In a conventional demolition project, construction companies have to rent equipment, fuel the equipment and put a crew of 20 or more workers at the top of a building for several months. It’s no surprise property owners are increasingly considering implosion as a cheaper, quicker and more effective demolition method.
“We took down the Marlborough-Blenheim Hotel in Atlantic City, New Jersey. The construction of the Blenheim was overseen by Thomas Edison. To take down something built by someone like that was big, but when I saw the state of disrepair it was in, there was no denying that it had to come down,” Loizeaux recalls.
Besides, he says, it’s not up to Controlled Demolition, Inc. to decide what gets taken down: “We’re not the judge or the jury. We’re the executioner.”
13 January 2017 by John Salustri