Innovative contractors, like AMG Demolition & Environmental Service Inc., realize today’s urban demolition requires a surgical precision traditional methods and equipment can’t provide. Instead, they look to remote-controlled demolition machines to make the impossible not only possible — but cost effective.
Recently, the company partnered with Brokk to complete an “impossible” project in the heart of downtown San Diego. The job required the top-down demolition of a five-story building. Low floor loads limited equipment choices, but an even bigger challenge lay beneath the surface — a three-level underground parking structure that had to remain open throughout demolition.
Established in 2002 by Annette and Mike Gafa, Sr., AMG is a family-owned demolition business specializing in structural, interior and selective demolition for residential, commercial and military entities, as well as general contracting, earthmoving, and mass excavations. AMG also performs asbestos and lead abatement services to meet growing demands associated with the removal of older buildings.
Over nearly two decades, the company developed a reputation for dependability — relying on thorough planning and creative problem solving to deliver on-time, cost-effective solutions. To that end, they have begun incorporating Brokk machines on a number of interior and top-down applications.
One such project in downtown San Diego proved the perfect “impossible” project to showcase Brokk’s surgical precision — removal of an existing five-story structure at 450 B Street.
First, AMG assessed the challenges presented by the concrete and glass building. The structure, a former bank, featured five 22-foot-wide-by-150-foot-long “stair steps” climbing 15 to 42 feet above the sidewalk. AMG needed to provide ample power to break through 24-by-36-inch concrete grade beams and 8-inch slabs without jeopardizing the structural integrity of the building or damaging the ground-level slab as they worked.
Below ground, there were even more challenges to contend with. AMG needed to find a way to ensure the safety and continued operation of a three-story parking structure while demolishing and excavating a 40-by-60-foot opening for a new elevator core and adding footings.
To complete everything within the eight-week timeframe, AMG needed to maximize crew utilization — taking down the building and excavating the elevator core simultaneously. The jobsite and equipment required the precision of a complex surgical operation to ensure safety and optimize productivity.
“When we assessed all of the challenges, we found our equipment choices were very limited,” said Mike Gafa, Jr., AMG senior estimator and owner. “We needed something with a small footprint but the hitting power of a much larger machine. We also needed superior precision. There would be a lot of people moving around below. For their safety, debris had to fall as intended. Finally, we needed a machine that could be operated by just one or two people, leaving more employees free for other tasks.”
AMG decided Brokk machines were the only option that could address all the challenges presented by the project.
After thoroughly planning every step of the process, AMG began top-down demolition with two Brokk 300s. The 8,047-pound machines, equipped with BHB 455 breakers, provided ample hitting power — on par with a 33,000-pound excavator — while remaining below the 10,000-pound maximum floor load. An experienced Brokk operator and a spotter were all it took to methodically maneuver the machines down through the building, allowing AMG to reallocate additional crew members to other tasks.
As the Brokk operators worked their way through the thick concrete, a crew of 15-20 quickly sorted, crushed and removed debris below. Steel plating, cushioned by tires, was employed to protect the slab.
While the structure came down over their heads, an additional crew of 20 tackled excavation of the elevator core.
“On a given day, we had about 40-50 people on the jobsite,” Gafa said. “In order to keep everyone safe and the project on schedule, all of those 40-50 people had to be working in concert — like a team of surgeons. At the end of each shift, we would re-evaluate our progress and shuffle crews and equipment to maximize productivity the following day.”
Thanks to a coordinated effort and the use of Brokk machines, AMG completed demolition in just 56 days. From the 30,000-square-foot building alone, 7,600 tons of concrete were demolished, with all of it being recycled. A further 1,000 tons of concrete were removed during excavation of the elevator core, along with 2,000 tons of dirt. In addition, AMG saved at least $50,000 in labor and equipment costs by using Brokk robots.
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// The Brokk team