Dismantling, cataloging and crating historic masonry façades for reuse is one of the services Wrecking Corp. provides.
“For 30 years, we’ve provided precisely engineered solutions for either demolition or historic preservation,” said Terry Anderson, executive vice president, Wrecking Corporation of America. “Working the Washington, D.C., market means we have to do everything just right. We have to bring down solidly built structures without damaging the surrounding occupied buildings. And preserving certain parts of historic façades requires our utmost attention to get it right.”
“This project is the demolition of three 12-story apartment towers for an entity of the D.C. Housing Authority,” explained Anderson. “Each of the towers has a footprint of about 60 by 200 feet. We’re razing them and crushing the resulting 30,000 cubic yards of concrete. We’ll use most of the crushed concrete to regrade the site, then we’ll add topsoil and plant grass. Eventually, the Authority will probably build housing on the site.”
The company is paying special attention to two of the three towers because they provide reinforcement to newer apartments located about 20 ft. (6 m) away.
“Working with consulting engineers, we developed a plan for providing both temporary and permanent reinforcement to the neighboring properties,” said Anderson. “Typically, we perform a comprehensive pre-construction analysis of the project. This helps us determine if we need additional engineering and consulting services to ensure the project can be fast-tracked skillfully, safely, and efficiently.”
To help execute its carefully made plans, Wrecking Corp. depends on its orange fleet. On this particular job there were five Hitachi excavators: a ZX270, two ZX330s, a ZX450, and a long-reach ZX850 taking care of the high work.
Anderson explained, “We like the Hitachi excavators. We’ve owned other brands, but I think Hitachi has the whole package. This is a severe-duty business, and we expect equipment to get really beat-up.
“We do everything we can to extend the life of our machines. We put on rock guards and steel plate on the underside, install steel cages around operator cabs, and add extra filtration. We also aggressively service and maintain our fleet. Still, where a pump might last 12,000 hours in a dirt application, we do well to get 6,000 hours.
“Overall, our Hitachi machines hold up better. They get the job done on a very cost-effective basis, they’re competitively priced, they get better fuel economy, and they’re tough.”
Wrecking Corp uses its Hitachi fleet to move, sort, and rough-crush demolished concrete. The concrete is then loaded into a C10 Extec jaw crusher. Every excavator is equipped with a thumb-equipped rock bucket. Some of the ZX450s are fitted with shears that tear out and cut steel beams. The ZX850 is used for selective high demolition.
Old School When It Works
“We have a tendency to go ’old school’ when it works and high-tech when we need to be especially precise,” noted Anderson. “On this project, the interiors were stripped to bare concrete by hand and materials moved out with the help of small skid steer loaders. The debris was then hauled to a local C&D reclamation site.”
The third tower was far enough from neighboring buildings to be razed with a 90-ton (81.6 t) truck crane and a 6,000-lb. (2,722 kg) ball.
“Nothing’s cheaper than gravity, so if you drop that ball enough times, the building will indeed come down.”
The remaining two towers require substantially more finesse. They will be selectively demolished by hand with jackhammers and the ZX850, which is equipped with an ultrahigh-reach telescoping boom that goes up 130 ft. (39.6 m). A universal processor tops the end. The ZX850 is used to surgically remove structures from each building.
“It’s a controlled process that lets us reach and remove material without compromising a building’s structural integrity or damaging adjacent structures,” according to Anderson.
“Since we know that we’re going to tear up our Hitachi excavators, it’s important to have an attentive dealer,” stated Anderson. “We’re going to need repair work, and we’ll need parts. We used to use another brand of excavator, and when it was down the dealer never seemed to have what it needed in stock. Then the solution was to ship it halfway around the world. We got tired of that. Our Hitachi dealer either has the part or can get it from a U.S-based regional depot nearly overnight. Their mechanics are good, and they come when we need them. Downtime is very expensive in this business, and with Hitachi, we don’t have much.”
This story was reprinted with permission from Hitachi Breakout Magazine, First Issue 2010.