Demolition: Study plans to create a big rubble pile

Demolishing buildings may seem like a mad smash-and-bash affair, but there are methods behind the madness, says Ken Mercurio, president of Diversified Demolition Co.

The company last week attacked the former Gottschalks building, the last piece of Park Lane Mall that remained standing.

Diversified Demolition crews first identify what construction methods and materials were used. Because the two-story, 130,000-square-foot Gottschalks building was constructed with steel columns and beams with eight-inch concrete block masonry walls, the best method for demolition called for traditional mechanical means two large excavators rather than a wrecking ball or implosion.

"We look at the makeup of a building, the materials and design, and at that point figure out how we are going to go after it," Mercurio says. "Once we figure out which way structural elements and support structures run, then we will go in and tear down accordingly."

With most old buildings, plans are either outdated or lost, so demolition companies typically must assess a building's structural elements through field inspections and measurements.

Once a demolition plan has been formulated, wrecking crews typically start chewing up softer and internal materials between structural column bays before biting into the structural elements. Once a building is gutted, crews fall different structural sections in a controlled manner.

Although demolition work looks dangerous, it's pretty much business as usual, Mercurio says, because each of the company's demolition operators have been doing demo work for more than a dozen years and have torn down several thousand structures.

"There is a comfort level with their knowledge, our knowledge and what we expect out of each other," Mercurio says. "A lot of it is just years of experience and understanding how structures work. You learn the different types of construction and how the building is going to act under a failure condition."

Diversified Demolition Company, a sister company to Diversified Concrete Cutting, expects the Gottschalks building to produce more than 8,500 cubic yards of waste material from sheetrock, flooring material, mechanical ductwork, steel studs, beams and columns. More than 2,200 cubic yards 4,500 tons of waste is from concrete rubble that will be crushed on site and used as a dust suppressant to be laid over

the footprint of the building once the job is finished.

In addition, more than 70 semi truckloads of structural steel will be recycled.

"We recycle anything and everything, all the metals, tins, concrete and block," Mercurio says. "We have been recycling for 15 years it is just good practice. You don't clog landfills with unnecessary stuff. We generate so much demolition debris over the course of a year, Diversified very emphatically is focused on diverting as much construction and demolition debris in the recycling effort."

Despite a sharp decline in the price of salvaged materials beginning in the second quarter of 2008 due to evaporating demand, the money recovered from salvage helps demolition companies be more competitive with their bids, Mercurio says. It also can be used to offset labor, trucking or dump fees.

The majority of smaller jobs, such as the Gottschalks building, call for mechanical demolition, but implosions are the cream of the crop in the demolition business. Diversified Demo's last implosion job was blowing up the main building of the Boardwalk Hotel in Las Vegas to make way for the massive 76-acre CityCenter development.

With implosions, Diversified handles all aspects of the demolition work, including designing a plan of attack, removing strengthening shear walls and stripping columns to bare steel so that the building comes down easier. Diversified Demo hires explosives experts to place charges and push the boom button.

The majority of the company's work comes from southern Nevada because of aggressive building on the Las Vegas strip, Mercurio says.

But the recession slowed work in Reno as well as in Las Vegas by about 35 percent from 2008 to 2007. As a

result, Diversified has made administrative cuts, shedding five of 30 office jobs. The company currently employs 130, but during peak summer months it has had more than 300 on its payroll. Last summer the company had 270 employees.