The nonstop pace of demolition, debris removal and site stabilization at Manhattan's World Trade Center complex has certainly taken its toll on construction workers. But the cleanup's six-month, 24/7 operation also has not been kind to equipment.
|(Photo courtesy of FEMA)|
Keeping the huge array of machines operating–let alone operating at peak performance–hasn't been easy for fleet owners, renters and maintenance crews. The demanding schedule and extraordinary conditions on the 16-acre site have stretched the limit of equipment endurance and repair, but managers say the experience has already provided valuable lessons that may help reduce costs on projects with less harrowing circumstances.
"The impact on machinery at Ground Zero has been horrendous," says Nick Mazzocchi, vice president of Mazzocchi Wrecking Inc., East Hanover, N.J., which supplied the lion's share of the site's heavy equipment. "We usually rebuild grapples once a year. There we were doing it once a month." David H. Griffin Jr., vice president of Greensboro, N.C.-based D.H. Griffin Wrecking Co. and demolition consultant to the WTC project, terms the site "one of the most severe applications you could put equipment through. There was extreme heat. Dust alone was an issue."
The number of machines used has fluctuated since September as tasks were defined and completed. Mazzocchi Wrecking alone had some 20 large pieces on site during peak activity. Its equipment included excavators, loaders, skid steers, trucks and custom-built cranes with 90-ft and 130-ft booms. "We had four mechanics working 24/7 just to keep the machines running," says Mazzocchi. He notes that the site's stubborn fires, which could heat steel debris to as high as 1,800°F, exacerbated machine-generated heat, causing hydraulic lines to burst. Despite round-the-clock pressure washing to cool down equipment, Mazzocchi says machine windshields have been replaced as many as 12 times.
The nonstop operation also tends to superheat oil used in equipment, breaking down its viscosity. "We do normal service at 300 hours; at Ground Zero, it was at 100 hours," says Mazzocchi. Air filters that usually last about 160 hours were replaced every 24 hours.
Unique conditions contributed to machine stress, particularly the handling of large pieces of twisted steel beams and flanges mixed with the painstaking task of search-and-recovery for bodies and body parts. "When the guys pick up and try to move beams, the heavier steel wins the battle," says Mazzocchi. The unstable debris created hazardous going for machine operators who often bumped, grinded, slid and dropped their way through the pile. Mazzocchi notes at least three sticks broken on machines, each costing about $70,000 to replace. One of the firm's excavators hit a gas pocket on site, causing the engine to over-rev and explode. "That cost us $180,000, and it was not covered under warranty," says Mazzocchi.
|MAKESHIFT Site adjacent to Ground Zero pit serves as maintenance and repair yard. (Photo by Debra K. Rubin for ENR)|
Most quick repair and maintenance was performed during the cleanup's 12-hour shift changes, in the early morning and evening. A site adjacent to the main Ground Zero excavation pit has been turned into a maintenance yard, although some major work requires equipment to be sent off site.
Just north of Ground Zero, officials of Weeks Marine Inc., the Cranford, N.J., firm responsible for offloading from Manhattan more than 1.2 million tons of structural steel and other debris, worried that the immediacy of the catastrophe last September did not leave much time to prepare marine equipment for the heavy labor ahead, particularly at the firm's yard in Jersey City, N.J. "In the beginning, we didn't know exactly what we'd be doing here," says John Devlin, Weeks' marine superintendent.
Weeks and others had been promised regular "maintenance days," says Devlin. While a work shutdown on the first-month anniversary of the attack and on Veterans' Day allowed time for equipment, pressure from victims' families for 24-hour operations has turned maintenance into a catchup activity.
The duration of the offloading task, which involves moving steel from the marine site into barges for the eventual trip to recycling yards across the Hudson River in New Jersey, was unusual for some of Weeks' equipment. Its custom-made "skip pans," which allow dump trucks to directly back up into them to unload debris, had never endured such constant use. "We never had so many cycles before," says Devlin. "A normal shift would be 30,000 tons over a week."
The firm fabricated three additional pans to accommodate the Ground Zero tonnage, each costing about $28,000. "Our pans are made of a special steel and are heavier," says George Wittich, Weeks' senior vice president.
|HEAVY LOADS Repairs to marine cranes loading debris were a challenge in a 24/7 environment. (Photo by Michael Goodman for ENR)|
Devlin says that some of the recycling operation's start-up problems stemmed from "new crews that didn't know our equipment." But he also credits the quality of personnel sent from city hiring halls and the onsite promotion of mechanic-trained stevedore operator Glen Bratcher into a maintenance supervisor with saving the day. "He made sure daily maintenance was done," says Devlin. "Our cranes are in better shape because of the daily attention." He adds that the lack of major equipment damage despite 1,500 barge loads is "phenomenal." Wittich says that having a maintenance supervisor will become "a model for our other jobs."
The site cleanup manager, New York City's Dept. of Design and Construction, is reimbursing firms for costs, including most equipment repairs and damage expenses. The Federal Emergency Management Agency is reimbursing DDC for most expenses. But traditional rules for allowable costs are different for a 24/7 operation. In some cases, contractors and city officials disagree over definitions of what's allowable, and there is concern about possible overinflated costs. A DDC official says one remaining dilemma is how to address cost reimbursement for owned equipment versus leased equipment.
Griffin notes that while the WTC cleanup, originally estimated at $1.2 billion, "is under budget and contractors have busted their tails," debate over equipment costs could continue for months, as "the accountants look over the numbers."