Feature Story

THE GEORGIA CONNECTION: ENGINEERS TURN PROBLEM-SOLVERS AT GROUND ZERO

The dark, choking cloud of terror was still hovering gloomily in lower Manhattan in the aftermath of the attacks on Sept. 11. Fire fighters, police and emergency medical units combed through and around the ragged rubble that remained where monoliths once stood. Joining the surge of activity on the day after was structural engineer Fred Krishon, senior vice president of Law Engineering and Environmental Services, headquartered in Atlanta.

Krishon works in the company's Alpharetta, GA, office and was on the scene 15 hours after the call from New York City.

"We were one of the first non-government teams to gain access to the buildings in the 'hot zone' and to perform comprehensive structural, mechanical and environmental surveys of the affected buildings," Krishon says.

One of the World Trade Center's neighboring buildings, a 40-story structure built in the 1930s, now used as a data center for processing daily transactions on Wall Street, had collateral damage from the collapse of WTC 7. Law's engineers were charged with assessing damage to the data center and developing a plan to handle any toxic materials.

Just to throw a wrench into the works, Law had to meet a deadline of re-opening the building by Monday, Sept. 17 at 9:30 a.m., when the New York Stock Exchange re-established operations.

Within 48 hours, temporary retrofits were made to the mechanical system of the data center building to prevent further dust contamination from outside. By the time the NYSE bell rang Monday morning, six floors of the data center were open, two more than originally needed.

At week's end, the entire building was cleared for occupancy.

"Once we made the initial analysis, the first job was to seal the building and make sure there were no contaminated spaces," says Krishon. "We had to examine every area of the building to locate dust, and to see how much dust had been ingested by the heating and cooling systems."

Law's team worked closely with the building's engineers to recommission all of the structure's systems, helping to begin the repair design process, surveying the building and developing a strategy to bring the systems back up without further contamination or equipment damage.

The contamination concerns of the engineers were well founded. Much of the steel, masonry, paper, acoustical tiles, glass, paper and other material in the World Trade Center was vaporized in the fire or from the crushing impact of the buildings' collapse. Tons of dust spread over lower Manhattan, and continued to blow through city streets and building systems for weeks. The city has worked to limit the effects of dust, spraying water on vehicles, construction equipment, streets, sidewalks and buildings.

To have buildings and mechanical systems secured, says Krishon, the potential for contamination from the dust (and any potentially hazardous material in it) had to be removed.

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