Univ. engineering professor studies Towers’ collapse

In the wake of the Sept. 11, 2001 attacks, a broken nation was left wondering how the iconic Twin Towers could have crumbled to the ground. For James Milke, a fire protection engineering professor at this university, this was a burning question he needed to answer himself.

Within a matter of weeks, Milke had enlisted to join a team of nearly 30 experts the federal government had tasked with debunking some of the theories that had begun to congest the news.

By October, Milke and the other team members were combing Ground Zero for clues, collecting everything from photographs to leftover pieces of the building to more than 100 hours of video footage.

"Once we appreciated the scale of the event, you'd be taken back by the enormity of what had happened," Milke said.

A circulating rumor at the time was that the Towers fell because the plane jet fuel burned in the buildings for a substantial amount of time, weakening the buildings structure — a theory the researchers proved false.

Using information from the plane manufacturer Boeing, Milke said the team estimated that each plane left behind about 7,000 gallons of burning jet fuel after colliding with the Towers — which took about seven minutes to burn off. And although the jet fuel helped spread the fire inside the Towers, it did not burn long enough to bring down the 110-story buildings.

"The jet fuel had a really important role that day that caused the office furnishings to be easily ignited," Milke said. "But we were able to say ‘no, that's not the reason.'"

Another mystery the team worked on was why the south tower — which was hit second — collapsed after only 57 minutes while the North Tower stood for 102 minutes after being hit. Milke said his team came up with several critical differences — mainly that the fact that the South Tower was hit much lower.

Although the team's study published in May 2002 did not provide a definitive answer to why the Towers collapsed, Milke said it laid the groundwork for other researchers to fill in the blanks in subsequent studies, including the federal government's official investigation.

"I'd like to think we built a foundation for some of those other inquiries," he said.

One later study came from fellow university fire protection engineering professor James Quintiere, who suggested a lack of proper insulation surrounding the internal steel structures of the buildings caused them to weaken when exposed to the fires — disputing the government's conclusion that the crash took off the building's insulation, thus causing the towers to collapse.

"Did they fall down because it was solely due to an airplane hitting the building or was there a defect in the building?" Quintiere said. "There wasn't enough insulation to begin with."

Even though experts disagree about what ultimately caused the buildings to collapse, Milke said the general consensus was that the exterior columns failed, causing the floors to fall.

Milke said his team's study helped give people peace of mind about the safety of working in highrise buildings and has helped the world better appreciate the importance of fire safety in designing certain structures — including the new World Trade Center.

"There are a number of things that have come to the forefront after 9/11," Milke said. "Certainly one of the things that has happened is there's a better appreciation of the fire protection world."

saravia at umdbk dot com