Ultimately, researchers hope their findings will improve the design and structural integrity of the nation's buildings, utilities and other infrastructure. The results may also improve emergency response to both natural and human-caused disasters.
Just a week after the terrorist attacks, the National Science Foundation awarded a $20,000 grant to David Frost, a professor of civil engineering, to assess the damaged area with an advanced digital data system he recently developed for earthquake reconnaissance missions. Frost's research team actually began data collection in a 10-square-block area in and around the WTC complex in mid-October and have undertaken several field exercises since then.
Frost's Palm Pilot software application called PQuake – which he beta-tested following the devastating earthquake in Gujarat, India, last year – allows several research teams to simultaneously collect and input digital data, including photos and GPS coordinates. Because the information is already digitized, it is quickly integrated in a geographic information system (GIS) database, Frost explains. Rapid data analysis can then follow.
"Our application was developed for post-earthquake field reconnaissance, but we anticipated there would be other applications," Frost says. ".... We found some differences right away in the damage from earthquakes and the damage in New York. In an earthquake, energy is released over a very large area. You can look at a building from one direction, and its condition will be the same on all sides because the energy passes through the entire site.
"At the World Trade Center, the energy came from a relatively concentrated source and dissipated more rapidly as it moved outward," he explains. "Two or three blocks out, the impact was much diminished.
photo by Norris Scott
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Georgia Tech students Scott Deaton, right, and Prateek Goel are part of the team assessing damage of the buildings surrounding the World Trade Center rubble.
(300-dpi JPEG version - 823k)
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It was a lot less energy than an earthquake. We found different damage on different sides of the buildings. So there was an orientation effect that required us to spend time modifying our software. We enabled it to let us describe in more detail how the damage varies from side to side and from upper levels to lower levels of buildings."
Researchers plan to investigate whether some non-structural elements could be improved to better withstand impact, Frost says. For example, the systems that connect glazing and granite fascia to buildings could be redesigned.
"We may find that different systems performed better than others under the same loading conditions," Frost says. ".... So this information could result in a major engineering benefit."
It's too early for researchers to make conclusions about structural damage, Frost adds. More research is needed. For example, forensic assessments might identify where pieces of steel came from in the building and correlate it with their condition. And simulation research might reveal how certain structural elements performed in such extreme conditions. Frost anticipates that some of his structural engineering colleagues at Georgia Tech will be involved in such longer-term studies.
Also, Frost believes his research in data collection and software development will continue in more detail and result in collaboration with other researchers. NSF plans to fund some follow-up projects to the studies it funded just after the attacks.
"We want to take digital data collection technology to the next level," Frost says. "We want to use a wireless communication network to upload the data we collect in the field in real time. Then we can make interpretations on the data as it's being collected.... Real-time analysis is an advantage, especially in earthquakes that have affected a large area. You want to cover as much area as you can without duplication or blanks in the data.
"Real-time analysis enhances the whole data collection process," Frost adds. "Even with preliminary analysis, you may see some trends that will guide you and direct the data collection and perhaps even assist in the recovery of victims. If we're able to assess a certain pattern of damage... it could help us understand where there is a more likely opportunity for a successful recovery."
Frost believes P-Quake and his digital data collection system may also have applications in other disasters, such as building fires, a catastrophic rail accident or a ship hitting a bridge. In addition, it could help in the analysis of damage from tornadoes, hurricanes and floods.
On a personal note, Frost says the experience of working at Ground Zero in New York was sobering. But he was not as surprised as some by the damage after having participated in four major earthquake reconnaissance studies.
"In New York, you almost had the feeling like you were working at a large construction site," he recalls. "Everything was operating in such an organized manner, it fools you into thinking this. But then you are brought back to reality when the activity suddenly stops. You see vehicles coming down the street carrying flowers and people. Firefighters and family members conduct a little service right at the site when they find remains.
"The sense of being at a construction site is in stark contrast to some of the earthquake zones I have visited where buildings have collapsed and the damage is so widespread," Frost says. "You find that little, if anything, is happening even several weeks later. People are just standing around. There's no active recovery going on. They just don't have the resources and the organization. The scale is so large. We take for granted here in the U.S. how organized we are and how quickly we can mobilize our resources."
For more information, contact David Frost, School of Civil and Environmental Engineering, Georgia Tech, Atlanta, GA 30332-0360. (Telephone: 404-894-2280 or 912-652-3585)
(E-mail: david.frost@ce.gatech.edu).
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Last updated: Feb. 9, 2002
