Release Date: October 3, 2001
BUFFALO, N.Y. -- In the aftermath of the terrorist attack on the World Trade Center, structural engineers are grappling with a question that a month ago would have been completely unthinkable: Can buildings be designed to withstand catastrophic blasts inflicted by terrorists?
Ten days after the terrorist attacks on the twin towers, structural engineers from the University at Buffalo and the Multidisciplinary Center for Earthquake Engineering Research headquartered at UB traveled to ground zero as part of a project funded by the National Science Foundation.
Visiting the site as part of an MCEER reconnaissance visit, they spent two days beginning the task of formulating ideas about how to design such structures and to search for clues on how to do so in buildings that were damaged, but still are standing.
Their work is continuing as one of several MCEER projects funded by a $100,000 grant from the NSF. The NSF awarded eight grants to fund post-disaster assessments.
The project involving the UB/MCEER engineers is the only one that includes examining structural performance of buildings from an earthquake-engineering perspective.
The team consists of George C. Lee, Ph.D., MCEER director and Samuel P. Capen Professor of Engineering at UB; Michel Bruneau, Ph.D., MCEER deputy director and UB professor of civil engineering, and Andrei Reinhorn, Ph.D., and Andrew Whittaker, Ph.D., both UB professors of civil engineering and MCEER investigators.
"Our objective in visiting ground zero was to go and look at the buildings surrounding the World Trade Center, those buildings that still standing are, but that sustained damage," said Bruneau.
"Our immediate hope is that we can develop a better understanding as to why those buildings remain standing, while our long-term goal is to see whether earthquake engineering technologies can be married to existing technologies to achieve enhanced performance of buildings in the event of terrorist attacks," he added.
Photographs taken by the investigators demonstrate in startling detail the monumental damage inflicted on the World Trade Center towers and buildings in the vicinity.
One building a block away from the towers remains standing, but was badly damaged when it was hit by a column from one of the collapsing World Trade Center towers.
"This building is many meters away from 2 World Trade Center and yet we see a column there that used to be part of that building," explained Whittaker. "The column became a missile that shot across the road, through the window and through the floor."
The visit to the area also revealed some surprises, according to the engineers. For example, the floor framing systems in one of the adjacent buildings was quite rugged, allowing floors that were pierced by tons of falling debris to remain intact.
"Highly redundant ductile framing systems may provide a simple, but robust strategy for blast resistance," he added. Other strategies may include providing alternate paths for gravity loads in the event that a load-bearing column fails.
"We also need a better understanding of the mechanism of collapse," said Whittaker. "We need to find out what causes a building to collapse and how you can predict it."
Reinhorn noted that "earthquake shaking has led to the collapse of many buildings in the past. It induces dynamic response and extremely high stresses and deformations in structural components. Solutions developed for earthquake-resistant design may be directly applicable to blast engineering and terrorist-resistant design. Part of our mission now at UB is to transfer these solutions and to develop new ones where none exist at present."
The NSF funding will support several graduate students on the project.
"Just as the top research universities of California have assisted that state in developing guidelines and technologies for reducing losses from future earthquakes, the MCEER and UB team stands ready to serve in an identical role for the State of New York, in the wake of the terrorist attacks on the World Trade Center," said Whittaker.
By 2004, UB's Department of Civil, Structural and Environmental Engineering will be home to the most versatile, high-performance structural engineering laboratory in the world as a result of grants totaling nearly $20 million from the NSF and the State of New York. While the lab is being constructed primarily for the earthquake-engineering research, the high-flow hydraulic system, high-performance actuators and reaction walls and floors are perfectly suited for blast-engineering research, Whittaker said.