Structural engineer quoted by Boston Globe

A chunk of metal suspended from a string served for the bomb. Mehrdad Sasani, an assistant professor of structural engineering at Boston's Northeastern University, aimed for the center support column on the base of a faux three-story building and loosed the makeshift projectile. The column, made of glass for ease of destruction, exploded with a sharp pop. Sasani, with his 1/8th-scale construction of reinforced concrete that was built to the structural specifications of a real building, was simulating the sudden loss of a key pillar - as if to an explosion - in an effort to learn how the rest of the structure would respond. The rare experiment last week was also a contest. Teams from 33 universities and firms across North America had submitted laborious calculations to predict what would occur when a main column shattered. In a dangerous era that has seen major public edifices from the U.S. embassy in Kenya to New York's World Trade Center reduced to smoking rubble by terrorists, structural engineers believe they need a deeper understanding of how damage inflicted on one part of a building can ripple through the rest of the structure in a devastating and often mystifying phenomenon known as "progressive collapse." The intent of the contest is to encourage young engineers to start thinking hard about how to protect against risks once considered unthinkable. Specialists say 80 percent of casualties in such attacks occur as the buildings undergo chain-reaction structural breakdown, not as the direct result of the blast. "It's a complicated problem, but if engineers could get a better handle on how buildings collapse during extreme events, we could make them better resistant to calamity," said Eric Williamson, professor of structural engineering at the University of Texas. "Work like this could yield important data to help make structures able to stand for a few extra hours or even precious minutes, to allow escape," he said from Austin. "It's not about saving buildings, it's about saving lives."

Boston Globe
Teams Compete to See How Buildings Fall Down
(Dec. 3)