Whenever a high-visibility infrastructure failure occurs, the main question everyone wants to know is: why? Was it a design error? A failure of materials? A result of human error? It is the job of the forensic engineer to investigate all the myriad of factors that might have led to a failure. Such investigations often are lengthy, and costly. But they are essential, to prevent recurrence of similar failures. The hosts talk with Dr. David Corr, Clinical Associate Professor in the Department of Civil and Environmental Engineering at Northwestern University, about this topic, with a focus on two significant infrastructure disasters: the collapse of the Mianus River Bridge on Interstate 95 in Connecticut in 1983, and the 2006 failure of ceiling panels in the Fort Point Tunnel – a part of the Big Dig in Boston. Also included are details on the Marcy Bridge Collapse, which occurred in 2002 in Upstate New York