Assistant Civil Engineering Professor Robort Connor was vacationing with his wife in Utah on August 1 when the I-35W bridge collapsed in Minneapolis, Minnesota. "I saw it on the news, and I thought I would probably get a call," he says. An expert on steel bridges and fatigue and fracture, Connor has consulted on many bridge failures, including the Milwaukee, Wisconsin, Daniel Hoan Memorial Bridge in 2000 and Pennsylvania's Kinzua viaduct collapse in 2003.

Twelve days after the I-35W collapse, Connor was on site and part of an investigating team comprising the state's Department of Transportation; Wiss, Janney, Elstner Associates, Inc.; and dozens of engineers and architects. At the meeting with the DoT, Connor says, "They requested I assist with providing an objective review of Minnesota DoT's inspection practices on the bridge as well as conduct a hands-on examination of damaged members as part of the overall failure investigation being led by the NTSB." It will likely be 12 to 15 months after the bridge's collapse, the time allotted for the National Transportation Safety Board to complete an official investigation, before the final cause of the disaster is released to the public.

As you read this, engineers and investigators like Connor are working to reconstruct the story of the bridge's fall by examining portions of the bridge that have been arranged downstream in a flat area. The demolition phase was completed in October, and the fact-finding portion is even now under way, but the theory and laboratory testing phase -- and with it the answers to why the bridge failed -- is still in its early stages. "Stay tuned," Connor says.

-Rebecca Goldenberg

(Taken from Engineering Impact, Winter 2007-2008 edition)