The team is developing two serpentine-like robots, one named Snoopy and the other Woodstock. The idea is that these kinds of robots could do the dangerous job of inspecting, while people monitor the progress in a safe location nearby.
"The benefit of having a snake is now you don't have to put a person in that cherry picker. That has a profound impact on safety," said Choset, referring to the basket crane.
There are other benefits as well. A digital camera at the inspecting end of the snake would record the examination in real-time, feeding video to a computer display for the engineer to watch. Image processing software would analyze the digital feed looking for flaws.
The images would go into a database and in the event of a collapse like the one on I-35, engineers could retrieve the archives and analyze them for a possible history of structural failure.
Bridge Health, From Birth to Death
By themselves, improved materials, smart sensors and capable robots represent valiant efforts toward safer bridges. But bridges, like any creation, have a beginning and an end, and could potentially be monitored not just during operation, but also from design to demolition.
So think researchers at Carnegie Mellon University's Center for Sensed Critical Infrastructure Research, who are developing sensors and laser technology that would allow engineers and contractors to track materials and their performance over a bridge's lifetime.
The idea is that during construction, thousands of tiny microchips could be embedded in structural components from beams to bolts. The sensors, which track temperature, strain and acceleration, could collect data to ensure the materials are not subjected to conditions that would reduce their quality.
Radio frequency tags could label materials so they are not misplaced, but installed in the precise location according to the designer's plan. Maturity meters embedded in concrete could monitor its strength.
During construction and after the bridge is up and running, a wide-area laser scanner could check the physical locations of the components to determine that they are properly placed and aligned.
"With laser scanning, you can go out, and in an hour you can get a complete collection of points over the structure and do some signal analysis to see if all of the points match up with how it was designed," said professor James Garrett, head of the department of civil and environmental engineering and co-director or the Center for Sensed Critical Infrastructure Research.
In the aftermath of an unfortunate collapse, the same laser could scan the structure, helping to put together a three-dimensional image of the disaster site.
Funding Fiasco
For the I-35 bridge, it's too late. It will take months of analysis, picking through the rubble, watching video, and creating computer models to establish what went wrong. It will cost millions.
U.S. Secretary of Transportation Mary Peters recently announced that $5 million in federal relief would be made available for repairs. And the House of Representatives is authorizing additional funds for repair and to relieve congestion.
The funding woes go much deeper. According to the American Society of Civil Engineers, it will cost $9.4 billion a year for 20 years to eliminate bridge deficiencies across the country.
"It's one of those seriously underfunded endeavors that deserves more attention," said Choset.
In the meantime, accidents like the one on I-35 and recently the collapse of 1-70 in 2005, which injured 70 people in Pennsylvannia, may continue to happen.
"I think that what happened on I-70 and this incident on I-35 are going to call attention to the need to do more for our bridges," said Garrett.
The hope is that technology can fill that need.
Related Links:
The Department of Transportation's fact sheet on the I-35 collapse.
Design News investigates the disaster.
The Center for Sensed Critical Infrastructure Research
Smart bridges
The Bridge Engineering Center at Iowa State
