Future Forward: Better Bridge Inspections Start with Quantifiable Results
Robert J. Connor is an associate professor of civil engineering as well as director of the Center for Aging Infrastructure and the Steel Bridge Research, Inspection, Training and Engineering Center (S-BRITE) at Purdue University. He also is involved in the Bowen Laboratory for large-scale civil engineering research.
He has been researching ways to quantify steel-bridge performance as well as standards to eliminate fracture-critical concerns in two-girder bridge systems. More recently, he’s been involved as co-project investigator with Professor Glenn Washer at the University of Missouri on a National Cooperative Highway Research Program project to develop reliable bridge-inspection practices.
S-BRITE is a 22-acre off-campus site designed as a gallery of old steel-bridge parts and old bridges where students can get an up-close view to see how these bridges were constructed and how they failed. The idea is partly a preservation of legacy knowledge about how older materials performed as well as a safe means to bring students into close contact to help understand these aging structures with many still in operation elsewhere.
“A big component of S-Brite is the training to help undergraduate students understand fatigue and fracture,” says Connor. “The other aspect is on the research side with probability of detection studies and looking at how steel corrodes over time.”
The live gallery of components does much more than a picture in PowerPoint could do to convey concerns and display these complex structures.
The mission to evaluate how well aging infrastructure is inspected is meant as an exercise to be confident with data and make the most of limited resources. The aim is to quantify how well we inspect bridges now for signs of corrosion, impact damage, scouring and other factors.
Again, the S-BRITE concept comes into play, which, according to Connor, is “to try and convey to an undergrad or a grad student or a professional who’s never gotten their head inside a giant truss connection, how are you going to inspect this, what are the challenges with inspection, what are the challenges of analyzing it, and how do you make measurements?
“I’d like to see, down the road, a national center, where to be a Level 1 steel-bridge inspector, you’d have to come to a facility like ours, and we can ensure a certain level of competency,” adds Connor. “We need to know that our inspectors can find fatigue cracks and that they properly measure corrosion. If not, we have to come up with a plan to help improve that person.”
Each day that infrastructure gets older means that it’s getting closer to failure, and the individuals who knew how it was designed and should perform are no longer available. The newer materials, technologies and techniques that we deploy are extending the lifespan of a bridge, but we need the knowledge to deal with older materials on aging infrastructure.
“The [original] inspection program was put in place for the younger and newer infrastructure,” says Connor. “Now that it’s old, it has to be done differently. I’m hopeful that the work we’re doing on older and newer structures will change so we prioritize what needs more attention and why, and we determine where we can be more effective to improve reliability and safety.”
The inspection of bridges is leading to new areas of technology application that include the use of sensors to read how a bridge is performing, use of unmanned aerial vehicles (UAVs) as sensing platforms as well as the use of augmented-reality learning environments that assist in learning proper bridge-inspection techniques. Although UAVs hold promise, they also come with concerns.
“There is a lot of opportunity, but my concern is that if we go too fast, and it isn’t well vetted, then all transportation people will say that UAVs don’t work,” says Connor. “They won’t single out the vendor that sold a bad solution; they just won’t trust anybody, because there’s no way to evaluate them objectively.”
Connor and his team have applied sensors to bridge structures to understand their current performance and determine where there might be problems, but he’s not a fan of long-term monitoring.
“There are a lot of bridges and a lot of owners that have an interest in bridge-health monitoring,” says Connor. “As they’re taking out the bridge that lasted 75 years, I ask them to go back 75 years, and what data would you have collected over the last 75 years that would have extended the life of the structure? Everybody I’ve ever talked to about this admits that they don’t know.”
Instead, Connor is in favor of short-term bridge sensing that’s outcome based.
“You shouldn’t put a single sensor on a structure until you know what you’re going to do with the information and how that impacts your management of the structure,” notes Connor.
Read the full interview here.