Union Pacific already inspects most of its bridges twice a year, which is double the amount mandated by the Federal Railroad Administration.
However, the Omaha-based company is always looking to improve safety, which is why it has partnered with the University of Nebraska-Lincoln to continuously monitor a bridge near Columbus.
The goal is to come up with an easily deployable and cost-effective method of detecting bridge problems, such as structural cracks, at early stages when they can easily be fixed and before they cause any problems.
“We want to know about potential problems between regular inspections, and if there’s a way to detect issues we want to take advantage of that,†said Union Pacific’s Director of Bridge Maintenance Todd Martindale.
At the Columbus bridge, postgraduate students in UNL's Civil Engineering program are using sensors on the bridge's steel support members to collect data and try to detect anomalies.
People are also reading…
The project has been going on for several months.
The team of students first installed sensors on specific bridge components, and after testing, created an analytical bridge model. This serves as the baseline, allowing them to revisit the site and continue collecting data. Any change in behavior could signify a potential defect.
The project so far has not detected any anomalies, "which is a good thing," said Daniel Linzell, chair of UNL's Department of Engineering.
Linzell said the bridge project not only seeks to gather data but also come up with new ways to package and use that data.
And while the goal is not necessarily to produce a commercial process or project, it is not purely an academic study.
"My goal is to put something together that they (UP) will use," Linzell said.
Of course, any system like that would supplement, not supplant, human inspectors.
"This doesn't mean we are taking human beings out of the process," he said. "Humans still need to be involved."
But humans can inspect bridges at most a few times a year. If anything goes wrong between inspections, it could be months before it's discovered.
By monitoring bridges with sensors, "Theoretically, there's always an 'inspector' there," Linzell said.
In addition to the safety factor, there is also the issue of efficiency in where to deploy both physical and financial resources for Union Pacific, which has about 18,000 bridges spread out over more than 32,000 miles of track.
"We have a pretty large inventory of bridges, and we try to make smart decisions on where to spend our money," Martindale said.
A system that constantly monitors bridges and identifies potential problems could help the railroad, "prioritize where we're going to do our work."
The bridge in Columbus, which crosses the Loup River just west of the city, was selected for a number of reasons.
That includes its age (it was built in 1908), its construction (steel plates and girders) and the fact that it is used a lot by trains with varying loads and weights.
It's also on a main line and "representative of other bridges in the system," Martindale said.
The bridge-monitoring project with UNL has no set time frame, so it will continue until one or both sides decide it is no longer worthwhile.
Union Pacific also is doing a similar project with the University of Michigan, which is monitoring two bridges near Memphis, Tennessee.
And it has collaborated with a company, SENSR Monitoring Technologies, on a system to detect movement or impact to a bridge pier.