EVANSTON — Travelers on Interstate 80 heading east through Evanston around the end of August were diverted around men and equipment on the bridge over the Bear River and the Union Pacific railroad line. An interesting test was being performed by Professor Michael Barker and Johnn Judd, assistant professor of Civil and Architectural Engineering at the University of Wyoming.
The testing took place on Aug. 22, and was done in partnership with the Wyoming Department of Transportation (WYDOT).
WYDOT has been conducting research in order to refine bridge design and to ensure safety on I-80. Officials have been studying load effects on bridges with heavy-truck traffic.
The objectives for Barker and Judd are to test a newly designed systematic testing system and to test that particular bridge because of its special design characteristics and the fact it serves as a major heavy-truck route. The initial bridge was built in the early 1960s and then widened in the 1980s to add a girder and width to the bridge.
The bridge has heavily skewed bridge abutments that are not straight across the travel lanes and the test examined the bridge response and performance with heavy loads. WYDOT emphasizes that the bridge is perfectly safe, but was chosen for the test due to its unique characteristics.
Randy Ringstmeyer, principal engineer with WYDOT, was in charge of running the “snooper” truck and communicating with WYDOT personnel who were driving trucks loaded with 50,000 pounds of gravel over the bridge at different intervals. The snooper truck has an articulated arm with a basket on it that Ringstmeyer maneuvered under the bridge so that stress and deflection measurement sensors connected at strategic places could be attached to the bridge girders under the bridge.
These sensors would then relay information through a wireless system to a laptop computer manned by international PhD student Renxiang Lu, who read and recorded the data. Lu will be doing his dissertation on the testing project.
The sensor measurements come to wireless boxes and are sent to the computer and Lu can look at what all sensors are doing simultaneously. This data will be used to examine the performance of the complicated bridge with Wyoming’s heavy truck traffic.
This wireless computer testing system takes only a day and a half to set up and take down, whereas traditional bridge testing would take four days or more. If the new testing system is successful, it will also be less expensive and require less manpower to utilize.
Barker has been teaching for 28 years, with 13 of those years at the University of Missouri. He came to UW in 2003. Judd is fairly new at UW, and this is the first project the two faculty have done together. Judd acts as lead for the project, coordinating and organizing all aspects of the objectives.
Barker is a field test expert and has been conducting bridge field tests for 25 years. They have also had graduate and undergraduate students working on the project in order to get research experience.
“We worked together to tackle obstacles of performing a complicated bridge test,” Barker said. “The local WYDOT personnel have been incredibly helpful in working with us on traffic control and making this a very successful test.”
Barker said the research team still has months of work ahead to reduce the data to engineering quantities, design factors, and draw conclusions on the performance of the bridge. If the test was successful for structural health monitoring, Judd’s plan for the future is to put fiber optic cables on select bridges that will communicate directly with WYDOT.