Texas has the second-most bridges of any U.S. state, trailing only California. However, 30% of those bridges do not have sufficient height, width, or capacity to handle the increasing volume and type of traffic using them, according to researchers at The University of Texas at Arlington (UTA) (Arlington, Texas, USA).
With that in mind, Nur Yazdani—a civil engineering professor at UTA—recently received a three-year, $997,275 grant from the Texas Department of Transportation (TxDOT) to evaluate the performance of selected deteriorating and aging highway bridges.
UTA’s Approach
Yazdani’s approach includes non-destructive evaluation (NDE), on-site load testing, and computer simulation, with a goal of helping engineers determine the current condition of bridges. From there, the objective is to figure out which are in need of repair and how to best accomplish that.
“The federal infrastructure bill has given TxDOT and local governments significant funding to apply toward upkeep and evaluation of bridges,” Yazdani says. “They want to ensure that they are using the funding wisely to identify bridges that might have issues. We are happy to apply our findings from current and previous work to help TxDOT ensure that Texas bridges are safe and usable for years to come.”
Tasks include evaluating hybrid steel and concrete girder bridges and the partial composite action in prestressed concrete I-girder bridges.
When existing concrete and steel girder bridges need additional lanes, TxDOT usually widens them by adding steel girders. However, new girders may not have the same characteristics as the old girders and may flex and wear differently, causing differential deflections, cracking, and safety issues, according to UTA.
As such, Yazdani plans to examine these issues on select bridges while finding ways to address any deterioration.
Composite Behavior
In previous research from the Dallas-Fort Worth area, Yazdani’s team conducted NDE and load testing on existing prestressed concrete bridges with composite deck-girders.
As part of that research, they found that both new and old bridges behave only as partially composite—despite being designed as fully composite structures.
Knowing that, the new grant will allow Yazdani to assess newly constructed bridges to evaluate how much composite action occurs between the deck and the girders, both during and after construction.
He and his team will then determine how to use materials, design, and construction modifications to increase the composite action.
Far-Reaching Effects
This project could have far-reaching effects on bridge infrastructure nationwide.
“Our work could have national implications, because federal and state governments publish specifications and guidelines for bridge design, construction, and maintenance,” Yazdani says.
“The overall area of bridge design, evaluation, and maintenance is a highly critical and contemporary issue,” he adds. “I tell my students that they cannot go wrong with making a career out of bridge engineering, with the recent national focus and the plethora of jobs available for them in this area for the foreseeable future.”
Source: UTA, www.uta.edu.