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New Method can Help Assess Bridge Repairs, Save Significant Cost

The $2 trillion American Jobs Plan from President Biden has placed the country’s infrastructure in the spotlight.

In 2007, the Interstate 35W bridge over the Mississippi River in downtown Minneapolis collapsed, sending cars plummeting into the river below. Thirteen people were killed, 145 more were injured. Image Credit: Getty Images.

Considering this initiative, a new study from the University of Georgia (UGA) has suggested that states can save costs and prolong the life of their bridges by adopting a new method on how they prioritize preventive maintenance.

Present-day national strategies developed for bridge maintenance prefer replacement rather than maintenance. In this case, a relatively simple depreciation formula is employed, which leads to overly conservative assessments of the long-term health of a bridge.

For the first time, scientists from UGA’s College of Engineering have suggested a new model in a study recently published in the American Society of Civil Engineers’ Journal of Performance of Constructed Facilities.

The novel method considers the interaction of around 60 to 80 bridge parts to estimate the long-term performance of the bridge and targets maintenance rather than replacement.

Rather than considering a bridge as a monolithic structure, the bridge coactive model assesses a bridge as a system in which changes in the condition of each coactive element not only directly affects the overall bridge performance but indirectly influences the performance of the other dependent elements.

Brian Oyegbile, Study Co-Author, University of Georgia

Oyegbile had recently received his PhD in engineering from UGA in 2020 and currently works with the California Department of Transportation.

As a case in point, Oyegbile believes that substituting a damaged expansion joint in a bridge is cost-effective and has a marginal effect on the overall short-term performance of the bridge. But in due course, salt from contaminated or de-icing water can penetrate a damaged expansion joint, speeding up the deterioration of more crucial elements underneath, for example, a column.

Similarly, when debris builds up in an expansion joint, a bridge deck can deteriorate more rapidly and would limit the normal contraction and expansion of the deck.

The UGA team suggested that if the elements are proactively substituted at the right time—even one as insignificant as an expansion joint—this can have a huge impact on the long-term health of the bridge.

According to the researchers, the new model can offer more robust data and more precise predictions of depreciation for state transportation companies as they plan the repair, replacement, and maintenance of bridges.

At the national level, bridges can last an average of 75 years. But with efficient and timely use of the available resources, such bridges can last for over a century, added the researchers.

In my eyes, the co-activeness is apparent in the bridge inspection data and we can scientifically leverage data analytics in bridge service-life predictions, saving money for the country’s infrastructure maintenance and construction.

Brian Oyegbile, Study Co-Author, University of Georgia

Regular Upkeep Would Save Money

According to Stephan Durham, one of the study’s co-authors and a professor from UGA’s College of Engineering, the heating and cooling system in homes provides an excellent analogy.

Like clockwork, I replace my air filters every two months whether the system has been in heavy use or not because it keeps the system operating efficiently. It’s the same thing with a bridge. If you’re replacing an expansion joint on a regular basis, whether it’s completely worn out or not, your bridge is going to perform better than if you let it degrade to the point a component absolutely must be replaced.

Stephan Durham, Study Co-Author and Professor, College of Engineering, University of Georgia

The team examined the data available in the Federal Highway Administration’s National Bridge Inventory for Georgia, Florida, and Alabama to construct and test their new model. There are over 15,000 bridges in Georgia alone. The National Bridge Inventory database comprises inspection reports on separate bridge elements, demonstrating a wealth of data for the team.

Mi Geum Chorzepa, the principal investigator of the study and an associate professor, stated, “Prior to our work, we hadn’t seen a mathematical model that considers the interaction between bridge elements. We need a more realistic way to assess bridge conditions and prioritize preventive maintenance, particularly in such a challenging budget environment.”

According to the researchers, if $10 billion is invested in suitable and timely preventive maintenance on the country’s bridges over three years, it would create a recurring saving of $20 billion by 2024. These savings could be invested elsewhere—like new infrastructure construction—and help boost economic growth, believes the team.

The Georgia Department of Transportation, which financially supported the study, has recently approved a grant for the investigators to extend their study. In the second stage of the study, the researchers will work with GDOT’s Offices of Transportation Data, Research, and Bridge Maintenance to design a bridge life-cycle assessment tool that can be used by county governments and GDOT throughout the state.

S. Sonny Kim, an associate professor in UGA’s College of Engineering, is also a part of the research team.

Journal Reference:

Oyegbile, O. B., et al. (2021) Novel Prioritization Mechanism to Enhance Long-Term Performance Predictions for Bridge Asset Management. Journal of Performance of Constructed Facilities. doi.org/10.1061/(ASCE)CF.1943-5509.0001531.

Source: http://www.uga.edu/

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