Researchers investigate improved bridge repair after collisions
Vehicle collisions with bridge supports or girders are the second leading cause of bridge collapse in the United States, with an average of three such collisions per day, according to researchers at Missouri University of Science and Technology who are studying ways to improve bridge repair and cut costs for cities and states.
A railroad bridge in Kansas City, Missouri, is an example. According to news reports, the Independence Avenue Bridge, has been struck by trucks multiple times in recent months despite signs warning of height restrictions. Reports indicate the Kansas City Terminal Railway has spent $100,000 on signage and repairs over the past decade.
The Missouri S&T research project could reduce those types of repair costs for municipal and state governments and enhance bridge safety by finding more efficient repair methods.
“We are looking at two things in this project,” says lead researcher Dr. Mohamed ElGawady, Benavides Faculty Scholar and professor of civil, architectural and environmental engineering at Missouri S&T. “First, we examine the remaining strength in a girder after impact. Second, we investigate how to repair the girders to recover their original strength.”
The research will address the lack of design tools that indicate how much load-bearing strength remains after impact, ElGawady says, adding that once repairs made, there is not much current research on the load-bearing capacity of the repairs.
ElGawady says there are two possibilities for repair – splicing together severed strands to repair damaged girders or making repairs using advanced materials such as fiber-reinforced polymers. ElGawady says the researchers will use materials that are readily available to entities needing to make repairs rather than researching new materials.
“We’re looking at very recent developments in ultra-high-performance concrete – state-of-the-art material that is emerging or on the market that they could use now,” he says.
ElGawady and his team at Missouri S&T are working with researchers at the University of Idaho to conduct numerical simulations that calculate damage from a vehicle hitting a bridge. Elgawady says they hope to secure an outdoor location where they could conduct actual tests with a mass hitting a girder.
The three-year research project is supported through $755,000 in pooled funding managed by the Missouri Department of Transportation. Other contributing states are Texas, Ohio, Mississippi, Idaho and Alaska, as well as the Federal Highway Administration. ElGawady says Mid-America Transportation Center has provided $85,000 in supplemental funding.
“During the COVID-19 pandemic and associated budget cuts, it was a really tense time for the states to dedicate money for this research,” says ElGawady. “That they did is another indication that this is a really serious issue.”