Columbia Bridges Will Be First in State to Use New Technology
COLUMBIA - Two bridges set to be built in Columbia will be the first in the state to use geosynthetic reinforced soil (GRS) technology.
The bridges set to be replaced are the Rustic Road bridge over Grindstone Creek and the Paris Road bridge over Business Loop 70. The Federal Highway Administration's National Bridge Inventory considers the bridges to be structurally deficient.
GRS involves layering concrete blocks on top of a reinforced soil foundation. Each layer of concrete blocks contains a mixture of geotextile (similar to what is used in landscaping projects) and compacted stone.
"It's kind of built a little bit like a layer cake," said Jen Harper, research engineer for MoDOT.
Harper said the technology has ancient roots, as it was used to build parts of the Egyptian Pyramids and Great Wall of China. She said engineers have only recently put the method to use to build bridges.
"It's really fairly new in the modern world to be using this," Harper said. "Now that we have newer technology in some of these geosynthetics, it's become very cost-effective...other states have found that they've had a savings of 20 to 60 percent."
"It's good technology for smaller bridges like these two," said Andrew Boeckmann, an MU civil engineer who specializes in bridges. Boeckmann will work with MoDOT and the Federal Highway Administration to monitor the bridge during construction. Boeckmann said GRS works best for smaller bridges like the two being replaced.
"You're not going to replace the Golden Gate Bridge with GRS," Boeckmann said.
Harper said MoDOT will fund the Paris Road bridge project. On the other hand, the Rustic Road bridge project will be funded by MoDOT, the city of Columbia, and Boone County. "The funding for that is an 80/20 match," said Steven Sapp, Columbia Public Works spokesperson. "MoDOT (pays for) about 80 percent of the project...Columbia and Boone County split the 20 percent (equally)."
Harper said only one company bid on the project. She said contractors have been hesitant to bid on a bridge using technology they are not familiar with.
"After talking with some of the contractors, we found that they just really had not taken the time to get familiar with the new technology," Harper said. "They were uncomfortable taking a risk on something they weren't quite sure about."
Harper said MoDOT will prioritize educating contractors about GRS technology in order to get more bids on the projects.
To learn more about GRS technology, click here to watch a video from the Pennsylvania Department of Transportation.
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