Bridge planks set in place on geosynthetic reinfornced soil integrated bridge system

Construction crews set the bridge planks in place for the Geosynthetic Reinforced Soil-Integrated Bridge System in Moniteau County. This innovative bridge design allowed for a natural stream bottom while decreasing construction time and impacts on travelers.

When it comes to replacement bridges, effective design must meet the community’s needs while accounting for each set of unique site conditions, so it is rarely a “copy and paste” job. This was especially true after a bridge in Tipton, Missouri, collapsed, and the creek under the bridge was identified as an endangered species habitat.

Moniteau County hired McClure Engineering Company (MEC) to design the replacement bridge. After assessing the site, MEC employed an innovative bridge system to protect the streambed for the endangered Topeka Shiner while decreasing construction time and preparing Moniteau County to save time and money on future bridges using this innovative technique.

The bridge design and construction, known as Geosynthetic Reinforced Soil-Integrated Bridge System (GRS-IBS), uses simple, readily available materials, and significantly reduces construction complexity. Since its use began in 2010, the GRS-IBS has been implemented on more than 200 bridges in 44 states. Additionally, unlike a traditional reinforced concrete box or a box culvert, the GRS-IBS allows for a natural stream bottom, which was essential to the project.

“It’s great for us to be on the forefront of technology for our region,” said Mike Stein, team leader of the structural department. “We already have several other counties interested in going out to see the bridge to evaluate it for future use. Hopefully, this is something we can implement in other suitable locations to help other communities more efficiently use their resources.”

The GRS-IBS is constructed using alternating layers of compacted granular fill and geosynthetic reinforcement. Unlike other bridges, the GRS-IBS does not use any deep foundations or cast-in-place concrete, which reduces construction time and impacts to the traveling public. The bridge in Moniteau County was constructed in just 30 days, rather than the typical 60 days it would take to construct a traditional bridge.

“By using the GRS system for this bridge, Moniteau County is now set up for future use of this technology throughout the county,” said Stein. “Since the construction method is very simple, once a county or municipality has completed construction for one of these bridges, replicating the process becomes even easier, faster and more cost-effective.”

For the project, MEC performed the survey, design and construction observation, which included being on site every day of construction to ensure each layer was constructed properly, with minimal impact on the creek and the endangered Topeka Shiner.

“Moniteau County has been a great client to work with,” said Stein. “They are open to newer technologies, and are good stewards of their community.”

Layers used in the construction of the GRS-IBS bridge in Moniteau County

The GRS-IBS is constructed using alternating layers of compacted granular fill and geosynthetic reinforcement. Unlike other bridges, the GRS-IBS does not use any deep foundations or cast-in-place concrete.

The Federal Highway Administration has been promoting the use of the GRS-IBS as part of their “Every Day Counts” initiative, which promotes innovative ways to complete transportation projects better, faster and smarter. This was the second GRS-IBS bridge that MEC designed in Missouri and only the fourth in the state.