All posts by micaelaresh

New Project: Proactive mapping helps MnDOT identify and respond to risk of slope failure along Minnesota highways

Slope failures can block roads, damage pavement and cause safety hazards. They can also be costly to repair.

For example, in June 2012, Carlton County received up to 11 inches of rain—causing flood damage and slope failures along Minnesota Highway 210. Reconstruction cost $21.3 million dollars, using federal and state emergency funds.

A recently funded research implementation project aims to help MnDOT identify areas that are susceptible to geohazards — such as landslides and rock falls— and better equip highway construction project managers to identify and mitigate risk.

A washed out ditch on Highway 169 in Belle Plaine, Minnesota.
The new GIS model identifies and maps slopes of high risk, like this ditch that washed out on Highway 169 in Belle Plaine.

Raul Velasquez, a geomechanics research engineer with MnDOT’s Office of Materials & Road Maintenance, is overseeing the study conducted by WSB & Associates.

The research team is analyzing satellite images to identify areas with geohazards. Geohazards include areas with shallow rock, sinkholes, and soft or sensitive soil. This information will then be added to map layers in Georilla—MnDOT’s internal web map application. Project managers can then pull this information during the scoping and planning phases of a construction project.

“The earlier we know about a risk, the better,” said Velasquez. “That way we can proactively mitigate the risk, or choose a different project location, if needed.”

This project builds on existing MnDOT statewide georisk modeling research. Phase 1 and Phase 2 were completed in 2019 and Phase 3 is expected to be completed by the end of August 2020.

Over the next six months, researchers will map northwest Minnesota (MnDOT District 2). Researchers will also refine and recalibrate existing maps. As slope failures occur, they will evaluate whether the tool accurately predicted the event.

Map of MnDOT District 2
Researchers are currently mapping risk to slope failure in counties in MnDOT District 2.

While geohazard mapping is applied in other industries in Minnesota, this approach is novel among state DOTs. This exciting work can reduce risk of future road closures due to slides and sinkholes, safety hazards to the public, and puts MnDOT in a position of mitigating risk instead of reactively responding to geological emergencies.

“Avoiding high risk areas can help us reduce material loss, improve human safety, and save taxpayer dollars,” said Velasquez.

The research team presented this project at the 2020 Geo-Congress.

To request project updates or learn more, visit MnDOT’s Office of Research & Innovation.

Methods to Mitigate Bridge Corrosion Show Mixed Results 20 Years Later

Well-documented efforts undertaken two decades ago to mitigate corrosion of a Highway 394 reinforced concrete bridge have given researchers the perfect scenario for evaluating the treatments’ long-term effectiveness. The test results are mixed: State-of-the-art methods for electrochemical chloride extraction and fiber-reinforced polymer wrapping of bridge elements performed well in combination, but poorly in isolation.

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Promoting Snow Fence Adoption in Minnesota

A new research study has shown that few landowners know about MnDOT’s snow fence program, its benefits to community safety and mobility, and incentives to install snow fences. Following community meetings and surveys in four regions of Minnesota, researchers identified promising promotional methods for the snow fence program, the constraints landowners face in adopting snow fences, and incentives and assistance to improve snow fence adoption. Project results will guide MnDOT’s efforts to expand the use of snow fences around the state

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Guide for Converting Distressed Low-Volume Paved Roads to Unpaved Roads

Working with an advisory panel of road managers from local agencies, researchers have developed a practitioner-ready guide for converting severely distressed low-volume paved roads to improved, easily maintained gravel roads. The guide includes decision-making tools and an online webinar for training.

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Guidance for Working With Potentially Acid-Generating Materials

A new resource is available to help agencies greatly reduce the risk of disturbing potentially acid-generating (PAG) rock in places like northern Minnesota when conducting road projects. When exposed to air and water, PAG minerals can generate drainage that is hazardous to the environment. A MnDOT-sponsored research team developed a best practices manual that provides comprehensive steps to identify, mitigate and monitor PAG material during highway construction.  

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Innovative Research to Improve Bumble Bee Habitat

Entomologists have developed an innovative method for surveying bumble bees alongside Minnesota roadways, the results of a new research study funded by the Minnesota Department of Transportation.

Research shows that MnDOT roadsides offer rich bumble bee habitats. The study offers information on surveying bee habitats and recommendations for improving habitats.

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Optimal Sight Distances at Rural Intersections

A new study sponsored by the Minnesota Local Road Research Board has identified 1,000 feet as an optimal sight distance for allowing drivers to make better crossing decisions at rural intersections. Researchers used a state-of the-art driving simulator to examine drivers’ ability to judge traffic speed and gaps between cars at unsignalized intersections with varying sight distances.

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New Spreadsheet Tool Helps Agencies Manage Gravel Road Systems

The Minnesota Local Road Research Board has developed a new gravel road management tool — a simple, customizable spreadsheet for inventorying a gravel road system, tracking maintenance activity and expenditures, and budgeting and planning future needs.

A related user guide provides details about required inputs, gravel road evaluation protocols, and customization based on needs and available data.

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Putting Research Into Practice: New Tool Estimates Bridge Construction Time

A new spreadsheet tool developed by the Minnesota Department of Transportation draws on historical data to help project engineers better estimate bridge construction time. The method allows users to project time-frames based on bridge design elements, work scheduling and other inputs, utilizing estimates from comparable projects in a 10-year database of bridge-building data.

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Taconite-Based Mixture Shows Further Promise for Repairing Potholes

Researchers have refined an innovative, quick pothole repair method for both concrete and asphalt pavements without using asphalt or cement materials. Based on taconite, a plentiful Minnesota material, the repair mixture can be applied fairly quickly and shows promise as a cost-competitive, long-term solution for potholes.

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