Emergency Slide Repair Work to be Completed on Interstate 90 West of Sheridan

The Wyoming Department of Transportation and its contractor GSI will begin collaborative work on an emergency slide repair west of Sheridan. Sheridan Media’s Ron Richter has the details.

The Wyoming Department of Transportation Commission approved emergency funding in the amount of $341,137 to District Four to mitigate a potential road-closing slope failure that has been moving for several years. This mitigation effort was needed to ensure mobility on Interstate 90 remains intact until the STIP construction project scheduled for this section can be completed. A common occurrence in Sheridan County, a slope failure happens when the soils, commonly clay, become overly saturated and lose their ‘sticky’ factor, and give way to gravitational pull. This particular slope failure is located on the eastbound lane of I-90 near mile marker 6.9 west of Sheridan.  

This slope failure was first noticed in May of 2017 by Sheridan maintenance staff and reported to WYDOT Geologists who have been monitoring it since. Due to the aggressive new movement of this slope failure, the lack of roadway embankment shoulder, and compromised temporary guardrail installation district maintenance staff determined the slide needed to be mitigated before the right lane of travel was compromised. WYDOT’s contractor GSI, is scheduled to begin work on the slope failure the week of August 19. The work will require WYDOT to temporarily close the right travel lane to motorists. Traffic control will include the closure of the eastbound, right travel lane near mile marker 6.9, and the speed limit will be reduced to 45 mph. Before the emergency funding request, construction plans were finalized to mill, level, and overlay I-90 from the Montana State lane from mile marker 0 to 8. This project is scheduled to be let and awarded in October of this year, with an anticipated start date of Spring 2025.

The scope of the project also includes shifting both lanes of eastbound travel toward the median in order to avoid this and other potentially compromising landslides from mile marker 3.88 to 8  The project also includes major repairs on two bridge structures and replacing four bridge structures with box culverts. This project has been in the State Transportation Improvement Program (STIP) since 2018 and is estimated to cost $36 million.