From Valleynewslive · · 1m 20s
Cass County engineer details Highway 81 collapse cause
Cass County engineer explains Highway 81 embankment failure cause and repair timeline.
In brief
Cass County engineer explains Highway 81 embankment failure cause and repair timeline. Cass County engineer says Highway 81 collapse caused by dry soil and water movement, with road expected to reopen as gravel by winter if weather permits. Originally reported by Valleynewslive.
Highway 81 closure confirmed
Cass County Engineer Kyle Litchy told the Commission on Monday, Sept. 21 that Highway 81 north of Hickson remains closed after a section of the Fargo-Moorhead Diversion Area Project collapsed.
Crack grew before Labor Day
Crews noticed cracking up and over the southern embankment before Labor Day, with a 1-inch crack turning into a 4-foot elevation drop within 72 hours.
Cause tied to soil moisture
The failure resulted from dry weather and the amount of water necessary in clay to meet compaction requirements, with slopes originally at 5-to-1 then breaking to 3-to-1.
Rebuild planned at six-to-one slopes
The solution is to remove failed material and reconstruct slopes to 6-to-1, with the failure limited to south and north of the southern embankment.
Road expected to reopen as gravel
There’s a 50-50 chance the road will reopen as gravel by winter if weather permits, but may stay closed if too much rain occurs.
Repair funding depends on prior events
The U.S. Army Corps of Engineers said who pays for repairs depends on what happened before the damage occurred.
The main idea
Cass County engineer says Highway 81 collapse caused by dry soil and water movement, with road expected to reopen as gravel by winter if weather permits.
