A 10-foot-deep sinkhole on the Mill Valley High School campus in Shawnee is getting repaired after underground corrugated pipes failed, the city says.
The Shawnee City Council on Monday voted 7-0 to approve a contract and materials needed to fill the sinkhole that opened up on the Mill Valley campus due to a failed pipe. Councilmember Angela Stiens was absent.
The vote authorized city staff to bid and award the contract to purchase materials for the emergency stormwater pipe repair at 5900 Monticello Rd.
The materials include a reinforced concrete box with a maximum cost of $170,000. In addition, a geopolymer lining — a sprayed concrete product — will line and stabilize the failed pipe and cost a maximum amount of $995,000. Installation and restoration costs are expected to cost an additional $335,570.
With some other costs included, the project is budgeted at roughly $2 million.
The contracts were awarded to Rinker Materials for the concrete box and SAK Construction LLC, for the geopolymer lining.
The sinkhole opened up in March
The sinkhole opened up on March 13 on the northeast corner of Mill Valley’s campus.
It measures about 12 feet across and 10 feet deep but has had no effect on students or operations at the school, Alvie Cater, USD 232’s communications director, said.
The source of the sinkhole is a failed 69-inch-by-96-inch corrugated metal arch pipe that was installed in 1999, according to the city.
After on-call city engineering staff and contractors surveyed the damage, they determined the pipe needed to either be replaced or rehabilitated.
The proposed project includes stabilization and lining of the pipe and replacing the pipe that goes under Monticello Road, as well as concrete reinforcements.
The project is planned for the summer
The project will require part of Monticello Road to be shut down while the project is underway. It is expected to occur in mid-July and take several weeks, according to city documents.
“We’re gonna have to open cut the road to do that. So we’re going to be closing Monticello,” Kevin Manning, Shawnee’s deputy public works director, said. “If that was done during the school year, it’d be a nightmare. So we want to avoid that at all costs.”
Noting that the contained area of the sinkhole was small, Councilmember Kurt Knappen wondered if there was a risk of the sinkhole going farther down.
“I wouldn’t say that thing is imminent, but we don’t want that sinkhole to spread further,” Manning said. “And we certainly don’t want any issues on Monticello, where the road would have to be closed down in an emergency manner. So to avoid all that, we’re making sure we we take care of the problem the right way.”
USD 232 does not expect operations to be impacted
Because the project will be taking place in the summer, USD 232 does not expect Mill Valley students or staff to be affected.
“There will be no impact on the remainder of the school year,” Cater said. “From the discussions we have had with the city’s stormwater department, we do not have any concerns with how the city plans to resolve the issue.”
