MANSFIELD — Like sands through an hourglass, so are the days of our sinkhole.
With apologies to actor Macdonald Carey, who voiced the intro to the “Days of Our Lives” popular daytime soap opera on NBC from 1965 to 2022, a similar flowing of sand likely led to a sinkhole that developed on Sturges Avenue early Wednesday morning.
City workers were back at the site between Ohio and Mendota streets on Friday morning, pouring concrete into the bottom of the now-excavated pit and then adding a crushed limestone fill mix.
City engineer Bob Bianchi worried Thursday that a corrugated steel culvert 84 inches in diameter at the bottom would need to be repaired or replaced.
He said Friday the culvert is sound and the street could be reopened late next week or early the week after.
(Photos taken Friday morning at a sinkhole on Sturges Avenue between Ohio and Mendota streets. City crews were on the scene making repairs and there are also photos looking down on the west side of Sturges to Ritter’s Run below where a corrugated steel storm sewer culvert begins. The story continues below the gallery.)
The aging culvert, part of the city’s storm sewer system, begins just west of Sturges Avenue and carries water under Ohio Street, Glessner Avenue and Mulberry Street and ultimately into the Ritter’s Run tunnel that flows through the downtown, according to Bianchi.
After investigating the sinkhole Thursday, Bianchi offered the most likely explanation for it.
He said a 10-inch sanitary sewer had been installed in the area in 1915 and that an arch-type bridge was later built over it. Bianchi said it appeared the arch “was cut in line with the sanitary sewer.”
“I think the sanitary sewer, which was clay pipe, failed under the arch. They realized they were not going to be able to bore or push a new section of pipe under the arch.
“They most likely decided, rather than repair the arch, let’s slide a corrugated metal pipe through the area to convey the water,” he said.
“They backfilled around the sanitary sewer with a sand mixture. When a corrugated steel pipe corrodes, it usually corrodes at the bottom of the pipe and you get holes in the steel. The material outside the corrugated metal can find its way through the holes and washes away down the pipe,” he said.
The sand erosion likely happened over decades, he noted.
“Where this became problematic, the material adjacent to the through holes was sand. That compounded the loss of materials because its nature,” Bianchi said. “It flowed through the holes in the steel and left a cavity around it.
“There was no sand at the bottom, but you can see it on the sidewalls (of the sinkhole).”
Also on Friday morning, Gordon Wendling, a 75-year-old retired Mansfield police officer who has lived his entire life on nearby Richland Avenue, offered his own thoughts as he peered down into the sinkhole.
“There was a sandstone block bridge here. It had a big arch with a red brick interior,” Wendling said, recalling his childhood days.
“I must have been 14 or 15 years old when they put the culvert in. It was a steel, 10-foot culvert. They ran it under the bridge and then they backfilled on both sides,” said Wendling, who retired from the MPD 14 years ago.
A heavy rain last fall helped lead to the problem, he said.
“Last fall, this (culvert) clogged up because they didn’t keep it cleaned out. The water was about 25 feet deep and I’m sure it undermined (the backfill) around the culvert.
“The bricks must have fallen out of the old bridge and that caused the sinkhole,” he said.
As he spoke, he looked down on the west side of Sturges Avenue, a hilly and wooded area that leads down to Ritter’s Run below.
“The water that day was the highest I have seen that water in my 75 years,” Wendling said. “And I have never been off of Richland Avenue. I have been here my whole life.”
Bianchi said it’s possible a strong storm and rising water could have exacerbated the existing sand-washing problem.
