SD&G/SOUTH DUNDAS – There’s been a revelation on why the United Counties suddenly closed a section of County Road 4 in South Dundas on Wednesday.
A section of the road, also known as Lakeshore Drive, was closed between County Road 2 and Parlow Road after a piece of paving equipment suddenly fell through the asphalt.
The machine is called a “Cold In Place” recycler, which grinds up existing asphalt and then spits it back on the road for paving, usually cutting the time for jobs in half as well as cost savings.
“They were just setting up to start and just as they were backing the equipment up to start their work, the track of the heaviest machine in that train fell through the void in the roadway,” County Engineer Ben de Haan told Cornwall Newswatch.
De Haan believes the void was probably there for “years and years” but never had anything heavy enough on it to allow it to give way.
The machinery can weigh 60,000-100,000 pounds (27,215-45,359 kilograms).
De Haan said the collapse was “a big surprise” for him because he had walked through the culvert pipe and inspected two days before the mishap. There were no warning flags or signs of a bigger problem, he said.
There was some deterioration at the ends of the pipe but no evidence that the sand fill had been eroding underneath the road next to the culvert.
Based on their investigation, it’s believed there was a “puncture in the pipe” below the low water level, possibly when the culvert was first constructed, and the sand slowly eroded away. The bridge over the culvert is roughly 50 years old.
As for the size of the cavity, it was very large.
“I could literally climb in there with couple other people and have a picnic in that void, it was unbelievable,”, de Haan told county council Monday morning.
While sand is an acceptable fill, de Haan said the county uses “granular B” gravel.
On Thursday and Friday, the county removed all the sand fill, wrapped the pipe with a filtration membrane and then replaced the fill with gravel.
The section of road was reopened around 7 p.m. Friday (Sept. 15).
The road has been going under rehabilitation work in the hopes it will be transferred to the Municipality of South Dundas in 2018.
Fortunately, there were no injuries, de Haan said.
As for the machine, a crane had to be brought it to lift it out, which would have cost around $2,400.
The revelation came as the county reviewed the preliminary 2018 roads budget, which includes $8.2 in road resurfacing.