Angus W. Stocking, L.S.
March - April 2015
When Robert Kincaid, PE, City Engineer for Jerseyville, Illinois heard about a two lane paved road failing in his jurisdiction, he wasn’t overly concerned at first. The road was slumping in lanes, with some small sinkholes just off the pavement, due to a failing corrugated metal pipe storm sewer running underneath the road, but cities deal with this kind of failure all the time. However, a closer look revealed serious challenges.
This was a 60-inch by 100 foot long CMP sewer in very bad shape; the invert was more or less completely rotted out, much of the pipe’s top arc was also failing, and the road slumping was caused by a wide gap near the middle of the sewer run where sewer sections were out of horizontal alignment by about eight inches. And, this sewer had limited staging areas, with a golf course on the south end and a treatment plant evaporation pool just 20 feet away on the north end leaving about a 14-foot pad for equipment. So trench-and-replace seemed like a bad strategy; Kincaid says, “Altogether, it would have been a horrible and costly dig for us.”