By: Angus W. Stocking, L.S
MSTT - MIDWEST JOURNAL OF TRENCHLESS TECHNOLOGY 2015
When a two lane paved road in Jerseyville, Illinois was failing, City Engineer Robert Kincaid, PE, discovered a 60-inch by 100 foot long CMP sewer was in very bad shape. The invert was close to being completely rotted out and much of the pipe’s top arc was also failing. The road was slumping due to a wide gap near the middle of the sewer run where sections were out of horizontal alignment by about eight inches.
Complicating matters, 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.”
Kincaid first thought cured in place pipe (CIPP) might be used to save the pipe without digging, but found that contractors were reluctant to even bid on such a large diameter repair, and when they did, “The price seemed extremely high.”