by Angus W. Stocking, L.S.
Lake City, in Clayton County, Ga., is part of the Atlanta metro core. In recent years, new construction has overgrown some existing underground assets, complicating rehabilitation of existing infrastructure.
In one case, a 66-in., 20-ft deep, 220-ft long corrugated metal pipe (CMP) culvert was failing so dramatically that parking lots and commercial buildings overhead were subsiding noticeably and had to be monitored throughout subsequent rehabilitation.
Inspection revealed inverts that were completely corroded, sidewalls that were curling up into the pipe interior and some collapsed pipe. After this discovery, the failure accelerated. From quote to award, the culvert had collapsed even further, and it was determined that typical procedures would not be enough for this project.