When the operators of Otay Landfill of San Diego, Republic Services, noticed erosion around a pipe inlet, an inspection was performed. The findings were severe failure and erosion in much of 200 ft of 48-in. corrugated metal pipe (CMP), ranging from 8 to 20 ft below grade.
Republic Services sought rehabilitation technology to address this storm water sewer challenge. Centri-Pipe, the centrifugally cast concrete pipe (CCCP) solution developed by AP/M Permaform, was selected for the large-diameter pipe structural repair and waterproofing.
The pipe uses a precisely controlled spincaster to cast a new, thin-walled pipe matching the contours of the existing, failing pipe, which can be round or elliptical and made of any material, including CMP, concrete, clay or brick. The spincaster is inserted into the horizontal pipe and withdrawn by winch at calculated speeds. Continuous runs greater than 400 ft are possible. While the spincaster is withdrawn, the operator in the pipeline visually confirms adherence and layer thickness, adjusting the withdrawal speed as needed. PL-8000, a fiber-reinforced mortar made by AP/M, was used for the invert and for spincasting the structural liner.
Eight days on site, including prep work and three passes, resulted in a clean, strong, rustproof pipe that only reduced the pipe’s inner diameter by 2.5 in. Republic Services was happy with the result.
“Centri-Pipe was shown to be cost-effective when compared with trenching, and the quality of the rehabilitation exceeded our expectations,” said a spokesperson for Republic Services. “We’ll be using Centri-Pipe on additional lengths of pipe as soon as our budget allows.”