Rehabilitation and Relining

Rehabilitation and Relining

Seal system helps rehabilitate vault pipe

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Centrifugally cast pipe used to rehabilitate interceptor

Problem: A routine five-year inspection of a 36-inch reinforced concrete sewer interceptor in Rockland County (New York) Sewer District No. 1 revealed that the top half of the interceptor, which had been in good shape just five years previously, was almost completely rotted out by microbiologically induced corrosion. Even the reinforcing rebar was gone in 20- to 30-foot stretches of the 750-linear-foot sewer; only solid root masses were holding the soil in place. A failure in this 36-inch interceptor, just a mile upstream of the region’s wastewater treatment plant, would affect hundreds of homes and businesses.

Solution: After consulting with contractors Ace Pipe and National Water Main Cleaning, the district selected a centrifugally cast concrete pipe process known as CentriPipe from AP/M Permaform to structurally rehabilitate the interceptor without digging. Some creativity was needed to stabilize the pipe prior to spincasting. Following stabilization and dewatering, the crew worked from manhole to manhole to apply a 1 1/2-thick concrete pipe in three half-inch passes. To prevent future microbiologically induced corrosion damage, the high-strength, fine-aggregate concrete liner (PL-8000) was mixed with ConmicShield, an additive that makes concrete intrinsically and permanently resistant to the formation of Thiobacillus bacteria.

Result: The Rockland sewer interceptor was repaired quickly, safely and cost-effectively, and the completed project is structurally sound and inherently resistant to microbiologically induced corrosion. 800-662-6465; www.permaform.net.


Prechlorinated pipe bursting provides new water mains without disturbing residents 

Problem: Bloomfield Village in Oakland County, Michigan, was ready to replace water mains, but it wanted to do so with minimal interruption of water service to local residents. Space along street right-of-ways was also limited, so officials wanted to limit excavation. 

Solution: The village specified prechlorinated pipe bursting replacement in its plans and chose to upgrade the existing mains with 8- and 12-inch HDPE pipe. Pipe bursting specialist Bidigare Contractors was chosen for the job. For bursting operations, Bidigare Contractors used its own hydraulic pipe bursting machine from the HammerHead Trenchless HydroBurst line. Although the machine was capable of up to 100 tons of pulling force, Bidigare Contractors said the average burst required only about 20 tons. 

Result: Bidigare Contractors replaced between 200 and 500 feet of pipe a day using this method. Residents were never without water service aside from the day the work was done. 800-331-6653; www.hammerheadtrenchless.com.


Seal system helps rehabilitate vault pipe

Problem: A 65-foot-deep vault containing a complex system of pipes, valves and infrastructure for drinking water sat approximately 45 feet below a major U.S. interstate. One of the 36-inch L-shaped joints of a cast iron, concrete-lined water main suffered a leak.

Solution: Foreman Patrick Whitehead reported to the site and conducted pre-job safety checks; he then ventured underground and found the leak. First he prepped the concrete with quick-curing hydraulic cement, then applied a 14-inch extra-wide WEKO-SEAL from Miller Pipeline. Once the seal was in place, he applied the standard two stainless steel retaining bands and one additional for added stability. Upon completion of the installation, an air test was performed on the seal.

Result: From start to finish, installing a WEKO-SEAL took just over four hours, instead of the days it would have taken to replace the leaking pipe. This created huge cost-savings, and service was only interrupted for a few hours. 800-428-3742; www.millerpipeline.com.


Epoxy allows company to construct full manholes in-house

Problem: In 2018, the city of Edmonton, Alberta, had several projects to install new manholes and replace old nonrepairable manholes.

Solution: The projects were awarded to concrete manufacturer LafargeHolcim. Instead of the labor-intensive process of installing manholes and lining them in the field, they lined manhole rings with one-step 3-gallon kits of Neopoxy International NPR-5305 Epoxy at their manufacturing facility. After installation, gaps between rings were filled with the same product.

Result: The company installed 80 manholes using concrete manhole rings lined with NPR-5305 epoxy resin. This approach resulted in less traffic disruption and improved lining quality, and it made the process faster and more efficient, thus reducing construction cost and time. 510-782-1290; www.neopoxy.us. 



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