Case Studies - January 2020

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CentriPipe saves large culverts under high-traffic roadway

Problem: Aware of aging and deteriorating infrastructure, the city of Aurora, Colorado, contracted with Wilson & Co., Engineering & Architects to conduct a comprehensive condition assessment of their corrugated metal pipe stormwater infrastructure and assess various rehabilitation methods based on a set of specific criteria with regard to hydraulic capacity, load capacity and impact on the environment and traveling public. Two 96-inch corrugated metal pipe culverts under a major arterial roadway at the intersection of Louisiana Avenue and Biscay Street were found to be severely deteriorated and deemed to be in imminent danger of failure. 

Solution: Ace Pipe Cleaning, a certified applicator of CentriPipe from AP/M Permaform, began the rehabilitation process with cleaning, invert repair, void grouting, stormflow diversion and sandbagging to ensure any large storm runoff wouldn’t flood the nearby neighborhood. They then applied the fine-aggregate cementitious CentriPipe liner in 1/2-inch passes to attain the engineered design thickness. 

Result: CentriPipe proved to be a viable and cost-effective rehabilitation method for the large-diameter corrugated metal pipe. The minimal footprint enabled it to be installed without disrupting traffic. 800-662-6465; www.centripipe.com.


Robotic water jetter effectively removes failed liner

Problem: A relining contractor in Empfingen, Germany, lined a 16-inch clay pipe with a 5 mm fiberglass liner with 1 million psi flexural modulus and it failed. Subsequently, they relined it with an undersized 5 mm fiberglass liner, which then failed too. The municipality now had to remove 10 mm of failed 16-inch liner 200 feet long.

Solution: I.S.T. North America was in the process of developing a robotic water jet cutter designed to work effectively in these sorts of situations. For this application, they decided to use a two-beam model. The robot provides up to 43,000 psi of water cutting power. They determined that only 26,000 psi at a flow rate of 6.8 gpm was needed to pierce the fiberglass and rip it apart while preventing damage to the host pipe. After the first day of training, they chose a cutting style of three-piece cross sections and removed the long strips with a jet truck. 

Result: It took only three days to fully remove the 200-foot section of double-lined 16-inch fiberglass liner. 212-419-0069; www.ist-na.com.


Inversion system allows for pipe relining without excavation

Problem: Columbia College in Missouri had 8-inch clay pipe with hairline fractures and root intrusions at the joints. The major concern was that this issue ran under a very nice courtyard with special glass drainage and fancy landscaping that they did not want to tear up. It had been a very expensive drainage system so tearing out 310 feet would have been a mess and very costly. 

Solution: Pipe Lining Supply used a manhole access point 18 feet underground to reach the problem. They used the Quik-Shot Inversion System with an 8-inch by 3 mm felt liner and Quik-Pox resin to reline 310 feet under the courtyard. The Quik-Roller Calibration Table helped get the exact right amount of Quik-Pox resin, while two Quik-Heaters helped provide the correct temperature.

Result: After inspection with the camera, all of the fractures were repaired. There were no more roots, with no digging at all, and the project was done in one day. 888-354-6464; www.pipeliningsupply.com.


Municipality finds solution to fill gap between lining on manholes

Problem: After relining many of its old and deteriorating manholes, a Georgia municipality needed a solution to fill a 3- to 5-inch gap between the new liners and the manholes.

Solution: Precision Fill from Prime Resins was chosen to fill this space due to its high expansion rate, the fact that it is hydro-insensitive and because its slower set time allows for a more consistent pour and prevents void pockets from forming. The project included several manholes, and each one used between 8 and 12 gallons of material. Recommended uses for Precision Fill include undersealing and stabilizing concrete slabs, compaction grouting of soils, stabilizing soils and filling voids behind pipes, walls, manholes and other structures.

Result: The process of lining and filling the annular space cost roughly a third less than tear-out and replacement. 800-321-7212; www.primeresins.com.



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