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Rehabilitation T E C H N O L O G Y Riverwalk Rehabilitation manufacturing requirements and past perfor- CIPP Saves Georgia Landmark mance record. Applied Felts is a leading felt liner manufacturer and a pioneer of the CIPP rehabilitation process. With method and materials decided, Am- Liner East decided to call a pre-construction job site meeting with all parties involved. “When we have signiﬁcant labor and ma- terials involved and a sensitive work area, we often make it a practice to call a meeting with everyone involved,” said Mel Willett, vice president of Am-Liner East. “This meet- ing really helps us all stay on the same page with regard to the project details and keep the project moving. Having Charlie Mattox, operations manager of Applied Felts, at this meeting was a key factor in determining the logistics of hauling and delivering a liner of this size which weighed in excess of 75,000 pounds.” Holding pre-construction job site meet- ings has enabled Am-Liner and its partners to foresee and tackle challenges long before they become obstacles of a job. Every detail of the project was discussed, including speciﬁcs like U Unbeknownst to the hundreds of daily bik- ers, walkers and joggers along the famous Riverwalk in Columbus, GA, trouble was looming below the ground. Like many oth- Because of the location of the project and the risk factors associated with a break, the Columbus wastewater utility moved quick- ly to ﬁx the damaged pipe. Working with an how to get an 115,000 pound by 120-foot long tractor trailer down a steep grade bike path. Decisions on intersection points, project er well-established American cities, aging engineer from CH2M Hill, a leading engi- time frame, how the resin tankers and cranes concrete sewer pipes are threatening the neering, consulting and construction ﬁrm, would be set up and methods to enable the infrastructure, and repairs are needed to three different solutions were considered: continued public use of the popular Riverwalk prevent a massive raw sewage overﬂow. 1) Excavate and replace; bike path were discussed. A treasured landmark adjacent to the 2) Slipline with ﬁberglass reinforced pipe; Chattahoochee River, the Columbus Riv- or CIPP solution erwalk is 16 miles long and built directly 3) Reline using a cured-in-place pipe (CIPP) Am-Liner East used the Premier-Pipe water above the largest sewer pipe in the Colum- process. inversion method for CIPP rehabilitation. bus sewer system, a pipe that carries 95 Due to the location, price and the strong The basic process begins by taking the lead percent of the sewage in the city. Even the track record for success, the CIPP method end of the Applied Felts resin-saturated lin- smallest break in the pipe could send toxic was chosen. The CIPP process was previous- er, turning it inside out for a predetermined waste into the river, putting residents at ly used to effectively repair the two 54-inch length, then clamping it to a collar over the great risk and posing an even bigger threat interceptor pipes. CIPP effectively relines manhole. Water is then introduced into the to the environment. the original pipe to create a new pipe within turned back section, creating a head, which the existing pipe, all without digging. This causes the lining to continue turning inside Discovering the problem trenchless method has become a preferred out along the defective pipe. The constant ad- solution for many residential and commer- dition of water maintains the inversion head, During a routine CCTV inspection, signiﬁ- cial applications because it’s fast, proven ef- inverting the liner and ensuring it is held cant deterioration was discovered in a por- fective and causes minimal disruption. ﬁrmly against the host pipe. When the instal- tion of a 72-inch diameter interceptor pipe Sterling, VA-based Am-Liner East Inc., a lation is complete, the water in the liner is that carries raw sewage from Ft. Benning, leader in providing quality full-service sani- circulated through a mobile hot water boiler, GA, to the sewage treatment plant. The tary sewer and manhole rehabilitation, was which gradually raises the water temperature damage, particularly at the crown of the hired to provide oversight management and to achieve a controlled cure of the resin. For pipe, was caused by hydrogen sulﬁde gases installation of the 72-inch by 41mm CIPP this project, three of Am-Liner’s boiler units created from decomposing waste. liner. Am-Liner East is also a certiﬁed in- were used. Once the cure is complete, the end The problem wasn’t unique. In 2004, a staller of the Premier-Pipe USA CIPP pro- of the newly formed pipe is cut and trimmed. section of two 54-inch diameter interceptor cess for sewer mains. The wet-out impregnation of the liner took pipes (which empty into the 72-inch pipe) “CIPP is the most useful, cost-effec- almost ﬁve days of round-the-clock labor. had to be rehabilitated for the same reason. tive way to structurally repair aging sewer Once the liner was in place, the actual cur- The intersection of these two pipes is where pipes,” said Jim Mortell, president of Pre- ing time was approximately six days from the a tremendous amount of turbulence oc- mier-Pipe USA. “cook to the cool down.” curs. This turbulence and churning of raw Once the decision was made on the meth- Because of the length and complexity of sewage causes the hydrogen sulﬁde gases to od of rehabilitation, careful consideration this project, Am-Liner East decided to con- escape and damage the concrete pipe walls, was given to the selection of materials. Ap- duct the CIPP inversion from the upstream resulting in cracks, leaks and corrosive de- plied Felts supplied the Premier-Pipe inver- location, where the two 54-inch sewer mains terioration. sion tube. It was selected for its ISO 9000 connected to the 72-inch main. 72 Underground Construction ucononline.com October 2007 “It was prudent to install the liner “over-the-hole” due to the com- plexity of the bypass pumping system, the size and weight of the CIPP liner, and the requirement to keep the Riverwalk open at all times,” said Mark Miles, operations manager of Am-Liner East. As implied, an “over-the-hole” wet-out is conducted over the exist- ing manhole structure. Overcoming challenges With any sewer rehabilitation project, safety is an utmost concern. This project was no exception. The task involved not only the safety of the employees installing the liner, but protecting the people who continued to use the Riverwalk on a daily basis throughout the proj- ect. Safety fencing was erected and carefully placed pathways were established. The swing radius of the 150-ton crane used to lift the lin- er caused a few raised eyebrows. Fortunately, the crane landed safely outside the line of safety fencing. One employee worked continuously as a ﬂagman to warn pedestrians. Because the Riverwalk never closed, an $80,000 crushed-stone ac- cess road was constructed (and then removed) to access the work site. Work vehicles, including a 120-foot long tractor trailer carry- ing 1,350 feet of 72-inch diameter felt liner, carefully drove this new road. Cleaning the lines, a task successfully led by Greensboro, NC-based KRG Utilities, was difﬁcult for two reasons: a large amount of 12- to 18-inch rip-rap boulders requiring manual removal; and the down- stream end of the sewer had to be plugged to prevent the sewer ﬂow from tracking back into the work zone. Another signiﬁcant challenge was the bypass pumping system that had to be set up to handle the 85 million gallons of daily wastewater ﬂow that can occur during rain events. Charlotte, NC-based Sunbelt Pump & Power designed, installed and maintained the bypass system for the project. “In just over two weeks, we established the bypass using 24,000 feet of 18-inch diameter high density polyethylene pipe (HDPE) and 23 each of 6- and 12-inch diesel power pump units,” said Sunbelt’s Atlanta Pump and Power Manager Ladd Gould. Six individual bypass lines needed to run parallel and tie into a common header pipe before discharging into the downstream sani- tary manhole. Additional challenges arose due to the ﬂatness of the pipe grade, which meant the downstream sewer ﬂow kept back ﬂowing into the pipe that needed to be rehabilitated. To ﬁx this problem, the crew in- stalled a 72-inch pillow plug to keep the pipe dry. A two and one-half inch rainfall made matters worse. “Like a well-oiled machine, all the groups involved in this project – engineer, cleaner, etc. – really worked well together to overcome the obstacles we faced,” said Willett. Despite all the challenges, the pipe lining and manhole rehabilita- tion work was completed on time and on budget. The 1,300 linear feet of pipe lining and manhole rehabilitation work was completed in 70 days and the site restoration and demobilization took an ad- ditional 20 days. “Trenchless technology was the ideal solution for this project,” said Miles. “We were able to keep the Riverwalk fully functional through- out our project; and we were in and out of there in a fraction of the time and cost that digging and replacing the pipe would have required.” FOR MORE INFORMATION: Felt Liners: Applied Felts, (203) 426-5948, appliedfelts.com Contractor: Am-Liner East, (703) 430-4120, (877) 265-4637, amlinereast.com CIPP: Premier-Pipe USA, (952) 944-8093, premierpipeusa.com Cleaning & CCTV Subcontractor: KRG Utilities, (828) 757-0006, krgutility.com Bypass Pumping Supplier: Sunbelt Pump & Power, (800) 736-2504, sunbeltrentals.com October 2007 ucononline.com Underground Construction 73