By acting before a problem became an emergency, planners in Hamilton Township, NJ, took a proactive approach to rehabilitating an existing sanitary sewer pipeline showing signs of deterioration in its crown. The 72" diameter reinforced concrete influent pipeline passed underneath Interstate I-195 and the township needed to keep the line in use during the necessary construction work. Since there was no practical way to bypass the flow, sliplining the pipe under flow conditions was the chosen installation method.
The slipline used in the Hamilton Township Treatment Plant Headworks Rehab Project, Final Phase, consisted of 330 linear feet of 66" diameter Flowtite® fiberglass reinforced plastic pipe. The pipe were delivered in 10 foot lengths for this gravity application. The pipe were unique in that each section was fitted with four 4" x 8" laminated skids, spaced 12" apart, in order to assist the contractor during installation.
"These skids helped with the alignment of the bell and spigot during the joint connection process," said Richard Palmer, PE, Tunneling Manager for Northeast Remsco Construction, of Farmingdale, NJ. "The skids also kept the coupling from scraping along the bottom of the host pipe during installation, avoiding potential damage to the coupling."
"The preparation and cleaning of the host pipe was probably the most challenging part of the project," Palmer said. "After providing mechanical ventilation, we used a combination of jet/vac cleaning and manned entry/clean-by-hand methods to extract the debris and verify that we had adequately cleaned the entire length of the host pipe prior to inserting the Flowtite pipe."
Flowtite is a fiberglass-reinforced pipe designed for aggressive sanitary sewer, water, and industrial environments. The pipe offers a smooth internal surface with improved hydraulic characteristics. The filament wound fibers used in the continuous advancing manufacturing process provide a true pressure pipe design with superior hoop strength.
The manufacturing process is unique in that it easily permits a custom product to be made to meet the specific project requirements. With the ability to make custom diameters, the company can create the optimum pipe size to match the inside diameter of the existing pipeline. This provides the maximum flow capability while still permitting ease of installation.
The ability to manufacture variable lengths (standard length 10, 20 or 40 feet) can further help reduce installation time. Reduced installation time means lower installed costs and less "down-time" for the pipeline that is being rehabilitated.
Standard Flowtite pipe can be assembled outside the deteriorated pipe and then pushed into place. For very large diameters (over 60 in.), the pipe can be carried using a light weight frame cart and assembled at its final position.
Palmer said the project team was pleased with the performance of the pipe and that delivery of the 33 10' pieces, along with a 66" x 36" Flowtite tee base fitting, was timely and according to schedule.
For more information on the pipe, visit the U.S. Composite Pipe South website at www.uscpsouth.com. WW
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