Stormwater September 2012 : Page 68
PROJECT PROFILE Fix It Before It Breaks Palm Beach uses trenchless methods to prevent saltwater damage in a storm sewer. BY ANGUS W. STOCKING T he town of Palm Beach, FL, is located on a long, narrow barrier island 65 miles north of Miami and is well known for its many multimillion-dollar mansions. The ex-pensive real estate and the ever-pres-ent saltwater are major complications for the Public Works Department; saltwater corrodes everything, and digging things up for repair is always costly. Therefore, maintenance and trenchless methods are high priori-ties, and the department is always alert for new technologies. As part of a larger project, Palm Beach recently cleaned and rehabili-tated 225 feet of 60-inch reinforced concrete pipe (RCP) storm sewer that was about 30 years old. “There were basically two access points,” says Brandon Depicciotto, owner of Underground Services of America, based in West Palm Beach, “the pump room, and the outlet in the In-tracoastal Waterway.” Depicciotto was working from the intracoastal side, and was using two relatively new technologies: a spray-on lining called COR+ROC, and an application meth-od called Centri-Pipe. Both are made by AP/M Permaform of Johnston, IA, a fi rm that specializes in trenchless solutions. “I’ve used similar products and methods on manholes,” explains Depicciotto, “but this was the fi rst time on horizontal pipe.” COR+ROC is a two-component, high-strength polymer gel intended for one-step structural lining and cor-rosion protection. It has several ad-vantages that made it especially well suited for the Palm Beach project. It doesn’t sag, so it can be used on hor-izontal pipe. It’s moisture insensitive and bonds well to wet surfaces, so the sewer’s constant coastal dampness wouldn’t be a problem. And, when set, COR+ROC is not only structural, adding signifi cant strength to rehabili-tated pipe, but also works much like epoxy coatings to prevent corrosion from saltwater. And Depicciotto says it’s relatively easy to work with: “I’m used to working with epoxies,” he says, “and if you’re used to epoxies you can work with COR+ROC. I like it; it has incredible bond strength and sticks to anything, it’s user-friendly, and cleanup wasn’t hard.” To dewater the system, Depic-ciotto devised a system of two tem-porary barrier walls and pumps that let him work at low tide. After using scraping and high-pressure washing to remove oysters and other buildup, he was ready to apply COR+ROC with Centri-Pipe. “The pipe actually looked pretty good after cleaning,” says Depicciotto, “which was good, of course; it meant we didn’t have to repair gaps before application and that we can stop corrosion before it happens. With the COR+ROC in place to protect against salt damage, For related articles: www.stormh2o.com/project-design this storm sewer should be trouble-free for decades.” Centri-Pipe is a spincasting sys-tem that was pioneered in manholes —its use in horizontal pipe is relative-ly new. It doesn’t require backhoes or big staging areas (which weren’t available on the Palm Beach project), and it works on pipe up to 120 inches in diameter. Basically, the spincaster is inserted into pipe and withdrawn at a calculated speed while a com-puter-controlled motor pumps ap-plies thin layers of structural grout or epoxy mortar. The fi nished product is smooth and tightly bonded, and it doesn’t signifi cantly reduce the pipe’s inner diameter or fl ow. Compared to other methods, like sliplining or cured-in-place pipe, Cen-tri-Pipe and COR+ROC offer several advantages: minimal fl ow reduction, added structural strength, minimal staging area, and speed. A pilot proj-ect by the Minnesota Department of Transportation found that it was also competitively priced. Fixing a pipe that “looked pretty good” might seem a little too effi cient in these budget-conscious times, but the Palm Beach Public Works De-partment feels it was a good value. By strengthening the pipe and pre-venting corrosion, the department has eliminated expensive repair for decades. Sometimes it pays to use a new technology, and to fi x a pipe before it’s broken. Angus W. Stocking, L.S. is a licensed land surveyor and full-time infrastructure writer. 68 September 2012 www.stormh2o.com
Project Profile: Fix It Before It Breaks
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