A Winning Combination

By Steven B. Gross, P.E., CertainTeed Corporation | September 28, 2010

Recently, the city of Roseville, MI, decided to replace an old, corroded cast iron water main that had caused its water and sewer department many headaches in recent years.

"Over the years, we experienced numerous breaks in this water main, which was installed in 1945," Brian McGrail, director of the Roseville Water and Sewer Department, said. "It was well past its youthful life, and the repairs were getting out of hand."

The city of Roseville hired Bricco Excavating, of Oak Park, MI, as contractor for the water main replacement and began the pipe selection process. Since cast iron water mains often experience significant increases in breakage with advanced age, the Detroit, MI, suburb wanted to replace the main with a pipe material they could count on for a longer period of time. After deliberating over three pipe material options, the city chose CertainTeed® Certa-Lok C900/RJ DR18 restrained-joint polyvinyl chloride (PVC) pipe, as it was the most beneficial to the municipality. Alternative thermoplastic piping would have required a much heavier wall for the same pressure rating, with negative consequences for flow efficiency and pumping and drilling costs.

"Using the Certa-Lok PVC pipe enables us to cut down the inventory we have to have in pipe repair parts," McGrail said. "We've used standard C900 PVC pipe often over the past 15 years for spot repairs, so we already have compatible PVC parts in stock. We won't need to stock up on several new repair parts, as we would with fusible pipe. In addition, the cost of ductile iron pipe has soared in recent years, making the Certa-Lok pipe even more of a cost-effective option."

The water main's route runs along Martin Road, a prominent thoroughfare for Roseville lined with 109 homes. Due to the highly populated surroundings of the route and an upcoming road-repaving project, the municipality agreed that using trenchless technology via horizontal directional drilling on the majority of the project was the best option.

"It's a high-traffic area, and we needed to expedite the project as quickly as possible because it was holding up the repaving of Martin Road," McGrail said. "By doing this as a directional boring project, we cut the project time in half and allowed the road crews to complete their repaving before winter. The directional boring also put much less impact on the residents along the route."

The use of cartridge-style Certa-Lok pipe helps keep disturbance down, as it can be assembled piece by piece in 20-foot lengths during pullback, eliminating the need for hundreds of feet of pre-fused pipe strung out through a neighborhood.

Bricco Excavating agreed to handle all of the project's 530 feet of open trench installation for service connections, and they subcontracted the directional drilling to S & S Directional Boring, of Bryan, OH. The project team ordered a total of 5,600 feet of 8-inch Certa-Lok C900/RJ pipe from distributor Michigan Pipe and Valve's Flushing branch.

Work began in June with the project's biggest challenge. Before drilling could begin, the subcontractor needed to locate water, sewer and gas services for each of the 109 customers, spaced about 100 feet apart. The homes along the route varied largely in age, making locations more difficult.

"We had numerous homes on the original map of the neighborhood that hadn't been updated over the years as more homes were built," McGrail said. "The biggest problem was getting into each home and debugging the sewer systems so we could allow drilling crews to make locate excavations."

The safety of work crews and homeowners depends on precise utility locations. S & S Directional Boring used a crew of two to locate utilities and to ensure that no water, sewer or gas mains were hit during drilling, so no workers or homeowners were put in danger. Once found, the gas service locates were either hand-dug or hydro-excavated with a Vac-Con? vactor truck, which was later used for vacuuming bore slurry during drilling and pipe pullback. The sewer laterals and water services were found in common trenches, so the crew exposed them with a Terex® excavator, also used later in the project.

"The contractors barricaded each locate hole until the job was done, and then they backfilled it," McGrail said. "And, we carefully plotted traffic control before the project began to ensure the safety of the workers on the road. Fortunately, everything ran very smoothly. There were no injuries to the public or the crews."

Job safety is a prominent concern of S & S Directional Boring's crews. Employees are required to wear hard hats and safety vests, attend a 16-hour safety training course and participate in monthly Toolbox Safety Talks produced by the National Association of Homebuilders' Labor, Safety and Health Services division. They are also required to be drug- and alcohol-free while on the job.

"We take job site safety very seriously," Tod Schlachter, a partner in S & S Directional Boring, said. "Our crews are very good about being careful on the job site as well."

The original water main was installed along a ditch line; however, after repavings and widenings of the road over the years, it had become covered by the road. Working with two crews of five, S & S Directional Boring was able to drill underneath the sidewalks on the south side of Martin Road, with only minimal disturbance, and install the new water main there. Having the water main under the sidewalks would create a more convenient access point for future maintenance, as road traffic would not have to be disturbed. The crews used a Vermeer® 36x50 Series II directional drill, with 36,000 pounds of pullback, and a Vermeer 33x44 directional drill. Both drills have a rotary torque of 4,995 pounds.

The crews bored straight through clay soil, with bore length ranging from 500 feet to 600 feet. Boreholes were pre-reamed with a 16-inch fluted reamer before the pipe was pulled. Crossovers with Martin Road and side streets on the north side of the road were also directional bored, and Bricco Excavating's crew used the open cut method to connect all of the streets on that side of the route. Thanks to a job well done in locating utilities, the job ran smoothly.

"There were no hidden glitches," Schlachter said. "We were able to install 500 feet to 600 feet of pipe per day and still maintain two lanes of traffic on Martin Road without any traffic regulators."

The job was recently completed, and the Certa-Lok pipe passed pressure testing with flying colors. This was the first time the city of Roseville has used restrained-joint PVC pipe, and they were very pleased with its performance during installation.

"Another reason we went with restrained-joint PVC pipe is because we wanted to make sure the joints wouldn't pull apart during installation," McGrail said. "The crews were able to pull all of that pipe in without a problem. We watched each joint go through perfectly."

Homeowners along Martin Road have also been pleased with the results of the water main replacement and have given good reviews to the Roseville Water and Sewer Department.

"Now, they are able to enjoy the benefits of their water service not being interrupted by a main break in the middle of the night or over holidays," McGrail said. "That's a big improvement over what they had previously experienced."