HDD, Restrained Joint PVC Pipe

When the Ohio Department of Transportation (ODOT) signed off on plans to repave a portion of Ohio Route 531 in Ashtabula, last year, it presented the Ohio American Water Co. with a valuable opportunity to replace an aging water main occupying the same space.

Nearly 8,000 ft long, the cast iron main was more than 50 years old and had experienced several breaks over the years. ODOT’s plans were well received, as the aging water main had become a maintenance challenge for Ohio American Water, as well as a significant community problem.

// ** Advertisement ** //

HDD, Restrained Joint PVC Pipe Keeps Disruption Low in Northwest Ohio Water Main Replacement“This water main was nearing the end of its expected life,” says Bill Dingledine, superintendent of operations for Ohio American Water-Ashtabula District. ” counted 36 repairs made to this section of 12-in. water main over the years, so it was time to replace it. We obtained funding from the EPA’s Revolving Load Fund and moved ahead with the project.”

ODOT needed Ohio American Water to move the location of the water main, as it had migrated underneath the highway, following various road-widening projects over the years. It was determined that the new water main be constructed in the “tree lawn” – the grassy area between the sidewalk and the curb – along Route 531, so future water main repairs would not require excavations into the roadway. This, of course, presented a challenge to the project team, as digging up the landscape and cutting down trees was not a desired option.

// ** Advertisement ** //

To work through these issues, Ohio American Water hired Gannett Fleming Inc., of Akron, Ohio, as consulting engineer and then Precision Directional Boring LLC, of Valley City, Ohio, as contractor.

“After discussing the sensitive nature of the project area with Ohio American Water, we decided to allow the option of directional boring or open-cut in the bid documents,” says Len Rychlik, P.E., manager of water and wastewater practice at Gannett Fleming. ìOf the three contractors that bid the job, two bid it as open-cut, and one, Precision Directional Boring, bid the job as a HDD project. Precision Directional Boring was the low bidder and was hired for the job.î  

// ** Advertisement ** //

Precision Directional Boring’s directional drilling suggestion made the most sense, especially when considering the water mainís surroundings. The Ashtabula portion of Route 531 is often congested with tourist traffic and is bordered by nearly 130 homes and a satellite campus of Kent State University, as well as several old sycamore trees near the shoulder of the road. It was suggested (and ultimately proven) that HDD would help the project team avoid costly landscaping and tree removal costs and minimize traffic and residential community disruption.

Another critical project selection that ultimately streamlined the installation of the critical water main was Gannett Flemingís specification of 12-in. DR18 CertainTeed C-900/RJ restrained-joint PVC pipe with Certa-Lok Restrained Joint System. Based on the recommendation of Precision Directional Drilling, the restrained-joint PVC pipe was selected as the better alternative to butt-welded pipe in this application. In addition to the PVC pipe product offering high durability and a non-corrosive surface in support of a longer useful service life for the new water main, its Certa-Lok restrained-joint technology allowed for fast and easy system assembly in a congested area.

// ** Advertisement ** //

With the installation crew able to assemble the pipe system in 20-ft lengths while concurrently securing it with spline-locked couplings as the pullback continued, the job went along smoothly and quickly.

Precision Directional Boring began work in May 2009, with two crews, each consisting of up to six workers. The biggest challenge of the project came at the beginning, when the project team had to locate gas, water and sewer lines for each of the 127 homes served by the water main and find an optimum location for the new water main.

“We had to carefully investigate the location of each home’s utilities in order to obtain a clear bore path, and the homes were very close together in some areas,” says Brian Willis, project manager for Precision Directional Boring. “We had eight homes every 200 ft, with three utility lines per home, so we would have to dig 24 potholes on one block. That was a very challenging and time-consuming part of the project.”

After the utility location was complete, the crews began making bores through clay soil with a Ditch Witch JT920L directional drill and a Ditch Witch JT4020 Mach 1. Bores varied in depth from 5 to 6 ft. After a bore was made, the 12-in. restrained-joint PVC pipe was attached to a backreamer and pulled back through. Due to the presence of storm sewers, the crews had to use open-trenching to install pipe across street intersections. Fortunately, the need to use open-trenching was kept at a minimum, amounting only to approximately 1,000 ft of the entire water main line.

Once the pipe was in place, Precision Directional Boring used a Ditch Witch JT2720 directional drill to install 127 copper service lines to all the homes along Route 531. The crews finished the job in October 2009.

The project ran smoothly and made a very good case for the use of directional drilling in pipe installation. By using HDD, Precision Directional Boring was able to avoid many expenses and hassles. For example, there was no need in the project to close lanes of traffic or call in electric company workers for help with supporting utility poles. The contractor also avoided extensive landscaping by boring under driveways and trees along the route. These benefits were a big hit with the customer, as well as the end users of the water main.

“I know we saved Ohio American Water somewhere between $20,000 and $30,000 by using HDD in this project,” Willis says. “This project turned out well for us and the customer. It was good for the end users as well because there was nothing in their daily lives that was disturbed. I don’t think the project could have been done successfully with any other method than directional drilling and any other material than restrained-joint PVC pipe. The combination of the two really helped keep disruption down.”

Ohio American Water was pleased with Precision Directional Boring’s work. This was the first time the company had approved the use of HDD for pipe installation, and they were happy with the results.

John Coogan is marketing and business development manager at CertainTeed Corp.