Large-diameter restrained-joint pipe plays a role in Texas’ Loop 335 project
Anyone who has traveled to Amarillo, Texas, has travelled Loop 335. This high-traffic loop encircles the city and connects motorists to every major highway that runs in and out of town. The south side of the loop currently is changing from Hollywood Road into a controlled-access highway that stretches from Interstate 27 to the BNSF Railway tracks on the east side of Amarillo. Before the new loop could be bulldozed and paved, the city had to relocate the water lines that ran beneath the original road.
“We needed to relocate the water main quickly. This required a lot of coordination between the Texas Department of Transportation, the city of Amarillo and all the contractors involved from the design phase through to the installation,” said Jonathan Gresham, the city’s chief water utilities engineer and project manager.
According to Becky Guy, sales representative for contractor Western Industrial Supply of Amarillo, the project called for 1,000 ft of 24-in. DR25 Certa-Lok C905/RJ restrained-joint PVC pipe in 40-ft lengths. The Certa-Lok pipe’s integrated restrained joint system utilizes a combination of precision-machined grooves, high-strength flexible splines and watertight O-rings. An additional 6,500 ft of conventional gasketed 24-in. DR25 PVC C905 pipe also was installed open-cut for the remainder of the project. Because both the Certa-Lok and the conventional PVC pipe are produced by Westlake Chemical Corp. companies—North American Specialty Products and North American Pipe Corp., respectively—it was easier for the city and contractors to oversee the details from specification to material selection and procurement for the quick-moving project. Guy confirmed that the project went to bid in June 2014 and the pipe was delivered to the site the first week of September.
The specified 24-in. diameter is a recent expansion of the Certa-Lok product line, and the addition of the 18- and 24-in. sizes has provided options for engineers and contractors in need of larger-diameter restrained-joint pipe, which is a growing segment of the market. The use of PVC pipe material gives it corrosion resistance and flow capacity.
For this project, Gresham directed that the pipe be installed by way of horizontal directional drilling (HDD). This enabled the pipe crew to avoid excavation of land at two entrances to a local high school, as well as avoid damage to a newly constructed all-weather track that circles the school’s football field. It also preserved the parking lot of the appraisal district offices, which otherwise would have been impacted by excavation.
Because the water main relocation needed to be done swiftly, the restrained joint of the Certa-Lok pipe was a necessity for the job. This type of segmented PVC pipe needs a small staging area, is easy to assemble in any weather condition and assembles quickly because the cooling time for fused solutions is eliminated.
“Amarillo Utility Contractors did a good job installing the pipe,” Guy said. “They are very knowledgeable in doing these types of HDD jobs, and they came through for us as usual.”
She noted that a sign in the parking lot of the appraisal district offices was the only source of trouble to arise during installation. Concrete pillars were set deeply into the earth to stabilize the sign, forcing the drillers to alter their bore path; however, they managed to make it work.
“They did an excellent job. They are very experienced in directional boring and very conscientious about their drilling and pullback. Plus, they are knowledgeable about the pipe, which is easy to connect and easy to assemble,” Guy said. “Certa-Lok provided a consistent experience and these contractors knew what they were doing with it.”
For the work, the locally owned Amarillo Utility Contractors utilized North American Specialty Product’s puller-head rental program.