Certa-Lok® Restrained-Joint PVC Pipe: Two Successful 600 LF HDD Pulls in Congested, Corrosive Urban Setting

• Install 1,450 LF of 12-in. DR14 C900 PVC water main along NW 5th Street, parallel to an existing 6-in. water line and 42-in. sewer.
• Highly corrosive soils demanded a fully corrosion-resistant material. Sandy conditions increased difficulty of horizontal directional drilling (HDD) method.
• The alignment sat just inside the curb and gutter. Utility conflicts ruled out open cut outside the pavement, and full street closure was prohibited due to severe impacts on businesses, residents, and traffic.
• A 20-in. steel casing was required beneath N. Douglas Avenue.

The design combined limited open cut tie-ins with HDD as the primary installation method to minimize surface restoration and traffic disruption. The original plans called for two HDD segments separated by open cut beneath N. Klein Avenue. Contractor Southwest Waterworks (SW Waterworks) accepted the bid alternate and converted the alignment into two 600 LF HDD pulls  along NW 5th Street including crossing under  N. Klein Avenue, further reducing pavement cuts and disruption. A separate HDD installed 20-in. steel casing was placed under N. Douglas Avenue.

Although the project specified fusible PVC, SW Waterworks selected 12-in. Certa-Lok® Restrained Joint Integral Bell (RJIB) PVC pipe. Certa-Lok eliminated the need for heat fusion in a high-traffic urban area while offering rapid spline-lock assembly, true bi-directional restraint, a significantly smaller bell OD, and complete immunity to the corrosive soils.

“It’s light, easy to handle, and the restraint mechanism is a piece of cake to assemble,” said Paul Matthews, owner of SW Waterworks. “We can lower it into the pit, connect it in seconds, and start pullback. In areas with residents and businesses, fusible simply isn’t an option—we’re far more comfortable with Certa-Lok.”

With only 100 ft of laydown space between businesses, crews pre-assembled pipe into four-joint segments to avoid blocking driveways and access points.

Total Boring Solutions, subcontracted by SW Waterworks, used a Ditch Witch JT28 rig throughout. The project began with successful HDD installation of the 20-in. steel casing under N. Douglas Avenue: first pull (608 LF) from just west of N. Klein Avenue to N. Western Avenue; second pull (600 LF) from just west of N. Klein Avenue to N. Douglas Avenue.

Each bore followed the same sequence:

• Pilot bore
• 12-in. reamer pass
• Final 24-in. reamer pass to ensure generous annular space

A Certa-Lok® pull-head (using the identical spline-locking restraint) was attached to the lead joint, followed by a swivel that prevented pipe rotation while the reamer was turned by the rig. Additional four-joint segments were assembled during pullback as the pipe was pulled into the borehole. Peak pull force reached only 5,800 LBF—less than 10% of the 60,000 LBF safe-maximum pull-force capability of 12-in. DR14 Certa-Lok RJIB. The low forces confirmed excellent borehole geometry and minimal frictional drag. After completing the final HDD section, Certa-Lok was used as carrier pipe through the previously installed casing. Thanks to Certa-Lok’s substantially smaller bell outside diameter versus traditional bell harness restrained C900, the pipe easily slid into the 20-in. casing with ample clearance and was joined using standard spline-locked joints.

Final tie-ins at N. Western Avenue and N. Douglas Avenue required only small pavement patches. Despite sandy soil complications that delayed the casing and first bore, the entire project, casing, two long HDD pulls, and connections, was completed in just under one month.

“We had no problems with the pipe—it worked really well,” said Jackson Matthews, COO of SW Waterworks. “Without the early soil issues, we would have finished in two weeks.”

This project is one of several large-scale Certa-Lok HDD installations SW Waterworks has successfully completed in the Oklahoma City area, with additional projects already in the pipeline.