Widening busy Ohio Route 170 to five lanes through the township of Calcutta involved moving utilities 15 feet beyond the path of two eastbound and three westbound lanes. Four major shopping plazas, several retail stores and restaurants line Dresden Avenue, serving shoppers from parts of Pennsylvania, West Virginia and Ohio.
The Ohio Department of Trans-portation District 11 stipulated that at least one traffic lane always remain open in each direction to minimize business disruption. So Bert Dawson, P.E., Columbiana County engineer, specified horizontal directional drilling under driveways and parking lots, and trench cutting in open areas.
Dave Sugar of Dave Sugar Excavating Inc. in Petersburg, contractor for the county, subcontracted Chuck Kirk of Kirk Excavating in Columbus to help install the new 12-inch potable water main. Kirk focused on the directional drilling portion. A restrained joint PVC pipe with fittings that matched the city’s 12-inch water mains became the key to an efficient job with little disturbance to the merchants.
Strong and rigid
Communicating with other contractors was critical. “As one of the last companies onsite, we had to be certain that everyone else finished their work before we started,” says Kirk. “For example, the telephone poles had to be moved and the road paved before we arrived.” The water main and gas line were relocated simultaneously.
The plans showed Kirk’s men where to directional bore, and the stations were marked with stakes. Occasionally, one of them had to pothole using a shovel to find gas and telephone lines. “Most directional drilling was beneath driveways,” says Kirk. “Whenever we hit an open area, we dug.” Sugar’s crew set up construction barrels and controlled traffic.
The pits, excavated in mostly clay with a John Deere backhoe, were 22 feet long by 8 feet deep by 4 feet wide to accommodate Kundel trench boxes. The PVC pipe — 1,670 feet of Certa-Lok C900/RJ with cast-iron O.D.s and 280 feet of Certa-Lok Yelomine from CertainTeed Corp. — was installed 6 to 9 feet deep, depending on the depth of utilities.
Dawson chose C900/RJ because it meets all performance requirements of AWWA C900 and eliminates concrete thrust blocks in properly engineered water systems. “PVC is two and a half times stronger than HDPE, and is extruded with a thinner wall for a larger I.D. to maximize flow performance,” he says. “The pipe also doesn’t stretch during installation, then pull out of the couplings when shrinking back.”
Other advantages were that the pipe did not require pre-fusing or heat-welding equipment. “Assembling the whole run was the exception,” says Kirk. “Most often, we joined the 20-foot lengths as they were pulled into the hole.”
Pipe and couplings have precision-machined grooves that, when aligned, lock together with an inserted nylon spline to form a circumferential restrained joint. Teflon-coated elastomeric O-rings in the couplings provide a reliable hydraulic pressure seal.
Down the hatch
One man ran the Ditch Witch JT4020 Mach 1 directional drilling machine while the other used a sonde to locate the boring head or clean up the mud with an HXX Prodigy HydroExcavator from Vactor Manufacturing.
Boring through the clay was uneventful until the duo struck a horizontal layer of shale 400 feet long. Kirk brought his D36x50 Series II Navigator from Vermeer Mfg. and armed it with a 4-inch Aggressive Incredibit from Railhead Underground Products LLC. The drill head withstood the challenge, but a worn, 15-foot rod broke on the boring machine, setting progress back half a day.
The broken rod was removed, the remaining rods re-hooked, and the pull continued. While boring between two newly set telephone poles, one began to lean. Work stopped immediately and the utility company was notified. A crew arrived with a boom truck and held onto the pole as the Ditch Witch operator finished pulling back the reamer, then the pipe. Once the latter was in place, the telephone pole was stabilized.
It took six pulls of 280 to 450 feet to install the C900/RJ. Dave Sugar used standard waterline fittings to connect the new pipe to the city’s water works. The 260 feet of 8-inch Class 200 Certa-Lok Yelomine pipe for the sewer was installed in one pull using horizontal directional drilling and trench cutting. The SDR 17 pipe, which ran through an area with fewer driveways and parking lots, is rated for 160 psi.
Motorists continued their east and west journeys through Calcutta more slowly than usual but could always reach the stores and restaurants. Few realized that trenchless technology and restrained joint PVC piping had made it possible.
