JOB PHOTO SLIDESHOW

Whispering Pines Development Corp., a large municipal contractor in Newburgh, was awarded the contract. John Leonette, Jr., co-owner, discussed the job with a contractor advising him on a different project and was offered an alternative - to test an untried new static puller.

Leonette presented the proposal to Osborne, who suggested a 300-foot trial run. Osborne also activated Stearns and Wheeler<92>s pipe-bursting plan that called for potholing service laterals. The combination replaced the failing main without disrupting homeowners or the handicapped occupants inhabiting group homes at the end of the street.< /p>

Minimizing the impact

A 24-inch concrete storm drain lay over the top of the sewer pipe. If Leonette had to excavate, the drain would require support, or removal and replacement, all at additional expense. Open cutting would close the street to pedestrian and vehicular traffic for three weeks, yet the group homes needed 24-hour access. The social impact of digging up Neversink was a major concern for the DWP.

The department and Leonette had never done pipe bursting before. "I got on the Internet, researched the subject, and contacted Todd Carter at TRIC Tools," says Leonette. "He and his brother, Ward, came to assist and supervise in the use of Ward's new WC44 low-pressure static puller."

Leonette hired two hydroexcavation trucks from Hydrovac Excavating Inc. in New Windsor, N.Y. to locate and pothole the six laterals on the 300-foot test run. The Hydrovacs, built by Presvac Systems, were mounted on 2004 Freightliner chasses. The unit s had 14-cubic-yard debris tanks, 1,200-gallon water tanks, 5,300 cfm/15 inches Hg Hibon blowers, and 9 gmp/5,800 psi water systems.

"One traffic lane remained open even when the machines were operating in the road, and the sidewalks were never closed," says Leonette. "At night, the 4- by 4-foot potholes were covered with steel plates and the work area cleaned up. We had no dirt piled on the street, and Neversink Drive was open every night."

As laterals were potholed, Leonette<92>s men excavated an 8- by 2-foot entry trench in front of the first manhole and a 4- by 3-foot exit (pull) pit behind the second manhole 300 feet away. The old manholes were encased in concrete, so they jack-hammered openings for the pulling head. Spoils were loaded into a dump truck and transported offsite.

On Tuesday, Leonette<92>s crew fused two sections of four, 40-foot lengths of 8-inch HDPE SDR-17 Driscopipe on the curbside. The Carter brothers set up the 2- by 2- by 1-inch thick aluminum resistant plate in the exit pit and laid 6- by 6-inch timbers in front of the plate to create a level floor for the WC44 static puller. The low-pressure machine is capable of 126 tons at 6,200 psi. Its special compact radius tri-wheel pulley base mounted to the resistant plate.

Round hole, wrong diameter

As Osborne and town officials watched, Ward Carter began the first pull. The pressure gauge hovered between 1,400 and 1,600 psi until the bursting head encounter ed a large rock or dense obstruction. The pressure rose to 2,500 psi, but that was well within the machine<92>s 3,200 psi limit.

The only problem arose as the bursting head approached the exit manhole. "We didn<92>t make the hole in the concrete structure big enough and that stopped the he ad," says Leonette. His men quickly excavated a 2- by 2-foot hole, jack-hammered more of the concrete, and the head popped through into the manhole.

The pull took almost a day as everyone became acquainted with the equipment. "It was an impressive demonstration of the WC44<92>s capabilities," says Leonette. " The new machine performed flawlessly." Osborne did a visual inspection and announced that all had gone well. He said that the storm drain didn<92>t have to be removed, and gave permission to replace the remaining pipe the next morning.

Leonette<92>s crew had a long night reinstating the six, 4-inch laterals. After cutting through the mainline wall, they used Inserta Tee <96> a PVC hub, rubber sleeve, and stainless steel band <96> to reconnect the service. "The pull was easy compared with hooking up those laterals," says Leonette.

The second pull involved excavating a 4- by 3-foot exit pit behind the third manhole, 440 feet upstream from the middle one. Once everything was set up, the pull took 90 minutes. After his men reinstated 11 laterals, Leonette used a P330 Flexiprobe push-rod camera system from Pearpoint Inc. to inspect the 740 feet of replaced pipe. Finding no flaws, insertion and pull pit openings and lateral potholes were backfilled to within four inches of grade with Crusher run (ungraded crushed stone).

The men saw-cut the asphalt at each hole to leave clean edges, then blacktopped them. Where laterals were close to the curb or the hydroexcavation trucks had driven on the grass, they spread topsoil, hand raked, seeded, and topped with covering hay.

"The trenchless solution took five days compared with three weeks to open cut, and vehicular and pedestrian traffic never stopped flowing," says Leonette. The town has since awarded Whispering Pines a 170-foot pipe-bursting project.