Major CA Bursting Project Proves Very Cost-Effective

By Jeff Griffin, Senior Editor | October 2013, Vol. 68 No. 10
Assisting pipe insertion to dive under and clear a water service while pipe bursting eight-inch vitrified clay pipe

Diverse route
The bursting route went through residential neighborhoods, commercial developments and some industrial areas.

“Much of the path ran under asphalt and concrete paved streets including the city’s main street, other heavily traveled streets and secondary roads,” said Morrow.

For the full length of the segment, Morrow said Mocon made 97 bursts. The average reach was 310 feet with some as short as 50 feet. The longest was 460 feet.

“Existing manholes remained intact and were rehabilitated at the same time as the pipe,” he continued. “Prime contractor Vasilj excavated pits and completed open-cut work. There were a lot of schools in the area. We did all reaches in front of schools during the summer so normal activities would not be disrupted. We also passed a hospital where it was important to limit interruption of everyday activities.”

As on most major projects, there were unexpected challenges. “We went through a mobile home park where a trailer was sitting halfway across a manhole,” said Morrow.

Morrow said one difficult reach required installing new pipe from a cul-de-sac, under a block wall and into a trailer park.

“Of course, trailers were parked on top of the line that was being replaced,” he said. “But even worse, one was parked halfway across the manhole opening. To solve this dilemma, we ran a double capstan winch from the next downstream manhole and ran the cable upstream and around a pulley – there also was an angle point at that particular manhole – and then up the insertion pit at the next street. Installation was achieved by using a reversible tool which allowed us to burst into the trailer park manhole without needing a receiving pit.”

Reversible Hercules Grundocrack pneumatic hammer with guide head passing through an intermediate manhole while pipe bursting 10-inch VCP and pulling in 12-inch HDPE.

The process then was duplicated on the next reach heading back upstream and received in the same trailer park manhole.

“In another area,” Morrow continued, “we went through a park with a baseball field and bursting allowed us to pass through the minimal excavation so only a small area in the park had to be shut down.”

Equipping the job

All the bursts were completed with one crew using TT Technologies Grundocrack pneumatic hammers with 10- and 20-ton variable-speed Grundowinch winches.