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Major CA Bursting Project Proves Very Cost-Effective
In California, the city of Covina is nearing completion of a citywide improvement program to upgrade and update the city’s underground sewer infrastructure.
“Our plan was to ‘fix’ the system under one comprehensive plan,” said Kalieh Honish, Covina director of public works. “The project was designed in 2011, the contract awarded in February 2012, and the upgraded system basically is complete and in service.”
One recently completed 6.2-mile segment replaced old vitrified clay pipe with HDPE pipe of several sizes. The project originally was planned to be mostly open-cut, but ended up with new pipe being installed primarily by pipe bursting.
Honish said the start of construction was delayed due to issues encountered during the initial bidding process. The first round of bidding allowed bidders to price the work either as open-cut or trenchless pipe bursting with a small portion specified for pipe bursting primarily because of surface conditions.
Because of various issues, the city chose to rebid the project, this time specifying that a higher percentage of the project be done by pipe bursting.
“When the prices came in on the second round of bidding, pipe bursting provided significantly lowered costs,” Honish continued. “Considering pipe bursting is a proven technology, it is less invasive, there is less disruption of traffic and less debris to clean up and remove, all with a substantial costs savings, the question was, ‘Why do open-cut?’ Simple math made pipe bursting the obvious choice.”
Engineering for the project was done by Willdan Engineering, Anaheim, CA; Vasilj Inc., Irwindale, CA, was prime contractor; and Mocon Trenchless Corp., Indio, CA, did the pipe bursting on this segment of the project.
“Our contract called for 28,541 feet of pipe bursting,” said Rob Morrow, Mocon president. “This was most of that section. There was a limited amount of open-cut work. As the job progressed change orders added more bursting footage, and we ended up doing 33,112 feet of bursting to install HDPE pipe in 8-, 10- and 12-inch diameters with some 16- and 20-inch pipe.”