Relief Sewer Project Wins Award

February 2010 Vol. 65 No. 2

The Grundoburst 2500G would prove necessary to use all of its 315 tons of pulling capacity in the difficult soil conditions encountered on the project. The machine could be easily rotated 180 degrees in the launching pit and begin bursting pipe from the opposite direction. The machine utilizes Quicklock rods. The rods were connected to a special expander for 18-inch VCP (22.14-inch O.D.). The expander O.D. was 24 inches. The expander had a special internal socket arrangement for the lead piece of VCP to butt against. As sections of pipe were installed, additional Quicklock rods were added to the trail end of the expander and then the new pipe section was slipped over the rods.

The cylinder pack with pressure plate that was pinned to the rods provided 40 tons of force to keep the assembled pipe segments in compression as the bursting head was pulled toward the static pipe bursting machine. Cycle times for each section of pipe to be assembled and pulled forward during bursting began at an average rate of 1 foot per minute. As the project progressed, the crew became much more efficient resulting in average rate of 2 feet per minute. Thus, a typical 350 linear foot reach was completed in 2 to 3 hours.