Overcoming aging water infrastructure: static pipe bursting. (Pipeline Rehab).
For the Kildeer Court water main replacement project, the choice was trenchless pipe bursting with the Grundoburst static pipe bursting system from TT Technologies (Aurora, Illinois). The contractor was D.F. Tomasini, Inc. (Waukesha, Wisconsin). The high-density polyethylene pipe (HDPE) and fusion equipment supplier was Forrer Supply (Germantown, Wisconsin).
While pneumatic bursting works well with a wide variety of fracturable host pipe materials and diameters, ductile iron and steel pipes have been a limitation of the pneumatic method. Advances in pneumatic bursting technology have improved its success rate with certain clamps and joints, but ductile iron sleeves and steel repair clamps can still be a limitation.
With the recent introduction of a new hydraulically powered static pipe bursting system, ductile iron, steel, and lined pipes, as well as pipes with ductile iron and steel repairs can be split and replaced.
During the static bursting process, the Grundoburst's specially designed bladed rollers are pulled through an existing line by a hydraulically powered bursting unit. As the bladed rollers are pulled through, they split the host pipe. An expander attached to the rollers forces the fragmented pipe into the surrounding soil while simultaneously pulling in the new pipe.
TT Technologies pipe bursting specialist Bill Brennan said, "The bladed roller configuration is an essential part of the Grundoburst's success. The specially designed bladed rollers actually split the host pipe instead of ripping or tearing it. This is a clean process and prevents potential damage to the product pipe.
"Patented Quicklock bursting rods are linked together. This system speeds the installation process as well as the breakdown procedure. The rods can be quickly removed one at a time at the exit pit as bursting is in operation."
ENVIABLE TRACK RECORD
Cast iron water mains have been used to carry water for hundreds of years. The first recorded uses of cast iron pipe date back to the 1500s. In the U.S., the pipe has been widely used since the 1800s.
But the old Kildeer Court cast iron system had suffered numerous water main breaks. Amazingly, the actual water carried in the pipes contributed to their problems. Glodoski said, "Lake Michigan is our main water source and it changes temperature really fast depending on the wind direction. It can go from 70 degrees Fahrenheit down to 45 degrees Fahrenheit in a day. That temperature swing can cause breaks." For years the utility has been repairing the breaks. How the repair materials would affect bursting efforts concerned Glodoski.
Kildeer Court was identified as a high priority area for total main replacement. Dealing with as many as 45 water main breaks, system-wide, a year, the Brown Deer Water Utility has used a wide range of techniques to repair the mains. This was true of the Kildeer Court section as well.
Glodoski said, "The concern about this main was we had a lot of repairs on it. We used solid sleeves, ductile iron, steel, and even some large cast iron sleeves for repairs. This main actually had six solid repair sleeves on it. And then we had some other repairs where we used large stainless steel repair clamps. To try and break the old iron pipe and all that stuff is difficult. I really wasn't sure that even the static bursting was going to do it."
This was the first time the D.F. Tomasini crew had used static bursting equipment. Tomasini Project Manager Bob Thogersen sees the potential of the trenchless application. He said, "When you're replacing a line under a roadway and you can save half the roadway by using a trenchless method and just digging up tap holes to reconnect laterals, that's value."
The crew divided the 600-ft main into two 300-ft sections. A launch pit was dug between two telephone poles where the sections created a 90-degree change in direction. An exit pit was dug at the end of each section.
After completing a temporary water bypass, the crew positioned the Grundoburst in the first exit pit and connected it to a hydraulic power pack. The crew then began inserting the Quicklock bursting rods through the host pipe and into the launch pit. A flexible guide rod attached to the front of the first rod was used to help ensure the smooth installation of rods.
Once at the launch pit, the crew removed the guide rod and attached the bladed rollers, bursting head, expander, and new HDPE. The entire configuration was then pulled back through the host pipe by the hydraulic bursting unit. The power of the Grundoburst combined with the specially designed bladed roller was able to burst the pipe and all repairs. The first 300-ft run of 12-in. HDPE was installed without incident.
Crews then set to work making lateral connections with electro-fusion couplings while the Grundoburst was repositioned for the second run. The second run went equally well, with no complications from the existing repairs. Both runs averaged one hour each.
The use of static pipe bursting was a perfect match for the Kildeer Court project for at least two reasons. First, the trenchless method allowed the utility to replace a water main located in a difficult easement. Second, the static equipment used specially designed bladed rollers, capable of overcoming cast iron, ductile iron, and steel repairs.
Thogersen believes that education will help grow the use of pipe bursting. He said, "Technology today is moving along so quickly. Projects like this help everybody learn and see what this technology has to offer and how we can utilize that knowledge in the future."
According to Glodoski, the project provided a great opportunity to gain practical pipe bursting experience. He said, "We worked right along side the Tomasini crew. It gave us the chance to get out in the field with the bursting equipment and get a feel for how the process works. That experience will help us tremendously when planning out future bursting projects."
The Brown Deer Water Utility is currently planning additional bursting projects for summer 2002.
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|Title Annotation:||Brown Deer Water Utility|
|Date:||Jun 1, 2002|
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