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by Jim
Schill
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The
Utility Solutions crew achieved an amazing level of
production on the Seaside Park Renovation project.
They successfully completed single, continuous bursting
runs of over 960 and 1,000 feet; bursting a total
of over 3,000 feet of cast iron water main in just
four days.
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Beneath
the beautiful parks and beaches of Bridgeport, CT a
deterioration process has been going on for years.
The area’s
cast iron water mains have slowly been eaten away by
salt water from the Atlantic Ocean. Over the past several
years water main breaks have become a more and more common
experience in Bridgeport. Water utility BHC Company,
Bridgeport, CT, is tackling the deteriorating infrastructure
head on, with a large-scale replacement program.
The Seaside Park Renovation Project is one part of the program.
Utility Solutions, Shelton, CT was contracted to replace
over 3,000 feet of 8-inch cast iron water main.
While the project was not specified as pipe bursting, Utility
Solutions Superintendent of Utility Operations Nick Teodosio
explained that it was the right choice for the project.
He said, "The road that a majority of the water main
ran under was being reconstructed. When the project came
up to replace the main, the final prep work was already
done on the road. Final grading was complete, the curbing
was in and it was ready to be paved. No one wanted to upset
the road project, so a trenchless method was preferable.
In addition, BHC had specified the use of High-Density
Polyethylene pipe (HDPE). So I proposed pipe bursting the
line and it was ultimately chosen."
The Utility Solutions crew used a 8.5-inch diameter pneumatic
Grundocrack Hercules pipe bursting tool from TT Technologies,
Aurora, IL and 8-inch SDR 11 HDPE pipe for the project.
Contractor
Background
Utility
Solutions is affiliated with John J. Brennan Construction
(JJB), Shelton, CT, which celebrated 105 years in business
this year. Utility Solutions focuses on all types of utility
work with an emphasis on trenchless rehabilitation and
replacement techniques. Teodosio said, "Utility solutions is something
we developed to try and better market the trenchless methods.
We felt as though we weren’t marketing it very well
under JJB. JJB has been in business so long and does so
many things that the trenchless always fell to the side
when we got busy."
Utility Solutions’ repertoire of trenchless methods
is impressive. According to Teodosio, a large amount of
trenchless experience was gained through JJB. He said, "We’ve
been sliplining with HDPE for over 20 years. We have rodding
trucks, flushing trucks; we do a lot of pipe jacking and
tunneling. We have a lot of underground experience."
In addition, the company utilizes pneumatic piercing tools,
pipe ramming, vacuum excavation and more. Pipe bursting
is one of the latest trenchless methods to be added to
the Utility Solutions arsenal. With twenty-plus years of
experience handling HDPE, pipe bursting was a perfect fit.
And judging by the results achieved for the Seaside Park
Renovation Project, the Utility Solution’s crews have
become proficient at the method very quickly.
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A
constant tension, variable speed Grundowinch was used
to guide the bursting tool through the host pipe.
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Seaside Park
BHC
Company is a subsidiary of Aquarion Company and serves
over 500,000 residents in 29 cities throughout Connecticut.
In business since 1857, BHC Company is the largest
investor-owned water utility in New England and one
of the ten largest in the United States. Over the
past several years, the utility has embarked on a
system upgrade and improvement program. A history
of problems made the water main at Seaside Park a
prime candidate for the program.
Since the project took place in a coastal area, the Utility
Solutions crew faced a high water table. Even though the
existing cast iron main was located only five feet below
the surface, the crew needed to de-water the launch and
exit pits constantly while working.
The high water table ultimately contributed to the main’s
demise. The years of exposure to salt water had taken its
toll and the main was deteriorating from the outside, in.
Numerous main breaks finally prompted BHC to replace the
pipe. This is also the reason BHC specified HDPE as the
replacement pipe, in an effort to avoid salt water deterioration
in the future.
The main started along the beach and traveled under a storage
yard for the mounted division of the Bridgeport police.
From the storage yard the main ran underneath the newly
set granite curb into thegraded roadway. The Utility Solutions
crew set to work on fusing pipe and prepping the tool for
the first run.
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The
Utility Solutions crew used an 8.5-inch diameter Grundocrack
Hercules equipped with a 10.5 inch rear expander to
burst the deteriorating 8-inch cast iron water main.
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Tool Configuration
The
Utility Solutions crew used an 8.5-inch diameter Grundocrack
Hercules pneumatic pipe bursting system, equipped with a
10.5-inch rear expander, for the 8-inch cast iron main.
A 10-ton constant-tension, variable speed Grundowinch was
used to guide the bursting tool through the host pipe.
According to TT Technologies Pipe Bursting Specialist Ric
Micellota the tool and configuration used by Utility Solutions
is standard gear for high production pipe bursting. He
said, "The rear expander tool is a second generation
tool. When we began bursting in the late 1970s and early
1980s, straight barrel tools with front expanders were
used. They can be removed through manholes or reversed
out through the newly installed pipe. Their effectiveness,
however, is somewhat limited by soil conditions, length
of run and host pipe material.
"Today the rear expander configuration is the one most
commonly used in the industry. It provides several key
advantages. First, it allows the use of bentonite in conditions that
warrant it. Second, the rear expander tool configuration
means that a majority of the tool itself is actually in the pipe. This increases
bursting power and assists in maintaining line and grade. Utility Solutions achieved
an amazing level of production in terms of time and footages on the Seaside
Park project."
Also aiding in the success of the job was the use of a guide
head. The guide head is attached to the front of the pipe
bursting tool and adds needed tool length. It allows the
tool to get into the pipe and break it at its weakest point,
the inside.
Bursting
Cast Iron
Cast
iron pipe tends to break several feet in front of a standard
pipe bursting tool. This causes the potential for two major
problems. First, the shards of cast iron pipe are sharp
and can actually cut winch lines. Second, pipe fragments
can build up making the host pipe impassable. This can cause
the tool to change direction and veer off course.
The guide head is the solution. Besides adding tool length,
the guide head helps protect the winch line. In many configurations,
the winch line is connected to the front of the guide head
instead of the front of the tool. This keeps the line ahead
of the actually bursting and out of the way of shards of
pipe.
Micelotta said, "Cutting blades can be used in conjunction
with a guide head. The blades are welded directly to the
guide head. The blades focus the percussive action of the
tool and greatly enhance overall bursting power, allowing
the tool to successfully burst difficult host pipes, like
cast iron as well as many point repairs like PVC."
Beach Burst
Before bursting, the Utility Solutions crew checked
the integrity of the existing pipe. Teodosio
said, "The
pipe was deteriorating from the outside, but we didn’t
know what it was like on the inside. We used our rodder
truck and rodded the main, then pulled a poly pig through
it. The pipe was in pretty good shape on the inside."
With the integrity of the line in check, the Utility Solutions
crew was ready to start bursting the 3,000 feet of cast
iron pipe. The crew prepared a launch pit and put de-watering
pumps in place. Five hundred feet from the launch pit, the
crew positioned the Grundowinch and prepared the exit pit.
Again the pit was de-watered. The first burst set the tone
for the entire project.
Teodosio explained, "The very first day we started
off with a 500-foot burst. The thing went so well, that
the next day we decided to try more. We didn’t have
a specific exit point in mind; we just placed the winch
about 1,200 feet away from the launch pit, hooked up the
tool and let it go. About 960 feet down the road, we stopped
it because we had a hydrant connection to make. If we didn’t
have to make that fire hydrant connection I would have
let it keep going."
On the third day, the Utility Solutions crew out did themselves
again, bursting a single, continuous run of over 1,000 feet.
The crew finished up the fourth day with the remaining 500
feet. According to Teodosio, bursting times ranged between
three and four feet per minute. The final pipe bursting
results were impressive- single runs of over 900 and 1,000
feet, and a total of over 3,000 feet in just four days.
The BHC Company performed final testing and chlorinated
the main before it was put back in service.
Reaction
The project received great reviews from everyone involved.
Teodosio said, "We were very pleased with the
results. And we look forward to more bursting. We
have several pipe bursting projects lined up including
a sewer line burst at a depth of 22 feet. I really
think pipe bursting can make a big impact in the
New England area in the near future."
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The
Utility Solutions crew used an 8.5-inch diameter Grundocrack
Hercules pneumatic pipe bursting system, equipped
with a 10.5-inch rear expander, for the 8-inch cast
iron main. A 10-ton constant-tension, variable speed
Grundowinch was used to guide the bursting tool through
the host pipe.
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