Pipe Bursting Keeps Automotive Center Moving
by Jim Schill
The Roto-Rooter team was able to replace the 110-foot
sewer lateral through lateral pipe bursting without
interrupting business at a large automotive center.
The cast iron lateral had completely deteriorated
on the bottom and was heavily turberculated as well.
A failing lateral
sewer line is often associated with a residence, but commercial
properties have to contend with aging infrastructure as
well. The effect at commercial properties can not only cause
great inconvenience, it can also cost a great deal in terms
of lost time, business, wages, etc if the business has to
shut down in order to make repairs.
This was the type of situation Greg Smith, Regional Manager
of Roto-Rooter, Mobile, Ala. was called in to remedy at
a major automotive service center in Mobile. Smith said, "Obviously
the failing sewer lateral is something that needs to be
fixed, but closing the shop down to do it was not an option.
We were called in to provide a solution. The solution we
provided was trenchless pipe bursting."
Smith chose the Grundotugger lateral bursting system from
trenchless equipment manufacturer TT Technologies, Aurora,
Ill. to attempt the difficult bursting project.
back-ups at the automotive center prompted the store manager
to call in Smith and the team at Roto-Rooter. According
to Smith, they responded to the call with the intention
of unstopping a plugged lateral. Upon arriving at the site,
Roto-Rooter service technician Keith Dubose attempted to
run a cable through the line. The cable was only able to
penetrate the line 10 feet.
At this point Dubose decided to insert a "see-snake"
camera into the line. The camera revealed major deterioration
in the cast iron lateral. According to Smith the entire
bottom of the cast iron line was deteriorated and the remaining
portion of the pipe was heavily turberculated. It was clear
the lateral would have to be replaced.
It was also clear the team faced an extremely challenging
project. Smith explained, "The lateral ran from well
inside of the building, starting at the centers restroom
facilities and traveled under the garage service area, then
under a road where it eventually connected to the main.
To make the project even more difficult, the 110-foot long
lateral contained two 45 degree bends in it."
Dubose called in General Manager David Etheredge and Plumbing
Supervisor Bill Wilmoth for technical support. They reviewed
the layout and determined lateral pipe bursting was the
correct method to replace the failed line. According to
Smith the next step was convincing the building owner and
store manager that the process was right for the job. He
said, "We met with both the building owner and the
manager of the store and went over the options for replacing
the lateral. The store manager was very concerned about
the impact this project could have on the productivity of
the store and the inconvenience of not having restroom facilities.
We assured him that the facilities would not be down for
more than six hours and that disruption to the store would
be kept to a minimum throughout this process."
The rapid growth in lateral pipe bursting has come about
recently for several key reasons. Inherently the method
is well suited for lateral replacement. It provides a trenchless
option for lateral replacement that utilizes the existing
line and allows for increase or upsize of the original host
pipe diameter. That fact alone is extremely valuable on
jobs where lines are being replaced because of capacity
According to TT Technologies Pipe Bursting Specialist Stacy
Lynn, the acceptance of lateral pipe bursting is not surprising.
He said, "Bursting laterals is not new, but for a long
time, pipe bursting contractors focused on larger and larger
diameter pipes. So, the method was not considered viable
by plumbing contractors as means to replace sewer laterals.
The same was true to an extent with equipment manufacturing.
Bigger was the goal in many cases. But thats changing.
High quality and highly capable lateral bursting equipment
is being manufactured. And its being used in the
According to Lynn, a successful lateral bursting system
meets several criteria. First, the system needs to be portable.
Being able to travel from job to job with the equipment
in a utility van or pick up truck is very advantageous.
Second, the system needs to have the power to burst size
to size and even upsize. And third, the system needs to
be affordable and easy to use. He said, "If you can
meet those criteria, youll have a successful lateral
Grundotugger static bursting system is specifically
designed for lateral bursting applications. Pipe bursting
laterals has gained popularity over the past several
years because the method is well suited for the application
and keeps disruption to a minimum.
The Set Up
Roto-Rooter crew needed to overcome two 45-degree bends
in the run under the automotive center. According to Lynn
overcoming turns and bends in the line is one of the benefits
of the static system, but utilizing a proper power supply
is key to success.
He said, "While the equipment can negotiate turns and
bends a proper hydraulic system needs to be powerful enough
to overcome these difficult areas of the run. The system
also needs to be capable of handling foreign material and
other contaminants found at every jobsite. An electro-hydraulic
system is the best option for hydraulic power. A simple
industrial hydraulic system with a sequence valve design
doesnt survive long in the field."
The decision was made to burst through one of the 45 degree
bends, and excavate the second, dividing the run into two
sections with the exit pit in the middle. The crew excavated
a launch pit behind the restroom facilities. After rodding
the existing line and placing the winch cable, the crew
positioned the Grundotugger static bursting unit in the
exit pit. At the launch pit, a standard direct bolt expander
was connected to the approximately 75-foot long section
The connection between the new HDPE and the expander is
another critical component in lateral bursting. Lynn said,
"The direct bolt method is a very common way of connecting
the expander to the new pipe in main line bursting, but
it can also be used for lateral bursting. For difficult
lateral projects, a pneumatic piercing tool can be used
to assist bursting operations from the inside of the new
HDPE, behind a direct bolt expander. A quick grip type expander
connection is also common in lateral bursting, but does
not allow the piercing tool assist option." After the
expander was connected the fused HDPE, the winch line was
The crew then connected the hydraulic power pack to the
bursting unit. After all of the connections were made, bursting
operations began with the bursting unit steadily pulling
the new pipe through the existing line. Within an hour the
first burst was complete and the 75-foot section of new
HDPE was in place.
According to Lynn the lateral bursting process is simple.
He said, "Youre dealing with a very basic concept.
The hydraulic tugger unit pulls the winch cable, expander
and new pipe through the existing line. The expander fractures
the existing pipe and displaces the fragments into the surrounding
soil while the new pipe is pulled in behind."
At this point, the Grundotugger bursting unit was re-positioned
in the exit pit to facilitate bursting the second section
of the lateral. Crews fused together 35 feet of HDPE and
made the necessary connections. Bursting was again underway
and a short time later the second section of new HDPE was
in place. During both bursts, business continued at the
service center as if nothing was going on.
After the bursts were complete, the Roto-Rooter crew made
all the necessary connections to get the line back in operation.
Restoration work then began on the exit and launch pits.
lateral line under the automotive center contained
two 45-degree bends. The Roto-Rooter team burst through
one of the bends and excavated the other in order
to divide the run in half.
At a rate of
at least one bursting project a week Smith sees the impact
bursting is having on the industry. He said, "As more
people learn about the pipe bursting method and become familiar
with its benefits, there will obviously be more opportunity.
On this particular project, we estimate that the automotive
center saved over $20,000 by bursting instead of open cutting.
With benefits like that, people are going to take notice."
Cleaner, October 2003