|
|
The
Powers Lake Construction crew used pipe ramming to install
an 82-inch O.D. casing 150 feet under Highway 120 in McHenry,
Ill. Pictured: The 32-inch Grundoram Apollo
pneumatic pipe ramming tool.
|
by Jim Schill
Skill,
attention to detail, solid preparation and confidence are a
few characteristics of any successful contractor. Powers Lake
Construction Co. Inc., Twin Lakes, WI., embodies these important
qualities and more. According to Aaron Karow, Powers Lake Construction
Project Manager, everything all relates back to the goals of
the company. He said, “We
are always trying to improve. Our goal is to become a full service
company. We really want to get to the point where, not only can
we do a little bit of everything, we excel at everything we do.” It
is that dedication that proved invaluable on a recent ramming
project.
The project was completed for Meyer Materials, an aggregate company located in
McHenry, Ill. The company was looking to expand its gravel operation. To facilitate
the expansion a conveyor system needed to be installed between the new gravel
pit and the crushing equipment. The company faced one major obstacle to the expansion,
the crushing equipment was located on one side of State Highway 120 and the new
pit was on the other.
The solution to the problem was to install a casing underneath the highway that
would allow for the conveyor system to travel from one side of the road to the
other without inhibiting traffic. The project was specified as pipe ramming and
Meyer Materials contracted Powers Lake Construction for the project.
Karow said, “In order to install a casing under the highway we needed to
use the pipe ramming method as specified by the state. The soil conditions in
the area are rather sandy. An augering application was not considered because
of the possibility of undermining the road. We have done numerous ramming projects
in the past. This, however, was the largest diameter ram we’ve attempted.”
In order to install the required 82-inch O.D. casing 150 feet under the highway,
Powers Lake needed powerful ramming equipment. They turned to Pipe Ramming Specialist
Mike Schwager from TT Technologies for a solution.
|
Once
in place, the 150-ft casing would facilitate the expansion
of a gravel operation. A conveyor system will be placed through
casing to carry gravel from a new pit on one side of the
highway to the crushing facility on the other.
|
Large Diameter
Ramming
According to Schwager, pipe ramming
capabilities continue to grow. He said, “Large diameter ramming has become increasingly
common over the last five years or so. We’ve seen the diameter
of rammed casings increase from 50 inches to over 120 inches and
more. We’re now ramming in the 140-inch range and I expect
soon that we’ll see even larger diameters. I believe our
technical knowledge has contributed greatly to that, along with
equipment development. But it’s contractors like Powers Lake
that really help make it all happen.”
Schwager said that much of the impetus for the large diameter ramming has been
parks and recreation related. Bike paths, and walking and cycling trails under
rail lines and roadways have all been catalysts for large diameter ramming projects.
Schwager has also been on several projects similar in nature to the one in McHenry,
Ill.
All of the projects, include the Powers Lake Construction job, have required
considerable planning, preparation and the right equipment. Schwager moved to
secure the ramming equipment, a 24-inch diameter Grundoram Taurus, while the
Powers Lake crew began readying the jobsite.
On the Job
Powers Lake crews set to work preparing the jobsite for the
large diameter casing by fabricating a rail system to facilitate
the ramming. The rail system consisted of a 24-inch wide I-beam
set in concrete with cross beams every 20 feet. The configuration
was positioned at a 1.5% downhill grade. Grade was critical to
avoiding a high-pressure gas main 30 feet into the ram.
The pipe arrived on the jobsite in three sections. Each piece of the 82-inch
diameter O.D. steel casing weighed in excess of 43,000 lbs. Using a 70-ton mobile
crane crews moved the pipe sections into position on the rail system. Welding
the sections took approximately one day per joint. After the sections were welded
together, a cutting shoe was welded on the lead casing. Two 1/2-inch bentonite
lines were added along the top of the casing.
According to Schwager, using bentonite on a ramming project can
be very effective, but difficult as well. He said, “In this particular case, and in the case
of most large diameter ramming, using bentonite is almost essential. For this
ram we used two bentonite lines, one at ten o’clock and one at two o’clock.
The bentonite lubricates the outside of the casing, helping reduce the soil friction.
Using the right amount and delivering it properly is based on years of experience.
Keeping the bentonite line in place during ramming represents one of the biggest
challenges.”
The Powers Lake crew was meticulous during set up, a quality trait
Karow considers essential. He said, “Set up is always key to the successful completion
of a project. When you have time to prepare and get ready; and you’re not
rushed or forced to hurry and make mistakes, those are the ingredients to success.”
Next, crews used the crane to place the Taurus ramming tool in position and made
the connection between the tool and the casing. A series of ram cones were used
to accomplish this. An 80-inch diameter ram cone reduced the overall diameter
from 80 inches to 31 inches. A second ram further reduced the overall diameter
from 31 inches to 24 inches to make the connection with the tool. Two Ingersol
Rand 1300 CFM compressors were connected to the tool and ramming was ready to
begin.
|
Two
pipe rammers were used on the project. The 24-inch diameter Grundoram Taurus
started the project then moved to another jobsite. The 32-inch
diameter Grundoram Apollo
was brought in to finish the job.
|
The Tale of the Tape
At a total weight of 129,000 lbs.,
ramming the 150 feet of 82-inch casing was no easy task, even for
the former world’s
largest pipe ramming. At the 92-ft mark the Taurus was removed
and sent on to another jobsite. Schwager then brought in the reigning
world’s largest pipe rammer, the Grundoram Apollo.
Schwager explained, “The Taurus was scheduled for work elsewhere
and being in such close proximity to the TT Technologies facility,
we were able to bring in the Apollo to finish up the project without
missing a beat.”
According to Schwager, the Apollo is expected to push the limits
of pipe ramming diameters into the 160-inch range. The 32-inch
diameter tool has a 36-inch rear flair and measures 173 inches
in length. It weighs 25,500 lbs., and delivers over 29,000 ft-lbs.
of impact energy at 180 strokes per minute. Introduced earlier
this year, the Apollo takes the title of the world’s largest
pipe rammer from the Grundoram Taurus.
|
Powers
Lake Construction prides itself on quality work and attention
to detail. Here Powers Lake Construction President Mark Karow
(left) and Project Manager Noel Karow (Aaron’s father)
pose next to the world’s largest pipe rammer.
|
The Final Push
The Powers Lake crew removed the 24-inch diameter ramming tool and removed some
of the spoil from the installed casing before moving the Apollo into position.
Once all the connections were made with the new tool, ramming was underway.
Within two and a half hours the remaining 58 feet of the casing was installed
on grade.
Karow said, “I believe everyone was really impressed with
the project. It was a big ram. Meyer Materials was very happy to
have the casing installed on line and grade and we were pleased
to be able to successfully complete the project.”
Trenchless Technology, November
2003
|
