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The
Boyer crew utilized a 24-inch diameter Grundoram Taurus pipe
rammer to install the 66-inch diameter casing underneath
the rail line. The casing functioned as a bypass siphon for
a water canal while the original siphon was under repair.
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NUCA contractor Boyer,
Inc., Houston TX, recently completed a difficult casing installation
under a heavily used rail line in Highlands, TX. The project
called for the installation of approximately 70 feet of 66-inch
casing under a section of Union Pacific railroad tracks for the
San Jacinto River Authority (SJRA). The casing, once installed
would serve as a bypass siphon to move water from an adjacent
canal on one side of the tracks to the other. The bypass would
also facilitate the repair of the original siphon that was failing.
According to Boyer Project Manager William O’Fiel, signs of the failing
siphon were apparent for quite sometime. He said, “For several months prior
to the project, Union Pacific Track Maintenance Crews were having to bring in
right-of-way ballast rock and equipment to re-grade a reoccurring depression
beneath the section of U.P. track above the existing siphon. Upon close investigation,
it was concluded that the SJRA siphon must have been collapsing due to its age
(installed in the 1940’s) and the heavy rail loads.”
In order to install the 66-inch casing under the tracks, the Boyer crew used
a 24-inch diameter Grundoram Taurus pneumatic pipe rammer from Associate NUCA
member TT Technologies, Aurora, Ill.
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The
first section of pipe was installed without difficulty.
Crews then removed the Taurus, positioned the next section
of casing in the pit and welded it to the first casing.
The ramming tool was then re-positioned to continue ramming.
The second section of casing was also installed without incident. According to
O’Fiel, from start to finish the entire ramming process took nine hours
to complete, including five hours of welding time.
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Pipe Ramming
According to O’Fiel, the SJRA
managers faced a major dilemma with this project. The rail spur
over the deteriorating siphon is used hourly to serve the Exxon
Petrochemical Complex in Baytown, TX and stopping rail traffic
in order to repair the siphon would not be considered. On the
other hand, the siphon is an important part of the SJRA Raw Water
Canal System that supplies water to the city of Baytown, as well
as several industrial complexes, including the Exxon plant.
Determining a solution was a difficult task. O’Fiel said, “We
had previously rehabilitated another siphon for the SJRA, using
a bypass pumping system to maintain flow and allow excavation.
That project was fairly straightforward. This latest project however,
was more complicated. Review of the conditions dictated the need
for a second siphon to maintain the flow and repair of the failing
siphon without interrupting rail traffic. Shutting down either
the rail or canal to make the repair was out of the question.”
It was determined that a casing needed to be installed under the
tracks to serve as a bypass while the original siphon was repaired.
According to O’Fiel,
pipe ramming was the method of choice. He said, “In order to install the
secondary siphon beneath the railroad without shutting it down or causing R.O.W.
earth settlement we elected to utilize pneumatic pipe ramming. We had used this
method on several 60-inch railroad crossings during a recent project for the
City of Galveston, Texas. The railroad industry, because of the absence of soil
settlement, is universally accepting of this method. The soil is compacted instead
of loosened, as in conventional excavation, and then removed from the casing
while supporting the soil around it.”
On The Job
According to TT Technologies Pipe Ramming Specialist Mike Schwager two 66-inch
diameter casings arrived, one 35-foot section and one 40-foot section. The Boyer
crew prepared a pit for ramming and moved the 35-foot section of casing in place
for ramming. The connection between the 66-inch casing and the 24-inch diameter
Taurus ramming tool was made using a 66-inch segmented ram cone, a 60-inch tapered
ram cone and a 31-inch tapered ram cone. Once the equipment was positioned and
all connections made ramming was ready to begin.
The first section of pipe was installed without difficulty. Crews
then removed the Taurus, positioned the next section of casing
in the pit and welded it to the first casing. The ramming tool
was then re-positioned to continue ramming. The second section
of casing was also installed without incident. According to O’Fiel,
from start to finish the entire ramming process took nine hours
to complete, including five hours of welding time.
Boyer crews went on to successfully repair the original siphon. The original
siphon was put back in operation. The bypass remained in operation as well in
an effort to increase flow capacity.
NUCA, November 2003
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