Underground Construction - August 2020 - 21

Phase 1, the first and shortest of three
phases, began in December 2016 and
was completed by March 2017.
"Phase 2B replaced an existing 18-inch
and 24-inch sewer line that was over
capacity," Poynor said. "We wanted a sewer
pipe that would last at least 50 years, so
we replaced the sewer line with two and a
half miles of 36-inch and 48-inch Hobas
pipe. The terrain is hilly and in some
places, the pipe goes to depths of 24 feet."

Phase 2
The installation of a 48-inch sewer main
which spanned 4,550 feet was the goal of
Phase 2a, which started in January 2019
and finished in May 2019.
"The manholes are made of composite
polymer concrete material, so they don't
corrode," Poynor added. "The fittings
in the manholes were installed at the
factory. When the manholes arrived,
workers were able to plug the Hobas pipes
right into them. This step saved time and
made for a cleaner installation."
The objective of Phase 2b, which
commenced in October 2019, was to
install 10,960 feet of 36-inch pipe and
48-inch pipe to replace an existing,
over-capacity, 18- and 24-inch sewer
line. "We wanted a sewer pipe that would
last at least 50 years," Poynor said.
The sewer was finished by May 2020,
even though it was given 480 days
for completion.
"Very surprising" is how Poynor
described Phase 2b's time frame. "One
stretch that involved the installation of
48-inch pipe was 320 feet long. A pipe
had to go inside of a 72-inch steel casing
that was tunneled under a State Route
89A interchange - an active highway -
with no shutdowns.
"The bypass plumbing was one of the
biggest tasks that Fann Contracting, the
contractor for all three phases, had to
do. The workers actually dug the hole by
hand without using the auger machine."
Considered a separate project, the Sundog
Lift Station and the Sundog Trunk Main are
located about three miles upstream.
"Right now, they are further down in
the system as far as being able to move
and change how the system currently
works for the centralization," Dotseth
said. "The design is complete, and we

Over the past three years, the city of Prescott has been installing Hobas pipe on different phases of
the overall Airport Trunk Main Project.

State Route 89A interchange remained active as the 48-inch pipe was installed via trenchless methods.

are working with a community partner
in obtaining easements to allow the
project to go forward."
Plans call for the Sundog Wastewater
Treatment Plant to eventually go
off-line and connect to the expanded
Airport Water Reclamation Facility,
about one-half mile from the state's
third-busiest airport. With capacity

of 3.75 million gallons per day, the
facility currently treats wastewater
from residential, commercial, and
industrial sectors. *
FOR MORE INFORMATION:
Fann Contracting, (928) 778-0170,
fanncontracting.com
Lyon Engineering 928-776-1750,
lyonengineering.com
Hobas Pipe USA, (800) 856-7473,
(281) 821-2200, hobaspipe.com
UConOnline.com | AUGUST 2020

http://www.fanncontracting.com http://www.lyonengineering.com http://www.hobaspipe.com http://www.UConOnline.com

Underground Construction - August 2020

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