Underground Construction - December 2017 - 24

Stormwater Drainage
water collection and disposal at
civilian airports. The decision to
recognize polypropylene pipe as an
equal alternative to other materials enables design engineers and
contractors to leverage the benefits of the light-weight, cost-effective and durable solution for water
collection and removal under
airfield pavements. This action followed the FAA approval of HDPE
pipe for under pavement use in
all airport areas, including deicing
pads, runways and taxiways.
Coulter has more than 18 years
of experience, with most of that
time spent overseeing pipe being
put into the ground at Sea-Tac.
"We've gone away from RCP (reinforced concrete pipe) out here
a long time ago," he stated. "The
ADS pipe comes in longer, 20foot lengths and that also means
a lot fewer joints along the entire
system.
"One of the things that was very
hard with this project was the limited duration we had to accomplish
it. We were doing a lot of work in
180 days.
"Obviously, the pipe was a
small monetary part, but a large
time-saving component. We could
not shut down the whole runway
at once because aircraft still had to
get through the area safely. There
wasn't a whole lot of time to put
pipe in the ground as we were concentrating on paving and grading
- that's the job. The pipe work had
to go quickly. We use the term 'set
it and forget it.'"

Southern success
In November 2015, the new
stormwater drainage system was
completed for the Jackson-Medgar
Wiley Evers International Airport
(JAN) in Jackson, MS. Key to the
required installed efficiency of the
project was the use of 13,000 feet
of thermoplastic pipe in diameters
up to 5 feet. The pipe was used to
replace RCP that was failing, and
also for new runs. The project was
designed and overseen by WEI/
AJA, a joint venture between

ucononline.com

Upgrading the stormwater drainage system at a Sea-Tac runway required nearly 3 miles of large-diameter thermoplastic pipe.

Waggoner Engineering and AJA
Management & Technical Services,
both of Jackson, MS.
"The project was initiated
because the airport was having
issues maintaining the airfield,"
explained Will Pentecost, P.E.,
manager of the project for WEI/
AJA. "The original concrete pipe
had reached its design life. It had
been in the ground for well over
60 years and was starting to experience joint failures, causing
sinkholes which were safety risks.
What they had was a safety issue
for maintenance personnel, and
the sinkholes could have caused
damage to an aircraft if it left the
runway. There were some large
sinkholes on the airfield where
they were losing material through
the concrete pipe joints. Also, if
the drainage could not be maintained, it would allow water to
accumulate and be a concern because birds would congregate there
and increase the potential for bird
strikes.
"We conducted an evaluation of
all the storm drainage on the airfield and compiled a report on the
condition of each pipe run and inlet. We then designed a project to
meet the airport's current budget
and needs at the time, and to immediately address the worst areas."
The airport, with two runways,
encompasses some 3,300 acres
and services approximately 20
commercial aircraft daily. It is also
home of the 172nd Airlift Wing
of the Mississippi Air National
Guard.
"Originally the project was de-

signed using reinforced concrete
pipe in order to meet FAA specifications," Pentecost continued.
"But I liked the idea of fewer joints.
Generally, in concrete pipe that
is where we have the most issues,
and on that airfield most of the
pipe was fairly deep."
In addition to meeting long-life
and other performance criteria,
the pipe would need to provide
an efficient means of installation.
"Speed was the key," exclaimed
Pentecost. "There are only two
runways, so shutting down one
for an extended period of time to
install the pipe was not a favorable
option."
The bid specifications from
Waggoner called for ADS HP pipe
to be considered as an alternate.
"This did help to keep the prices
in line with the budget and added
competition to the bidding process," he stated.
ADS HP pipe is a high-performance polypropylene pipe designed and manufactured by the
company for gravity-flow storm
drainage applications. It couples
advanced polypropylene resin
technology with a dual-wall profile
design for superior performance
and durability. The smooth interior wall offers additional strength
and flow. HP pipe has a patented,
extended, reinforced bell with a
polymer composite band and dual
gaskets that add an additional
factor of safety within each joint.
Pipe sections are 20 feet long and
can be easily moved with minimal
equipment and crew.
"The ADS HP pipe fit (the spec-

ifications) and at the same time
the FAA was in the process of approving that pipe," he continued.
"It all just kind of fell together. It
was after we advertised the project
that the FAA approved the ADS
HP pipe. So we included it as an alternate by addendum prior to the
bid. For Hemphill Construction
this was the first time they used it
and they seemed to like it because
the pipe was easy to handle and
install."
The system was designed by
Pentecost and his WEI/AJA team
members for a 25-year storm.
They reevaluated the hydraulics of
the entire field and resized some
areas that had added or expanded
buildings and parking lots. The watertight pipe ranged from 24 to 60
inches in diameter and traditional
precast structures were also used.
The new pipe was installed as
the old RCP was being removed,
using the same pathway. Burial
depth ranged from 4 to 16 feet
with the average being 8 to 10 feet.
"In the design process, we were going to specify a granular material
for bedding," explained Pentecost,
"but ADS preferred to use a select
sandy material instead of having
granular material to the spring line
of the pipe and another backfill
material above it. They preferred a
homogeneous material all the way
around the pipe."
FOR MORE INFORMATION:
Advanced Drainage Systems Inc.,
(419) 424-8275, ads-pipe.com
Underground Construction December 2017

http://www.ads-pipe.com http://www.ucononline.com

Underground Construction - December 2017

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