Hoosier Energy needed a stable lay-down area near a construction site that was underlain with up to 30 feet of soft fly ash deposits. Burns & McDonnell recommended reinforcing the subgrade with Tensar BX1200 Geogrids to create a stable base using less aggregate. Rode Construction installed a 24-inch layer of bottom ash, covered it with geogrids and 8 inches of crushed limestone. This stabilized the subgrade and allowed construction to continue through wet weather at a lower cost than a thicker aggregate base.

1. CASESTUDY
SUBGRADE IMPROVEMENT S60
Tensar®
BX1200 Geogrids stabilized the subgrade in the lay-down area.
lay-down area as close to the construction site as
possible. It was also essential that the area remain
usable even during wet weather.
Site Conditions: The proposed lay-down area had
been used for fly ash disposal. This byproduct of
coal combustion is commonly used as structural
fill, but it can become extremely soft when exposed
to moisture. The proposed lay-down area was
underlain with fly ash deposits up to 30 ft in depth.
The Solution: Burns & McDonnell recommended
using the Spectra®
Roadway Improvement System
with Tensar®
BX1200 Geogrids to stabilize the
subgrade in the lay-down area. This approach
provided an affordable solution that could be
installed very close to the construction zone while
delivering performance that was equivalent to a
traditional thick-base strategy. Reinforcing with
BX1200 Geogrids provided the strong construction
platform that was essential for transporting and
assembling the project's heaviest components.
“We could have just put down a really thick layer
of rock,” says Burns & McDonnell Senior Civil
Engineer Dave Kunstel. “But we knew they would
be a lot better off using less rock along with
geogrid to reinforce the subgrade. That was our
recommendation based on experience.”
RATTS GENERATING STATION
PIKE COUNTY, INDIANA
Application: Hoosier Energy needed to stage
materials for a new fly ash handling, storing and
unloading system at its Frank E. Ratts Generating
Station. Burns&McDonnell, the energy cooperative’s
project engineers, suggested using geogrid
reinforcement to create a stable and weather-
resistant lay-down area near the construction zone.
The Challenge: Location and performance were
significant project drivers. To optimize productivity
on the project, the customer wanted to locate the
PROJECT HIGHLIGHTS
Project:
Frank E. Ratts Generating Station
Location:
Pike County, Indiana
Installation:
September 2008
Product/System:
Tensar®
BX1200 Geogrid
Spectra®
Roadway Improvement System
Quantity:
7,000 square yards
Owner/Developer:
Hoosier Energy
Design Engineer:
Burns & McDonnell
Distributor:
CONTECH Construction Products, Inc.
Materials Supplier:
Erosion Resources & Supply, Inc.

2. CASESTUDY
Tensar International Corporation
5883 Glenridge Drive, Suite 200
Atlanta, GA 30328
800-TENSAR-1
www.tensar-international.com
For more information on the Spectra Roadway Improvement System or other Tensar Systems,
call 800-TENSAR-1, e-mail info@tensarcorp.com or visit www.tensar-international.com.
©2008, Tensar International Corporation. Certain products and/or applications described or illustrated herein are protected under one or more U.S. patents.
Other U.S. patents are pending, and certain foreign patents and patent applications may also exist. Trademark rights also apply as indicated herein. Final
determination of the suitability of any information or material for the use contemplated, and its manner of use, is the sole responsibility of the user.
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Distributed by:
SUBGRADE IMPROVEMENT
SPECTRA_CS_RATTS_12.08
Rode Construction built the lay-down by leveling
and rolling the subgrade and covering it with a
24-inch-thick base layer of bottom ash, which is
another non-combustible coal constituent. After
the base layer was leveled and rolled, it was
covered longitudinally with BX1200 Geogrids
sourced from Erosion Resources and Supply, Inc.
An 8-in. layer of crushed limestone was then
installed and compacted.
"Using Tensar BX1200 Geogrids enabled the
customer to stage the construction where they
wanted," says CONTECH Construction Products,
Inc., Regional Tensar Project Consultant Matt
McCants. "It provided them with a very stable
platform with a minimal amount of aggregate."
Hoosier Energy representatives were impressed
with how quickly the system installed, Kunstel
says. Completing this portion of the project,
while staying on schedule and within budget,
was viewed as a significant accomplishment.
The Spectra System Advantage: More owners
are selecting the Spectra System to:
• Reduce aggregate thickness.
• Reduce excavation requirements.
• Simplify and speed construction while
increasing subgrade performance.
• Decrease labor and equipment requirements.
• Improve durability by changing the dynamics
of load interaction with the subgrade and
more evenly distributing load pressure.
• Enable construction to proceed even in
difficult working conditions.
Additional Information and Services:
Tensar International Corporation, the leader in
geosynthetic soil reinforcement, offers systems
for improving structures such as roadways, lay-
down areas, construction platforms and parking
lots. Our products and technologies, backed by
the most thorough quality assurance practices,
are at the forefront of the industry. Highly
adaptable, cost-effective and installation-friendly,
they provide exceptional, long-term performance
under the most demanding conditions. Support
services including site evaluation, design consulting
and site construction assistance are available
upon request.
For innovative solutions to your engineering
challenges, rely on the experience, resources and
expertise that have set the industry standard for
more than two decades.