La Autoridad de Tránsito Regional de Nueva Orleans (The New Orleans Regional Transit Authority) aplicó el Spectra® Rail System para reforzar una sección de 14 millas de la línea de tranvía de la histórica St. Charles Avenue.

1. CASESTUDY
S49BALLAST REINFORCEMENT
Using Tensar BX Geogrid allowed the reduction of ballast thickness while
improving the line’s long-term, load-carrying capacity.
ST. CHARLES AVENUE
STREETCAR LINE
NEW ORLEANS, LOUISIANA
Application: The New Orleans Regional Transit
Authority relied on the Spectra®
Rail System
to reinforce a 14-mile section of the historic
St. Charles Avenue streetcar line.
The Challenge: The St. Charles Avenue trackbed
had not been renovated in nearly 80 years.
The project was part of a $47 million effort that
included installing new tracks, ties and ballast.
The challenge was to reduce the ballast thickness
while limiting vertical stress on the subgrade
to 20 psi as recommended by the American
Railway Engineering and Maintenance of Way
Association (AREMA).
Site Conditions: The existing light-rail bed
included more than two feet of ballast placed
on top of a cypress plank foundation. Soft
conditions were a challenge due to a high water
table throughout the rail corridor.
Alternative Solutions: Tensar®
Biaxial (BX)
Geogrids were the only solution considered for
this project. The Spectra Rail System was
recommended as a lower cost alternative to
traditional strategies of increasing ballast
thickness. Reinforcing the new ballast with Tensar
BX1300 Geogrid would produce a strong
construction platform with less need for the
excavation of the existing subgrade or importing
of new aggregate material.
The Solution: Design calculations indicated that
using a single layer of Tensar BX Geogrid along
the main line segments and two layers at each
road crossing would decrease the effective stress
at the bottom of the trackbed by up to 65 percent
thus offering longer life and less maintenance
relative to an unreinforced section. The geogrid
would also reduce the total ballast profile from
PROJECT HIGHLIGHTS
Project:
St. Charles Avenue Streetcar Line
Location:
New Orleans, Louisiana
Installation:
1994
Product/System:
BX1300 Geogrid/Spectra Rail System
Quantity:
80,000 sq yds
Owners:
New Orleans Transit Authority
Design Engineer:
Daniel, Mann, Johnson, Mendenhall Inc.,
New Orleans, Louisiana
General Contractor:
Comtrak Inc., Atlanta, Georgia
Materials Supplier:
CONTECH Construction Products, Inc.
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2. CASESTUDY
SPECTRA_CS_RSTCHAR_6.07
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BALLAST REINFORCEMENT
26 inches to 12 inches while improving the line's
long-term, load-carrying capacity.
The St. Charles Avenue trackbed was prepared
by removing the old rails and ties and then
excavating the existing ballast to the top of the
cypress plank foundation or to a maximum depth
of 26 inches. In areas where the cypress planks
were exposed, a one inch thick layer of sand was
placed and compacted.
Next, a layer of filter fabric was installed to help
maintain free drainage. The filter fabric was
covered with four inches of rock ballast followed
by Tensar BX1300 Geogrid. The larger aperture
size of BX1300 allowed the ballast rock to strike-
through the reinforcement. The end seams of
each roll were overlapped by 12 inches before
covering with an additional 8 inches of
compacted railroad ballast.
The Spectra Rail System Advantage:
The New Orleans Transit Authority benefited from
the Spectra Rail System by substantially reducing
the construction time and costs associated with
renovating the track. It was able to improve
subgrade performance and durability by reducing
and more evenly distributing the load imposed
on the subgrade. The authority gained these
advantages even while reducing the required
ballast thickness. Overall, the project required
less excavation and the installation was simpler,
faster and less expensive than traditional
solutions. Work was able to continue even when
the installers encountered difficult working
conditions such as inclement weather.
Additional Information and Services:
Tensar International Corporation, the leader in
geosynthetic soil reinforcement, offers systems for
improving structures such as roadways, railyards,
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. Our support services
include site evaluation, design consulting and
site construction assistance.
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.
The Spectra Rail System was used to get the historic
St. Charles Avenue streetcar line back on track.
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