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BALLAST REINFORCEMENT S46

Owners:

Utah Transit Authority

Design Engineer:

Terracon Consultants, Inc.

General Contractor:

Commuter Rail Constructors (a joint ventureof Stacy and Witbeck Inc., and HerzogContracting Corp.)

Materials Supplier:

CONTECH Construction Products, Inc.

PROJECT HIGHLIGHTS

Project:

Railroad Sub-Ballast Reinforcement Project

Location:

Weber County to Salt Lake City, Utah

Installation:

Spring 2005 to mid-2008

Product/Systems:

Spectra® Rail System

Quantity:

300,000 square yards of BX1200 Geogrid

UTAH TRANSIT AUTHORITY,LIGHT RAIL PROJECTWEBER COUNTY TO SALT LAKE CITY, UT

Application: The Utah Transit Authority(UTA) is relying on the Spectra® Rail System to reinforce large sections of a 44-mile-longcommuter-rail line.

The Challenge: The FrontRunner commuter-rail line is intended to alleviate automobilecongestion on regional roads. To keep the projecton budget and schedule, the design-build generalcontractor had to use fast, affordable strategiesfor installing track, ties, sub-ballast and ballast.

Site Conditions: The rail line is located on anexisting right-of-way that runs parallel with theWasatch Mountains. The area is part of a naturaldrainage basin that includes abundant soft soilsand shallow groundwater. The subgrade consistsof low-to medium-strength cohesive soils andloose to dense sand.

Alternative Solution: A traditional design would have used thick sections of sharp stone,sub-ballast and ballast to help bridge the softsoils. Given the extensive soft-soil conditionsand costs associated with importing high-qualitystone, this approach would have increased theconstruction budget considerably.

The Solution: Tensar International Corporationand Terracon Consultants, Inc., the project’sgeotechnical engineering firm, recommendedusing Tensar® Biaxial (BX) 1200 Geogrid to reduce the thickness of the sub-ballast.

“We were able to show that Tensar Geogridscould provide a strong construction platform with a thinner section,” says Branden Reall, Tensar Mountain West regional manager. “It would provide the reinforcement needed to carry heavy-rail traffic while reducing the sub-ballast layer from 12 inches to 8 inches.”

Terracon’s project engineer Rick Chesnutdeveloped the Spectra® Rail System design.The transition zone is stabilized by incorporating Tensar’s BX Geogrid.

CA

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SPECTRA_CS_UTRAIL_9.06

Tensar International Corporation

5883 Glenridge Drive, Suite 200

Atlanta, GA 30328

800-TENSAR-1

www.tensar-international.com

For more information on the Spectra® Rail System or other Tensar Systems,

call 800-TENSAR-1, e-mail info@tensarcorp.com or visit www.tensar-international.com.

©2006, Tensar International Corporation, Limited LLC, Inc. Certain products and/or applications described or illustrated herein are protected under one or moreU.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. Printed in the U.S.A.

Authorized Representative:

BALLAST REINFORCEMENT

Following his specifications, the contractor’screw graded and proof-rolled the subgrade. They then covered the subgrade with filter fabricfollowed longitudinally with Tensar BX1200Geogrid. Where the stabilization zone needed to be wider, the geogrids were overlapped by18 inches to provide a stable transition zone.

“Going with Tensar Geogrids allowed us to stayout of the soft subsoil conditions,” says Chesnut."It prevented having to dig down deeper andhelped us avoid groundwater. In one case, it alsoallowed the general contractor to avoid movingover 900 feet of buried utilities. That was a hugesaving all on its own.”

With the Spectra® Rail System, the work on theline is proceeding more quickly and with asignificant reduction in material and labor costs.

Spectra® Rail System Advantage: More ownersare selecting the Spectra® Rail System to:

• Reduce ballast and sub-ballast requirements.

• Reduce or eliminate subgrade excavation.

• Extend the design life of ballast layers byup to a factor of 5.

• Simplify and speed construction while increasingsubgrade performance.

• Decrease labor and equipment requirements.

• Enable construction to proceed even in difficultworking conditions.

Additional Information and Services:Tensar International Corporation, the leader ingeosynthetic soil reinforcement, offers systems forimproving structures such as roadways, railyards,construction platforms and parking lots. Ourproducts and technologies, backed by the mostthorough quality assurance practices, are at theforefront of the industry. Highly adaptable, cost-effective and installation-friendly, they provideexceptional, long-term performance under themost demanding conditions. Our support servicesinclude site evaluation, design consulting and site construction assistance.

For innovative solutions to your engineeringchallenges, rely on the experience, resources andexpertise that have set the industry standard formore than two decades.

By using Tensar’s BX Geogrid the Utah Transit Authorityhad significant reduction in material and labor costs.