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FHWA Home / Safety / Roadway Departure / Safety Eligibility Letter

Safety Eligibility Letter B-173

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U.S. Department of Transportation
Federal Highway Administration

1200 New Jersey Ave. S.E.
Washington, D.C. 20590

March 25, 2008

In Reply Refer To: HSSD/B-173

Owen S. Denman, P.E.
President and CEO
Barrier Systems, Inc.
180 River Road
Rio Vista, California 94571

Dear Mr. Denman:

This letter is in response to your request for Federal Highway Administration (FHWA) acceptance of a roadside safety system for use on the National Highway System (NHS).

You requested that we find this system acceptable for use on the NHS under the provisions of National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway Features.”

Requirements
Roadside safety devices/systems should meet the guidelines contained in the NCHRP Report 350, "Recommended Procedures for the Safety Performance Evaluation of Highway Features". FHWA Memorandum “Action: Identifying Acceptable Highway Safety Features” of July 25, 1997, provides further guidance on crash testing requirements of longitudinal barriers.

Description
ArmorGuard™ Barrier (AGB) is the new name of a steel safety-shaped barrier system tested and accepted as the SafeGuard Gate System in FHWA Acceptance Letter B-87 dated July 6, 2001, and as the SafeGuard Link system in B-108 dated November 4, 2002.

The AGB sections are constructed of metal and are assembled in 8.5 meter (28 foot) increments. The sections are hinged at both ends and can be unpinned, jacked up on wheels and moved in any direction. One end can be unpinned and swung open or both ends of a section can be released to remove the whole section.

A drawing of a typical ArmorGuard™ Barrier Section is shown in Appendix “D”. The length of each AGB including the hinge assembly is 8.5 m (28 feet) and the effective overall height is 847 mm (33.3 inches). The effective width of the upright portion of the base is 727 mm (28.6 inches) and the effective width of the “T” top section is 513 mm (20 inches). The mass of an 8.5 meter AGB section is approximately 1350 kg (2,975 lbs.). The hinge assemblies at each end of the gate are protected from impacts by removable aluminum or steel covers that are held in place by removable pins. The section hinges are connected to each other with a 28.6 mm (1.125 inches) diameter ASTM C1018 steel connecting pin.

Currently Accepted For these uses: New Testing, proposed approval for use:
Attached to 6 m (20 foot) portable concrete barrier (B-108, 11/04/2002) Test 1 Attached to 3m (10 foot) portable concrete barrier (Test WGB03) (Figure 1, enclosed)
Single sections used between permanent median barrier (B-87, 07/06/2001) Test 2 Multiple sections used between permanent median barrier (Test WGB04) (Figure 6, enclosed)
8 meter panels consisting of two 4 meter panels spliced together Test 3 Solid 8 meter panel sections
(Figure 11, enclosed)

As shown in the table above, the purpose of test WGB03 is to have the AGB approved for use in combination with 3 meter (10 foot) or longer portable concrete barrier sections attached at the ends. The condition that is currently approved is with 6 meter (20 foot) sections of portable concrete barrier attached at the ends. The concrete barrier segments are not pinned along their length but free to move except at the end.

The second test, WGB04, was conducted using multiple sections of AGB installed between a permanent median barrier. The condition that is currently approved was tested with a single AGB barrier section installed between permanent median barrier.

The third test was run to validate the performance of solid 8 meter panel sections.
Previous designs consist of two 4 meter panels spliced together.

These tests also validate the design and performance of an alternate universal transition that was not previously tested.

Request for Acceptance

You specifically requested the following for the ArmorGuard Link and Gate systems:

1) The system name changes from SafeGuard Link to ArmorGuard Link and SafeGuard Gate to ArmorGuard gate.

2) The application of multiple ArmorGuard Link segments connected directly to or between permanent barriers.

3) The application of multiple ArmorGuard Link segments connected to or between any crashworthy temporary concrete barrier arrays with minimum barrier lengths of 3 meters.

4) The use of the alternative transition assembly as tested for ArmorGuard Link or Gate systems.

5) The use of the redesigned bulkheads and full length 8 meter panels into the ArmorGuard Link and Gate systems.

Crash Testing

Test Level Test Designation Impact Conditions Impact Point
NCHRP 350 Test No. Safe Technologies Test No. Vehicle Nominal Speed (km/h) Nominal Angle (deg)
3 3-21 WGB03 2000P 100 25 CIP
3 3-21 WGB04 2000P 100 25 CIP
3 3-21 AG8M1 2000P 100 25 CIP

Crash test data summary sheets for these three tests are enclosed for reference. In each test the vehicle was redirected without noticeable snagging and did not experience appreciable pitch or roll.

Findings

The system described in requests 1 through 5 above and detailed in the enclosed drawings and crash testing is acceptable for use on the NHS under the range of conditions tested, when proposed by a State.

Please note the following standard provisions that apply to FHWA letters of acceptance:

 

Sincerely yours,

Signature of David A. Nicol

David A. Nicol, P.E.
Director, Office of Safety Design
Office of Safety

2 Enclosures

Page last modified on June 24, 2011.
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