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                Safety Eligibility Letter B-222
  
  **Hardware Type:**
            Longitudinal Barriers and Bridge Rails
                          **Code:**
            B-222
                          **Date:**
            01/27/2012
                          **Testing Criteria:**
            NCHRP 350
                          **Manufacturer:**
            Armorflex
                          **Device Description:**
            TL-4 Armorwire Cable  Barrier
                          **View PDF:**
            b222.pdf (2.78 MB)
    
    Safety Eligibility Letter B-222

			

						
**Download Version**PDF [755 KB]

DOT logoU.S. Department of Transportation**Federal Highway Administration**

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

January 27, 2012

In Reply Refer To: 
HSST/B-222
Mr. Dallas James
  Armorflex International Ltd
  156 Foundry Road
  Silverdale 0932
  Auckland
  New Zealand
Dear Mr. James:
This letter is in response to your request for the Federal Highway Administration (FHWA) to review 
  a roadside safety system for eligibility for reimbursement under the Federal-aid highway program.
Name of system:

 	 ArmorwireType of system:

 	 Cable Barrier with 3 or 4 CableTest Level:

 	 NCHRP Report 350 TL-3 & TL-4Testing conducted by:

 	 Holmes Solutions Ltd (HSL)Date of request:
   	   December 15, 2010Date initially acknowledged:
   	   December 17, 2010Task Force 13 Designator:
   	   SGM33 a-b**Decision:**
 The following device is eligible, with details provided below:
Armorwire Cable Barrier with 3 or 4 CableBased on a review of crash test results submitted by the  manufacturer certifying the device described herein meets the crashworthiness  criteria of the National Cooperative Highway Research Program (NCHRP) Report  350, the device is eligible for reimbursement under the Federal-aid highway  program.  Eligibility for reimbursement  under the Federal-aid highway program does not establish approval or  endorsement by the FHWA for any particular purpose or use.
The FHWA, the Department of Transportation, and the United  States Government do not endorse products or services and the issuance of a  reimbursement eligibility letter is not an endorsement of any product or  service.****
**Requirements**
  Roadside safety devices should meet the guidelines  contained in NCHRP Report 350 (Report 350) if tested prior to January 1, 2011,  or the American Association of State Highway and Transportation Officials'  Manual for Assessing Safety Hardware (MASH) if tested after that date.  The FHWA Memorandum “Identifying Acceptable  Highway Safety Features”, dated July 25, 1997, provides further guidance on  crash testing requirements of longitudinal barriers.
**Description**
  The  Armorwire systems use either 3 (for TL-3) or 4 (for TL-4) 19  millimeters (3⁄4-inch) 3 x 7 strand galvanized pre-stretched cable with a  breaking strength in excess of 227kN. The lower 3 cables are the same  configuration for each system with cable heights of 530 millimeters (20.8  inches), 650 millimeters (26.0 inches) and 770 millimeters (30.3 inches) to the  centre of the cable from ground level. For the 4 cable system, a second cable  is added to the top slot in the post at a height of 790 millimeters (31.1  inches) from ground level. The cables are housed in galvanized steel, flat  sided oval posts 1220 millimeters (48 inches) long and 3 millimeters (1⁄8-inch)  thick. Once connected to the appropriate terminal ends, the system is tensioned  to a nominal 25kN (5,600 pounds) at 21 ̊C (70 ̊F).  Each post has a notch on each side and 1 slot  cut into the top of the post. All posts used in the Armorwire cable barrier are  installed in 350 millimeters (13.8 inches) deep plastic sockets cast into  concrete foundation piles 300 millimeters (11.8 inches) in diameter by 750  millimeters (29.5 inches) deep.  The soil  was AASHTO 'standard' soil.  Drawings of  both Armorwire designs are provided as an enclosure to this correspondence.
**Crash Testing**
  The following four (4) tests for  a re-directive cable barrier as per Report 350 TL-3 and TL-4 were conducted.  The barrier was anchored using the ATE-4 cable terminal which was  previously   accepted by the FHWA Letters CC-105 and  CC-105A as either a 3 or 4 cable terminal end.
Test  4-10 was conducted with the 820C test vehicle on the 4 cable system which was  115 meters (377 feet) long including two 8 meters (26 feet) long Terminal Ends.  The CIP was mid-span between posts 10 and 11, and the posts were installed on 3  meters (9.83 feet) centers in the impact area.  The vehicle was smoothly re-directed by the  barrier with all 4 cables remaining in contact with the impact side of the  vehicle. The occupant risk values were all below the preferred limits.  The dynamic deflection was 1280 millimeters  (50.4 inches).

  Test  3-11 was conducted with the 2000P truck on the 3 cable system which was 130  meters (427 feet) long including two 8 meters (26 feet) long Terminal Ends. The  CIP was 2 meters (6.56 feet) upstream of post 13, and the posts were again installed  on 3 meters (9.83 feet) centers in the impact area. The vehicle was slowed and  smoothly re-directed by the barrier. The occupant risk values were all below  the Report 350 preferred limits. The dynamic deflection was 1540 millimeters  (60.6 inches).

  Test  4-11 was not conducted since it is identical to test 3-11.
  Test  4-12 was conducted with the single-unit truck on the 4 cable system which was  130 meters (427-foot) long including two 8-meter (26-foot) long Terminal Ends.  The CIP was at post 13, with the posts again installed on 3-meter (9-foot-10-inch)  centers in the impact area. The vehicle was slowed and smoothly re-directed and  captured by the barrier. The occupant risk values were all below the preferred  limits.  The dynamic deflection was 1650-millimeter  (65.0-inch).
  Test  3-11 was conducted with the 2000P truck a second time on the 3 cable system  which was 115 meters (377feet) long including two 8 meters (26 feet) long  Terminal Ends. The CIP was mid-span between posts 10 and 11, this time with the  posts installed on 9 meters (29.5 feet) centers in the impact area. The vehicle  was smoothly re-directed and captured by the barrier with all  3 cables remaining in contact with the impact side of the vehicle. The occupant  risk values were all below the preferred limits.  The dynamic deflection was 3270 millimeters  (128.7 inches).The crash test summary sheets are included as an enclosure  to this correspondence.
**Findings**
  The systems described above passed all required Report 350  crash tests. Occupant Impact Velocities (OIV) associated with all tests are  below the preferred limit and Occupant Ridedown Acceleration (ORA) for all  tests were below the preferred limit.
In your letter, you requested FHWA review of the following  configurations for the Armorwire as an NCHRP 350 TL-3 and TL-4 Longitudinal  Barrier:
*Armorwire TL-3 Cable Barrier* – 3-cable  system, for use with post spacing of 3 meters (9.83 feet) through to 9 meters (29.6  feet).
*Armorwire TL-4 Cable Barrier* – 4-cable  system, for use with post spacing of 3-meters 9.83  feet) through to 9 meters (29.6 feet).We concur that the 3-cable  design described above and detailed in the enclosed drawings is eligible for  reimbursement as an NCHRP Report 350 barrier at TL-3 with a post spacing  ranging from 3 meters (9.84 feet) to 9 meters (29.53 feet) under the range of  conditions tested, when such use is acceptable to a highway agency. We further  agree that the 4-cable design is eligible for reimbursement as an NCHRP Report  350 barrier at TL-4, but only with the 3 meters (post spacing that was actually  tested. Based on that one test, there is no reliable method by which the  dynamic deflection of the system with 9 meters post spacing can be accurately  predicted for an impact with the single-unit truck. A secondary concern is that  with large barrier deflections over non-level (sloping terrain), a high center  of gravity vehicle is more likely to overturn, rather than be contained and  redirected.
Please note the following standard provisions that apply  to FHWA eligibility letters:
This  letter provides a AASHTO/ARTBA/AGC Task Force 13 designator that should be used  for the purpose of the creation of a new and/or the update of existing Task  Force 13 drawing for posting on the on-line 'Guide to Standardized Highway  Barrier Hardware' currently referenced in AASHTO Roadside Design Guide.
  This  finding of eligibility is limited to the crashworthiness characteristics of the  systems and does not cover their structural features, nor conformity with the  Manual on Uniform Traffic Control Devices.
  Any  changes that may influence the crashworthiness of the system will require a new  reimbursement eligibility letter.
  Should  the FHWA discover that the qualification testing was flawed, that in-service  performance reveals safety problems, or that the system is significantly  different from the version that was crash tested, we reserve the right to  modify or revoke this letter.
  You will  be expected to supply potential users with sufficient information on design and  installation requirements to ensure proper performance.

  You will  be expected to certify to potential users that the hardware furnished has the  same chemistry, mechanical properties, and geometry as that submitted for  review, and that it will meet the crashworthiness requirements of the NCHRP  Report 350.
  To  prevent misunderstanding by others, this letter of eligibility is designated as  number B-222 and shall not be  reproduced except in full.  This letter  and the test documentation upon which it is based are public information.  All such letters and documentation may be  reviewed at our office upon request.
  This  letter shall not be construed as authorization or consent by the FHWA to use,  manufacture, or sell any patented system for which the applicant is not the  patent holder.  The finding of  eligibility is limited to the crashworthiness characteristics of the candidate  system, and the FHWA is neither prepared nor required to become involved in  issues concerning patent law. Patent issues, if any, are to be resolved by the  applicant.
  The  Armorwire systems are patented products and considered proprietary.  If proprietary systems are specified by a  highway agency for use on Federal-aid projects: (a) they must be supplied  through competitive bidding with equally suitable unpatented items; (b) the  highway agency must certify that they are essential for synchronization with  the existing highway facilities or that no equally suitable alternative exists;  or (c) they must be used for research or for a distinctive type of construction  on relatively short sections of road for experimental purposes.  Our regulations concerning proprietary  products are contained in Title 23, Code of Federal Regulations, Section  635.411.
  Although  the barrier performed well under ideal test impact conditions with the two test  vehicles, the likelihood of passenger car underrides of any cable system may  increase as the post spacing increases, particularly when the barrier is  installed on non-level or slightly irregular terrain and the cables are not  restrained from lifting at each post.   Consequently, some transportation agencies have limited post spacing to  approximately 6m (20 feet) for cable barriers.   The dynamic deflection of the barrier is likely to increase when it is  installed along the convex sides of horizontal curves, and when distances  between anchorages exceed the 115- to 130-m (377- to 427-foot) test  lengths.Sincerely yours,
   
   */* Signature of Michael S. Griffith */*
   
   Michael S. Griffith
 Director, Office of Safety Technologies
 Office of SafetyEnclosures U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

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