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                Safety Eligibility Letter B-151
  
  **Hardware Type:**
            Longitudinal Barriers and Bridge Rails
                          **Code:**
            B-151
                          **Date:**
            11/21/2006
                          **Testing Criteria:**
            NCHRP 350
                          **Manufacturer:**
            Wyoming DOT
                          **Device Description:**
            W-beam to thrie beam transitions
to thrie beam transitions
                          **View PDF:**
            b151.pdf (1.24 MB)
    
    HSA-10/B-151



DOT logo
U.S. Department of Transportation
**Federal Highway Administration**
400 Seventh St., S.W.
Washington, D.C.  20590November 21, 2006
In Reply Refer To: HSA-10/B-151

Mr. William B. Wilson, P.E.
	Standards Engineer
	Wyoming Department of Transportation
	3500 Bishop Blvd
	Cheyenne, WY  82009
	
Dear Mr.  Wilson :

Thank you for your letter of March  17, 2006, requesting the Federal Highway Administration's (FHWA) acceptance of  your State's w-beam to thrie beam transitions to the Wyoming test level 3  (TL-3) and TL-4 bridgerails for use on the National Highway System (NHS). Accompanying your letter were drawings and a  discussion of the proposed transition designs.  Based on the similarity of these designs to the crash-tested Alaska transition,  you requested that we find the Wyoming designs acceptable as TL-3 or TL-4  transition, respectively, 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."
**Introduction**
The FHWA guidance on crash testing  of roadside safety hardware is contained in a memorandum dated July 25, 1997,  titled "INFORMATION: Identifying Acceptable Highway Safety  Features." A brief description of the  transition designs follows:
As shown in detail in the enclosed  drawings, both transitions consist of two nested 12-gauge thrie-beam panels  connected to a TL-3 or TL-4 Wyoming Two-Rail Bridge Rail with a standard  thrie-beam terminal connector and a fabricated steel connection plate. The connection plate was designed to attach  to either the TL-3 or TL-4 versions of the bridge rail. A 12-gauge thrie-beam to w-beam transition  piece is used from posts 1 through 3.  Posts 1 through 9 are W6 x 9, with post 1 having a 6" x 8" x 14" wood  blockout, post 2 having a 6"x 8"x 19" wood blockout, and posts 3 through 9 each  having W8x15 steel blockouts. Post 9,  immediately adjacent to the bridge, is offset 47.5" from the first bridge rail  post. The concrete curb is flared back  4.5" over its last 18" to minimize wheel snagging at that point.
As noted above, this transition  design is based on the Alaska transition, originally found acceptable in the  FHWA acceptance letter B-55A dated September 2, 1999, except for minor  connection details, including:
Different       dimensions for the transition plates to account for variations in heights       and widths of bridge rail elements.
Extending       the transition plates beyond the back of the bridge rail elements.
Different       bolt locations on the thrie beam end plate to account for variations in heights       and widths of bridge rail elements.**Findings**
Based on staff review of the Wyoming designs compared to the Alaska  transition, I concur that the Wyoming thrie-beam transition design to your TL-3  and TL-4 bridge rails may be used on the NHS when such use is requested by a  transportation agency. I understand  that the design, like the bridge rail, is non-proprietary and that copies of  detailed plans and specifications can be obtained from your office.
Please note the following  standard provisions that apply to the FHWA letters of acceptance:
Our       acceptance is limited to the crashworthiness characteristics of the       devices.
Any       changes that may adversely influence the crashworthiness of the device       will require a new acceptance letter.
Should       the FHWA discover that the qualification testing was flawed, that       in-service performance reveals unacceptable safety problems, or that the       device being marketed is significantly different from the version that was       crash tested, it reserves the right to modify or revoke its acceptance.
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 essentially the same chemistry, mechanical properties, and geometry as       that submitted for acceptance, and that they will meet the crashworthiness       requirements of the FHWA and the NCHRP Report 350.
To       prevent misunderstanding by others, this letter of acceptance, designated       as number B-151 shall not be reproduced except in full. This letter, and the test documentation       upon which this letter is based, is public information. All such letters and documentation may       be reviewed at our office upon request.
This       acceptance letter shall not be construed as authorization or consent by       the FHWA to use, manufacture, or sell any patented device for which the       applicant is not the patent holder.       The acceptance letter is limited to the crashworthiness       characteristics of the candidate device, 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.Sincerely yours, 


						**/original signed by/**				
	
						John R. Baxter, P.E.
						Director, Office of Safety Design
						Office of Safety

10 Enclosures U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

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