Federal Highway Administration
400 Seventh St., S.W.
Washington, D.C. 20590
October 30, 2007
In Reply Refer To: HSSD/B-164
Mr. Kevin E. Lathan, P.E.
Barrier Connection, LLC
976 Narcissus Avenue
Clearwater, FL 33767-0564
Dear Mr. Lathan:
Thank you for your August 14, 2007, letter requesting the Federal Highway Administration’s (FHWA) acceptance of an F-shape portable concrete barrier wall as a test level 3 (TL-3) device for use on the National Highway System (NHS). Accompanying your letter were drawings of the details of the barrier, connections, and reinforcement and a comparison of this design with previously crash tested barriers. You requested that we find this device 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.”
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.”
The barrier segments were fabricated in accordance with the Virginia Department of Transportation (VDOT) drawing 501.45 (revised August 1997, copy enclosed for reference). The one difference between the VDOT design and the barrier design you are requesting is the lack of the #4 reinforcing bar at the top of the wall. The FHWA acceptance letter B-54 dated May 18, 1999, describes the VDOT barrier:
“The tested barrier was an 810-mm tall F-shaped concrete barrier 6100-mm long. Each segment was made from 30 Mpa concrete (28 day compressive strength) and contains three longitudinal #19 bars [#6 bars U.S. units] and one longitudinal #13 bar [#4 bar, U.S. units]. Adjacent segments areconnected by 25-mm diameter ASTM A36 steel pins 610-mm long which pass through loops fabricated with 20-mm diameter steel bars. ASTM F-488 steel washers are used under the pin head and above the 25-mm hex nut used to retain the pin at the bottom.”
The VDOT barrier was found acceptable in both 10-foot and 20-foot long sections. An analysis of the reinforcing steel shows that, even minus the #4 bar noted above, the longitudinal steel in the barrier you requested iscomparable to that found in other crash tested barrier segments such as the JJ-Hooks Temporary Barrier described in the FHWA acceptance letter B-52 dated March 26, 1999.
The F-shape portable concrete barrier wall described above and detailed in the enclosed drawing is acceptable for use on the NHS as it is deemed an equivalent material meeting NCHRP 350 TL-3, when proposed by a highway agency. The connection pin, nut, and washers should be at least 1 inch in diameter and secured with nuts and washers as were the crash tested VDOT barrier segments. Barrier segment lengths may be 10 feet or 20 feet.
Please note the following standard provisions that apply to the FHWA letters of acceptance:
George E. Rice, Jr.
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