November 2, 2005
Refer to: HSA-10/CC-26H
Mr. Barry D. Stephens, P.E.
Sr. Vice President Engineering
Energy Absorption Systems, Inc.
3617 Cincinnati Avenue
Rocklin, California 95678
Dear Mr. Stephens:
In your September 29, 2005, letter to former Associate Administrator for Safety George Ostensen, you requested formal Federal Highway Administration (FHWA) acceptance of a modified anchorage design for your REACT 350 crash cushion. This proposed design requires fewer anchors than the design originally accepted by the FHWA in a letter to Mr. Scott Walter dated June 25, 1997, (reference letter CC-26E). You explained that Energy typically specifies an anchoring system called "MP-3" which utilizes either 7-inch or 18-inch long 3/4-inch diameter threaded rods placed in appropriate depth holes in concrete or asphalt, respectively, and anchored using a rigid two-part polyester grout. The self-contained REACT base track was redesigned to reduce the number of anchors from 56 to 34, while the number of anchors for concrete backed systems was reduced from 40 to 28. The modified designs for each of these applications are shown in the enclosure to this letter.
To verify acceptable crash performance of the REACT 350 with fewer anchors you conducted the National Cooperative Highway Research Program (NCHRP) Report 350 Tests 3-31 and 3-37 when the unit was anchored in a worst-case application, i.e., a self contained unit positioned on 6 inches (150 mm) of asphalt over an 8-inch (200-mm) compacted sub base. It was anchored with thirty-four 3/4-inch diameter x 18-inch long (19-mm x 457-mm) ASTM A193 B7 threaded rods and your two-part MP-3 polyester grout. Both tests met the NCHRP Report 350 evaluation criteria and the REACT 350 base remained stationary with no lifting or bending noted. I agree that these tests on asphalt represent a worst case anchoring condition and validate the acceptable performance of the self-contained and the concrete-backed the REACT systems when attached to either asphalt or concrete foundations as per your specifications.
Based upon the information presented, I agree that the REACT 350 system with your modified anchor designs remains acceptable as an NCHRP Report 350 TL-3 crash cushion and may continue to be used on the National Highway System (NHS) when selected by a transportation agency.
Please note also the following provisions that apply to all the FHWA letters of acceptance:
/original signed by/
John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety
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