Federal Highway Administration
400 Seventh St., S.W.
Washington, D.C. 20590
June 15, 2005
In Reply Refer To: HSA-10/CC-12N
C. Eugene Buth, Ph. D., P.E.
Senior Research Engineer
Texas Transportation Institute
College Station, Texas 77843-3135
Dear Dear Dr. Buth:
In your May 17, 2005, letter to Mr. Richard Powers, you requested the Federal Highway Administration (FHWA) approval of a modified cable release post (CRP) as an alternative anchor post to the design originally tested and accepted for use with the ET-2000 family of W-beam guardrail terminals and for a high-tensioned cable rail. You also provided information on the results of pendulum testing done to verify that the new design would allow the upper section of the anchor post to release when struck from either direction, yet remain intact when the rail was impacted downstream from the end post to transfer tensile load into the anchor.
You stated that the primary design change was the use of ½-inch and ¾-inch thick flat steel plate to form the upper and lower inclined surfaces, respectively, in lieu of the channel sections used in the original design. Additionally, the steel side plates on the bottom post were lengthened to reduce deformation of the post flanges under loads, thereby reducing maintenance requirements. These changes are shown as an enclosure to this letter.
I agree that the changes described above and depicted in the enclosure are not likely to affect the performance of any currently approved ET designs or your cable anchor and that the new post can be considered an acceptable alternative design to the end post that was described in the FHWA acceptance letters CC-12J, dated June 24, 2002, and CC-76, dated August 29, 2002.
(Original Signed by)
John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety
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