December 15, 2006

Refer to: HSA-10/LS-61

Mr. Robert Sik
Vice President
Akron Foundry Company
2728 Wingate Avenue
P.O. Box 27028
Akron. OH 44319-0009

Dear Mr. Sik:

Thank you for your letter dated October 12 requesting the Federal Highway Administration (FH\VA) acceptance of a modification to your company’s TB·9 breakaway cast aluminum transformer base for use on the National Highway System under the provisions of the National Cooperative Highway Research Program Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway Features."

You requested that we find the TB-9 base acceptable when used on a 10-1/2 inch diameter bolt circle. With the exception of the internal ear length used to bolt the base in place, the typical base assembly is identical to your previously accepted TB-9 transformer base. Attachment to the base at the internal ears using standard round washers that lay flat or attachment using the previously accepted modified stack pack washer arrangement (LS-58) will provide full support when bolted in place.

We have reviewed the results of prior crash testing of the IB-9 base, which had been found acceptable when used with standard round washers on a bolt circle of 12 inches, and concur that this modification would have no significant impact on the breakaway performance of your company's transformer base. An appropriate conditions in the previous FH\VA acceptance letters dealing with Akron Foundry cast aluminum transformer bases continue to apply,

Sincerely yours,

/original signed by /

John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety


FHWA Safety Home | FHWA Home | Feedback
FHWA
United States Department of Transportation - Federal Highway Administration