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Federal Hlghwoy 

Admlnistlunon 

JUL 22 i991 

Refer to: HNG-14 

Mr. Robert A. Sik 

Vice President 

Akron Foundry Company 

2728 Wingate Avenue 

Akron, Ohio 44314 

Dear Mr. Sik: 

Thank you for your June 28 letter to Mr. Nicholas Artimovich requesting the 

Federal Highway Administration's (FHWA) acceptance of revisions to your 

company's TB-1, TB-2, and TB-3 cast aluminum transformer bases. The FHWA had 

previously accepted these bases for use on Federal-aid highway projects as . 

meeting our breakaway requirements. The proposed revisions consist of adding 

stiffener ribs to the inside of the m of the transformer base. The 

stiffener ribs are intended to improve the load carrying ability of these 

bases. To support your request, you submitted a letter from the Southwest 

Research Institute which stated that none of the pendulum tests on these bases 

showed any cracking at the top. Therefore, we concur with the conclusion that 

stiffening the top of TB-1, TB-2, and TB-3 transformer bases, as shown in the 

enclosed drawings, will not have an adverse effect on their breakaway 

performance. They are, therefore, acceptable for use on Federal-aid highways, 

subject to the same restrictions, if any, in our original acceptance letters. 

Our acceptance is limited to the breakaway characteristics of the bases and 

does not cover their structural features. Presumably, you will supply 

potential users with sufficient information on structural design and 

installation requirements to ensure proper performance. We anticipate that 

the States will require certification from the Akron Foundry Company or other 

suppliers of your company's bases that the castings furnished have essentially 

the same chemistry, mechanical properties, and geometry (except as revised) as 

the castings used in the tests qualifying the original bases, and that the 

castings will meet the FHWA change in velocity requirements. 

Since your company's breakaway support designs are proprietary items, to be 

used in a Federal-aid highway project they; (a) must be supplied through 

competitive bidding with equally suitable unpatented items; (b) the State 

highway agency must certify that they are essential for synchronization with 

existing highway facilities, or that no equally suitable alternate exists; or 

(c) they must be used for research or for a distinctive type of construction 

on relatively short sections of road for experimental purposes. 
2 

Our regulations concerning proprietary products are contained in Title 23, 

Code of Federal Regulations, Section 635.411, a copy of which was provided 

with earlier correspondence. 

Sincerely yours, 

L. A. Staron 

Chief, Federal-Aid and Design Division 

Enclosures 

Geometric and Roadside Design Acceptance Letter Number LS-24 
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