JAN I 2 1989 REFER TO: 

HNG-14. 

Mr. Robert A. Sik 

Vice President, Permanent Mold Division 

Akron Foundry Company 

2728 Wingate Avenue 

P.O. Box 27028 

Akron, Ohio 44319-0009 

Dear Mr. Sik: 

This is in response to your letter of December 15, 1988, requesting that the 

Federal Highway Administration (FHWA) issue a new letter of acceptance for 

your company's TBl series transformer bases. ConditionaS acceptances were 

granted on June 29, 1988. As a result of the FHWA adoption of Section 7 of 

the hmerican Association of State Highway and Transportation Officials 

(AASHTO) 1985 "Specifications for Structural Supports for Highway Signs, 

Luminaires and Traffic Signals'", we are able to remove the pre~vious 

restrictions on our acceptance of your company's hardware. 

Enclosed with your original request, dated April 1, were seven Southwest 

Research Institute test reports (Project No. 06-2128-103) dated March 1988. 

The tests were with an instrumented 1,800-pound pendulum fitted with a 

lo-stage crushable nose which simulates a 1979 Volkswagen Rabbit. The 

measured and extrapolated results from the tests were as follows: 

Test 

N*. - 

1. 

2. 

-. 

3 

4A. 

48. 

5A 

5B 

Date 

Z-21-88 6.19 fps 

2-21-88 7.17 fps 

2-21-88 6.44 fps 

2-22-88 10.1 fps 

2-22-88 1l.lE-i fps 

2-22-88 9.33 fps 

2-22-88 9.92 fps 

Measured Change 

in velocity at 20 m.p.h. 

Extrapolated Change 

in velocity at 60 m.p.h. 

8.24 fps 

10.23 fps 

14.44 fps 

15.76 fps 

16.12 fps 

15.43 fps 

15.61 fps 

(Tests 46 and 58 are retests of tests 4A and 5A.) 

*Base broke away completely. No remains other than mounting bolts. 

The enclosed Table 1 lists the test numbers and the pole types corresponding 

to the the tests qualifying bases TBl-AF 1315-17, TBl-AF 1315-171W, and TSl-AF 

Modified-17. The information shows that the actual tests and calculated 

changes in velocity of the pole-base combinations shown in Table 1 meet the 

change in velocity and stub height provisions of Section 7 of the 1985 AASHTO 

"Standard Specifications for Structural Supports for Highway Signs, Luminaires 

and Traffic Signals" as modified by the FHWA. (A copy of FHWA's final rule as 

published in the January 5, 1989, Federal Register is enclosed.) 

Stub 

Height 

* 

* 

* 

* 

3.06" 

5.75" 

* 
LS 4 -1 CONT 

2 

The bases shown in Table 1 and the enclosed drawings (2) are acceptable for use on 

Federal-aid projects, within the range of conditions tested, if proposed by a State. 

These acceptances are limited to breakaway characteristics of the bases and do not 

cover structural features. Presumably, you will supply potential users with 

sufficient information on structural design and installation requirements to ensure 

proper base performance. 

We anticipate that the States will require certification from Akron Foundry Company 

that castings furnished have essentially the same chemistry, mechanical properties, 

and geometry as the castings used in the tests and that the castings will meet the 

FHWA change in velocity requirements. 

Sincerely yours, 

L. A. Staron 

Chief, Federal-Aid and Design Division 

Enclosures 
, 

Test Base 

Mnber Nunber 

Top Bottom Pole Pole Weight Nominal Top Top Top Bottom Bottom Bottom 

Bolt Bolt Type height W/Arm & Luninaire Washers Washers Washers Washers Washers Washers 

Circle Circle Dummy Mounting Outside Inside Thick- Outside Inside ThickDiameter Diameter Height Diameter Diameter ness Diameter Diameter ness 

1 

2 

3 

4A 

08 

5A 

5B 

TBl-AF 1315-17 15” ALLMINUM 35’ 437 # 42.0’ 2 l/2” 1 l/16” 3/8” 2 3/4” 1 l/16” l/2” 

TBl-AF 1315-17 IW ‘,;:: ALUMINUM 44.5’ 511 # 51.2’ 2 l/2” 1 l/16” 3/E” 2 3/4” 1 l/16” l/2” 

TBl-AF 1315-17 13” STEEL 35’ 832 # 42.0” 2 l/2” 1 l/16” 3/8” 2 3/4” 1 l/16” l/2” 

TBl-AF 1315-17 IW 13” 15” STEEL 44.5’ 778 # 50.0” 2 l/2” 1 l/16” 3/8” 2 3/4” 1 l/16” l/2” 

TBl-AF 1315-17 IW 15” STEEL 44.5’ 778 # 50.0” 2 l/2” 1 l/16” 3/8” 2 3/4” 1 l/16” l/2” 

TBl-AF MODIFIED-17 :;: 10.5” STEEL 35 ’ 832 # 42.0’ -2 l/2” 1 l/16” 3/8” 2 l/2”* 1 l/16”* 3/a”* 

TBl-AF MODIFIED-17 12” 10.5” STEEL 35’ 832 # 42.0’ 2 l/2” 1 l/16” 3/8” 2 l/2”* 1 l/16”* 3/a”* 

VW” refers to an internal weld inside the base l assembly also requires rectangular washer: 2 314” X 4 l/4” X 518” thk 

TABLE NUMBER 1 
AKRON FOUNDRY CO. I 
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s ALL WA$nER8 TO DE ZINC YECHAWICAL COATED PER A8TY 8 08848 CLAIS 80 

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