Refer to: HNG-14 

Mr. Joseph J. Brindlinger 

Manager Engineering Services 

Union Metal Corporation 

P.O. Box 9920 

Canton, Ohio 44711 

Dear Mr. Brindlinger: 

Thank you for your letter of July 3 to Mr. Thomas 0. Willett requesting 

the Federal Highway Administration's (FHWA) acceptance for your company's 

A2849 transformer base shown on the enclosed drawing. You enclosed the 

Pendulum Test Report No. UK-15 by the Southwest Research Institute (SWRI) 

which detailed the test article and impact results for the 20 mph test. 

A 20 to 60 mph extrapolation of the velocity change was also included in that 

report. In addition, fully dimensioned drawings and a material certification 

were included with your letter. 

The test used an instrumented 1,800-pound pendulum fitted with a IO-stage 

crushable nose, which simulates a 1979 Volkswagen Rabbit. The results are 

sununarized below: 

Test speed 

Velocity change 

Stub height 

Base tested 

20 mph 

10.1 fps 

2.4 in. 

A2849 15-inch bottom bolt circle. 

Nuts torqued to 200 foot-pounds. 

Aluminum alloy S356 T6 

Pole used 

Mast arm lengths 

111-9.0” x 4.82” x 41’9” steel. 

15.0 feet, (two were mounted perpendicular to 

the direction of impact.) 

Luminaire mounting height 50 feet 

Test article weight 810 pounds 

Calculated 60 mph velocity 

change 

12.89 fps 

This information shows that the test and calculated change in velocity and 

stub-height of the tested pole-base combination met the breakaway requirements 

adopted by the FHWA. 
2 

Thus, this base, with a bottom bolt circle diameter of u 15 inches and 

maximum bolt torque of 200 foot-pounds, as shown on the enclosed drawing, is 

acceptable for use on Federal-aid highway projects, if proposed by a State 

when used with support and luminaire combinations weighing up to 900 pounds. 

The use of this base with heavier poles is unacceptable without further 

justification. This acceptance is limited to breakaway characteristics of the 

base and does not cover its 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 Union Metal Corporation that the 

bases furnished have essentially the same chemistry, mechanical properties, 

and geometry as the base used in the tests, and that the bases will meet the 

FHWA change in velocity requirements. 

Since your company's transformer base design is a proprietary ,item, to be used 

in a Federal-aid highway project it; (a) must be supplied through competitive 

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

must certify that it is essential for synchronization with existing highway 

facilities, or that no equally suitable alternate exists; or (c) it must be 

used for research or for a distinctive type of construction on relatively 

short sections of road for experimental purposes. Our regulations concerning 

proprietary products are contained in Title 23,,Code of Federal Regulations, 

Section 635.411, a copy of which was provided with prior correspondence. 

Sincerely yours, 

L. A. Staron 

Chief, Federal-Aid and Design Division 

Enclosure, 

Geometric and Roadside Design, Branch acceptance letter number LS-20