t3

U.S.DQXl~t

ol Tmmpwtatiwl

Fedeml Highway

Mmlnirhation

Refer to: HNG-14

Hr. Robert A. Sik

Vice President, Akron Foundry Company

2728 Wingate Avenue

P.O. 80x 27028

Akron, Ohio 44319-0009

Dear Mr. Sik:

Thank you for your April 20 letter requesting revisions to our previous

acceptance of your TB-1 and TB-2 cast aluminum breakaway transformer bases

for use on Federal-aid highway projects. Our January 12, 1989, letter

accepted your company's TB-1 transformer base with a maximum pole weight of

832 pounds. Our January 24, 1990, letter accepted your company's TB-2

transformer base with a 10.5-inch maximum bolt circle limitation. Your

April 20 letter referenced two Southwest Research Institute (SwRl) reports

(Project No. 06-3116-516, Test 9 and t h Test) d,ated April 1990, containing e

results of pendulum tests on a TB-1 base supporting a 950-pound pole, and a

TB-2 base mounted on a 12-inch diameter bolt circle, the maximum for which

this base was designed. The tests were conducted to assess the compliance of

these pole and base combinations with the Federal Highway Administration

(FHWA) breakaway requirements, which cite Section 7 of the 1985 American

Association of State Highway and Transportation Officials' (AASHTO) St;;dard

Soecifications for Structural Suooorts for Hiahwav Sians. Luminaires a

Traffic Sianals.

The tests used an instrumented 1,800-pound pendulum fitted with a 10 stage

crushable nose, which simulates a 1979 Volkswagen Rabbit. Measured and

extrapolated results of the tests, referenced as "Series Ill,” are summarized

in enclosure number I. (Previous tests of Akron Foundry transformer bases are

also shown on this enclosure as Test Series I and Il.) The reported stub

k;;;hts were 3.3 inches which is the measurement to the top of the anchor

. In both tests, a shard of aluminum from the transformer base remained

in place to a height of 6.0 or 6.7 inches. We concur with the SwRl conclusion

that these protrusions above the 4-inch maximum do not,constitute "substantial

remains" as referred to in Section 7 of the AASHTO specifications.

The 16.7 fps calculated change in velocity of Test 9 using the TB-1 exceeds

FHWA requirements by 0.7 fps. However, as the evidence you presented in your

submission indicates, the calculated changes in velocities nearly always over

estimate the 60-mph results. Therefore, we will consider the results as

meeting the new FHWA requirements.
2 

In both tests machined washers were used on the bolts attaching the bottom of 

the base to the test pad. As these smoother surfaced washers develop less 

friction than typical galvanized ones, the breakaway performance may have been 

enhanced. Thus, our acceptance is limited to the use of similarly machined 

washers for the use with the anchor bolts. We also note that the nuts on the 

anchor bolts were tightened using an air impact wrench. The SwRI estimates 

that the torque values are in the range of 190 to 215,foot-pounds. Our 

acceptance, therefore, is further conditioned by limiting the torque of the 

anchor bolt nuts to 200 foot-pounds. 

In Test-9 and all the Series I tests of the TB-1 base, l-inch diameter anchor 

bolts were used. Our January 12, 1989, letter accepted the TB-1 for use 

"within the range of conditions tested." Your drawings of the TB-1 bases 

permit a 1 l/4-inch diameter anchor bolt. The use of larger fasteners than 

those used in the tests is considered to be outside of the range of conditions 

tested and is, therefore, not acceptable for use on Federal-aid highway 

projects without further testing. 

The above information shows that the test results of the subject pole and base 

combinations can be considered as meeting the change in velocity and stubheight requirements adopted by the FHWA. Thus,. TB-1 bases with poles weighing 

up to 950 pounds and having a bottom bolt circle of up to 15.0 inches using 

l-inch bolts torqued to a maximum of 200 foot-pounds, and TB2 bases with poles 

weighing up to 550 pounds and having a bottom bolt circle diameter up to 

12.0 inches, as shown on enclosures 2 and 3, are acceptable for use on 

Federal-aid highway projects if proposed by a State. 

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 Akron Foundry Company that the 

castings furnished have essentially the same chemistry, mechanical properties, 

and geometry as the casting used in the relevant test, 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 
3

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 is provided as

enclosure 4 for your information.

Sincerely yours,

L. A. Staron

Chief, Federal-Aid and Design Division

Enclosures

Endorsement to FHWA Field Offices:

Geometric and Roadside Design acceptance letter number LS-15

The cast aluminum transformer base Akron Foundrv TB-1 is nominally the same as

the Valmont part number 0283093 base which is the subject of a same-dated

letter to Dennis O'Brien of Valmont Industries (Geometric and Roadside Design

Acceptance letter LS-14). The TB-1 base was also the subject of letters to

Akron Foundry dated 6/29/88 (LS-2) and l/12/89 (LS-4).
; I

! Base

TPC, Test Base i lest Calc'd Stub Pole i Pole Naninal Mast f B%m Bottom Bottom Bottom : Top Top Top Top

rmber Number ! Delta V Delta V Height Ueight ! Type Luminaire Arm ’ Bolt Bolt Washer Uasher ! Bolt

i Circle Diameter Outside ThickBolt Yasher Washer

! @ ZOmoh C 60moh (In.1 U/arm G : Mounting Length : Circle Diameter Outstde Thick-

. . . .

Series N;

: (fpsj -(fpsj . . ~IAIIUIIY ! Height- (fi)

: (pounds) ! (feet)

!DiKt;' (in;) Iliyt;r ness iDiameter (in.) Diameter ness

n. (in.) ! (in.) (in.) (in.)

~*.***~~~~**~*.t*******l*t******~~*~t*t**lrt**t*tt*****t~*~~**~**~**~~~~***tt**t**t****tttttt*tt***~*t**tt*****ttt*t**t******t**t**ttH*~*t*tt*t***tt*t~*tlt*tt**t*t*lc***nt

:

: 2 1 TB-1AF TB-1AF 1315-17 1315-17 I.W.+: i 6.19 7.17 10.23 8.24 l * 437 511 f : 42.0 51.0 unk. unk. ! : 15 15 1.00 1.00 f ::: l/2 i i:: 2 2 l/2 l/2 3/B

: 4A 3 TB-1AF TB-1AF 1315-17 1315-17 I.W. i ’ 6.44 10.1 14.44 15.76 l 832 778 ! ! steel steel 42.0 50.0 unk. unk. ! ! 15 15 1.00 1.00 : ::: ;;: l/2 I i 13 1.00 1.00 2 l/2 :::

I 48 TB-1AF 1315-17 1.W. ! 11.18 16.12 3f06 778 ! steel 50.0 unk. : 15 1.00 2 3/4 l/2 ! i33 1.00 x ::: :f

I 5A 58 TBl-AF TBl-AF MODIFIED-17 MDIFIED-17 : ! 9.33 9.92 15.43 15.61 5.75 l 832 832 ! ! steel steel 42.0 42.0 unk. unk. ! 1 . 10.5 10.5 1.00 1.00 2 2 1/2** l/2*' 3/8" 3/8f* ! : 12 12 1.00 1.00 2 2 l/2 l/2 ::t

! ! : :

*I*.*t**.*t*t****tt*.~~~~~.~~~~*~~!*t****t~*tt*****tttt~~*~*~~~~~~~~~~~~~~~~~~~~~*~~~~****t+*t*t*t.*t***************ttt*******~~~~~~~~,~~~~~~~~~~~*~.~~~~~~~~~~~~~~~~~~~ i I

i i

:

II AF-1 TBP-AF 1012 I.W.-17 f:': 12.0 2:O 494 steel 40.8 15.0 ! 10.5 1.00 2 3/4 l/2 i 1.00 2 l/2

II AF-2 TB3-AF 1517-17 ’

i !

15.6 778 ! steel 50.0 15.0 ! 17.25 1.25 2 3/4 l/2 :

;:

I: AF-4 AF-3 TB3-AF TB3-AF 1517 1517 I.W.-17 l.W.-17 10.3 6.4 16.3 15.0 * * 778 778 ! ! steel steel 50.0 50.0 15.0 15.0 : : 17.25 15 1.00 1.25 2 2 3/4 3/4** 3/8*f l/2 : : 1: I ! 8 !

III TEST-l TB-2-AF-1012-I.W-17 i 14.6 12.83 3.3/6.0+* 548 t steel 40.0 13.0 i 12 1.00 2 3/4 l/2 12 1.00 2 l/2 3/8

(see note 1 below) !

;

III TEST-9 TB-1-AF-1315-I.W. i 9.5 16.7 3.3/6.7++ 950 : steel 55.p (two)l5.01 15 1.00 2 3/4 l/2 : 13.5 1.00 2 3/4 l/2

(see note 2 below) : ! : :

! ! ! !

t*t*******t**********tt**tt***t*tt*!***ttt**t******t**t*~~~*~~*~~~~~~~!***~*****t*t*~*t*t.****t***t*t********~~~~~~~~~~*~~~~~~~~~~~~~~~~~.~~~~~~-.~.~~.~~~~~~~~~~

+I.W. SIGNIFIES INTERNAL WELD

l Only mounting bolts remained.

** Anchor bolt n&s should not be torqued over 200 ft-lbs.

++ Anchor bolts are 3.3" high. The second dimension Is the aluminum shard.

** In addition, 2.75 inch X 4.25 inch X 0.625 inch thick rectangular washers were also used.

Acceptance letter for series I dated January 12, 1989

Acceptance letter for series II dated January 24, 1989

Acceptance letter for series III dated May, 1990

Note 1. Series II/Test AF-1 also relates to the TB-2 base.

Note 2.All Series I tests also relate to the TB-1 base.
F 1316 - 17 I.W. ‘BUY AMERI 

\- 1.69R 

L 9675 x 11.75 DOOR 

\ L- MIG 4043 WIRE JIITH l/4 APPROX. 5 - OF WELD ON EACH 

OF THE ( 4 ) INTERNAL CORNERS 

- 2 314 DIA. x 1 l/16 I.D. x 1/2‘TK. STEEL WASHERS FOR ‘I’ DIA. ANCHORAGE 

QR 1 s/l6 DIA. LO. FOR 1 (r/S DlAa ANCHORAGE 

4 PLS. EQ. SPACED ON 43.00 01 A-TO 15.00 DIA. BOTTOM GROUND B.C. 

l/2 -13 TAP THRU FOR GROUND SCREW 

20 TAP THRU FOR GROUND SCRE 

I 

2 l/P 014 )( 1 l/l6 k 3/B TK. OR 2 3/4 PIA, jc 1 l/l6 _K l/2 TK, STEEL WASHERS. 

4 PLS. EO. GPACED ON lQ50 DIAI THRU 13.500 PI& B.C. 

DOW SUPPLIED/BLANK OR LOGO IN ALUMINUM.QR.P;LASTIC W.lfH OR Wl1HQU.T. #IWOE 

ST.0 l/4 -20 B.B.HEX. SCREW OR VANDAL SCREW TO FIT YOUR SFECIFICATIQNS 

ALL WASHERS TO ‘BE ZINC MECHANICAL COATED PER ABTM B 696 ‘: 85 CLASS 60 

366 T-8 ALUMINUM ALLOY 1’8.8. WHEELABRATED FINIBH CHE&AL AND PHY. CERTS TO BE SUPPLIED WITH EACH SHIPMENT 

.. 

._ 

ADHESIVE BRE’AK-A-WAY AHid CAUTIQN LABELS *TQ’APPEAR 

ON INSIDE WALL OPPOSITE DOOR OPENING 

: 

1 

; 

! 

i 

) 

.J 

f 

f 

) 

_I 

:, 

3 

MATERIAL MELTED AND MANUFACTURED IN THE USA. CASTINGS PRODUCED IN THE USA. 
..-xsy. 

. ..___..____...j_.:. _~ -- __.____ ______.__ 

1 

r oETAIL2 

TAIL 2 1 POLE 8A8C 

Enclosure 2 

Page 2 of 2 
l/2 -13 TAP THRU FOR QROUND SCkEW 

l/4 - 20 TAP THRU FOR GROUND SCRE 

/ 

f 

13.08 SO. 12.04 SO. 

\ 9.76 x il.76 DO-OR 

1 

L 

L- MIG 4043 WIRE P l/4 WITH APPROX. 5 - OF WELD ON EACf( 

0F THE ( 4 ) INTERNAL CORNERS 

2’ 3/;i DIA. )r q 4/16.l.D. t 112 TK. STEEL WASHERS’ FOR 1’ DIA. ANCHOPAGE 

4-PLSIIEa SPACED ON ‘lO.DO DIA. ‘THRU ‘I 2;OO DIA. QROUND B.C. 

2 l/2 DIA. x 1 l/,16 I.D. x 3/8 TK. OR 2 3/O DIA. jt 1 ,l/i6 I.D. x l/2 TK. STEEL WASHERS 

4 ~L~~;EIQ.‘SPACED 0~ ‘10,Do QIA. THR~ $2.00 iiCA:-il:C: 

..:_ \ 

DOOR SUppLIED/8LANK OR LOGO IN ALUMINUM OR PLASTIC WITH OR WITHOUT UINGE 

ST’0 l/4 -20 S.S.HEX. SCREW OR VANDAL SCREW TO FIT YOUR SPECIFICATIONS 

ALL WASHERS TO ‘8E ZINC MECHANICAL COATED PER ASTM B 696 c: 86 CLASS 60 

AKRON FOUNDRY CO. 

ADHESIVE BREAKAWAY AND CAUTIPN LABELS TO APPEAR 

ON INSlPE ‘WALL OPPOSITE POOR OPENING 1986 AASHTO T-BASE 

!-26-88 T82 - AF 1012 - 17 1.W. 

MATERIAL MELTED AND MANUFACTURED IN THE USA. CASTINGS PRODUCED IN THE USA. 
I MOUNTINO HElO 

ho” 

@ ’ OCTAOWAL $TQEL POLE / 11 112 SO FLANOZ! 

18°&c.Fon 1 gBOLTS 

U(I8 8 l/t 0.0. % 1: l/ 10 LD. X 3/8 TK. OTLIC WA$tiLRS 

POL@ WOT.* 347 Ibs 

ARM WOT. 151 lb8 

LUMINAIRE WOT. 50 Ibs 

TOTAL OR088 WOT, 548 lb8 

ASRON F0UNQR.Y CO.. .T-pAse TYP8 TO20Ai 1012 I.W.-1.7 

*VmA. OnOUn’D UOUWT 9. C..U,lMd 1’ DNA; COWNLCTIWO’ 8oLt 

WITH 2 a/4 0.0. x l l l/18 I.D.. K ‘312 TK.. @tfLt. WAOHOR8’ 

,AKRON FOUNDRY CO. 

TB2-Ar; 1012 1.W.: -17 

-UTHWI$T RL$LAICH INSTITUTE 1800’ LB. PENDULUM IMPACi TE3T