is-3) 

Mr. David R. Lewis 

Vice President, Marketing 

Syro Steel Company 

1170 N. State Street 

Girard, Ohio 44420 

Dear Mr. Lewis: 

400 smwlm at.. SW. 

Wuhhgm”. DC. m5Kl 

Refer to: HNG-14 

Thank you for your May 18 letter requesting acceptance of the AD-IV breakaway 

timber utility pole, which was delivered May 19 when you and Mr. Don Ivey met 

with my staff. Your letter was accompanied by.attachments which reported on 

pendulum and full-scale crash testing done by the Texas Transportation 

Institute (TTI). You also supplied a video tape documenting those tests. The 

testing was done to assess the compliance of the AD-IV breakaway system with 

the recommendations of National Cooperative Highway Research Program tN:HRF) 

Report 230, Recommended Procedures for the Safetv Performance Evaluat o o 

Hiohwav Aonurtenances. 

The AD-IV breakaway system is similar to the Federal Highway Administration's 

Breakaway Timber Utility Pole (FHWA-BTUP), classified as operational on 

January 27, 1993, in that they are both slip base designs, with upper hinge 

mechanisms installed to limit damage to conductors in the event of a crash. 

The AD-IV system uses a four-bolt slip base design, compared to the FHWA-BTUP 

six-bolt design. The AD-IV system also modifies the upper hinge to make it 

easier to realign the top of the pole after deflection caused by strong wind 

loads. The drawings of the AD-IV system are enclosed. 

TTI submitted information on two non-standard pendulum tests of the AD-IV 

system in 1991 and requested FHWA acceptance. The pendulum mass was 2,250 

pounds and was fixed with a hard rubber nose. TTI contended that the AD-IV 

design compared favorably to the FHWA-BTUP and that standard crash test 

results would be lower for the AD-IV than for the FHWA-BTUP. Via a letter 

dated June 28, 1991, to Mr. Don Ivey, we denied TTI's request and recommended 

that full-scale 20-mph and 60-mph tests be conducted using 1800-pound cars. 

A pendulum test could be used as a substitute for the low speed car test. 
2 

Two tests were conducted in 1992 and 1993 on the AD-IV system, and they are 

summarized here: 

Test Number 1 6018A-Pl 6018A-1 

Test Device, Mass, kg (lbs) Pendulum, 1099 (2415) Automobile, 816 (1800) 

Impact Angle (degrees) 0 15 

II Impact Speed, kmh (mph) 1 32.2 (20.1) 195.9 (59.6) II 

Velocity Change, m/s (fps) 2.1 (7.0)* 6.0 (19.7) 

Stub Height, mm (in) 100 (4) 100 (4) 

*The low speed test used the TTI crushable nose pendulum which has 

significantly greater mass than the preferred 1,800 pounds. The result, 

therefore, cannot directly be used as a measure of crashworthiness. However, 

it may be compared against the, results of three tests on the FHWA-BTUP using 

the same pendulum but different bolt torques. The TTI analysis shows that 

the AD-IV system test had a lower peak force when torqued to 271 N'm (200 

foot'pounds) than did the FHWA-BTUP. 

The result of the high-speed test (#6018A-1) meets the change in velocity 

requirement of the NCHRP Report 230, which is a maximum velocity change of 

9.1 m/s (30 feet-per-second) for timber utility poles. The result of the lowspeed test (non-standard pendulum) shows that the AD-IV is comparable to the 

FHWA-BTUP. In addition, the stub height requirements of FHWA are also met. 

Therefore, the AD-IV breakaway timber utility pole described above and 

illustrated in the enclosed drawings (3 sheets) is acceptable for use on 

National Highway System (NHS) projects, within the range of conditions tested, 

if proposed by a State. 

Our acceptance is limited to breakaway characteristics of the system 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 or 

utility companies will require certification from Syro Steel or TTI that the 

timber utility poles modified with the AD-IV system will meet the FHWA change 

in velocity requirements and that hardware furnished for the modification has 

essentially the same composition, mechanical properties, and geometry as that 

used in the acceptance testing. 

The AD-IV breakaway timber utility pole is proprietary. Thus, to be used in a 

Federal-aid highway project on the NHS: (a) they 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 alternative 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. Our 
3 

regulations concerning proprietary products are contained in Title 23, Code of 

Federal Regulations, Section 635.411, a copy of which is enclosed. 

Please be advised that the FHWA is in the process of adopting NCHRP Report 

350, Recommended Procedures for the Safetv Performance Evaluation of Hiahwav 

Features, as the FHWA's guide for crash testing. When that occurs, the FHWA 

will no longer review tests which use pendulum masses above the 820-kg (1,800- 

pound) range. 

Sincerely yours, 

c 

Lawrence A. Staron 

Chief, Federal-Aid and Design Division 

2 Enclosures 

Geometric and Roadside Design Acceptance Letter LS-31 
s . 

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PLAN VIEW 

SCALE: 111*-f’ 

, 

IfCTJON A-A 

l-l/r’ 014. I 2.lI2’ LONO 

A22S BOLT Wln4 

1.112’ x 114’ WASHER 

U?PER (IASI ?LATE 

I/8’ WASHER KEEPER PLATE 

LOWER EASE ?LAtE 

&OCR WASHER 

f/r’ WASHER 

I of3 

TUBE AND SHEAR BASE’. 

ELEVATION 

SCALE: ~/1*-f’ 

BOLT CONNECtlON DETAfL Figure 8. AD-IV Slip Base 

SCALE: t/Z’-1’ (Lower Connection) 

U.S. Patent Pendfna 

The Texas A&M University System. 

TEXAS TRANSPOR.TAT10N INSTITIJTE 

COLLEGE STATION, TEXAS 77843 

+---k-4 AD-Z SiFEt;r’UODfFfCAtlON 

FOR TIWBER UTILITY -POLES I 

20~3. 
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BRACKETS 

WIN0 eoLrs 

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y ---as 2.so//ooc 

-WIN0 BOLT 

lRACK ETS 

ROTATION STRAPS 

L POLE STEP LOCATIONS 

AS NEEDED 

WIND BOLT 8 BRACKET OPTION 

SCALE: 714’-1* 

SECTION A-A. 

SCALE: 114’-1’ 

Figure 9. AD-IV Hinge 

(Upper Connection) 

U.S. Patent Pending 

The Texas A&M University System 

Rmrl*rons TEXAS TRANSPORTATION INSTITUTE 

s.1 Dal* oy COLLEGE STATION, TEXAS 77843 

I I ro-1P SAFETY YODlFlCltlON 

I. I FOR’tlYIER UTlLltY POLES 
WIND 8OLl 

8RACKET 

-WIND 8OLT 

LlsACKET 

/ 8OLI 

#‘LONG WlrH 

J’rnRCADS 

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SIDE VIEW 

SCALE: 7/2*-f’ 

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2’ 

1, 

I 

1.214’ 

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1 

f-111’ OIA. UOLE 

. 

2-JI4’ 

ROTATlON STRAP DETAIL 

SCALE: l/2’-1’ . 

WIND 8OLt 8RACKCI -ll - 

J U.S. Patent Pending 

-.. __ 

WlND BOLT C BRACKET DETAIL 

FRONT VlEW 

SCALE: 112”I’ 

Figure 10. Detail of Rotation Strap, 

Wind Bolt and Bracket