LS -32J 

Memorandum 

f: ACTION: Breakaway Design for 

the Modification of limber Utility 

Poles, Operational Classification 

1: Director, Office of Engineering 

Date: JAN 2 7 &g 

Reply to HNG-12 

A,,"~ 01: HNG-14 

1, Regional Federal Highway Administrators 

Federal Lands Highway Program Administrator 

The Federal Highway Administration (FHWA) sponsored research during the 

early 1980's to develop an economical breakaway timber utility pole that 

would increase the safety of passengers in impacting vehicles and satisfy 

design criteria of the utility industry. The resulting design, called 

the Hawkins Breakaway System (HBS), was successfully crash tested at the 

Texas Transportation Institute and, by 1986, was deemed ready for 

selective implementation. Information about the development and testing 

of the H8S and recoamrandations for its use are contained in FHWA Research 

Report Number FHWA/RD-86/154, "Safer Timber Utility Poles: Volume 1 - 

Susmiary Report," September 1986. 

The FHWA provided funds in recent years for "experimental" installations 

of the H8S in Kentucky and Massachusetts. The reconmtended design 

provided some flexibility in determining appropriate materials and 

dimensions, and both States took advantage of this flexibility to adapt 

to unique needs. For example, Kentucky retrofitted 35-foot to 45-foot 

Class 3 (heavier) timber poles in lieu of the recommended 40-foot Class 4 

poles; and Massachusetts installed some new 35-foot poles, used allthread bolts with sleeves instead of lag screws to secure the hinge 

straps, and used existing telephone cables (double dead-ended) in lieu of 

installing upper support cables. Typical specifications and plans for 

the H8S as used in Massachusetts are attached. Three other States-- 

Virginia, Washington, and Texas--are presently developing projects to use 

breakaway timber utility poles. 

Evaluations of the experimental breakaway timber utility pole 

installations In Kentucky and Massachusetts have been underway for more 

than 2 years. Poles in both States have been subjected to adverse 

environmental conditions (wind, snow, ice) and several in Massachusetts 

have been impacted by errant vehicles. In all cases the poles have 

performed well. Consequently, the H8S breakaway design for the 

modification of timber utility poles is now being placed in an 

"operational" category for use on Federal-aid highway projects. 

Operational, relative to the HBS, means the breakaway device has 

performed satisfactorily in full-scale crash tests and has demonstrated 

satisfactory in-service performance. It may now be used routinely on all 

Federal-aid highway projects. Even though the FHWA now considers the HBS 
2 

to be operational, the final decision on whether it should be deployed as 

experimental or operational should be made by the States. Regardless of 

how a State chooses to deploy it, in-service evaluations remain 

important. Ye urge that all new installations receive some form of 

continued monitoring. This will allow the FHWA to obtain further 

operational information on the practical aspects of construction, 

maintenance, and most importantly, performance under field conditions. 

Making the HBS design operational does m mean that use of the device is 

mandated by the FHWA. Rather, this breakaway device now becomes an 

additional countermeasure available to a State as it considers what 

actions to take in addressing utility pole safety. Further, there are 

limitations regarding use of this breakaway device. It should not be 

used on poles heavier than Class 3 poles. Also, a clear recovery area 

must be available behind any utility pole that is modified with breakaway 

hardware so the device has room to perform properly. In addition, use of 

a breakaway design may not be appropriate where an impacted pole might 

adversely effect pedestrians or nearby buildings or where fallen wires 

could interfere with traffic. On the other hand, the field installations 

have demonstrated that the device wtll perform satisfactorily in nontangent roadway sections. 

Three FHWA offices have been working together to develop promotional and 

technology transfer materials. A final evaluation report on the 

Massachusetts installations has been prepared by a consultant and will 

soon be distributed to the field by the Office of Technology Applications 

(HTA-31). A slide presentation on the Massachusetts installations/ 

accident experience has been developed by the Office of Highway Safety 

(HHS-11) and may be obtained from them. An evaluation report on the 

Kentucky installations is available from the Office of Engineering 

(HNG-12). 

The Office of Engineertng (HWG-12, HNG-14) will continue to evaluate the 

design details, specifications, and crash test results 

breakaway utility pole designs, and to establish their 

use on Federal-ajd.highway projects. 

for proposed new 

acceptability for 

&A* 

Thomas 0. Willett 

Federal Highway Administration 

HNG-12:CPScott/Jm)verton:cad:60450:1-4-93 

kli-1 HNG-10 HNG-12 

Official File, 3132 Reader File, 3212 

Reader File, 3206 Reader File, 3132 

Pending 

FITe. 150.06 . 
RECOMMENDED 

SPECIAL PROVISIONS, MATERIAL SPECIFICATIONS, AND PLANS 

B-WAY TI&% UTlLiY POLES 

Based upon the Special Provisions, Material Specifications, 

and Plans used in Massachusetts for the fabrication, assembly, 

and delivery of 20 composite slip base utility pole systems. 

Federal Highway Administration 

Office of Engineering 

Federal-Aid Program Branch (HNG-12) 

December 1992 
DeSCXiDtiOn O f Work

Work to be performed under the fabrication contract shall consist

of and be limited to the fabrication, complete assembly by the

fabricator, and delivery to the designated delivery locations of

twenty (20)compoeite slip base utility pole systems, complete with all required hardware, in accordance with the attached plans

and material specifications. In addition, certain system

components, to be utilized as replacement parts, shall be

furnished in the quantities hereinafter specified.

Each individual system shall consist of an industry standard

pressure treated, 35 ft., Class 4, wooden utility pole, squarely

cut at dimensions 6 ft. - 6 in. and 21 ft. - 0 in. from the butt

end base. The resultant pole sections shall be securely fitted,

at the designated locations, with an upper and lower slip base

device, intermediate hinge connector assembly, and overhead guy

wire connector in compliance with the following assembly

specifications. Pole sections shall be placed and centered

within the slip base devices. Vertical alignment shall be

accomplished by adjusting the 3 alignment bolts provided on the

slip base devices. Approximately, equal distances, not less than

3/4 in. shall remain between the slip base tubing and the pole

section at the bolt points of application. A poleset compound of

a compressive strength of approximately 1,000 psi or that equal

to the pole in a plane perpendicular to the grain, shall be used

to completely fill the remaining voids and insure a permanent

bond and a water tight top seal. Such a compound shall be

allowed to properly cure and attain an acceptable working stress

prior to any movement of the assemblies. After the curing

process has been completed, the exterior portions of the

adjustment bolts shall be carefully cut flush with the outer face

of the slip base devices, to provide a smooth surface. Required

holes shall be drilled in the pole sections at the locations

indicated on the plans. The pipe sleeves shall be tapped through

the drill holes and cut flush with the exterior faces of the

poles. The pole bands shall be tightened to a torque of 100 ft.-

lbs. Guy wire connectors shall be attached to the upper pole

sections of each individual system. The furnishing of guy wire,

for these connectors, will not be required under this Contract.

Each composite system shall be delivered completely assembled to

the designated delivery areas hereinafter designated. Extreme

caution shall be exercised by all parties in the loading,

transport, and unloading of the composite systems to insure that
no damage is incurred during the delivery process. In addition 

to the 20 assembled composite systems, the furnishing of the 

following component replacement parts shall be required under 

this Contract: 

40 - Steel strap assemblies 

40 - No. A325 slip base bolts with washers and nuts 

10 - 26 gauge keeper plates 

20 - 1 in. through bolts with washers and nuts 

10 - l/4 in. pipe sleeves 

Wooden poles shall be initially and completely pressure treated 

with a Pentachlorophenol solution in accordance with industry 

standards and methods. After cutting and altering, any resultant 

exposed surface shall receive an application of the same 

solution. All fabricated metal components and assembly methods 

shall conform to the current' edition of A.I.S.C. %anual of Steel 

Construction.* Welding materials and processes shall conform to 

the Structural Welding Code - Steel (C1.l) of the American 

Welding Society. Wooden poles shall be in accordance with the 

American National Standard Institute (ANSI) Specification 05.1 - 

1972, "Specifications and Dimensions for Wood Poles." Pole 

preservative treatment shall be in accordance with the American 

Wood Preservation Association (AWPA) Standard P-S. Bonding with 

Poleset or an approved equivalent shall be in accordance with 

manufacturers' recommendations. All completed composite slip 

base utility pole systems and component replacement parts shall 

be delivered to the designated delivery locations within one 

hundred twenty (120) days from the effective date of this 

Purchase Order. 

Deliver-v LoThe 20 composite slip base systems, 

manner previously specified, 

completely assembled in a 

together vith the required number of 

component replacement parts, shall be delivered in the stated 

quantities to the following locations: 

ENTER THE NAME AND ADDRESS OP DELIVERY LOCATIONS, AND 

QUANTITIES OF WATEBIAIS TO BE DELIVERED TO EACH. 

Public Safe&! 

The contractor shall observe all relevant Massachusetts State and 

Department of Public Utilities rules and regulations in the 

loading and delivery of the systems. 
Compensation for work required under this Contract, specifically

for the fabrication, partial assembly, and delivery, to the

previously designated locations of twenty (20) composite slip

base utility pole systems and required system component

replacement parts, including all necessary hardware required for

field erection, pole cutting, and preservation treatment,

galvanizing of metal components, and other labor, materials,

assembly, and transport of systems shall be paid on a Contract

unit price basis, per system furnished and delivered in

accordance with the attached plans and specifications. No other

method of compensation, exclusive of the previously stated, shall

be allowed.

Aareement

To the party of the first part:

The undersigned, as bidder, declares that the only persons or

parties interested in this proposal as principals are those named

herein; that this proposal is made without collusion with any

other person, firm, or corporation: that the location of the

proposed work has been carefully examined; that, if this proposal

is accepted, all necessary machinery, tools, apparatus,, and other

means of construction will be provided: #at all work will be

performed in the manner and time required: and that the following

unit prices will be accepted in full payment for the work:

ITEM ESTIMATED ITEM WITH UNIT BID PRICE UNIT

HQLaUANTITY WRITTEN IN WORDS EuEAnouNT

1 20 Systems Composite Slip Base

Utility Pole Systems

The stated bid price shall include the furnishing and delivery of

all component parts, including replacement, the acquisition and

assembly of all materials, the performing of all the labor

requisite or proper, and the providing of all necessary

machinery, tools, apparatus, and other means of construction: and

the doing of all the above mentioned work in the manner set

forth, and the completion therefor will be on or before one

hundred twenty (120) days from the award of the Contract.
Poles selected shall be Class 4, 35 ft. Ponderosa Pine, Douglas 

Fir, or Southern Pine either kiln dried or air seasoned in 

accordance with current ANSI standards and meeting the following 

weight and dimension requirements: 

UDcth - 35 ft. Clase 

vol. - 17.1 cf. Min. Top Circ. - 21" 

Min. Top Dia. - 6.7" Weight - .30/.38 # Penta 941 lbs. 

Hin. Circ. at 6 ft. from butt - 31.5 in. 

Treatmenk 

All poles shall be pressure treated with a Pentachlorophenol 

solution conforming to the requirement of AWPA Standard P-8. The 

pentachlorophenol shall be carried in a heavy petroleum solvent 

solution in accordance with the requirements of Section 2, AWPA 

Standard P-9. The poles shall be treated in accordance with AWPA 

Standard C-4. Ponderosa Pine and Southern Pine poles shall be 

treated to a retention of 0.38 pet penta as determined by an 

assay or borings representing the wood l/2' to 2" below the 

surface. Douglas Fir poles shall be treated to the same 

retention as determined by an assay or borings representing the 

wood l/2" to 1" below the surface. 

Fabricated Steel Sectipna 

All system metal components shall be fabricated from the steel 

types designated and in the methods as specified by the AISC 

"Manual of Steel Constructionw and in accordance with ASTM 

specifications. All welds shall be 3/8w fillet at the locations 

indicated and for the lengths specified and shall be in 

conformance with the Structural Welding Code - Steel (Cl-l) of 

the American Welding Society. All fabricated metal components 

shall be galvanized in accordance with ASTM Designation A123. 
Following is a Table listing the fabricated metal component, 

number required per svstm, base steel type, and section 

dimensions. 

2 

2 

12 

6 

6 

6 

12 

12 

1 

4 

4 

TABLE OF MATERIALS 

14* 0-D. x l/4* Wall x 29-l/4* Schedule 10 Pipe 

22-l/4" dia. x 3/4" Thick Bass Plates 

(A36 Steel or equivalent) 

2-15/16" x 7-3/gn x l/2" Triangular Gusset Plates 

l-1/8* dia. x 3-l/2" A325 Bolts 

Ruts for l-1/8" A325 Dolts 

2-l/2" x l/8" Washers 

2-l/2" x l/4" Washers 

l/4" Lockwashers 

26 Gauge x 22-l/4" dia. Keeper Plate 

Straps l/2" x 2-3/4" x 2' 2-l/2" 

Pipe Sleeves, Welded and Seamless 

ASTM A53, 1.666" O-D., l/4" X 15" 

1" dia. x 15" A325 Threaded Rod 

Ruts for 1" A325 Threaded Rods 

1-1/4n x l/4" Washers (hinge) 

l/4" Lockwashers (hinge) 
0 

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SLIP SsE UTlLlTY Rxz SYSTEM . 

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INTERMEDIATE HINGE CONNECTOR DETAIL 

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NO. 2 

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NO. 4 

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2 l/2" 

4 

2" 

NOT26 

1 

2. 

3. 

4 

6 

6 

STEEL STRAP’DETAIL G 

NOT TO SCALE